Vibration frequency sweep test tool and vibration frequency sweep test method for motor stator

Abstract

The invention discloses a motor stator vibration frequency sweep test tool and a motor stator vibration frequency sweep test method.A limiting seat of the motor stator vibration frequency sweep test tool is connected with a mounting base, the limiting seat and the mounting base are arranged in a spaced mode in the first direction, and the limiting seat is provided with a through hole used for mounting a stator; the axial direction of the through hole is the same as the first direction and the axial direction of the stator; the fastening seat is located on the side, opposite to the mounting base, of the limiting seat in the first direction, and the fastening seat is connected with the limiting seat and / or the mounting base and used for fastening the stator to the through hole; the conductive connecting base is located on the side, opposite to the installation base, of the limiting base in the first direction, connected with the limiting base and used for being electrically connected with the stator. By applying the technical scheme of the invention, the technical problems of high cost and incapability of directly observing the quality of the welding spots in the stator caused by the fact that vibration testing is carried out by depending on a whole machine large assembly in the prior art can be solved.

Description

Technical Field

[0001] This application relates to the field of motor vibration testing technology, specifically to a vibration sweep frequency testing fixture for a motor stator and a vibration sweep frequency testing method for a motor stator. Background Technology

[0002] Vibration testing is a core component of reliability verification for motors and electric drive systems. It has wide applications in electric vehicles, industrial automation, and aerospace, and is used to assess the structural integrity and functional stability of products under complex vibration environments.

[0003] In existing technologies, the common approach is to perform overall vibration testing on the electric drive assembly. The complete assembly, including the motor stator, rotor, and housing, is fixed to a vibration table using a special fixture. According to international standards, sweep frequency vibration loads in three orthogonal directions (X, Y, and Z) are applied for 8 hours in each direction to simulate vibration excitation under actual working conditions and to detect the contact state and structural bias between components.

[0004] However, in the existing technology, the evaluation of the vibration characteristics of the motor stator must rely on the complete motor assembly, which makes it difficult to directly obtain the dynamic response data of key components inside the stator during the testing process, and significantly increases the consumption of testing resources. Summary of the Invention

[0005] In view of the above problems, this application provides a vibration sweep frequency test fixture and a vibration sweep frequency test method for a motor stator, which can solve the technical problems of high cost and inability to directly observe the quality of internal weld points of the stator caused by relying on the whole machine assembly for vibration testing in the prior art.

[0006] According to one aspect of the embodiments of this application, a vibration sweep frequency testing fixture for an electric motor stator is provided, comprising a mounting base; a limiting seat connected to the mounting base, the limiting seat and the mounting base being spaced apart along a first direction, the limiting seat having a through hole for mounting the stator, the axial direction of the through hole being the same as the first direction and the axial direction of the stator; a fastening seat located along the first direction on the side of the limiting seat opposite to the mounting base, the fastening seat being connected to the limiting seat and / or the mounting base, and used to fasten the stator to the through hole; and a conductive connecting seat located along the first direction on the side of the limiting seat opposite to the mounting base, the conductive connecting seat being connected to the limiting seat, and used to electrically connect to the stator.

[0007] In an optional exemplary embodiment, the fastening seat includes a plurality of fasteners, each of which is located along the first direction on the side of the limiting seat opposite to the mounting base and is connected to the limiting seat and / or the mounting base; each of the fasteners is arranged at intervals around the through hole and is used to fasten the stator to the through hole.

[0008] In one optional exemplary embodiment, the fastener includes a base portion, a telescopic rod, and a positioning portion. The base portion is located along the first direction on the side of the limiting seat facing away from the mounting base, and is connected to the limiting seat and / or the mounting base. The telescopic rod passes through the base portion and is capable of telescopically extending or retracting in a direction away from or towards the through hole. The positioning portion is detachably connected to the base portion and the telescopic rod for positioning the telescopic rod.

[0009] In one optional exemplary embodiment, the telescopic rod includes a rod body and an arc-shaped adapter. The rod body passes through the base body and is capable of telescoping in a direction away from or towards the through hole. The arc-shaped adapter is fixedly connected to the rod body and is used to adapt to and contact the stator.

[0010] In an optional exemplary embodiment, the positioning part includes a front nut and a rear nut, the rod part is provided with a threaded structure, the front nut and the rear nut are located on two opposite sides of the seat part along the axial direction of the rod part, and are both threadedly connected to the rod part through the threaded structure, so as to position the rod part on the seat part.

[0011] In one optional exemplary embodiment, the mounting base is provided with a plurality of waist holes that penetrate the mounting base for positioning the stator.

[0012] According to another aspect of the embodiments of this application, a vibration sweep frequency test method for a motor stator is provided. The vibration sweep frequency test method includes: disassembling the stator of the motor and installing the stator in a through hole of a vibration sweep frequency test fixture, such that the axial direction of the stator is parallel to the axial direction of the through hole; fastening the stator in the through hole by a fastening seat and electrically connecting the stator to a conductive connector; arranging acceleration sensors at a first target position and a second target position of the stator, wherein the distances between the first target position and the second target position and the center of the stator are different; and performing a sweep frequency vibration test in response to input test boundary conditions to obtain vibration sweep frequency test data of the stator.

[0013] In an optional exemplary embodiment, the method for performing a sweep frequency vibration test includes: performing sweep frequency vibration on the vibration sweep frequency test fixture and the stator on a vibration table; and acquiring vibration acceleration data during the sweep frequency vibration process as the vibration sweep frequency test data.

[0014] In one optional exemplary embodiment, the method of performing frequency sweep vibration on the vibration sweep test fixture and the stator on a vibration table includes: performing frequency sweep vibration on the vibration sweep test fixture and the stator in the height direction, width direction and length direction on the vibration table.

[0015] In an optional exemplary embodiment, the vibration sweep frequency test method further includes: acquiring vibration sweep frequency test data of the motor; if the vibration sweep frequency test data of the stator does not match the vibration sweep frequency test data of the motor, then optimizing the test boundary conditions based on the vibration sweep frequency test data.

[0016] In this application, the mounting base of the vibration sweep frequency test fixture for the motor stator provides a stable mounting foundation, ensuring a reliable connection between the fixture and the vibration table, thereby establishing a stable vibration transmission path. Furthermore, the limiting seat and the mounting base are spaced apart along a first direction and have coaxial through holes, ensuring precise alignment between the stator axial direction and the through hole axial direction, effectively constraining the stator posture and eliminating installation misalignment. Based on this, the fastening seat is located on the side of the limiting seat facing away from the mounting base and rigidly locks the stator within the through hole, significantly improving the reliability of vibration load transmission and preventing stator loosening during testing. Simultaneously, the conductive connecting seat is rigidly connected to the limiting seat, achieving electrical connection of the stator and ensuring the stability of electrical signal acquisition during vibration testing. Ultimately, this design not only achieves decoupled testing of the stator from the overall machine but also supports direct observation of key components such as weld points inside the stator, significantly reducing fixture costs and shortening the testing cycle.

[0017] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more obvious and understandable, specific implementation methods of this application are described below. Attached Figure Description

[0018] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A three-dimensional structural schematic diagram of the vibration sweep frequency test fixture for the motor stator provided in this application is shown.

[0019] Figure 2The diagram shows a top view of the vibration sweep frequency test fixture for the motor stator provided in this application.

[0020] Figure 3 The diagram shows a bottom view of the vibration sweep frequency test fixture for the motor stator provided in this application.

[0021] Figure 4 A flowchart of the vibration sweep frequency test method for motor stator provided in this application is shown.

[0022] Icon labels: 11. Mounting base; 12. Limiting seat; 13. Fastening seat; 13a. Fastener; 131. Seat body; 132. Telescopic rod; 1321. Rod body; 1322. Arc-shaped adapter; 133. Positioning part; 1331. Nut; 1332. Rear nut; 101. Through hole; 14. Conductive connector; 102. Waist hole. Detailed Implementation

[0023] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0024] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0025] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0026] In this application, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0027] Current motor vibration sweep frequency testing generally relies on the entire machine assembly (such as the electric drive assembly 18488) to conduct sweep frequency vibration tests in the X, Y, and Z directions. This has problems such as large equipment size, high cost of special fixtures, and long test cycle. At the same time, the stator is encapsulated in the motor housing, and the busbar welding area is completely invisible. It is impossible to observe the dynamic response of the weld points in real time during vibration. Half-range testing requires disassembling the housing cover, which leads to test interruption, accumulation of repeated assembly and adjustment errors, and distortion of the weld point status. In addition, in the whole machine test, the vibration load is transmitted through multiple stages such as the housing, end cover, and bearings, resulting in modal coupling and energy attenuation. This makes it difficult to accurately peel off and reproduce the actual acceleration response boundary of the stator body, affecting the accuracy and traceability of the busbar structure reliability assessment.

[0028] Based on this, combined Figures 1 to 4 As shown, this application proposes a vibration sweep frequency test fixture for motor stators, which can solve the technical problems of high cost and inability to directly observe the quality of internal stator solder joints caused by relying on the entire machine assembly for vibration testing in the prior art.

[0029] Combination Figures 1 to 3 As shown, the vibration sweep frequency test fixture for the motor stator includes a mounting base 11, which serves as the basic support platform for the fixture and is used for rigid connection with the external vibration table surface. Its structural form can be a flat plate, a frame, or a box with reinforcing ribs, depending on the vibration table interface size and the maximum test load.

[0030] Combination Figures 1 to 3 As shown, the vibration sweep frequency test fixture for the motor stator also includes a limiting seat 12, which is connected to the mounting base 11. The limiting seat 12 and the mounting base 11 are spaced apart along the first direction (the axial direction of the stator). The limiting seat 12 has a through hole 101 for mounting the stator, and the axial direction of the through hole 101 is the same as the first direction and the axial direction of the stator. Among them, the limiting seat 12 is the core component for realizing the axial attitude constraint of the stator. It is spaced apart from the mounting base 11 along the first direction (i.e., the axial direction of the stator). The limiting seat 12 has a through hole 101 at its center. The through hole 101 is cylindrical, and its diameter is slightly larger than the outer diameter of the stator (typical gap is 0.1–0.3 mm) to take into account both assembly convenience and radial constraint accuracy. The axial direction of the through hole 101 is strictly parallel to the first direction, that is, it coincides with the geometric axis of the stator to be tested, ensuring that the stator is naturally in a non-skewed state after insertion.

[0031] Combination Figures 1 to 3As shown, the vibration sweep frequency test fixture for the motor stator also includes a fastening seat 13. The fastening seat 13 is located on the side of the limiting seat 12 facing away from the mounting base 11 along the first direction. The fastening seat 13 is connected to the limiting seat 12 and / or the mounting base 11 and is used to fasten the stator to the through hole 101. The function of the fastening seat 13 is to apply radial clamping force after the stator is installed in the through hole 101, rigidly locking the stator in the limiting seat 12 to prevent relative displacement or loosening during vibration. The fastening seat 13 can be connected separately to the limiting seat 12 or can be connected across the mounting base 11. The connection methods include threaded fastening, pin positioning, welding or quick-change buckle; its structure is not limited to an integral pressure plate.

[0032] For example, the fastening action of the fastening seat 13 can be manual (such as screw + handwheel), pneumatic (such as cylinder pushing pressure block), or electric (such as stepper motor driving lead screw).

[0033] Combination Figures 1 to 3 As shown, the vibration sweep frequency test fixture for the motor stator also includes a conductive connector 14. The conductive connector 14 is located on the side of the limiting seat 12 facing away from the mounting base 11 along the first direction. The conductive connector 14 is connected to the limiting seat 12 and is used for electrical connection with the stator.

[0034] It should be understood that the function of the conductive connector 14 is to provide a stable, low-impedance, vibration-resistant electrical connection interface for the stator winding leads (such as the U / V / W three-phase lines and the neutral point).

[0035] For example, the conductive connector 14 is rigidly connected to the limiting seat 12 (e.g., fixed to the end face or side wall of the limiting seat 12 by bolts). The conductive connector 14 includes a conductive base and replaceable connecting terminals. The conductive base is made of copper or copper alloy (e.g., H62 brass) and is silver-plated or tin-plated to reduce contact resistance. The connecting terminals can be pluggable aviation plugs (e.g., M12×1 or D-Sub series), bolt-pressed terminals (compatible with M6 / M8 studs), or spring-clamped terminals (e.g., Weidmüller series), all of which have anti-misinsertion, anti-loosening, and IP54 or higher protection ratings. Their placement avoids key observation areas such as busbars and IPin solder joints to prevent obstruction or stress interference.

[0036] Optionally, the conductive connector 14 may integrate a temperature sensor (such as a PT100 or thermocouple) or a high-frequency probe interface to support simultaneous acquisition of multiple physical fields; it may also integrate the conductive function with the fastening function (for example, embedding a conductive path inside the fastener 13a) so that the clamping action can be completed simultaneously to achieve electrical connection.

[0037] In this invention, after the stator is inserted into the through hole 101 of the limiting seat 12 along the first direction, one end of its axial direction abuts against the mounting base 11; then the stator is subjected to radial clamping force by the fastening seat 13, and the stator core is positioned in the through hole 101; the conductive connection seat 14 simultaneously completes the reliable connection of the winding lead; at this time, the vibration table applies frequency sweep excitation, and the energy is directly transmitted through the mounting base 11 → limiting seat 12 → stator core body, with a short path, less coupling, and clear modes. During this process, since the stator is not enclosed by the shell, the Busbar welding area is fully exposed, allowing for in-situ dynamic observation using high-speed cameras, microscopic thermal imaging, or laser vibration meters during vibration. Furthermore, because the axial direction of the through hole 101 is strictly coaxial with the stator axis, the measured acceleration response truly reflects the inherent modes and dynamic amplification characteristics of the stator body under pure axial excitation. This solves the fundamental defects caused by whole-machine testing, such as load boundary distortion, unreachable observation, and uncontrollable disassembly and assembly, providing an independent, reliable, and reproducible technical basis for the vibration reliability verification of Busbar welding quality.

[0038] Combination Figures 1 to 3 As shown, the fastening seat 13 includes a plurality of fasteners 13a, which are all located on the side of the limiting seat 12 away from the mounting base 11 along the first direction and are all connected to the limiting seat 12 and / or the mounting base 11; each fastener 13a is arranged around the through hole 101 at intervals and is used to fasten the stator to the through hole 101.

[0039] In this embodiment, multiple independently adjustable fasteners 13a are evenly distributed circumferentially on the back side of the limiting seat 12, forming a radially symmetrical constraint on the outer circle of the stator. This significantly improves the uniformity and repeatability of the clamping stiffness without changing the axial positioning reference. This structure avoids local core indentation, lamination misalignment, and vibration mode distortion caused by single-point clamping, and also prevents the fasteners 13a from intruding into the sensor layout area or conductive connection path, providing a reliable mechanical constraint basis for frequency sweep response testing.

[0040] For example, "multiple fasteners 13a" refers to no less than three, and optionally three to six, discrete mechanical fastening units. The number configuration must meet the circumferential torque balance condition: when the stator outer diameter is Φ180–Φ320 mm, four fasteners 13a are used, which can take into account both operational convenience and clamping stability; when the outer diameter is extended to Φ320–Φ450 mm, six fasteners 13a can be selected to suppress circumferential deformation of large-diameter thin-walled structures.

[0041] In this invention, by replacing the traditional single-sided pressure plate or single-point bolt with multiple geometrically symmetrical fasteners 13a, the force on the outer circle of the stator under frequency sweep excitation becomes more uniform, effectively suppressing the micro-slippage of the core laminations, local resonance amplification, and modal coupling distortion caused by uneven clamping. At the same time, the independent adjustable feature of each fastener 13a allows it to adapt to stators with different outer diameter specifications. Only the extension and retraction of a single fastener 13a needs to be adjusted to complete the changeover, without the need to replace the special fixture, thus improving the versatility and response efficiency of the testing fixture.

[0042] Combination Figures 1 to 3 As shown, the fastener 13a includes a base portion 131, a telescopic rod 132, and a positioning portion 133. The base portion 131 is located on the side of the limiting seat 12 facing away from the mounting base 11 along a first direction, and is connected to the limiting seat 12 and / or the mounting base 11. The telescopic rod 132 passes through the base portion 131 and can extend and retract in a direction away from or towards the through hole 101. The positioning portion 133 is detachably connected to the base portion 131 and the telescopic rod 132 for positioning the telescopic rod 132.

[0043] In this invention, during vibration sweep frequency testing of the motor stator, when multiple fasteners 13a move synchronously, each telescopic rod 132 first extends radially until the arc-shaped adapter 1322 lightly touches the outer surface of the stator. At this time, the stator has not yet been clamped. Subsequently, the operator locks the telescopic rod 132 axially through the positioning part 133. At this time, the positioning part 133 adheres to the outer circle of the stator with a constant positive pressure, forming a uniform circumferential constraint. Since the telescopic rod 132 has independent telescopic capability, even if there are depressions or protrusions on the outer circle of the stator corresponding to multiple fasteners 13a on the same limiting seat 12, each telescopic rod 132 can still adjust its extension amount, ultimately achieving a full circumferential gapless envelope. This process avoids the point contact stress concentration caused by the deformation of the stator due to rigid pressure blocks, and prevents clamping failure due to small size. Thus, within a wide range of stator manufacturing tolerances, the clamping stiffness and vibration transmission path are stably maintained.

[0044] Combination Figures 1 to 3 As shown, the telescopic rod 132 includes a rod body 1321 and an arc-shaped adapter 1322. The rod body 1321 passes through the base body 131 and can extend and retract in the direction away from or towards the through hole 101. The arc-shaped adapter 1322 is fixedly connected to the rod body 1321 and is used to make contact with the stator.

[0045] For example, the arc-shaped adapter 1322 is a functional end that acts directly on the outer circle of the stator. Its main outline is an arc with a radius of curvature R equal to the design radius of the outer circle of the stator core being measured, and the tolerance is controlled within ±0.15 mm.

[0046] In this embodiment, the arc-shaped adapter 1322 is a rubber block with an arc length of 60°, used for flexible contact with the stator.

[0047] In this invention, by setting the rod body 1321 and the arc-shaped adapter 1322, when performing vibration sweep frequency testing on the stator of P1 / P3 dual-model motors, the telescopic rod 132, through the precise guiding extension and retraction of the rod body 1321, and the curved surface of the arc-shaped adapter 1322, makes the fastening force evenly distributed on the outer circle of the stator core. Because the geometric curvature of the arc-shaped adapter 1322 is consistent with that of the outer circle of the stator, the local contact pressure is significantly reduced, avoiding crushing of the core lamination edges and cracking of the insulating varnish layer around the Busbar solder joints. Furthermore, the surface contact greatly improves the static friction constraint capability, suppressing the slight relative sliding between the stator and the tooling under high-frequency vibration, ensuring the path transmission of vibration energy from the table through the tooling to the stator. This also avoids the problems of stress concentration, surface damage, and vibration response distortion caused by point / line contact.

[0048] Combination Figures 1 to 3 As shown, the positioning part 133 includes a front nut 1331 and a rear nut 1332. The rod part 1321 is provided with a threaded structure. The front nut 1331 and the rear nut 1332 are located on two opposite sides of the seat part 131 along the axial direction of the rod part 1321, and are threadedly connected to the rod part 1321 through the threaded structure to position the rod part 1321 on the seat part 131.

[0049] It should be understood that during the vibration sweep frequency test of the motor stator, the telescopic rod 132 in the fastening seat 13 is subjected to high-frequency, high-acceleration (measured up to 40g), wide-band (100–440 Hz) reciprocating vibration load for a long time. Due to inertial force, the rod body 1321 is prone to slight axial movement. At the same time, the single nut 1331 locking structure is prone to self-loosening of the thread pair under continuous vibration, resulting in attenuation of clamping force and stator positioning deviation. Therefore, the front nut 1331 provides the main clamping force facing the stator and limits the excessive extension of the rod body 1321 towards the through hole 101. The rear nut 1332, by tightening in the opposite direction, forms a reaction fulcrum on the other side of the seat body 131, making the seat body 131 itself the intermediate load-bearing body of the preload, thereby avoiding the local bending deformation of the seat body 131 caused by concentrating all the preload on one side.

[0050] Combination Figures 1 to 3 As shown, the mounting base 11 has multiple waist holes 102, which penetrate the mounting base 11 for positioning the stator.

[0051] It should be understood that the waist hole 102 refers to a long strip-shaped through hole 101 extending along a single main direction (e.g., parallel to the X or Y direction of the vibration table), with a rectangular cross-section or a through hole 101 with semi-circular arcs at both ends.

[0052] For example, each waist hole 102 is arranged at equal intervals along the length of the base, with a center distance of 60–100 mm between adjacent holes, and a number of 3–5 holes; all waist holes 102 completely penetrate the base body, that is, they run from the upper surface to the lower surface, without blind holes or stepped structures.

[0053] In this invention, a plurality of through-holes 102 are provided on the mounting base 11, so that the stator can be precisely calibrated relative to the mounting base 11 by adjusting the axial position of the bolts in the holes 102; since the holes 102 provide continuously adjustable stroke, manufacturing tolerances and cumulative assembly errors can be eliminated during installation.

[0054] Combination Figure 4 As shown, this embodiment also provides a vibration sweep frequency test method for a motor stator, which includes steps S110-S140; detailed description is as follows: Step S110: Disassemble the stator of the motor and install the stator in the through hole 101 of the vibration sweep frequency test fixture so that the axial direction of the stator is parallel to the axial direction of the through hole 101.

[0055] In this embodiment, disassembling the motor stator refers to separating the stator assembly from the assembled drive motor. This includes disconnecting all mechanical and electrical connections between the stator and the housing, end covers, rotor, and cooling structure, while preserving the integrity of the core structure, including the stator core, windings, busbar, IPin wires, and three-phase leads. This disassembly operation is performed according to the motor's structural type (e.g., P1 or P3) and the corresponding process specifications to avoid mechanical or thermal stress damage to the busbar solder joints, winding insulation, and core laminations.

[0056] Furthermore, the through hole 101 installed in the vibration sweep frequency test fixture refers to the through hole 101 provided by the limit seat 12, which is used to coaxially insert the stator along the first direction (i.e., the axial direction of the stator); the through hole 101 is a through cylindrical channel.

[0057] Step S120: Secure the stator to the through hole 101 using the fastening seat 13, and electrically connect the stator to the conductive connection seat 14; In this embodiment, the stator is fastened in the through hole 101 by the fastening seat 13. The positioning part 133 (front nut 1331 and rear nut 1332) of each fastener 13a works together to lock the telescopic rod 132, so that its arc-shaped adapter part 1322 presses against the outer circle surface of the stator; the radius of curvature of the arc-shaped adapter part 1322 is consistent with the design radius of the outer circle of the stator.

[0058] Furthermore, electrically connecting the stator to the conductive connector 14 means establishing a low-impedance electrical path with the three sets of elastic probes or plug-in copper bus terminals provided on the conductive connector 14, respectively, with the stator three-phase winding lead-out terminals (U / V / W phases).

[0059] For example, the conductive connector 14 is made of T2 copper with a silver-plated surface and a contact resistance of ≤5 mΩ; the probe substrate is made of beryllium copper alloy with a spring force range of 8–12 N / pin and a stroke of ≥1.2 mm, ensuring continuous and reliable contact during vibration.

[0060] Step S130: An acceleration sensor is arranged at both the first target position and the second target position of the stator, wherein the distance between the first target position and the second target position and the center of the stator is different.

[0061] In this embodiment, the first target position and the second target position are two measuring points on the stator structure with a clear geometric reference system. Both are located on the outer circle generatrix of the stator core and are within the same axial section. The first target position is set at the near end of the stator axial direction (close to the non-lead end face of the stator), and the axial distance from the geometric center of the stator is L1 = 0.15D (D is the total length of the stator core). The second target position is set at the far end of the stator axial direction (close to the three-phase lead end face), and the axial distance from the geometric center of the stator is L2 = 0.35D. The radial heights of the two measuring points are consistent, and both are located in the neutral layer of the outer circle of the core (i.e., at the midpoint of the outer circle generatrix) to eliminate the additional rotational effect caused by bending vibration.

[0062] Step S140: In response to the input test boundary conditions, a sweep frequency vibration test is performed to obtain the stator vibration sweep frequency test data.

[0063] In this embodiment, the test boundary condition in response to the input refers to loading a preset acceleration-frequency control spectrum into the vibration control system (such as the LDS SCADAS Mobile + VibrationVIEW software platform). This boundary condition reproduces the X / Y / Z triaxial excitation characteristics of the electric drive assembly 18488 measured in the vehicle-level vibration test.

[0064] Furthermore, performing a frequency sweep vibration test refers to fixing the fixture with the stator installed onto the surface of an electric vibration table and conducting sinusoidal frequency sweep tests sequentially. The frequency sweep mode is a linear frequency sweep superimposed with a dwell frequency sweep. The duration of a single test in each direction is 2 hours, and the total test cycle is 6 hours. The data acquisition system synchronously records the output signals of the two accelerometers with a sampling rate of not less than 51.2 kHz, and stores them in TDMS format after anti-aliasing filtering (cutoff frequency 20 kHz).

[0065] Furthermore, the vibration sweep test data includes time-domain acceleration waveforms, spectral amplitude curves (FFT resolution ≤ 0.5 Hz), coherence functions, modal confidence criterion (MAC) matrix, and identification results of natural frequencies and damping ratios at each order; this data can be further used to construct finite element models of stator structures to correct parameters, or as a dynamic stress input source for predicting the fatigue life of Busbar weld joints.

[0066] In this invention, the vibration sweep frequency testing method for motor stators decouples the stator from the overall machine environment into an independent test object without disrupting its original assembly state and electrical connections. Simultaneous multi-point fastening and conductive connections achieve dual reproduction of mechanical constraint stiffness and electrical load state. Furthermore, a differentiated axial measuring point layout effectively excites and captures the bending and torsional coupling modes of the stator core-winding-Busbar system, ultimately obtaining physically interpretable intrinsic vibration response data. Therefore, this method overcomes the shortcomings of whole-machine testing, such as the inability to directly observe the dynamic behavior of Busbar weld points, long testing cycles (8 hours / direction), high equipment costs (requiring large vibration tables and specialized fixtures), and insufficient modal parameter identification accuracy. Ultimately, it shortens the single-stator vibration testing time and improves efficiency.

[0067] Furthermore, the method for performing a sweep frequency vibration test includes: performing sweep frequency vibration on the vibration sweep frequency test fixture and the stator on a vibration table; and acquiring vibration acceleration data during the sweep frequency vibration process as vibration sweep frequency test data.

[0068] In this invention, the vibration sweep frequency test fixture and the stator are constructed as a single rigid test object on the vibration table to eliminate false high-frequency responses caused by loose assembly; and the vibration acceleration data during the sweep frequency vibration process are directly obtained, providing traceable, reproducible and quantifiable experimental basis for subsequent Busbar weld fatigue life prediction, vibration boundary inverse fitting and electric drive system NVH forward design based on the stator level.

[0069] Furthermore, the method of performing frequency sweep vibration on the vibration sweep test fixture and the stator on the vibration table includes: performing frequency sweep vibration on the vibration sweep test fixture and the stator in the height direction, width direction and length direction on the vibration table.

[0070] In this embodiment, the height direction corresponds to the Z-axis in the vehicle coordinate system, which is the vertical direction perpendicular to the ground, and also the normal direction of the axial projection plane of the motor stator. This direction simulates the vertical excitation caused by road surface unevenness during vehicle operation, such as the inertial load borne by the stator under conditions like bumps, potholes, and speed bumps. In the experiment, a sinusoidal / random frequency sweep excitation is applied to the vibration table surface along the Z-axis. The entire vibration frequency sweep test fixture (including the mounting base 11, limit seat 12, fastening seat 13, conductive connection seat 14, and the assembled stator) is fixed to the table surface as a rigid unit to ensure that the vibration transmission path in the Z-axis is direct and undecoupled.

[0071] For example, the frequency sweep range in the height direction covers 100 Hz to 440 Hz, with a focus on enhancing the resonant sensitive frequency band of 220–320 Hz. The peak response of the P1 stator is located in the range of 225–256 Hz (acceleration up to 158 m / s²), and the peak response of the P3 stator is located in the range of 295–306 Hz (acceleration up to 226–230 m / s²).

[0072] Optionally, vertical vibration can be achieved using a hydraulic exciter or a high-thrust electric vibration table; when using an electric vibration table, its maximum displacement should be no less than ±50 mm and its maximum acceleration should be no less than 200 m / s², in order to meet the high amplitude excitation requirements in the Z direction.

[0073] Furthermore, the width direction corresponds to the Y-axis in the vehicle coordinate system, which is a horizontal direction perpendicular to the motor rotation axis and parallel to the vehicle's lateral (left-right) direction. This direction simulates the coupling effect of lateral inertial force and bending moment on the stator under conditions such as vehicle turning, crosswinds, and single-sided obstacle crossing. In the experiment, a sweep frequency excitation was applied to the vibration table surface along the Y-axis. The fixture was mounted on the table surface through a high-rigidity L-shaped transition bracket or a double-ear cantilever structure to avoid introducing additional torque due to support eccentricity.

[0074] For example, the sweep frequency range in the width direction is also 100–440 Hz. According to the measured data in the Y direction, the key excitation frequency band is concentrated in 180–320 Hz. The stators P1 and P3 both show significant acceleration peaks at 241 Hz (111 m / s² and 115 m / s², respectively), indicating that the Busbar solder joint is prone to shear stress concentration in this frequency band.

[0075] Alternatively, the vibration in the width direction can be achieved using a single-axis vibration table with a lateral guide mechanism.

[0076] Furthermore, the length direction corresponds to the X-axis in the vehicle coordinate system, which is the axial direction parallel to the motor's rotation axis, i.e., the vehicle's forward / braking direction. This direction simulates the tensile / bending fatigue of the Busbar lead wire caused by the axial relative displacement between the stator core and the housing under conditions such as acceleration, braking, and climbing. In the test, a sweep frequency excitation was applied to the vibration table surface along the X-axis. The fixture was fixed to the table surface through an axial rigid connecting flange. The flange and the mounting base 11 were pre-tightened with M12×1.75 high-strength bolts (performance grade 10.9) with a pre-tightening torque of 120 N·m to suppress low-frequency (<150 Hz) rigid body displacement in the X-axis direction.

[0077] For example, the sweep frequency range along the length is still 100–440 Hz. According to the measured data in the X direction, the P1 stator reaches a maximum acceleration of 89 m / s² at 185 Hz, and the P3 stator reaches 85 m / s². Both of them show significant attenuation above 300 Hz.

[0078] Optionally, vibration in the length direction can be achieved using a long-stroke linear motor vibration table.

[0079] It should be understood that the vibration tests in each direction are independent and not superimposed; only one direction's excitation channel is activated each time, while the other two directions are mechanically locked or disabled by software to ensure directional input of vibration energy and decoupling of response signals. The frequency sweep vibration sequence in the three directions can be set according to the test objectives: the conventional sequence is X-axis first, then Y-axis, and finally Z-axis, to avoid the high amplitude vibration in the Z-axis causing slight loosening of the fastener 13a, affecting the repeatability of the data in the first two directions; alternatively, it can be ordered according to the principle of "low frequency dominance → high frequency dominance", that is, Z-axis first (225 Hz main peak), then Y-axis (241 Hz main peak), and finally X-axis (185 Hz main peak), which facilitates the staged calibration of sensor sensitivity and acquisition system gain. All direction frequency sweeps adopt a constant acceleration amplitude control mode, with a starting frequency of 100 Hz, an ending frequency of 440 Hz, a sweep rate of 1 octave / min, and a continuous test time of 8 hours for each direction.

[0080] In this invention, the application achieves a complete reproduction of the three-dimensional spatial vibration load borne by the motor stator in the actual application environment of the vehicle. By clearly defining the sweep frequency vibration in three orthogonal directions of height (Z), width (Y), and length (X) and implementing them separately, the technical problem that single-direction vibration testing cannot cover the multi-dimensional dynamic load of the stator and leads to the one-sidedness of reliability assessment is solved. Since the vibration in each direction acts on the overall assembly of the tooling and stator, and the excitation direction strictly corresponds to the vehicle coordinate system, the obtained acceleration response data has clear physical meaning and can be directly used to construct the three-dimensional vibration transfer function of the stator assembly. Because the test data in the three directions are coordinated with the dual measurement point layout of the first target position (such as the far end of the stator) and the second target position (such as the near end of the stator), a three-dimensional vibration vector field can be synthesized, thereby identifying the modal stress distribution characteristics of the Busbar weld under different excitation directions, providing a quantitative basis for the optimization of welding process parameters.

[0081] The vibration sweep frequency test method also includes: acquiring the vibration sweep frequency test data of the motor; if the vibration sweep frequency test data of the stator does not match the vibration sweep frequency test data of the motor, then optimizing the test boundary conditions based on the vibration sweep frequency test data.

[0082] In this embodiment, optimizing the test boundary conditions based on vibration sweep test data refers to parametrically modifying the original whole-machine test boundary using stator test data as a benchmark to form a new boundary that adapts to the single stator-whole-machine mapping relationship. Specifically, this includes: identifying resonant sensitive frequency bands in the stator data that are significantly higher than those in the whole-machine data (e.g., 89 m / s² at 185 Hz in the X direction of stator P1 vs. 37 m / s² in the whole machine), and increasing the boundary acceleration amplitude weight in this frequency band; reducing the boundary amplitude and increasing the damping compensation factor for frequency bands in the stator data that are not excited but have a significant response in the whole machine (e.g., 116 m / s² at 295 Hz in the Z direction of stator P3, while the whole machine is only 32 m / s² at this frequency); and finally generating the optimized test boundary curve through piecewise linear interpolation or B-spline fitting. This optimization process can adopt a multi-objective optimization strategy based on genetic algorithm (GA) to simultaneously consider matching accuracy, boundary smoothness, and test feasibility.

[0083] In this invention, by introducing quantitative comparison and boundary reverse correction of whole machine-stator data in the above-mentioned steps, this application realizes a closed-loop iterative mechanism for dynamically calibrating the whole machine vibration test boundary with single stator vibration characteristics as data anchor points; and solves the technical problem of the disconnect between single stator test and whole machine measured data, which cannot support the optimization of whole machine vibration performance.

[0084] In this application, unless otherwise expressly specified and limited, the terms "assembly," "connection," 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. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0085] 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 one or more of that feature. "A plurality of" means two or more, unless otherwise explicitly specified. The terms "some embodiments," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application.

[0086] The illustrative expressions of the terms used above do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of those different embodiments or examples, without contradiction.

[0087] Although embodiments of this application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application. Therefore, any changes or modifications made in accordance with the claims and description of this application should fall within the scope of the patent coverage of this application.

Claims

1. A vibration sweep frequency testing fixture for an electric motor stator, characterized in that, include Mounting base (11); A limiting seat (12) is connected to the mounting base (11). The limiting seat (12) and the mounting base (11) are spaced apart along a first direction. The limiting seat (12) is provided with a through hole (101) for mounting the stator. The axial direction of the through hole (101) is the same as the first direction and the axial direction of the stator. Fastening seat (13), the fastening seat (13) is located on the side of the limiting seat (12) opposite to the mounting base (11) along the first direction, the fastening seat (13) is connected to the limiting seat (12) and / or the mounting base (11), and is used to fasten the stator to the through hole (101). A conductive connector (14) is located along the first direction on the side of the limiting seat (12) facing away from the mounting base (11). The conductive connector (14) is connected to the limiting seat (12) and is used for electrical connection with the stator.

2. The vibration sweep frequency test fixture for the motor stator according to claim 1, characterized in that, The fastening seat (13) includes a plurality of fasteners (13a), all of which are located along the first direction on the side of the limiting seat (12) facing away from the mounting base (11), and are all connected to the limiting seat (12) and / or the mounting base (11). Each of the fasteners (13a) is arranged at intervals around the through hole (101) and is used to fasten the stator to the through hole (101).

3. The vibration sweep frequency test fixture for the motor stator according to claim 2, characterized in that, The fastener (13a) includes a base (131), a telescopic rod (132), and a positioning part (133). The base (131) is located on the side of the limiting seat (12) facing away from the mounting base (11) along the first direction, and is connected to the limiting seat (12) and / or the mounting base (11). The telescopic rod (132) passes through the base (131) and can extend and retract in a direction away from or close to the through hole (101). The positioning part (133) is detachably connected to the base (131) and the telescopic rod (132) for positioning the telescopic rod (132).

4. The vibration sweep frequency test fixture for the motor stator according to claim 3, characterized in that, The telescopic rod (132) includes a rod body (1321) and an arc-shaped adapter (1322). The rod body (1321) passes through the base body (131) and can extend and retract in a direction away from or towards the through hole (101). The arc-shaped adapter (1322) is fixedly connected to the rod body (1321) and is used to adapt and contact with the stator.

5. The vibration sweep frequency test fixture for the motor stator according to claim 4, characterized in that, The positioning part (133) includes a front nut (1331) and a rear nut (1332). The rod part (1321) is provided with a threaded structure. The front nut (1331) and the rear nut (1332) are located on two opposite sides of the seat part (131) along the axial direction of the rod part (1321), and are threadedly connected to the rod part (1321) through the threaded structure to position the rod part (1321) on the seat part (131).

6. The vibration sweep frequency test fixture for the motor stator according to claim 1, characterized in that, The mounting base (11) is provided with a plurality of waist holes (102), which penetrate the mounting base (11) for positioning the stator.

7. A method for vibration sweep frequency testing of an electric motor stator, characterized in that, The vibration sweep frequency test method includes: The stator of the motor is disassembled and installed in the through hole (101) of the vibration sweep frequency test fixture, so that the axial direction of the stator is parallel to the axial direction of the through hole (101); The stator is fastened to the through hole (101) by fastening seat (13) and the stator is electrically connected to conductive connection seat (14); Accelerometers are arranged at both the first target position and the second target position of the stator, wherein the distances between the first target position and the second target position and the center of the stator are different; In response to the input test boundary conditions, a sweep frequency vibration test is performed to obtain the vibration sweep frequency test data of the stator.

8. The vibration sweep frequency test method according to claim 7, characterized in that, The method for performing the sweep frequency vibration test includes: The vibration sweep frequency test fixture and the stator were subjected to sweep frequency vibration on a vibration table. The vibration acceleration data during the frequency sweep vibration process is obtained as the vibration frequency sweep test data.

9. The vibration sweep frequency test method according to claim 8, characterized in that, A method for performing frequency sweep vibration on the vibration sweep test fixture and the stator on a vibration table includes: The vibration sweep test fixture and the stator were subjected to sweep vibration in the height, width and length directions on the vibration table.

10. The vibration sweep frequency test method according to claim 7, characterized in that, The vibration sweep frequency test method also includes: Obtain the vibration sweep frequency test data of the motor; If the vibration sweep frequency test data of the stator does not match the vibration sweep frequency test data of the motor, the test boundary conditions are optimized based on the vibration sweep frequency test data.

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