Eddy current encoder assembly, wheel hub motor and wheeled device

Abstract

The application relates to an eddy current encoder assembly, comprising an integrated circuit board and an induction target; the integrated circuit board comprises an outer magnetic excitation coil, an inner magnetic excitation coil and a shielding ring, and the induction target comprises an outer rotor ring and an inner rotor ring. The outer rotor ring and the inner rotor ring can form an induction air gap with the outer magnetic excitation coil and the inner magnetic excitation coil respectively, so that double-channel independent signal acquisition on a single integrated circuit board is realized. Moreover, by arranging the shielding ring between the outer magnetic excitation coil and the inner magnetic excitation coil, the magnetic field coupling between the two can be effectively blocked, signal crosstalk is inhibited, and the waveform integrity of the double-channel signals is guaranteed. The signals collected by the double channels can be used as A / B quadrature incremental signals and Z reference pulse signals respectively, so that the electrical zero drift can be compensated in real time, and the continuous attenuation of the control accuracy in long-term operation is avoided. Therefore, the long-term stability of the above-mentioned eddy current encoder assembly is significantly improved. In addition, the application also provides a wheel hub motor and a wheeled device.

Description

Technical Field

[0001] The present invention relates to the technical field of electric drive, and in particular to an eddy current encoder assembly, a hub motor and a wheeled apparatus. Background Art

[0002] Eddy current encoders have been widely used in various industrial and transportation fields due to their advantages such as small size, non-contact measurement, and high accuracy. For example, an eddy current encoder can be integrated into a hub motor to collect the absolute angle and rotational speed information of the rotor in real time, and the above information is fed back to the motor controller to realize vector control of the motor. However, in the actual application process, factors such as long-term driving of the vehicle on bumpy road conditions, large-scale changes in ambient temperature, and slight wear of parts may all cause electrical zero offset of the eddy current encoder, which further results in large torque ripple of vector control in the low-speed range and obvious starting jitter. It can be seen that the stability of the eddy current encoders and related devices in the related art under long-term use conditions still needs to be improved. Summary of the Invention

[0003] Based on this, it is necessary to address the above problems and provide an eddy current encoder assembly, a hub motor and a wheeled apparatus with high long-term stability.

[0004] An eddy current encoder assembly comprises an integrated circuit board and a sensing target matched with the integrated circuit board; the integrated circuit board comprises an outer excitation coil, an inner excitation coil and a shielding ring, the outer excitation coil and the inner excitation coil are nested with each other, and the shielding ring is arranged between the outer excitation coil and the inner excitation coil; the sensing target comprises an outer ring rotor ring and an inner ring rotor ring, and the outer ring rotor ring and the inner ring rotor ring can be arranged corresponding to the outer excitation coil and the inner excitation coil respectively, forming a sensing air gap.

[0005] In one embodiment, the outer excitation coil and the inner excitation coil are each connected with a control switch.

[0006] In one embodiment, the shielding ring is configured as a copper ring.

[0007] In one embodiment, in the axial direction of the sensing target, the height of the outer ring rotor ring is greater than that of the inner ring rotor ring.

[0008] In one embodiment, the height difference between the outer ring rotor ring and the inner ring rotor ring is 0.6 mm to 1.5 mm.

[0009] In one embodiment, the outer rotor ring includes a plurality of outer sensing blocks spaced apart circumferentially along the sensing target, and the inner rotor ring includes a plurality of inner sensing blocks spaced apart circumferentially along the sensing target. The outer sensing blocks and the inner sensing blocks are arranged in a one-to-one correspondence, and each outer sensing block and the corresponding inner sensing block are arranged radially along the sensing target and integrally formed.

[0010] In one embodiment, an inclined slope is formed between two adjacent external sensing blocks.

[0011] In one embodiment, the sensing target is configured as an aluminum component.

[0012] In the aforementioned eddy current encoder assembly, the outer and inner rotor rings can respectively form induction air gaps with the outer and inner magnetic excitation coils, thereby achieving dual-channel independent signal acquisition on a single integrated circuit board. Furthermore, by nesting the outer and inner magnetic excitation coils and placing a shielding ring between them, the magnetic field coupling between the outer and inner magnetic excitation coils can be effectively blocked, suppressing signal crosstalk and ensuring the waveform integrity of the dual-channel signals. The signals acquired from the dual channels can be used as A / B quadrature incremental signals and Z reference pulse signals, respectively, to compensate for electrical zero-point drift in real time and avoid continuous attenuation of control accuracy during long-term operation. Therefore, the long-term stability of the aforementioned eddy current encoder assembly is significantly improved.

[0013] A hub motor, comprising: Support shaft; The stator assembly is fixed to the support shaft; A rotor assembly is rotatably disposed on the outer periphery of the stator assembly; and As described in any of the preferred embodiments above, in the eddy current encoder assembly, the integrated circuit board is fixedly mounted on the support shaft, and the sensing target is fixedly mounted on the rotor assembly and disposed opposite to the integrated circuit board.

[0014] In one embodiment, the rotor assembly includes two rotor end caps, which are disposed opposite to each other and rotatably mounted on the support shaft. The stator assembly is housed in a housing space formed by the two rotor end caps. The sensing target is mounted on the outside of one of the rotor end caps, and the integrated circuit board is disposed outside the housing space.

[0015] In one embodiment, the sensing target is integrally formed on the outer surface of the rotor end cap.

[0016] In one embodiment, a sealing cover is further included, which is rotatably fitted onto the support shaft and fixedly connected to the outside of one of the rotor end covers. The sealing cover and the rotor end cover form a sealed cavity, and the integrated circuit board and the sensing target are both housed within the sealed cavity.

[0017] A wheeled device includes a hub motor as described in the above embodiments, and the hub motor provides driving force. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the hub motor in a preferred embodiment of the present invention; Figure 2 for Figure 1 The cross-sectional view of the hub motor shown; Figure 3 for Figure 1 The exploded view of the hub motor shown; Figure 4 for Figure 1 The diagram shows the structure of the integrated circuit board in the hub motor. Figure 5 for Figure 1 The diagram shows the structure of the rotor end cover in the hub motor.

[0020] Explanation of reference numerals in the attached figures: Hub motor - 100; Sealing cavity - 101; Support shaft - 110; Stator assembly - 120; Rotor assembly - 130; Rotor end cover - 131; Wheel rim - 140; Sealing cover - 150; Mounting bracket - 160; Eddy current encoder assembly - 200; Integrated circuit board - 210; External magnetic excitation coil - 211; Internal magnetic excitation coil - 212; Shielding ring - 213; Induction target - 220; Outer rotor ring - 221; Outer induction block - 2211; Inner rotor ring - 222; Inner induction block - 2221; Slope protection - 223. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0027] Please see Figure 1 The present invention provides a hub motor 100. Furthermore, the present invention also provides a wheeled device, wherein the wheeled device includes the hub motor 100.

[0028] The aforementioned wheeled equipment is driven by a hub motor 100 to achieve movement. The hub motor 100 has wide adaptability and can therefore be integrated as a drive element into various types of wheeled equipment. The specific form of the wheeled equipment can be flexibly configured according to the power level of the hub motor 100. For example, the wheeled equipment can be a two-wheeled vehicle such as an electric bicycle, electric motorcycle, or electric scooter; it can also be an automated guided vehicle (AGV) with multiple wheels; or it can be a new energy vehicle. For different application scenarios, the hub motor 100 can be adjusted by changing its electromagnetic parameters, reduction ratio, and other parameters to meet the requirements of traction, speed, and torque.

[0029] It is understood that, given the high adaptability of the aforementioned hub motor 100, it is not only applicable to the civilian and industrial vehicles listed above, but can also be extended to special equipment fields such as military robots and electric wheelchairs. Any technical solution that uses the aforementioned hub motor 100 as a drive source should be understood to fall within the protection scope of this invention.

[0030] Please refer to the following: Figure 2 and Figure 3 In a preferred embodiment of the present invention, the hub motor 100 includes a support shaft 110, a stator assembly 120, and a rotor assembly 130.

[0031] The support shaft 110, serving as a supporting component for the hub motor 100, is typically made of high-carbon steel, possessing high bending strength and good toughness. It maintains structural stability under complex load conditions and is not prone to bending deformation or breakage. The support shaft 110 remains stationary during the operation of the hub motor 100. In specific applications, both ends of the support shaft 110 can be fixedly connected to the frame or suspension system, such as mounting it on the front fork or rear swingarm of an electric two-wheeler, thus providing a stable mounting base for the entire hub motor 100.

[0032] The stator assembly 120 is fixed to the support shaft 110 and remains relatively fixed to the support shaft 110 during operation. Specifically, the stator assembly 120 and the support shaft 110 can be fixedly connected by keyway fit, interference fit, or locking with set screws to prevent relative rotation between them. The stator assembly 120 generally includes a stator core and stator windings wound on the stator core. The stator core is formed by stacking multiple silicon steel sheets along the axial direction of the support shaft 110. Its inner circumferential wall generally matches the outer circumferential wall of the support shaft 110, and the two are circumferentially fixedly connected by a keyway fit. This prevents the stator assembly 120 from rotating circumferentially relative to the support shaft 110, thus ensuring that the stator assembly 120 remains stationary during operation. The stator windings generate a magnetic field when energized. The stator windings are embedded in slots in the stator core and electrically connected to an external power source via wires (not shown). When the power is turned on, the stator windings can generate a rotating magnetic field.

[0033] The rotor assembly 130 is rotatably disposed on the outer periphery of the stator assembly 120. The rotor assembly 130 generally includes permanent magnets and a rotor core. The permanent magnets are disposed on the rotor core and form alternating magnetic poles along the circumference, thereby establishing a stable excitation magnetic field on the air gap side of the rotor assembly 130. When the stator assembly 120 is energized and generates a rotating magnetic field, the rotating magnetic field interacts with the excitation magnetic field generated by the permanent magnets on the rotor assembly 130, thereby driving the rotor assembly 130 to rotate continuously relative to the stator assembly 120. The rotor assembly 130 outputs torque outward, driving the hub or load to operate.

[0034] The rotor assembly 130 can be connected to a reducer (not shown) to achieve increased torque output. Alternatively, the rotor assembly 130 can be directly connected to the rim 140, which mounts the tire and is the final actuator for the hub motor 100 to output power. The rotor assembly 130 drives the rim 140 and the tire mounted thereon to rotate, thereby achieving vehicle propulsion.

[0035] Specifically in this embodiment, the rotor assembly 130 includes two rotor end caps 131, which are disposed opposite to each other and rotatably mounted on the support shaft 110. The stator assembly 120 is housed in the housing space formed by the two rotor end caps 131.

[0036] The two rotor end caps 131 can be fixedly connected to the axial ends of the rotor core, for example, by means of bolts, riveting, or interference fit, to form an integral rotating assembly, so that the rotor assembly 130 can rotate synchronously when outputting torque. The rotor end caps 131 and the support shaft 110 can be rotatably connected by bearings, thereby ensuring that the rotor assembly 130 can rotate smoothly relative to the support shaft 110, while bearing the radial and axial loads generated during rotation.

[0037] Furthermore, by placing the stator assembly 120 between the two rotor end covers 131, the stator assembly 120 can be enclosed on both sides of the axial direction, which can play a certain role in preventing dust, water, and foreign object intrusion, reducing the pollution of the stator winding and air gap by the external environment, and improving the reliability of the hub motor 100 operation.

[0038] Furthermore, in a preferred embodiment of the present invention, the hub motor 100 also includes an eddy current encoder assembly 200. The eddy current encoder assembly 200 is used to acquire the angle and speed information of the rotor assembly 130 in real time and feed the above information back to the motor controller so as to realize vector control of the hub motor 100. Moreover, the above-mentioned eddy current encoder assembly 200 has high stability and anti-interference ability, which can effectively improve the stability and control accuracy of the hub motor 100 under long-term operation and complex working conditions.

[0039] Please refer to the following: Figure 4 and Figure 5 In a preferred embodiment of the present invention, the eddy current encoder assembly 200 includes an integrated circuit board 210 and a sensing target 220.

[0040] The integrated circuit board 210 and the sensing target 220 are configured in conjunction. Specifically, the integrated circuit board 210 is fixedly mounted on the support shaft 110, and the sensing target 220 is fixedly mounted on the rotor assembly 130 and positioned opposite to the integrated circuit board 210. The integrated circuit board 210 can be fixedly connected to the support shaft 110 via a mounting bracket 160. The mounting bracket 160 is annular and can be fixedly mounted to the support shaft 110 via interference fit or keyway fit. The integrated circuit board 210 and the sensing target 220 can maintain a preset sensing air gap along the axial direction of the support shaft 110. The sensing target 220 can rotate synchronously with the rotor assembly 130, thereby generating eddy current induction with the magnetic excitation coil on the integrated circuit board 210. This allows the integrated circuit board 210 to obtain sensing signals reflecting the position and rotational speed of the rotor assembly 130, enabling real-time monitoring of the angle and rotational speed of the rotor assembly 130. Preferably, the integrated circuit board 210 and the sensing target 220 are coaxially arranged to ensure that the sensing air gap is uniform along the circumferential direction, improving the symmetry of signal acquisition and detection accuracy.

[0041] The integrated circuit board 210 includes an outer magnetic excitation coil 211, an inner magnetic excitation coil 212, and a shielding ring 213. The outer magnetic excitation coil 211 and the inner magnetic excitation coil 212 are nested together, and the shielding ring 213 is disposed between the outer magnetic excitation coil 211 and the inner magnetic excitation coil 212. Further, the induction target 220 includes an outer rotor ring 221 and an inner rotor ring 222. The outer rotor ring 221 and the inner rotor ring 222 can be respectively disposed corresponding to the outer magnetic excitation coil 211 and the inner magnetic excitation coil 212, forming an induction air gap.

[0042] After the eddy current encoder assembly 200 is installed, the outer rotor ring 221 and the inner rotor ring 222 form induction air gaps with the outer magnetic excitation coil 211 and the inner magnetic excitation coil 212, respectively. High-frequency alternating current is passed through the outer magnetic excitation coil 211 and the inner magnetic excitation coil 212 to generate a columnar symmetrical magnetic field. When the rotor assembly 130 rotates, the outer rotor ring 221 and the inner rotor ring 222 can generate two eddy currents by inducing the columnar symmetrical magnetic field with the outer magnetic excitation coil 211 and the inner magnetic excitation coil 212, respectively. Then, two independent signals are obtained by the signal coil (not shown) in the integrated circuit board 210.

[0043] Specifically, the eddy current encoder assembly 200 operates based on the eddy current effect. The outer excitation coil 211 and the inner excitation coil 212 are nested within each other and operate independently. When high-frequency alternating current is applied to each, they each establish a columnar, symmetrical, high-frequency alternating magnetic field in their surrounding space. When the rotor assembly 130 drives the sensing target 220 to rotate, the outer rotor ring 221 and the inner rotor ring 222, acting as conductors, are respectively situated within the alternating magnetic field of their corresponding excitation coils. Closed eddy currents are induced on their surfaces due to electromagnetic induction. These eddy currents generate a reverse magnetic field opposite to the direction of the excitation magnetic field, thereby changing the equivalent impedance of the corresponding excitation coil. The signal coil in the integrated circuit board 210 detects this impedance change to obtain the induced signal that varies with the position of the rotor assembly 130, thus achieving independent dual-channel signal acquisition.

[0044] The inner rotor ring 222, in conjunction with the inner magnetic excitation coil 212, outputs a periodic signal as the rotor assembly 130 rotates. This signal serves as an A / B quadrature incremental signal for continuously calculating the real-time electrical angle of the rotor assembly 130. The outer rotor ring 221, in conjunction with the outer magnetic excitation coil 211, outputs a Z-reference pulse signal and a PWM zero-calibration signal, providing a reference zero point independent of the incremental signal. Therefore, while outputting a high-precision incremental angle signal, the eddy current encoder assembly 200 can also periodically compare the incremental angle of the inner ring channel with the reference zero point provided by the outer ring channel, dynamically compensating for electrical zero-point drift. This enables power-on coarse calibration and continuous online correction during operation, effectively improving the long-term stability of the eddy current encoder assembly 200.

[0045] The shielding ring 213 provides electromagnetic shielding and can be constructed using a copper ring or multilayer composite copper foil. Physically, the shielding ring 213 divides the integrated circuit board 210 into an inner and outer channel region, spatially separating the incremental signal traces from the reference calibration signal traces, reducing parasitic crosstalk between lines and simplifying PCB layout. Furthermore, when high-frequency excitation current is applied to the outer excitation coil 211 and the inner excitation coil 212, they generate alternating magnetic fields in their respective regions. If there is no effective isolation between them, their radial magnetic fields will couple, causing distortion of the induced sinusoidal waveforms of the A / B incremental signal and the Z / PWM reference signal, and a decrease in the signal-to-noise ratio. The shielding ring 213 utilizes the eddy current shielding effect, inducing reverse eddy currents within itself under the action of the alternating magnetic field, thereby blocking the radial magnetic field coupling between the outer excitation coil 211 and the inner excitation coil 212, preventing crosstalk between the two channels, and ensuring the integrity and signal quality of the two induced sinusoidal waveforms.

[0046] Furthermore, during the operation of the hub motor 100, the stator assembly 120 generates electromagnetic noise radiated outwards. The shielding ring 213 effectively shields this external electromagnetic noise, reducing its interference with the external excitation coil 211, the internal excitation coil 212, and the signal coil. This also helps improve the operational stability and signal reliability of the eddy current encoder assembly 200 in complex electromagnetic environments. In addition, the external excitation coil 211 and the internal excitation coil 212 generate heat when a high-frequency excitation current is continuously applied. The shielding ring 213 is generally made of a material with good thermal conductivity, so it can quickly conduct the heat generated by the coil operation and disperse it to other areas of the integrated circuit board 210, suppressing local temperature rise of the PCB and further improving the thermal stability and long-term reliability of the eddy current encoder assembly 200.

[0047] Specifically, in this embodiment, the external excitation coil 211 and the internal excitation coil 212 are respectively connected to control switches (not shown in the figure). The control switches can control the corresponding external excitation coil 211 or internal excitation coil 212 to turn on or off, thereby realizing the switching between single channel and dual channel. This allows the eddy current encoder assembly 200 to flexibly switch the working mode according to the operating status, ensuring detection accuracy while also considering power consumption and reliability.

[0048] For example, when the hub motor 100 is in the high-speed operating range, the outer channel where the outer magnetic excitation coil 211 is located can be shut down, and only the inner channel where the inner magnetic excitation coil 212 is located can be kept working. The position of the rotor assembly 130 is continuously tracked by the A / B quadrature incremental signal, thereby reducing the overall power consumption and pausing the online calibration process. When the hub motor 100 is in the low-speed operating range, the two channels are turned on simultaneously. The inner channel continuously outputs the incremental angle signal, and the outer channel continuously outputs the Z reference pulse and PWM zero-calibration signal, so as to periodically compare and dynamically compensate for electrical zero drift.

[0049] In addition, when any channel fails, the control switch can also work with the fault redundancy strategy to cut off the faulty channel and retain the normal channel, so that the hub motor 100 can maintain basic drive or safely stop, thus avoiding loss of control of the whole vehicle due to a single point of failure.

[0050] Specifically, in this embodiment, the sensing target 220 is made of aluminum. Because aluminum has excellent electrical conductivity and is non-ferromagnetic, the aluminum sensing target 220 allows the eddy current encoder assembly 200 to operate entirely based on the eddy current induction principle, without relying on a permanent magnet inductor. Therefore, the sensing target 220 will not demagnetize or fail due to interference from the alternating magnetic field inside the hub motor 100, thereby further improving the stability and reliability of the eddy current encoder assembly 200 under long-term operation and complex working conditions.

[0051] Specifically, in this embodiment, the sensing target 220 is integrally formed on the outer surface of the rotor end cover 131. In this way, the sensing target 220 and the rotor end cover 131 form an inseparable integral structure, and no additional connecting parts or fasteners are required between them, thereby reducing the number of parts, simplifying the assembly process, and reducing manufacturing costs.

[0052] Meanwhile, the integrated molding structure helps ensure the coaxiality and positional accuracy between the sensing target 220 and the rotor end cover 131 (rotor assembly 130), avoiding uneven distribution of the sensing air gap along the circumferential direction due to accumulated errors caused by separate assembly, thereby improving the signal acquisition accuracy and consistency of the eddy current encoder assembly 200. Moreover, the sensing target 220 rotates synchronously with the rotor end cover 131, eliminating the risk of relative loosening or displacement between the two. Even under long-term vibration and bumpy conditions of the hub motor 100, a stable sensing air gap can be maintained, effectively improving the long-term reliability and stability of the eddy current encoder assembly 200. Optionally, the sensing target 220 can be integrally molded with the rotor end cover 131 through die casting, stamping, or machining.

[0053] Please refer to it again. Figure 5 In this embodiment, the height of the outer rotor ring 221 is greater than that of the inner rotor ring 222 in the axial direction of the sensing target 220. In this way, the inner and outer channels can form differentiated sensing air gaps.

[0054] Because the outer rotor ring 221 is axially higher than the inner rotor ring 222, different axial distances are formed between them and the integrated circuit board 210. Specifically, the induced air gap between the outer rotor ring 221 and the outer magnetic excitation coil 211 is smaller, resulting in a relatively higher amplitude of the eddy current induced signal; the induced air gap between the inner rotor ring 222 and the inner magnetic excitation coil 212 is larger, resulting in a relatively lower amplitude of the eddy current induced signal. Therefore, the two channels naturally exhibit amplitude differences, allowing the back-end signal processing chip (not shown) to distinguish between the outer and inner channel signals based solely on the signal amplitude threshold, eliminating the need for complex carrier modulation and demodulation circuits, thus reducing signal processing difficulty and hardware costs.

[0055] Meanwhile, the axial height difference spatially separates the induced eddy current fields corresponding to the outer rotor ring 221 and the inner rotor ring 222, forming a dual anti-interference system together with the planar electromagnetic shielding effect of the shielding ring 213, further suppressing signal crosstalk between the two channels. The height difference between the outer rotor ring 221 and the inner rotor ring 222 also creates clearance space during assembly, reducing the risk of impact deformation of the induction target 220, and allowing the induction air gaps of the two sets of channels to be calibrated independently, relaxing the tolerance requirements for component processing and assembly.

[0056] Optionally, the height difference between the outer rotor ring 221 and the inner rotor ring 222 is 0.6mm to 1.5mm. More preferably, the height difference between the outer rotor ring 221 and the inner rotor ring 222 is 1mm, which is adapted to the standard assembly air gap range of the hub motor 100.

[0057] Specifically, in this embodiment, the outer rotor ring 221 includes a plurality of outer sensing blocks 2211 arranged circumferentially along the sensing target 220, and the inner rotor ring 222 includes a plurality of inner sensing blocks 2221 arranged circumferentially along the sensing target 220. The outer sensing blocks 2211 and the inner sensing blocks 2221 are arranged in a one-to-one correspondence. Each outer sensing block 2211 and the corresponding inner sensing block 2221 are arranged radially along the sensing target 220 and integrally formed.

[0058] Multiple outer sensing blocks 2211 are spaced apart to form the periodic sensing groove structure of the outer rotor ring 221; similarly, multiple inner sensing blocks 2221 are spaced apart circumferentially to form the periodic sensing groove structure of the inner rotor ring 222. Furthermore, each outer sensing block 2211 and its corresponding inner sensing block 2221 are arranged radially and integrally formed, allowing the outer rotor ring 221 and the inner rotor ring 222 to together form an integral aluminum sensing target 220, facilitating one-time molding through a single-piece processing method.

[0059] Furthermore, in this embodiment, an inclined retaining slope 223 is formed between two adjacent outer sensing blocks 2211. Specifically, the gap between two adjacent outer sensing blocks 2211 forms an outer sensing groove, and the retaining slope 223 is formed at the bottom of the outer sensing groove.

[0060] The slope protection 223 prevents direct impact to the edge of the outer sensing block 2211, effectively preventing the sensing target 220 from being bumped and deformed, and ensuring the long-term uniformity of the sensing air gap. The slope protection 223 has a chamfered structure, which can form a smooth transition at the opening of the outer ring sensing groove of the sensing target 220, avoiding sharp corners or burrs at the edge of the groove. Moreover, the slope protection 223 can also optimize the cross-sectional transition at the root of the outer sensing block 2211, eliminate stress concentration at sharp corners, suppress the small deformation of the sensing target 220 under the high-speed rotation of the rotor assembly 130, and further improve the long-term reliability of the eddy current encoder assembly 200.

[0061] In addition, please refer to again Figure 2 and Figure 3 In this embodiment, the sensing target 220 is installed on the outside of one of the rotor end caps 131, and the integrated circuit board 210 is disposed outside the receiving space formed by the two rotor end caps 131.

[0062] By placing the sensing target 220 and integrated circuit board 210 outside the rotor end cover 131, i.e., outside the housing space, the space occupied inside the hub motor 100 can be effectively reduced, making the internal structure of the hub motor 100 more compact. At the same time, the external arrangement also facilitates the assembly, debugging, and maintenance of the eddy current encoder assembly 200. The integrated circuit board 210 or sensing target 220 can be operated or replaced without disassembling the stator assembly 120 or rotor assembly 130 inside the hub motor 100, which helps to reduce assembly difficulty and maintenance costs.

[0063] Furthermore, by placing the integrated circuit board 210 outside the housing space, it can be kept away from the high-heat area and strong electromagnetic environment inside the hub motor 100, thereby reducing the impact of temperature rise and electromagnetic interference on the signal channel inside the integrated circuit board 210 to a certain extent, which helps to further improve the operational stability and detection accuracy of the eddy current encoder assembly 200.

[0064] Furthermore, in this embodiment, the hub motor 100 also includes a sealing cover 150, which is rotatably sleeved on the support shaft 110 and fixedly connected to the outside of a rotor end cover 131. The sealing cover 150 and the rotor end cover 131 surround to form a sealing cavity 101, in which the integrated circuit board 210 and the sensing target 220 are both housed.

[0065] Specifically, the sealing cover 150 rotates synchronously with the rotor end cover 131, and together with the rotor end cover 131, forms a relatively closed sealing cavity 101 to house the integrated circuit board 210 and the sensing target 220. The sealing cavity 101 effectively isolates the eddy current encoder assembly 200 from the external environment, preventing rainwater, mud, dust, and other foreign objects from entering its interior, avoiding erosion and wear on the working surface of the sensing target 220 or short circuits and corrosion of the integrated circuit board 210, thereby ensuring the long-term stable operation of the eddy current encoder assembly 200 under complex working conditions.

[0066] Furthermore, the sealed cavity 101 also provides mechanical protection for the integrated circuit board 210 and the sensing target 220, reducing the impact of external bumps and shocks on the eddy current encoder assembly 200. At the same time, housing the integrated circuit board 210 and the sensing target 220 together in the same sealed cavity 101 helps maintain the stability of the sensing air gap between them, avoiding air gap fluctuations caused by changes in the external environment, thereby further improving the detection accuracy and long-term reliability of the eddy current encoder assembly 200.

[0067] It should be noted that the eddy current encoder assembly 200 described above is not limited to the hub motor 100, and the sensing target 220 can also be used as an independent component. Those skilled in the art should understand that the eddy current encoder assembly 200 described above can also be applied to other rotary motors or rotating mechanisms that require angle and speed detection, such as servo motors, brushless DC motors, robot joints, power tools, and industrial automation equipment. As long as there is a relatively rotating stator and rotor structure, the eddy current encoder assembly 200 of this solution can be used for position detection and online calibration.

[0068] The aforementioned eddy current encoder assembly 200, with its outer rotor ring 221 and inner rotor ring 222 forming induction air gaps with the outer excitation coil 211 and inner excitation coil 212 respectively, enables dual-channel independent signal acquisition on a single integrated circuit board 210. Furthermore, by nesting the outer excitation coil 211 and inner excitation coil 212 and placing a shielding ring 213 between them, the magnetic field coupling between the outer excitation coil 211 and inner excitation coil 212 can be effectively blocked, suppressing signal crosstalk and ensuring the waveform integrity of the dual-channel signals. The signals acquired by the dual channels can be used as A / B quadrature incremental signals and Z reference pulse signals respectively to compensate for electrical zero-point drift in real time and avoid continuous attenuation of control accuracy during long-term operation. Therefore, the long-term stability of the aforementioned eddy current encoder assembly 200 is significantly improved.

[0069] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0070] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An eddy current encoder assembly (200), characterized in that, The system includes an integrated circuit board (210) and a sensing target (220) that is matched with the integrated circuit board (210). The integrated circuit board (210) includes an outer magnetic excitation coil (211), an inner magnetic excitation coil (212), and a shielding ring (213). The outer magnetic excitation coil (211) and the inner magnetic excitation coil (212) are nested together, and the shielding ring (213) is disposed between the outer magnetic excitation coil (211) and the inner magnetic excitation coil (212). The sensing target (220) includes an outer rotor ring (221) and an inner rotor ring (222). The outer rotor ring (221) and the inner rotor ring (222) can be respectively disposed corresponding to the outer magnetic excitation coil (211) and the inner magnetic excitation coil (212) to form a sensing air gap.

2. The eddy current encoder assembly (200) according to claim 1, characterized in that, The external magnetic excitation coil (211) and the internal magnetic excitation coil (212) are respectively connected to control switches.

3. The eddy current encoder assembly (200) according to claim 1, characterized in that, The shielding ring (213) is a copper ring.

4. The eddy current encoder assembly (200) according to claim 1, characterized in that, In the axial direction of the sensing target (220), the height of the outer rotor ring (221) is greater than that of the inner rotor ring (222).

5. The eddy current encoder assembly (200) according to claim 4, characterized in that, The height difference between the outer rotor ring (221) and the inner rotor ring (222) is 0.6 mm to 1.5 mm.

6. The eddy current encoder assembly (200) according to claim 1, characterized in that, The outer rotor ring (221) includes a plurality of outer sensing blocks (2211) spaced apart circumferentially along the sensing target (220), and the inner rotor ring (222) includes a plurality of inner sensing blocks (2221) spaced apart circumferentially along the sensing target (220). The outer sensing blocks (2211) and the inner sensing blocks (2221) are arranged in a one-to-one correspondence. Each outer sensing block (2211) and the corresponding inner sensing block (2221) are arranged radially along the sensing target (220) and integrally formed.

7. The eddy current encoder assembly (200) according to claim 6, characterized in that, An inclined slope (223) is formed between two adjacent external sensing blocks (2211).

8. The eddy current encoder assembly (200) according to claim 1, characterized in that, The sensing target (220) is made of aluminum.

9. A hub motor (100), characterized in that, include: Support shaft (110); The stator assembly (120) is fixed to the support shaft (110); The rotor assembly (130) is rotatably disposed on the outer periphery of the stator assembly (120); and In the eddy current encoder assembly (200) as described in any one of claims 1 to 8, the integrated circuit board (210) is fixedly mounted on the support shaft (110), and the sensing target (220) is fixedly mounted on the rotor assembly (130) and disposed opposite to the integrated circuit board (210).

10. The hub motor (100) according to claim 9, characterized in that, The rotor assembly (130) includes two rotor end caps (131), which are arranged opposite to each other and rotatably mounted on the support shaft (110). The stator assembly (120) is housed in a housing space formed by the two rotor end caps (131). The sensing target (220) is mounted on the outside of one of the rotor end caps (131). The integrated circuit board (210) is located outside the housing space.

11. The hub motor (100) according to claim 10, characterized in that, The sensing target (220) is integrally formed on the outer surface of the rotor end cap (131).

12. The hub motor (100) according to claim 10, characterized in that, It also includes a sealing cover (150), which is rotatably sleeved on the support shaft (110) and fixedly connected to the outside of one of the rotor end covers (131). The sealing cover (150) and the rotor end cover (131) form a sealing cavity (101), and the integrated circuit board (210) and the sensing target (220) are both housed in the sealing cavity (101).

13. A wheeled device, characterized in that, Includes a hub motor (100) as described in any one of claims 9 to 12, and the hub motor (100) provides driving force.

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