Micro motor stator automatic plug wire on-off detection device and method

Abstract

The invention discloses an automatic plug wire on-off detection device and method for a micro motor stator, and the device employs a preset space arrangement rule on the surface of a probe, enables the number of conductive nodes actually participating in contact to generate nonlinear gradual change along with the press-in depth, and enables the probe to be mechanically pressed into the invisible physical depth. According to the method, a dynamic impedance signal is converted into a dynamic impedance signal with a specific slope attenuation characteristic, and the waveform characteristic of the signal is extracted, so that the probe is endowed with extremely high three-dimensional space assembly track sensing capability on the premise of not adding an additional mechanical displacement sensor, and false positive misjudgment caused by mechanical dislocation is fundamentally eliminated.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic detection technology, and in particular to a device and method for detecting the continuity of automatic stator wiring in a micro motor. Background Technology

[0002] In the precision manufacturing of micromotors, the quality of the electrical connection between the stator windings and the terminals is a core factor determining the stability and lifespan of the motor. As micromotors develop towards higher power density and miniaturization, the internal space of the stator is extremely compressed, and the diameter of the conductor terminals is increasingly approaching the micrometer level, with the surface typically covered by a highly insulating enamel coating. In automated production, the insertion of the stator winding conductor terminals into the terminals is an interference fit process accompanied by high mechanical resistance, usually requiring a highly rigid actuator to complete.

[0003] Traditional manufacturing processes often separate the mechanical wiring action from the subsequent electrical continuity testing into two independent workstations. That is, after the wiring assembly is completed, a subsequent workstation uses probes for contact testing. This process separation not only reduces production efficiency but, more importantly, leads to a lag in testing information. It fails to identify transient dynamic defects that occur during the wiring process in real time, such as probe position misalignment, stress concentration microcracks, or uneven terminal deformation. This results in low closed-loop control efficiency of the production line, making it difficult to meet the stringent requirements of zero-defect assembly in modern precision motor manufacturing.

[0004] Therefore, it is necessary to design an automatic stator connection continuity detection device and method for micro motors to solve the above problems. Summary of the Invention

[0005] This invention overcomes the shortcomings of the prior art and provides a device and method for automatic stator connection continuity detection of micro motors.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for automatically detecting the continuity of stator wiring in a micro motor, comprising the following steps: Step S1: Acquire the dynamic impedance signal generated by the probe during the process of pressing it into the terminal under test; Step S2: Based on the preset spatial arrangement pattern on the probe surface, extract the characteristic information of the dynamic impedance signal changing with time and displacement; Step S3: Determine the electrical connection status and assembly trajectory status of the terminal under test based on the feature information, and output the test results.

[0007] In a preferred embodiment of the present invention, in step S1, the acquisition of the dynamic impedance signal includes: A high-frequency carrier signal is continuously injected into the probe that is being pressed in. Analyze the voltage and current data generated by the high-frequency carrier signal to obtain the impedance value; Impedance values ​​are recorded according to a time series to generate a dynamic impedance signal.

[0008] In a preferred embodiment of the present invention, in step S2, extracting the feature information of the dynamic impedance signal includes: The dynamic impedance signal is calculated within a preset time window, and the amplitude characteristics are extracted; the amplitude characteristics are used to characterize the degree of compression of the insulation layer of the conductor terminal. The fitting degree of the dynamic impedance signal is calculated, and waveform features are extracted; the waveform features are used to characterize the indentation trajectory of the detection mechanism.

[0009] In a preferred embodiment of the present invention, in step S2, a plurality of conductive sensing units are arranged on the surface of the probe, and the plurality of conductive sensing units are arranged in a non-uniform manner along the axial pressing direction of the probe; wherein, the non-uniform arrangement is manifested in that the arrangement density or adjacent spacing of the conductive sensing units varies with a preset gradient along the axial pressing direction.

[0010] In a preferred embodiment of the present invention, step S3 includes: A first preset threshold and a second preset threshold are preset based on amplitude characteristics and waveform characteristics, respectively; The intensity change characteristics are compared with a first preset threshold. When the amplitude characteristics are greater than or equal to the first preset threshold, the electrical coupling state is deemed qualified. Calculate the similarity between the waveform features and the preset waveform model. When the similarity is greater than or equal to the second preset threshold, the contact trajectory is determined to meet the preset conditions.

[0011] When both the effective electrical coupling condition and the trajectory stability condition are met, the output shows that the electrical connection is qualified and the assembly is in place; otherwise, the output shows that the assembly is abnormal.

[0012] In a preferred embodiment of the present invention, in step S1, a circuit breaker reference signal under no-load conditions is obtained; wherein, the circuit breaker reference signal is used to determine the reference response value under a fully open circuit condition.

[0013] A micro motor stator automatic connection continuity detection device includes: The probe is used to provide axial support force during the wiring process and serves as a sensing front end for sensing the electrical connection status. A high-frequency carrier excitation module, electrically connected to the probe, is used to inject a high-frequency AC carrier signal into the probe; The signal acquisition and preprocessing module is electrically connected to the probe and is used to capture the high-frequency carrier signal of the probe in real time during the process of pressing the probe into the stator terminal, and to filter and analyze the high-frequency carrier signal to obtain the dynamic impedance signal. The central logic determination unit, communicatively connected to the signal acquisition and preprocessing module, is used for dynamic impedance signal analysis and continuity / disconnection determination algorithms to output the determination result of the electrical connection status; and The testing mechanism integrates the probe, high-frequency carrier excitation module, signal acquisition and preprocessing module, and central logic determination unit.

[0014] In a preferred embodiment of the present invention, the plurality of metal wires in the mesh layer include a first group of spiral metal wires and a second group of spiral metal wires; the second group of spiral metal wires is wound in a clockwise spiral direction around the outer surface of the elastic spiral skeleton, and the second group of spiral metal wires is wound in a counterclockwise direction; the first group of spiral metal wires and the second group of spiral metal wires are interwoven along a nonlinear gradient distribution to form multiple intersection points.

[0015] In a preferred embodiment of the present invention, the metal wire is made of gold-plated copper alloy wire with a diameter of 20-50 μm; A three-dimensional protruding node is welded at the intersection point. The three-dimensional protruding node protrudes radially outward relative to the surface of the metal wire, with a protrusion height of 5-15μm, and its top end has a hemispherical structure. The three-dimensional protruding nodes are used to generate a stress concentration effect on the contact surface of the conductor terminal insulation varnish under mechanical pressure, thereby reducing the thickness of the insulation medium by squeezing to reduce the capacitive impedance of the contact interface. The distribution density of the three-dimensional protruding nodes on the surface of the elastic helical skeleton changes synchronously with the density of the axial winding pitch of the mesh layer, thereby physically encoding the indentation depth of the probe into the topological characteristics of the impedance signal.

[0016] In a preferred embodiment of the present invention, under mechanical pressure, the three-dimensional protruding node and the insulating varnish of the conductor terminal are subjected to stress concentration effect. The thickness of the insulating medium is reduced by squeezing to reduce the capacitive impedance of the contact interface, and the insulating varnish on the surface of the conductor terminal is squeezed to establish a transient capacitive coupling channel.

[0017] This invention addresses the shortcomings of the prior art and has the following beneficial effects: This invention employs a preset spatial arrangement pattern on the probe surface, causing the number of conductive nodes actually involved in contact to change non-linearly with the indentation depth. This transforms the invisible physical depth of the probe's mechanical indentation into a dynamic impedance signal with a specific slope attenuation characteristic. By extracting the waveform characteristics of this signal, the probe is endowed with extremely high three-dimensional spatial assembly trajectory perception capability without adding an additional mechanical displacement sensor, fundamentally eliminating false positives caused by mechanical misalignment.

[0018] This invention features three-dimensional raised nodes at the intersections of a conductive grid. Combined with a high-frequency carrier excitation signal, the hemispherical structure at the top of the raised nodes generates a significant stress concentration effect on the microscopic contact surface under mechanical pressure. This compresses the insulating enamel coating on the conductor surface without puncturing it, thereby establishing a transient capacitive coupling channel. This allows for the extraction of electrical continuity signals while preserving the integrity of the conductor's insulation layer. It eliminates the risk of mechanical damage to the fine wires of micromotors caused by traditional puncture-based testing, avoiding wire breakage or reduced withstand voltage due to testing, and ensuring the long-term reliability and safety of the finished motor.

[0019] This invention extracts amplitude and waveform features and performs a decision to accurately identify false conduction signals. By using the mutual verification of multi-dimensional features, it effectively solves the identification blind zone caused by probe slippage or accidental contact with the iron core. Without adding a displacement sensor, it significantly reduces the misjudgment rate and missed detection rate in the precision assembly process. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 This is a flowchart of an automatic stator connection continuity detection method for a micro motor according to the present invention; Figure 2 This is a schematic diagram of the combination of the elastic helical skeleton and the mesh layer structure of the present invention; Figure 3 This is a schematic diagram of the structure of a local protruding node of the present invention; In the diagram: 1. Elastic spiral skeleton; 2. Mesh layer; 3. Metal wire; 4. Raised node. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0023] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application 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, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] Example 1: As Figure 1 As shown, a method for automatically detecting the continuity of stator wiring in a micro motor includes the following steps: Step S1: Acquire the dynamic impedance signal generated by the probe during the process of pressing it into the terminal under test; Step S2: Based on the preset spatial arrangement pattern on the probe surface, extract the characteristic information of the dynamic impedance signal changing with time and displacement; Step S3: Determine the electrical connection status and assembly trajectory status of the terminal under test based on the feature information, and output the test results.

[0026] In step S1, after mechanical clamping is completed, the spatial relative position of the stator and the conductor is optically calibrated. A top view image is obtained by a high-resolution industrial camera. The image processing algorithm confirms that the end of the conductor is within ±0.05mm of the center of the terminal opening before proceeding to the next step.

[0027] When the drive probe advances at a constant speed perpendicular to the stator end face and begins to physically press the insulation layer of the terminal under test, the computing device synchronously applies a high-frequency carrier signal, continuously injecting a high-frequency sinusoidal AC carrier signal with a frequency of 100-500kHz into the detection mechanism in the pressing action.

[0028] During this extrusion process, the probe surface compresses the insulating enamel of the conductor, causing the insulating enamel on the conductor surface to become microscopically thinner without physical cracking, thus forming an extremely thin insulating dielectric layer between the conductive core wire and the detection mechanism.

[0029] The high-frequency alternating electric field injected by the computing device penetrates the extremely thin insulating dielectric layer, establishing a transient capacitive coupling channel.

[0030] During the brief time window during which this channel is maintained, the computing device acquires loop voltage and current data across the channel in real time through its signal acquisition interface at a sampling rate of up to 0.8-1.2MHz.

[0031] The acquired voltage and current waveforms are analyzed and subjected to Fourier transform to extract the impedance values ​​that are not affected by parasitic capacitance. The impedance values ​​are then timestamped and continuously recorded according to the time sequence, thereby generating a complete dynamic impedance signal.

[0032] It should be noted that, considering the technical problems such as electromagnetic noise in the workshop environment, inherent parasitic capacitance of the equipment, and system hardware substrate drift in the actual automated production and testing environment of micro motors, background interference will inevitably be superimposed on the weak high-frequency electrical signal, thus seriously affecting the system's accurate identification of minute changes in contact state. Therefore, this application acquires a circuit breaker reference signal under no-load conditions before the probe is pressed into the terminal. This allows for the accurate measurement and recording of the reference response value of the current environment and system under a completely open circuit condition. The core advantage of acquiring this signal is that the computing device can use this noise floor data as a calibration basis to adaptively calculate and determine the reference comparison line for subsequent state judgment comparison. This effectively compensates for and filters out static interference deviations from the environment and the device itself in subsequent real-time feature extraction, ensuring that the final extracted amplitude and waveform features purely reflect the true physical coupling state between the probe and the wire. This greatly improves the anti-interference capability of the entire continuity detection algorithm and the accuracy of the final judgment result.

[0033] In step S2, because the conductive sensing units of the probe are arranged in a non-uniform gradient along the axial direction, the number or area of ​​nodes participating in electrical contact changes non-linearly during the physical process of being pressed into the stator terminals at a uniform speed. This structural non-uniformity at the physical level is perfectly modulated and mapped into the dynamic impedance signal sequence generated in step S1. Therefore, this one-dimensional time-series signal actually contains a displacement code in three-dimensional space.

[0034] After acquiring the underlying electrical data, the computing device immediately executes step S2, which is to extract features from the dynamic impedance signal sequence based on the preset spatial arrangement model on the surface of the probe mechanism. This extracts amplitude features to characterize the contact state and waveform features to characterize the insertion trajectory. This solves the problem that traditional wire insertion detection often relies solely on a single impedance threshold drop to determine continuity, without being able to perceive the actual insertion depth of the probe inside the terminal. This makes it easy to misjudge the sudden drop in impedance caused by probe slippage or momentary accidental contact with the stator core as normal continuity, resulting in an extremely high false positive rate and extremely poor error prevention and correction capabilities.

[0035] This invention utilizes the fact that, during the continuous compression of the probe into the terminal, the non-uniformly arranged conductive sensing units cause the number or area of ​​nodes actually involved in electrical contact to exhibit a non-linear gradual change with the compression depth, which is mapped onto the time axis of the aforementioned dynamic impedance signal. Therefore, in this step, the computing device does not simply compare the absolute values ​​of the impedance, but performs a two-dimensional feature extraction operation on the signal sequence.

[0036] Specifically, the computing device performs mathematical calculations on the signal strength of the dynamic impedance signal sequence within a preset time window to extract amplitude characteristics, and uses these characteristics to accurately quantify and evaluate the degree of extreme compression of the terminal insulation layer and the connectivity strength of the effective electrical coupling. On the other hand, the computing device uses a preset waveform model to calculate the fitting degree of the trajectory shape and slope attenuation of the dynamic impedance signal, extracts the waveform features, and uses this to reverse-engineer the actual pressing sliding trajectory and spatial attitude of the detection mechanism.

[0037] Furthermore, the one-dimensional time series signal was successfully parsed into composite data containing three-dimensional spatial displacement codes. Without adding any additional high-precision mechanical displacement sensors, it can not only identify whether the electrical layer is effectively conductive, but also clearly identify whether the probe has undergone the correct mechanical pressing process. This eliminates false positive conduction phenomena caused by probe slippage, deflection, or accidental contact with the iron core, effectively solving the problem that existing technologies cannot identify misalignment and accidental contact, and significantly improving the error prevention and correction capabilities of automated detection systems.

[0038] This invention utilizes the localized ultimate pressure generated by a tiny contact surface under mechanical pressure, inducing a significant stress concentration effect. This localized extrusion force compels the polymer insulating enamel on the conductor surface to undergo intense elastic or plastic rheological changes. Combined with an injected high-frequency AC carrier signal, a transient capacitive coupling channel is instantaneously formed between the extremely thin residual insulating medium and the probe's conductive sensing unit. Leveraging its physical property of easily penetrating tiny capacitors, the high-frequency signal successfully achieves cross-medium extraction of high signal-to-noise ratio electrical signals without compromising the overall insulation and airtightness of the conductor.

[0039] In step S3, after feature extraction is completed, the amplitude and waveform features are used to determine whether the terminal under test has formed effective electrical coupling and is properly assembled, and the detection result is output. This solves the problem that in the actual automated wiring process of existing detection equipment, if the detection mechanism deviates and slips during pressing, it directly touches the stator core. The measurement circuit will also generate an extremely low impedance value instantly. The traditional single-dimensional detection algorithm only looks at whether the absolute value of the impedance is low enough, and cannot distinguish whether it is a real insertion of the wire terminal or a short circuit caused by probe slippage. As a result, misaligned defective products will be misjudged as qualified products, causing defective products to flow into the next process.

[0040] In step S3 of this invention, the extracted amplitude features are judged to determine whether they reach the preset conduction threshold, thereby confirming whether the probe and the terminal coating are effectively squeezed and formed with effective electrical coupling. At the same time, the extracted waveform features are judged to determine whether they match the waveform model, thereby verifying whether the probe's downward trajectory conforms to the real sliding law from shallow to deep, and thus confirming whether the terminal is truly assembled in place.

[0041] The system will only output a qualified release result when both the amplitude characteristic representing the electrical connectivity strength and the waveform characteristic representing the mechanical motion trajectory meet the requirements.

[0042] When the detection mechanism slips or accidentally touches the iron core, even if its instantaneous impedance is extremely low and the amplitude characteristics appear acceptable, the impedance curve will inevitably drop sharply because the probe has not experienced the actual friction and compression process inside the terminals, resulting in severely abnormal waveform characteristics. In this case, the judgment algorithm in step S3 can decisively utilize the abnormal waveform characteristics to identify false continuity, thus detecting mechanical misalignment phenomena such as probe slippage and skewness, completely eliminating the blind spots of traditional purely electrical testing.

[0043] Example 2: A micro motor stator automatic connection continuity detection device, comprising: The probe is used to provide axial support force during the wiring process and serves as a sensing front end for sensing the electrical connection status. A high-frequency carrier excitation module, electrically connected to the probe, is used to inject a high-frequency AC carrier signal into the probe; The signal acquisition and preprocessing module is electrically connected to the probe and is used to capture the high-frequency carrier signal of the probe in real time during the process of pressing the probe into the stator terminal, and to filter and analyze the high-frequency carrier signal to obtain the dynamic impedance signal. The central logic determination unit, communicatively connected to the signal acquisition and preprocessing module, is used for dynamic impedance signal analysis and continuity / disconnection determination algorithms to output the determination result of the electrical connection status; and The testing mechanism integrates the probe, high-frequency carrier excitation module, signal acquisition and preprocessing module, and central logic determination unit.

[0044] In this invention, such as Figure 2 and Figure 3 As shown, the mesh layer contains several metal wires, including a first group of spiral metal wires and a second group of spiral metal wires; the second group of spiral metal wires is wound in a clockwise spiral direction around the outer surface of the elastic spiral skeleton, and the second group of spiral metal wires is wound in a counterclockwise direction; the first group of spiral metal wires and the second group of spiral metal wires are interwoven along a nonlinear gradient distribution, forming multiple intersection points.

[0045] In this invention, the metal wire is made of gold-plated copper alloy wire with a diameter of 20-50 μm; A three-dimensional protruding node is welded at the intersection point. The three-dimensional protruding node protrudes radially outward relative to the surface of the metal wire, with a protrusion height of 5-15μm, and its top end has a hemispherical structure. The three-dimensional protruding nodes are used to generate a stress concentration effect on the contact surface of the conductor terminal insulation varnish under mechanical pressure, thereby reducing the thickness of the insulation medium by squeezing to reduce the capacitive impedance of the contact interface. The distribution density of the three-dimensional protruding nodes on the surface of the elastic helical skeleton changes synchronously with the density of the axial winding pitch of the mesh layer, thereby physically encoding the indentation depth of the probe into the topological characteristics of the impedance signal.

[0046] In this invention, under mechanical pressure, the three-dimensional protruding node and the insulating varnish of the conductor terminal are in contact with each other, resulting in a stress concentration effect. The thickness of the insulating medium is reduced by squeezing to lower the capacitive impedance of the contact interface, and the insulating varnish on the surface of the conductor terminal is squeezed to establish a transient capacitive coupling channel.

[0047] In actual automated wiring production, in order to obtain clear electrical signals, traditional testing techniques typically use probes with sharp edges to directly pierce or scrape the insulating enamel coating on the surface of the stator conductors. However, when dealing with micro-enameled wires with a diameter often less than 0.1mm, this destructive technique can easily cause irreversible mechanical damage and stress concentration to the fragile copper core, leading to insulation breakdown of the motor during subsequent high-voltage testing.

[0048] In this embodiment, the probe includes: an elastic helical skeleton 1, and a conductive mesh layer 2 for performing electrical detection tasks is tightly wrapped around and attached to the outer surface of the elastic helical skeleton 1.

[0049] To address the problem of instantaneous signal jumps and the inability to acquire continuous, gradual analysis data caused by the pressure of traditional rigid probes, this embodiment employs a high-elasticity beryllium bronze alloy, such as C17200, which has undergone special age-hardening treatment, and uses micron-level precision machining to fabricate an elastic helical skeleton 1. This skeleton is defined as a thin-walled helical cylinder with a constant outer diameter, and to achieve precise mechanical impedance matching, the linear elastic coefficient of the elastic helical skeleton 1 is adjusted within a closed range of 0.5 N / mm to 2.0 N / mm.

[0050] If the elastic coefficient is too low, below 0.5 N / mm, the probe will excessively yield when overcoming the interference friction of the terminal under test, resulting in a serious lack of actual insertion depth. If the elastic modulus is too high, above 2.0 N / mm, the structure will be too rigid and will not be able to generate enough axial compressive deformation within a very short insertion time window.

[0051] A reasonable elasticity coefficient ensures that the probe can transform rigid physical impact into a flexible compression stroke with a time span, thus providing the necessary physical buffer time and displacement expansion space for subsequently encoding the three-dimensional mechanical indentation depth into a one-dimensional dynamic impedance signal.

[0052] The surface of the elastic helical skeleton 1 is provided with a conductive mesh layer 2. The mesh layer 2 is formed by several metal wires 3 with a diameter between 20μm and 50μm and a uniformly plated high-purity gold layer on the surface of the elastic helical skeleton 1, which are cross-wound and multi-directionally interwoven.

[0053] In the actual automatic stator insertion process of micro motors, pressing the wire terminals into the insulation groove is an interference fit process accompanied by extremely high mechanical friction resistance. Due to the extremely small internal space of the micro motor and the smooth and cylindrical curved surface of the enameled wire, the probe is very prone to micron-level lateral deflection and slippage when a downward pressure of tens of Newtons is applied, thus instantly deviating from the target wire and directly touching the metal surface of the adjacent stator core.

[0054] Since the stator core itself is a huge good conductor, the false positive low impedance caused by momentary slippage and accidental contact is almost exactly the same in absolute value as the low impedance when it is normally pressed in and turned on.

[0055] In this embodiment, the metal wires 3 on the probe surface are arranged in a non-uniform, equidistant, pre-defined spatial pattern. Specifically, the metal wires 3 are attached to an axially compressible elastic helical skeleton 1. The groups are divided into a first group of clockwise spirally wound metal wires 3 and a second group of counter-clockwise spirally wound metal wires 3, with the two groups interlacing on the skeleton surface. Along the longitudinal axial pressing direction of the probe, i.e., from the probe tip that first contacts the wire towards the probe root connecting to the drive mechanism, the axial pitch between adjacent groups of wound metal wires 3 exhibits an arithmetic progression of continuously decreasing spacing, forming a gradient arrangement structure with sparser spacing at one end and denser spacing at the other.

[0056] The specific pitch calculation formula is as follows: In this formula, Defined as the first pitch at the tip, set between 0.1 and 0.3 mm. The preset step increment ranges from 0.05P1 to 10.15P1.

[0057] When the probe is pressed into the wire terminal, it needs to continuously overcome the interference resistance, and the elastic spiral skeleton 1 is gradually compressed. In the initial contact stage, the sparser metal wires 3 at the probe tip contact the wire first, and the impedance drops rapidly; as the probe continues to press deeper, the elastic skeleton contracts deeply, and at this time, the extremely dense metal wire area in the middle and rear of the probe begins to participate in the contact.

[0058] As the number of new contact nodes per unit axial indentation displacement gradually saturates with the increase of wire density, this forces the dynamic impedance signal in the measurement circuit to exhibit a nonlinear dynamic impedance curve with an extremely steep initial slope and a gradually smoothing curvature in the middle and later stages.

[0059] Furthermore, when the probe skews and slips, accidentally touching the stator core, the metal wires 3 on the probe surface, whether sparse or dense, will all short-circuit simultaneously because the core surface is a flat and rigid large conductor. At this time, the collected dynamic impedance signal will completely lose the aforementioned nonlinear gradual change characteristic from steep to gentle, directly manifesting as a step-straight line with no transition and a vertical drop.

[0060] By extracting the waveform features of the signal, once a step line lacking gradual change characteristics is found, it can be determined that a physical slippage has occurred.

[0061] Furthermore, by extracting the waveform characteristics of the dynamic impedance signal as it changes over time, it is possible to accurately deduce that the probe has actually undergone a complete and genuine deep-pressure sliding process; thus completely eliminating false positives caused by the probe being misaligned or accidentally touching the stator core during insertion. Without adding any high-precision mechanical displacement sensors, the assembly trajectory of the terminals can be accurately determined.

[0062] It should be noted that, under the premise that the overall macroscopic insertion force of the probe is constant, the contact stress is widely dispersed, resulting in a severe lack of pressure per unit area. This makes it impossible to force the tough polymer insulating enamel layer to undergo significant compression and thinning. At this time, the insulating dielectric layer still maintains a physical thickness of tens of micrometers, the coupling capacitance formed in the measurement circuit is extremely small, and the obtained dynamic impedance signal is extremely weak with a very low signal-to-noise ratio. This can easily cause the system to misinterpret normal physical insertion as no contact or an open circuit.

[0063] To address the technical problem of insufficient contact pressure in mesh layer 2, which prevents signals from effectively penetrating the insulating layer, this embodiment adds discrete three-dimensional protrusion nodes 4 at each spatial intersection of the two sets of metal wires 3 overlapping in mesh layer 2. Through ultra-precision micro-laser spot welding or micro-electroforming processes, the geometry of each three-dimensional protrusion node 4 is precisely controlled to be a micro-hemispherical protruding radially outward from the cylindrical surface of the metal wire 3, with its height limited to the range of 5μm-15μm.

[0064] When the probe is pressed against the stator conductor with mechanical insertion force, the large-area line / surface contact between the metal wire 3 and the conductor is instantly transformed into an extremely small hemispherical point contact by the three-dimensional raised node 4. According to Hertz's contact theory in classical mechanics, under the condition that the macroscopic pressure remains unchanged, since the effective contact area of ​​the micro-hemispherical approaches infinitesimal, an extreme local stress concentration effect of up to hundreds of megapascals or even gigapascals will be instantaneously generated at the micro-contact interface.

[0065] Under the extreme pressure stress induced by the three-dimensional raised node 4, the insulating enamel coating composed of polymer is forced to undergo intense elastic compression and plastic rheology around the node. However, thanks to the smooth hemispherical curvature transition design at the top of the three-dimensional raised node 4, the sharp shearing force brought by the sharp probe is fundamentally eliminated. Therefore, although the enamel coating is extremely compressed, its underlying polymer chain network is not completely torn or physically punctured, and an extremely thin continuous insulating dielectric layer can still be maintained between the copper conductor core and the gold-plated three-dimensional raised node 4.

[0066] The insulating medium, which is extremely compressed and thinned by the three-dimensional protrusion node 4, causes a transient coupling capacitor with a very large capacitance to be formed instantaneously at this microscopic intersection. At this time, the high-frequency alternating electric field, with its extremely low capacitive reactance, passes through the thinned insulating medium to establish a transient capacitive coupling channel between the probe and the metal core of the wire.

[0067] Example 3: When extracting amplitude features to characterize the intensity of energy release during the instant of compression of the insulation layer, the specific technical problem faced in this example is that the thickness and dielectric constant of the insulation enamel of enameled wires from different batches and manufacturers exhibit objective, slight fluctuations. Simultaneously, in actual workshop environments, temperature, humidity, and the movement of surrounding metal fixtures can cause parasitic capacitance drift in the measurement circuit. If a fixed frequency band is used for energy integration of the signal, the extracted feature values ​​are easily distorted due to background noise or resonant point shifts.

[0068] When extracting amplitude features, the extraction process is as follows: Perform a short-time Fourier transform on the dynamic impedance signal to obtain the energy spectral density of impedance value as a function of displacement. Select a penetration-sensitive frequency band, such as 0.8-1.2 MHz, and integrate the energy spectral density within this band over the displacement interval [0.3, 0.7] mm to obtain the integrated penetration energy value. .like Greater than the first preset threshold If the insulation layer has been effectively penetrated, it is determined that the first preset threshold is calculated based on the actual situation. For example... .

[0069] When extracting waveform features, it's important to consider that the probe pressing into the lead wire terminal involves interference friction, which inevitably produces a stick-slip effect in micromechanics, resulting in intermittent micro-vibrations. These mechanical vibrations cause minute sawtooth-like fluctuations in the impedance signal. If conventional curve smoothing or differentiation algorithms are used, normal micro-mechanical vibrations can easily be misinterpreted as abnormal probe jamming or slippage, leading to an extremely high false negative rate.

[0070] Specifically, the dynamic impedance signal is plotted as a curve and divided into multiple continuous segments; a third-order local polynomial function is fitted to each segment. ; Calculate the difference of the first derivative of the fitting function of adjacent segments at the connection point. Specifically, represents the absolute value of the difference of the first derivative at the kth connection point; This represents the first derivative of the fitted curve of the (k+1)th sub-segment at the connection point; This represents the first derivative of the fitted curve of the k sub-segments at the connection point; This represents the physical displacement coordinates corresponding to the connection point of two adjacent consecutive segments.

[0071] like The absolute value exceeds the second preset threshold. The second preset threshold is set according to the actual situation, for example, If a point is identified as a structural abrupt change, then that point is marked as such; count the number of structural abrupt changes throughout the entire journey. and its distribution entropy To form a trajectory stability index ,in This is the weighting coefficient. If... Falling into the preset abnormal range If so, it is determined that there is an insertion skew or a loose connection.

[0072] It should be noted that the extraction of amplitude features incorporates an adaptive frequency band selection mechanism. Wavelet packet decomposition is performed on the curve formed by the dynamic impedance signal, and the sub-band with the highest energy concentration is selected as the penetration-sensitive frequency band, rather than using a fixed range of 0.8-1.2MHz, to accommodate the differences in dielectric properties of different batches of enameled wire insulation materials.

[0073] In the extraction of topological features, the determination of structural abrupt change points introduces a dynamic threshold: a second preset threshold. Adjust dynamically based on historical data of the current batch. ,in and These are the historical qualified samples. The mean and standard deviation are used to improve robustness to process fluctuations.

[0074] In the final logic synthesis and output stage, based on the above amplitude and waveform characteristics, combined with the impedance value, a cross-decision matrix is ​​executed.

[0075] The specific judgment rule follows the following physical logic: when the energy distribution characteristics satisfy the penetration condition... Furthermore, its trajectory stability index shows excellent performance. When the impedance value is below the abnormal warning line and the measured impedance value drops to a safe low impedance level, the system output conduction is good. If the energy distribution integral value is extremely low, but the impedance value shows a low-resistance conduction state, it indicates that the system is conducting electricity directly without reasonable coupling evolution. The system identifies this as a suspected loose connection and issues a warning. If the final impedance value remains high, it is directly determined that the circuit is open. Most importantly, if the energy penetration integral meets the standard, but the trajectory stability index... If the impedance is significantly exceeded, meaning a large number of illegal abrupt changes occur, even if the final impedance is low, the system will still use dual criteria to forcibly identify the false alarm and accurately output the mechanical misalignment diagnosis that the probe has slipped or accidentally touched the iron core.

[0076] To ensure the final test results have quantifiable process traceability, the system calculates a comprehensive confidence score based on the dispersion of various features before outputting the release signal. ,in , Only when Only when the product is ready can it proceed to the next stage of the process.

[0077] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for automatically detecting the continuity of stator wiring in a micro motor, characterized in that, Includes the following steps: Step S1: Obtain the dynamic impedance signal generated by the probe during the process of pressing it into the terminal to be tested; wherein, the dynamic impedance signal refers to the impedance data that evolves with the displacement of the probe. Step S2: Based on the preset spatial arrangement pattern on the probe surface, extract the characteristic information of the dynamic impedance signal changing with time and displacement; Step S3: Determine the electrical connection status and assembly trajectory status of the terminal under test based on the feature information, and output the test results.

2. The method for automatic connection continuity detection of a micro motor stator according to claim 1, characterized in that: In step S1, obtaining the dynamic impedance signal includes: A high-frequency carrier signal is continuously injected into the probe that is being pressed in. Analyze the voltage and current data generated by the high-frequency carrier signal to obtain the impedance value; Impedance values ​​are recorded according to a time series to generate a dynamic impedance signal.

3. The method for automatic stator continuity detection of a micro motor according to claim 1, characterized in that: In step S2, extracting the feature information of the dynamic impedance signal includes: The dynamic impedance signal is calculated within a preset time window, and the amplitude characteristics are extracted; the amplitude characteristics are used to characterize the degree of compression of the insulation layer of the conductor terminal. The fitting degree of the dynamic impedance signal is calculated, and waveform features are extracted; the waveform features are used to characterize the indentation trajectory of the detection mechanism.

4. The method for automatic stator continuity detection of a micro motor according to claim 1, characterized in that: In step S2, the probe surface is provided with multiple conductive sensing units, and the multiple conductive sensing units are arranged non-uniformly along the axial pressing direction of the probe; wherein, the non-uniform arrangement is manifested in the arrangement density or adjacent spacing of the conductive sensing units increasing in a preset gradient along the axial pressing direction.

5. The method for automatic connection continuity detection of a micro motor stator according to claim 1, characterized in that: Step S3 includes: A first preset threshold and a second preset threshold are preset based on amplitude characteristics and waveform characteristics, respectively; The amplitude characteristic is compared with a first preset threshold. When the amplitude characteristic is greater than or equal to the first preset threshold, the electrical coupling state is deemed qualified. Calculate the similarity between waveform features and preset waveform model. When the similarity is greater than or equal to the second preset threshold, it is determined that the trajectory stability condition is met. When both the effective electrical coupling condition and the trajectory stability condition are met, the output test result indicates that the electrical connection is qualified and the assembly is in place; otherwise, the output test result indicates that the assembly is abnormal.

6. The method for automatic connection continuity detection of a micro motor stator according to claim 1, characterized in that: In step S1, a circuit breaker reference signal under no-load conditions is acquired; wherein, the circuit breaker reference signal is used to determine the reference response value under a fully open circuit condition.

7. A micro motor stator automatic connection continuity detection device, based on the micro motor stator automatic connection continuity detection method according to any one of claims 1-6, characterized in that, include: A probe is used to provide axial support force during the wiring process and to serve as a sensing front end for sensing the electrical connection status; wherein, the probe includes an elastic helical skeleton and a mesh layer; the mesh layer covers the outer surface of the elastic helical skeleton and is formed by several metal wires being gradient-cross-wound along the surface of the elastic helical skeleton; A high-frequency carrier excitation module, electrically connected to the probe, is used to inject a high-frequency AC carrier signal into the probe; The signal acquisition and preprocessing module is electrically connected to the probe and is used to capture the high-frequency carrier signal of the probe in real time during the process of pressing the probe into the stator terminal, and to filter and analyze the high-frequency carrier signal to obtain the dynamic impedance signal. The central logic determination unit, communicatively connected to the signal acquisition and preprocessing module, is used for dynamic impedance signal analysis and continuity / disconnection determination algorithms to output the determination result of the electrical connection status; and The testing mechanism integrates the probe, high-frequency carrier excitation module, signal acquisition and preprocessing module, and central logic determination unit.

8. The micro motor stator automatic connection continuity detection device according to claim 7, characterized in that: The mesh layer contains several metal wires, including a first group of spiral metal wires and a second group of spiral metal wires. The first group of spiral metal wires is wound in a clockwise spiral direction around the outer surface of the elastic spiral skeleton, and the second group of spiral metal wires is wound in a counterclockwise direction. The first group of spiral metal wires and the second group of spiral metal wires are interwoven along a nonlinear gradient distribution, forming multiple intersection points.

9. The micro motor stator automatic connection continuity detection device according to claim 7, characterized in that: The metal wire is made of gold-plated copper alloy wire with a diameter of 20-50μm; Three-dimensional protruding nodes are welded at the intersections where the metal wire is gradient-crossed along the surface of the elastic helical skeleton. The three-dimensional protruding nodes protrude radially outward relative to the surface of the metal wire, with a protrusion height of 5-15μm, and their tops have a hemispherical structure. The three-dimensional protruding nodes are used to generate a stress concentration effect on the contact surface of the conductor terminal insulation varnish under mechanical pressure, thereby reducing the thickness of the insulation medium by squeezing to reduce the capacitive impedance of the contact interface. The distribution density of the three-dimensional protruding nodes on the surface of the elastic helical skeleton changes synchronously with the density of the axial winding pitch of the mesh layer, thereby physically encoding the indentation depth of the probe into the topological features of the impedance signal.

10. The micro motor stator automatic connection continuity detection device according to claim 9, characterized in that: Under mechanical pressure, the three-dimensional protruding node and the insulating varnish of the conductor terminal are in contact with each other, resulting in stress concentration. The thickness of the insulating medium is reduced by squeezing to lower the capacitive impedance of the contact interface, and the insulating varnish on the surface of the conductor terminal is squeezed to establish a transient capacitive coupling channel.

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