A device for finishing the inner wall of a motor housing

Abstract

The application relates to the technical field of motor shell processing devices, in particular to a motor shell inner wall finishing processing device, which aims to solve the problems of thermal deformation, resonance instability and chipping during motor shell finishing. The device comprises a cast iron base, a workpiece positioning and clamping system, a main shaft finishing execution system, a dynamic monitoring and feedback system and a circulating chip removal and cooling system. The finishing head of the main shaft finishing execution system is integrated with a piezoelectric ceramic micro-displacement driver, which cooperates with a laser interferometer measurement module and an acoustic emission sensor to realize closed-loop monitoring. Through the above technical scheme, the application can perform microsecond-level dynamic compensation for machining errors, efficiently remove chips by using a high-pressure air curtain, effectively suppress machining chatter, and significantly improve the size accuracy, roundness and surface roughness of the motor shell inner wall.

Description

Technical Field

[0001] This invention belongs to the field of motor manufacturing, and specifically relates to a device for trimming the inner wall of a motor housing. Background Technology

[0002] In modern industrial automation and precision manufacturing, electric motors, as the core driving component for energy conversion and kinetic energy output, directly affect the operational efficiency, noise control, and service life of the overall mechanical system due to the precision of their manufacturing process. As a crucial component of the motor, the motor housing not only plays a vital role in supporting the internal stator and rotor and dissipating heat, but the machining accuracy of its inner wall directly determines the quality of the interference fit of the stator core and the uniformity of the air gap distribution. With the continuous expansion of applications for high-performance permanent magnet motors and variable frequency motors, the industry has placed increasingly stringent requirements on the dimensional tolerances, geometric tolerances, and surface roughness of the motor housing's inner wall. This makes the finishing of the inner wall after housing formation a critical process in the motor manufacturing chain.

[0003] With the continuous development of related technologies and the increasing demands for motor power density and lightweighting in specific application scenarios, the inherent characteristics of the aforementioned existing technical solutions at the principle level have gradually revealed insurmountable limitations when dealing with the machining of high-performance thin-walled housings. The underlying technical contradictions are mainly reflected in the following dimensions: First, the contradiction between thermal coupling deformation during the cutting process and the mismatch in machining accuracy. During high-speed dressing operations, a large amount of cutting heat is instantly generated between the cutting tool and the inner wall of the housing. For motor frames with sensitive thermal conductivity or uneven wall thickness distribution, this localized heat accumulation leads to non-uniform thermal expansion of the material. Because traditional dressing devices mostly adopt a rigid feed strategy, they cannot sense and compensate for this instantaneous micro-deformation. As a result, after machining and cooling, the inner wall of the housing often exhibits excessive roundness or taper deviation due to elastic rebound and thermal stress release, seriously affecting the coaxiality of the subsequent stator press-fitting.

[0004] Furthermore, existing equipment lacks sufficient adaptive compensation capabilities when dealing with blank errors in different batches of castings, often relying on manual experience for secondary centering or frequent calibration, which is particularly inefficient in highly intelligent and flexible production lines. In summary, how to achieve efficient removal of excess material while effectively suppressing thermal stress-induced deformation, ensuring the real-time and thorough removal of fine debris, and solving the vibration control problem during cantilever machining has become a key challenge for those skilled in the art. Therefore, developing a motor housing inner wall finishing device that can simultaneously achieve high-precision dimensional control, excellent surface texture quality, and dynamic error compensation capabilities has become an urgent technical problem to be solved to improve the overall manufacturing process of motors and break through the bottlenecks in high-performance motor production. Summary of the Invention

[0005] To address the technical problems of existing motor housing inner wall trimming devices during processing, such as heat-induced deformation during cutting, resonance instability of thin-walled structures, surface scratches caused by residual micro-debris, and lack of dynamic error compensation capability, this invention provides a motor housing inner wall trimming device.

[0006] The motor housing inner wall trimming device provided by this invention is built on a cast iron base with high damping characteristics. The top surface of the cast iron base is precision ground, and its flatness error is controlled within 0.01 millimeters per meter. Above the cast iron base are a workpiece positioning and clamping system, a spindle trimming execution system, a dynamic monitoring and feedback system, and a circulating chip removal and cooling system. These systems are mechanically connected by high-strength bolts and locating pins embedded inside the base, and electrically connected to the main control cabinet via shielded cables.

[0007] In a preferred embodiment of the present invention, the workpiece positioning and clamping system includes a flexible centering clamping mechanism disposed at one end of the base. The flexible centering clamping mechanism includes a central base with three jaws moving synchronously, and each jaw has an array of pressure sensors on its inner side. The pressure sensor array adopts a thin-film piezoresistive structure, which can sense the distribution of clamping force on the outer wall of the motor housing in real time. A two-millimeter-thick polyurethane elastic buffer pad is attached to the contact surface between the jaws and the motor housing to absorb local stress concentrations generated during clamping. The central base achieves radial extension and retraction through a precision ball screw pair driven by a servo motor, achieving a positioning accuracy at the micrometer level. To accommodate motor housings of different diameters, the effective working radius of the jaws can be continuously adjusted between 80 mm and 350 mm.

[0008] Furthermore, the spindle dressing actuator system is the core power source of this device, mounted on a suspended beam that can move three-dimensionally along the base guide rail. The suspended beam is made of carbon fiber reinforced composite material to reduce motion inertia and improve structural rigidity. The spindle dressing actuator system integrates a high-speed electric spindle with a maximum speed of 30,000 revolutions per minute and a radial runout of less than one micrometer. At the front end of the spindle is a dressing head with self-compensation function. The dressing head consists of a ceramic-based composite abrasive, a piezoelectric ceramic micro-displacement actuator, and a non-contact thermocouple sensor. The piezoelectric ceramic micro-displacement actuator is located inside the flange connecting the abrasive and the spindle. By changing the input voltage, it can achieve ultra-precise displacement compensation within a 10-micrometer range in both axial and radial directions, with a compensation response time of less than five milliseconds.

[0009] In a preferred embodiment of the present invention, the grinding surface of the dressing head is formed by sintering a mixture of diamond micron powder and cubic boron nitride, with a particle size distribution between 800 and 1200 mesh. A through-hole is formed at the geometric center of the dressing head, which communicates with a hollow channel inside the spindle, forming part of a circulating chip removal and cooling system. The surface of the internal channel of the spindle is coated with a Teflon anti-friction layer to reduce resistance when high-speed fluid passes through.

[0010] Furthermore, to address the thermal coupling deformation problem during the cutting process, the spindle dressing execution system also integrates a thermal balance control module. This module includes a spiral cooling pipe surrounding the spindle housing, within which a constant-temperature coolant circulates. A first platinum resistance thermometer and a second platinum resistance thermometer are respectively installed at the inlet and outlet of the cooling pipe. Based on the temperature difference between these two points, the thermal balance control module automatically adjusts the compressor power of the refrigeration unit to ensure that the spindle's temperature rise does not exceed five degrees Celsius during prolonged continuous operation.

[0011] In a preferred embodiment of the present invention, the circulating chip removal and cooling system includes not only the aforementioned internal spindle channel but also an annular air curtain generator disposed on the outer edge of the dressing head. The annular air curtain generator consists of a set of evenly distributed nozzles with an inclination angle of 30 to 45 degrees, capable of spraying high-pressure dry air at a pressure of 0.6 MPa into the machining area. The sprayed high-pressure air forms a conical flow field surrounding the grinding point. Through the negative pressure effect generated by the high-speed airflow, the generated metal chips are rapidly carried away from the inner wall of the outer casing and enter a collection hood disposed behind the dressing head. The collection hood is connected to a 5.5 kW centrifugal vacuum cleaner via a large-diameter corrugated pipe, ensuring that the dust concentration in the machining area is less than 2 milligrams per cubic meter.

[0012] Furthermore, the dynamic monitoring and feedback system provides a closed-loop guarantee for achieving machining accuracy. This system includes a laser interferometer measurement module mounted on the spindle mount and an acoustic emission sensor mounted on the base. The laser beam emitted by the laser interferometer measurement module, after passing through a beam splitter, is partly directed towards the machined surface on the inner wall of the motor housing, and partly towards a reference mirror. By detecting changes in the interference fringes, the diameter error and shape deviation data of the inner wall are acquired in real time. The acoustic emission sensor is used to collect high-frequency vibration signals during the cutting process, with a frequency response range between 50 kHz and 800 kHz. By analyzing the amplitude and energy distribution of the acoustic emission signal, the system can identify abnormal wear conditions of the grinding wheel or early resonance signs appearing in thin-walled sections of the motor housing.

[0013] In a preferred embodiment of the present invention, the motor housing inner wall trimming device further includes a multi-degree-of-freedom support mechanism specifically designed for ultra-long or ultra-thin motor housings. The support mechanism is located in the middle section of the motor housing and comprises an annular support and four magnetofluid variable stiffness support heads disposed inside the support. Each support head is filled with magnetofluid, and the viscosity of the magnetofluid is changed by adjusting the coil current, thereby achieving dynamic adjustment of the radial stiffness of the motor housing. During processing, when the acoustic emission sensor detects a vibration peak at a specific frequency, the control system immediately adjusts the stiffness of the magnetofluid support head to change the system's natural frequency, thereby effectively suppressing processing chatter.

[0014] Furthermore, the spindle dressing actuator is equipped with a set of preloaded double-row cylindrical roller bearings in the axial feed direction to ensure high stability of the axial feed. The feed power is provided by a high-precision torque motor via a planetary gear reducer, achieving a feed speed resolution of 0.1 millimeters per minute. A rotary encoder is installed at the end of the feed screw, delivering one million pulses per revolution to ensure absolute certainty in axial position positioning.

[0015] In a preferred embodiment of the present invention, the overall control logic of the device follows a preset expert system database. This database stores process parameters for motor housings made of different materials (such as cast aluminum, ductile iron, and stainless steel). Before initiating the trimming procedure, the system first confirms the geometric deviations of the blank through laser scanning and automatically generates the optimal cutting path. During the trimming process, if a sudden change in cutting force caused by uneven local hardness is detected, the piezoelectric ceramic micro-displacement actuator will immediately perform microsecond-level avoidance or compensation actions to prevent excessive cutting marks from forming on the inner wall surface.

[0016] Furthermore, the coolant used in the circulating chip removal cooling system is a water-based emulsion containing extreme pressure additives, which possesses excellent permeability and lubricity. The coolant is pressurized by a circulating pump and enters the dressing head through a rotary joint located at the end of the spindle. Inside the dressing head, the coolant is atomized into micron-sized droplets and mixed with the high-pressure airflow to form a micro-lubricating mist. This micro-lubrication method effectively reduces the temperature of the cutting area while avoiding the environmental pollution and subsequent cleaning difficulties caused by traditional large-volume coolant spraying.

[0017] In a preferred embodiment of the invention, six active vibration-damping pads are installed beneath the cast iron base. Each vibration-damping pad contains an air spring and an electromagnetic vibrator. The vibration damping system senses vibration interference from the ground via a triaxial accelerometer mounted at the bottom of the base and counteracts the interference by generating a force with opposite phase through the electromagnetic vibrator, ensuring that the repair work is not affected by the operation of surrounding heavy equipment.

[0018] The motor housing inner wall trimming device described in this invention has the following logical relationship between its various components: the workpiece positioning and clamping system provides a stable physical reference for the workpiece to be processed; the spindle trimming execution system, driven by the multi-dimensional moving system, performs the excess removal action according to the preset trajectory; the dynamic monitoring and feedback system senses the changes in the processing environment and workpiece quality in real time and converts these physical quantities into digital signals; and the circulating chip removal and cooling system simultaneously completes the cleaning and thermal control of the processing area.

[0019] Furthermore, the dressing head replacement mechanism adopts the HSK-A63 standard interface and features automatic tool changing. A disc-type tool magazine is located on the side of the dressing execution system, capable of holding eight dressing tools of different sizes. Each dressing tool has an embedded electronic tag on its shank, recording its initial dimensions, cumulative usage time, and estimated remaining lifespan. Upon receiving an instruction, the tool-changing robot can complete a precise tool change within fifteen seconds, ensuring the continuity of the production process.

[0020] In a preferred embodiment of the present invention, for complex structures on the inner wall of the motor housing, such as irregularly shaped surfaces with keyways or local protrusions, the device is equipped with a dedicated trajectory interpolation control mode. The control unit reconstructs the geometric model of the inner wall in real time by reading the three-dimensional point cloud data fed back by the laser interferometer. When the trimming head passes the edge of the keyway, the spindle speed and axial feed are automatically adjusted according to the dynamic balance logic of the material removal rate, thereby eliminating the impact force caused by intermittent cutting and ensuring the flatness and dimensional accuracy of the keyway edge.

[0021] Furthermore, all motion axes of the device are equipped with a high-precision grating feedback system, and the linear expansion coefficient of the grating is matched with the base material. By cross-referencing the position data collected from the grating feedback with the data from the encoder at the motor end, positioning errors caused by thermal expansion of the lead screw can be corrected in real time.

[0022] In a preferred embodiment of the present invention, the negative pressure dust collection module of the circulating chip removal cooling system is equipped with a three-stage filtration structure. The first stage is a cyclone separator for removing large metal debris; the second stage is a stainless steel wire mesh filter for intercepting medium-sized particles; and the third stage is a high-efficiency particulate air (HEPA) filter capable of filtering fine dust particles with a diameter of 0.3 micrometers or larger. The filtered clean air is directly discharged into the factory, meeting industrial hygiene standards.

[0023] The motor housing inner wall finishing device involved in this invention is designed with engineering application reliability in mind. All exposed sensor cables are sheathed in stainless steel flexible tubing to prevent corrosion from splashing debris or coolant. All sliding guides are equipped with telescopic protective covers made of oil-resistant and aging-resistant synthetic rubber. A non-contact air seal structure is also provided at the front end of the spindle, which prevents grinding dust from entering the spindle bearing by introducing slightly positive pressure air through the axial clearance.

[0024] Furthermore, to achieve online assessment of the surface roughness of the inner wall of the motor housing, the dynamic monitoring and feedback system also integrates an optical roughness sensor based on the principle of light scattering. This sensor is mounted on an auxiliary measuring arm next to the spindle. After the final finishing process, the measuring arm automatically extends into the housing cavity, emits a helium-neon laser beam with a wavelength of 633 nanometers, and receives the reflected speckle signal. Utilizing the physical relationship between scattering intensity and roughness parameters, the average roughness Ra value of the machined surface is directly output.

[0025] In a preferred embodiment of the present invention, the electrical control system of the trimming device adopts a distributed architecture. The bottom-level drive controller is responsible for the real-time current loop, speed loop, and position loop control of each motor; the middle-level process controller is responsible for logic coordination, safety interlocking, and data preprocessing; and the top-level host computer is responsible for graphical interface display, database management, and remote network communication. Data exchange between each level is achieved through gigabit industrial Ethernet, ensuring the real-time performance and scalability of the control system.

[0026] The technical solution provided by this invention has the following specific workflow: First, the motor housing blank to be processed is placed in the clamping area on the base, and the flexible centering clamping mechanism automatically performs centering and clamping. Then, the laser scanning module performs a full scan of the inner wall to construct an initial three-dimensional deviation map. Next, based on the deviation map, the spindle dressing execution system selects a suitable grinding wheel and starts the circulating chip removal and cooling system. During the formal processing stage, the spindle rotates at high speed and feeds at a uniform speed along the axial direction. The dressing head dynamically corrects itself based on real-time feedback of thermal deformation data and geometric position data via a piezoelectric actuator. After each process is completed, the acoustic emission sensor and the laser measurement module jointly determine whether the preset quality threshold has been reached. If it does not meet the threshold, the compensation amount is automatically calculated for secondary dressing; if it meets the threshold, the tool changing mechanism replaces the polishing head for final surface treatment. Finally, the roughness sensor performs a final inspection, outputs a complete processing report, and the clamping mechanism releases the workpiece, completing a complete dressing cycle.

[0027] Furthermore, the piezoelectric ceramic micro-displacement actuator described in this invention is composed of multiple layers of piezoelectric materials stacked together, and its exterior is encapsulated in a fully sealed metal bellows to isolate it from moisture and oil in the environment. The actuator also integrates a resistance strain gauge, forming a local displacement closed loop, thus eliminating the influence of the inherent hysteresis and creep characteristics of piezoelectric materials on compensation accuracy.

[0028] In a preferred embodiment of the invention, to meet the needs of large-scale continuous production, the device is also equipped with a preheating management module. During equipment idling, this module maintains the coolant flow at the rated temperature and keeps the spindle running at a low speed, ensuring that the thermal performance of all components of the machine remains stable and eliminating initial processing errors caused by cold starts.

[0029] Furthermore, the base of the workpiece positioning and clamping system is cast from polymer concrete with high damping characteristics. This material, combined with the cast iron base, forms a multi-stage vibration damping structure. When clamping the motor housing, the system can automatically identify the natural frequency of the housing and adjust the clamping force distribution of the jaws according to this frequency. Through the design of the prestress field, the vibration dynamics characteristics of the thin-walled housing are changed, reducing the vibration amplitude during processing by more than 70%.

[0030] In a preferred embodiment of the present invention, the electric spindle used in the spindle dressing execution system employs oil mist lubrication. The oil mist generator can precisely control the oil supply volume per hour to between 0.1 ml and 0.5 ml. After fine filtration, the lubricating oil enters the bearing area with compressed air, not only providing lubrication but also carrying away some of the heat generated by the bearing operation. The lubricating oil is then discharged through the exhaust port at the front end of the spindle, further enhancing the cleanliness and protection of the spindle.

[0031] The motor housing inner wall trimming device provided by this invention exhibits extremely high technical certainty during the processing. It eliminates uncertainties caused by environmental factors and material differences through multi-sensor fusion sensing; it eliminates accumulated chain errors in the mechanical transmission system through high-frequency micro-displacement compensation; and it ensures the consistency of the physical environment during processing through forced chip removal and temperature control. This systematic design means that the trimming accuracy of the motor housing inner wall no longer depends on the operator's experience, but is determined by the device's closed-loop control logic and physical structural rigidity.

[0032] Furthermore, each kinematic pair of the device employs high-precision crossed roller guides. These guides are capable of withstanding loads from any direction and maintain extremely high running straightness even during prolonged operation. The surface of the guides undergoes ultrasonic hardening treatment, achieving a hardness of HRC60 or higher, effectively resisting abrasive wear from grinding dust.

[0033] In a preferred embodiment of the present invention, the optical path of the laser interferometer measurement module is specially compensated. An airflow stabilizing tube is installed along the path of the measurement beam. By filling the tube with a small flow rate of dry nitrogen, the influence of cutting fluid mist and temperature fluctuations at the machining site on the laser refractive index is eliminated, ensuring that the measurement accuracy remains stable at the level of one hundred nanometers.

[0034] Furthermore, to address potential microcracks on the inner wall of the motor housing, the dynamic monitoring and feedback system integrates an eddy current detection probe. While the dressing head is feeding, the eddy current probe scans the machined surface non-contactly. If a microscopic discontinuity is detected within the material, the system immediately marks the location in the detection report and stops the machining process to prevent tool chipping or machining accidents caused by housing defects.

[0035] In a preferred embodiment of the present invention, the centrifugal vacuum cleaner of the circulating chip removal and cooling system is equipped with a noise reduction device, and its operating noise is controlled below 70 decibels. The vacuum cleaner's filter is equipped with an automatic pulse back-blowing mechanism, which periodically removes accumulated dust from the filter surface through the instantaneous impact of compressed air, ensuring that the suction power is always maintained within the rated range.

[0036] This invention discloses a motor housing inner wall trimming device, which has a complete structure covering the entire chain of functions from blank loading, real-time measurement, dynamic trimming, environmental remediation to final inspection. The physical connection interfaces, electrical communication protocols, and fluid coupling methods of each subsystem all adhere to strict industrial standards, ensuring the stability and reliability of the entire machine's operation. The application of this device can significantly improve the dimensional tolerance control level of the motor housing inner wall, increasing roundness and coaxiality to within 0.005 mm and reducing surface roughness to below Ra 0.4 micrometers, thereby providing crucial technical support for the production of high-performance motors.

[0037] Furthermore, a set of dynamic counterweights is also installed on the suspension beam of the spindle dressing execution system. These counterweights are driven by hydraulic cylinders and adjust the center of gravity distribution in real time according to the position of the spindle on the beam. This dynamic gravity compensation technology eliminates the micro-deflection deformation of the beam caused by spindle movement, further improving the trajectory accuracy during large-span machining.

[0038] In a preferred embodiment of the present invention, the central control cabinet of the device adopts a fully enclosed design and is equipped with an industrial air conditioner for environmental regulation. All electronic components are mounted on a backplate with a shock-resistant structure, and the inlet and outlet ports are subject to strict electromagnetic shielding treatment to prevent high-frequency harmonics generated by the frequency converter from interfering with sensitive measurement sensors.

[0039] Furthermore, the grinding assembly of the dressing head adopts a modular design, and changing the grinding material (such as from diamond to alumina) only requires loosening three end face screws. This design greatly reduces the changeover time when processing workpieces of different materials. Simultaneously, each grinding module is equipped with a physical identification code, which the system can automatically read and call upon the corresponding grinding force model.

[0040] In a preferred embodiment of the present invention, the three grippers of the flexible centering clamping mechanism adopt an independent servo drive mode, rather than a traditional linkage synchronous mechanism. This structure allows the system to achieve true centripetal alignment when clamping original castings with large non-circularity by independently adjusting the radial position of each gripper, thus avoiding pre-stress deformation of the shell caused by forced synchronous clamping.

[0041] In summary, the motor housing inner wall finishing device of the present invention achieves deep control over the entire machining process of the motor housing inner wall through the coupling and cooperation of its various precision subsystems. From the physical damping characteristics of the base to the nanosecond-level response of the micro-displacement actuator, from active thermal balance control to multi-stage filtration closed-loop chip removal, every technical aspect aims to eliminate error sources in traditional machining methods. This invention not only solves the problems of vibration and thermal deformation during the machining of thin-walled parts, but also ensures, through a high-precision online monitoring and feedback mechanism, that every motor housing leaving the factory meets the precise geometric parameters required by the design, demonstrating significant technical advantages and broad engineering application value.

[0042] Furthermore, a layer of high-polymer viscoelastic damping material is provided at the connection interface between the spindle actuator and the suspension beam. This material absorbs the high-frequency harmonics generated by the high-speed rotation of the spindle, preventing them from being transmitted to the beam and base. Simultaneously, the displacement feedback sensor is mounted on a support away from the heat source and connected to the moving parts via an indium steel rod with a near-zero coefficient of thermal expansion, ensuring the long-term thermal stability of the position feedback signal.

[0043] In a preferred embodiment of the present invention, the dust collection hood of the circulating chip removal cooling system is dynamically sealed to the end face of the motor housing using an inflatable sealing ring. When the dressing head enters the deep cavity of the housing, the sealing ring inflates and expands, closing the opening of the housing. This forces the airflow to pass only through the spindle channel and the gap between the grinding head, thereby creating a controlled directional airflow field and maximizing the efficiency of metal chip collection.

[0044] Furthermore, the servo control system of this device incorporates speed feedforward control and gravity compensation technology. During axial feed, the controller adjusts the current output in advance based on the real-time changes in load inertia, eliminating the lag phenomenon at the moment of mechanical start-up. In the vertically mounted embodiment, the gravity compensation function offsets the influence of the spindle assembly's own weight through the pre-output torque of the servo motor, ensuring that the upward and downward movements have completely symmetrical dynamic characteristics.

[0045] In a preferred embodiment of the present invention, the laser interferometer measurement module is equipped with an automatic calibration unit. The calibration unit includes a standard ring gauge with known dimensional accuracy. Every thousand hours of equipment operation or when the ambient temperature fluctuates by more than five degrees Celsius, the measuring arm automatically moves to the standard ring gauge for calibration, automatically acquiring and updating the system's system error compensation coefficient.

[0046] The motor housing inner wall trimming device involved in this invention embodies a leap from static precision to dynamic precision in its design logic. By capturing and intervening in various physical variables during the processing in real time, it transforms originally uncontrollable random errors into compensable deterministic motion, fundamentally solving the precision bottleneck problem in the manufacturing of high-performance motor housings. The device's component selection, material application, and system integration method all meet the stringent requirements of modern ultra-precision machining equipment, and can satisfy the extreme manufacturing needs of motor drive components in aerospace, medical devices, and high-precision automated equipment.

[0047] Furthermore, an auxiliary dynamic balancing device based on magnetic levitation support is employed inside the spindle. This device includes two mutually perpendicular pairs of electromagnets mounted at the end of the spindle and a displacement monitoring system. When the spindle experiences a slight dynamic imbalance due to wear of the grinding wheel during high-speed rotation, the electromagnet pairs generate a magnetic pull opposite in phase to the unbalanced force, thereby counteracting the vibration of the spindle in real time during rotation and ensuring a smooth dressing trajectory.

[0048] In a preferred embodiment of the present invention, the length-to-diameter ratio of the spindle is optimized for machining the housing of deep-hole motors. The spindle sleeve is made of a graded functional material, with an outer layer of high-rigidity cemented carbide and an inner layer of porous metal with high energy absorption characteristics. This structure maintains the rigidity of the long shaft while greatly suppressing the bending vibration of the long cantilever structure.

[0049] Furthermore, the overall maintenance system of the device integrates online lubrication status monitoring. Through pressure switches and oil level sensors installed at key lubrication points, the system can monitor the supply pressure and residual amount of grease in real time. When abnormal pressure or insufficient oil occurs in the lubrication system, the system will automatically issue a warning signal and mark the fault location on the display interface, improving the maintainability and operational safety of the equipment.

[0050] The present invention discloses a motor housing inner wall trimming device, the structural parameters of which are as follows: the weight of the cast iron base accounts for more than 60% of the total weight of the machine to ensure a stable center of gravity; the maximum torque of the main shaft can reach 100 Nm in the low-speed range to meet the needs of large-scale rough trimming; in the fine trimming stage, the repeatability of the axial feed reaches ±0.5 micrometers. All air and hydraulic connections adopt a quick-connect self-locking structure and are equipped with anti-misconnection markings, which greatly facilitates subsequent system upgrades and module replacements.

[0051] In a preferred embodiment of the present invention, the host computer software of the control system adopts modular programming and has an open underlying API interface. This allows users to develop and load specific trajectory planning plugins or signal processing modules according to specific process requirements. Simultaneously, the software incorporates a three-dimensional virtual machining simulation module, which can perform interference checks and force predictions on the machining program before actual finishing, further reducing machining risks.

[0052] Through the aforementioned precise and complex system design, the motor housing inner wall trimming device of this invention completely changes the current situation of poor precision consistency and unstable surface quality in traditional motor housing trimming processes. It is not only a processing device, but also an all-around process platform integrating precision measurement, adaptive control, thermal management, and fluid dynamics optimization. Whether processing mass-produced ordinary induction motor housings or processing single-piece, small-batch customized high-precision servo motor housings, this device provides superior processing performance, significantly shortening the optimization time for subsequent assembly and enhancing the overall competitiveness of motor products. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the overall structure of a motor housing inner wall trimming device according to the present invention.

[0054] Figure 2 This is a partial structural schematic diagram of the flexible centering clamping mechanism in this invention;

[0055] Figure 3 This is a cross-sectional view of the spindle dressing execution system in this invention.

[0056] Figure 4 This is a schematic diagram of the layout of the circulating chip removal cooling system and the dynamic monitoring system in this invention;

[0057] Figure 5 This is a schematic diagram of the multi-degree-of-freedom support mechanism in this invention.

[0058] The attached figures are labeled as follows: 1. Cast iron base; 2. Workpiece positioning and clamping system; 3. Spindle dressing execution system; 4. Dynamic monitoring and feedback system; 5. Circulating chip removal and cooling system; 6. Main control cabinet; 7. Flexible centering clamping mechanism; 8. Central base; 9. Gripper; 10. Pressure sensor array; 11. Polyurethane elastic buffer pad; 12. Suspension beam; 13. High-speed electric spindle; 14. Dressing head; 15. Piezoelectric ceramic micro-displacement actuator; 16. Thermal balance control module; 17. Spiral cooling pipe; 18. First platinum resistance thermometer; 19. Second platinum resistance thermometer; 20. Annular air curtain generator; 21. Collection hood; 22. Centrifugal vacuum cleaner; 23. Laser interferometer measurement module; 24. Acoustic emission sensor; 25. Multi-degree-of-freedom support mechanism; 26. Annular bracket; 27. Magnetohydrodynamic variable stiffness support head; 28. Active shock-absorbing feet; 29. ​​Tool changing robot; 30. Optical roughness sensor. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the present invention clearer, the following describes in further detail a motor housing inner wall trimming device of the present invention with reference to the accompanying drawings and embodiments.

[0060] This invention provides a device for trimming the inner wall of a motor housing. Its core structural design aims to establish a multi-dimensional controlled processing environment. Through physical rigid support, dynamic compensation, and comprehensive environmental parameter monitoring, it solves the precision bottleneck in trimming the inner wall of thin-walled parts in high-performance motor manufacturing. The basic physical structure of the device is supported by a cast iron base 1 with high damping characteristics. This cast iron base 1 is made of HT300 ductile iron material that has undergone two artificial and natural aging treatments. It has an internal asymmetrical rib structure to eliminate low-frequency resonance during processing. The top surface of the cast iron base 1 serves as the reference plane for the entire system. After ultra-precision grinding, its static flatness error is strictly controlled within 0.01 millimeters per meter, providing a high-precision spatial positioning reference for the subsequent installation of various subsystems. On the layout of the cast iron base 1, the workpiece positioning and clamping system 2, the spindle dressing execution system 3, the dynamic monitoring and feedback system 4, and the circulating chip removal and cooling system 5 form a closed-loop machining chain. These systems are fixed to the preset installation position on the base by high-strength positioning pins and pre-tightening bolt groups, and achieve collaborative operation through the distributed control unit in the main control cabinet 6.

[0061] In the design of the workpiece positioning and clamping system 2, this invention employs a flexible centering clamping mechanism 7 to meet the process requirements of a typical thin-walled part like a motor housing. The core of this flexible centering clamping mechanism 7 is a three-jaw synchronously moving central base 8, powered by a high-torque servo motor driven by a planetary reducer and a precision-ground ball screw pair. The radial travel of each jaw 9 is calibrated, achieving a positioning accuracy of three micrometers. To achieve precise control of clamping stress, a pressure sensor array 10 is installed on the inner side of each jaw 9. This array consists of multiple thin-film piezoresistive elements, capable of capturing the normal force distribution on the contact surface of the motor housing. A two-millimeter-thick polyurethane elastic buffer pad 11 with a Shore hardness of A70 is attached to the contact interface between the jaw 9 and the motor housing. This structural design effectively transforms point contact into surface contact, avoiding out-of-round deformation of the housing caused by localized stress concentration. The effective working radius of the center base 8 is designed to be between 80 mm and 350 mm. By adjusting the initial position of the gripper 9, it can cover the trimming needs of housings ranging from micro motors to large drive motors.

[0062] The spindle dressing execution system 3, serving as the kinetic energy core of this device, is mounted on a span-adjustable suspension beam 12. To achieve extremely high dynamic response speed, the suspension beam 12 is made of carbon fiber reinforced composite material with a modulus exceeding 230 GPa, and employs a one-piece molding process to reduce the number of connecting parts. Its structural rigidity is increased by more than 40% compared to a steel beam of the same weight. A high-speed electric spindle 13 is integrated inside the suspension beam 12. This spindle is supported by ceramic ball bearings, with a maximum operating speed set at 30,000 revolutions per minute. Throughout the entire speed range, the radial runout at the spindle end remains between 0.8 micrometers and 1 micrometer. The front end of the spindle is connected to a dressing head 14 with self-compensation function via an HSK-A63 interface. The dressing head 14 embeds a piezoelectric ceramic micro-displacement actuator 15, which is composed of multi-layered piezoelectric materials and utilizes the inverse piezoelectric effect to generate sub-micrometer-level expansion and contraction deformation under the action of an input voltage. Through a precise flexible hinge amplification mechanism, this deformation is converted into positional compensation of the dressing head 14 in the radial and axial directions. The piezoelectric ceramic micro-displacement actuator 15 has a compensation bandwidth of 2 kHz, which can compensate for elastic yielding errors caused by cutting force fluctuations in real time during machining.

[0063] The spindle dressing execution system 3 also ensures thermal stability during the machining process through a thermal balance control module 16. This module has a spiral cooling pipe 17 inside the outer housing of the high-speed electric spindle 13, filled with a high specific heat capacity coolant. High-precision first platinum resistance thermometer 18 and second platinum resistance thermometer 19 are installed at the inlet and outlet of the cooling pipe 17, respectively, with a measurement resolution of 0.01 degrees Celsius. The control system collects the temperature difference between the two points in real time and compares it with the ambient temperature of the base. The compressor speed of the cooling cycle system is adjusted in real time via a frequency converter, ensuring that the temperature rise of the spindle assembly is always controlled within five degrees Celsius. This thermal management strategy eliminates the impact of spindle thermal expansion on the consistency of machining dimensions, ensuring that the dimensional deviation between the first and last pieces is within the same confidence interval during large-volume continuous dressing.

[0064] In the specific implementation of the dressing process, the grinding surface of the dressing head 14 uses a ceramic-based sintered material made of a mixture of diamond micropowder and cubic boron nitride (CBN) in a certain proportion. The particle size of the abrasive is strictly limited to between 800 and 1200 mesh. This ratio can balance the material removal rate and surface roughness. The dressing head 14 has a through hole with a diameter of 8 mm in the central axis. This hole serves as one end of the circulating chip removal and cooling system 5 and is precisely connected to the hollow channel inside the spindle. The inner wall of the channel is treated with chemical nickel plating and Teflon spraying to form a self-lubricating and friction-reducing layer, ensuring that the metal chips carried by the high-speed airflow will not cause erosion and wear on the channel wall when passing through.

[0065] The circulating chip removal and cooling system 5 is equipped with an annular air curtain generator 20 on the outside of the dressing head 14. This device consists of twelve circumferentially evenly distributed Laval nozzles, with the nozzle axes forming a 35-degree angle with the machining surface. When compressed air at a pressure of 0.6 MPa passes through the nozzles, a conical airflow wall tightly surrounds the machining point. Utilizing the jet negative pressure effect of fluid mechanics, dust and debris from the cutting area are forcibly sucked into the collection hood 21 behind. The collection hood 21 is then connected to a centrifugal vacuum cleaner 22 located outside the device via a flexible, large-diameter corrugated pipe. The vacuum cleaner 22 has a rated power of 5.5 kW and features a three-stage filtration system, including a primary cyclone settling zone, a medium-efficiency bag filter zone, and a terminal HEPA high-efficiency filter layer, ensuring that the exhaust air cleanliness meets the Class 10,000 purification standard and completely eliminating secondary scratches caused by fine particles remaining on the inner wall of the motor housing.

[0066] For accuracy feedback during the machining process, the dynamic monitoring and feedback system 4 integrates a laser interferometer measurement module 23. This module is installed on the side of the spindle seat and employs a frequency-division heterodyne interferometry principle to measure the diameter error, cylindricity, and surface morphology changes of the inner wall online. Simultaneously, acoustic emission sensors 24 are arranged at key nodes of the cast iron base 1 to capture stress wave signals generated during material removal. The frequency response of the acoustic emission sensors 24 covers 50 kHz to 800 kHz, enabling sensitive identification of specific spectral characteristics caused by mold wear, coating peeling, or resonance in thin-walled sections of the motor housing. The control system fuses multi-source information—geometric data from the laser interferometer and energy data from the acoustic emission sensors—to adjust machining parameters in real time.

[0067] For extra-long motor housings, this invention features a multi-degree-of-freedom support mechanism 25. Located in the center of the workpiece, this mechanism consists of a ring-shaped support 26 and four magnetofluid variable stiffness support heads 27 distributed within the inner ring. Each support head 27 is internally sealed with a magnetofluid material with high saturation magnetic induction intensity. By adjusting the current of the excitation coil according to the real-time processing conditions through the main control system, the apparent viscosity and stiffness of the magnetofluid change instantaneously, thereby altering the natural frequency of the entire workpiece system. When the dressing execution system moves to the thin-walled region, the support head 27 automatically increases its damping strength to absorb processing chatter, reducing the depth of the chatter marks formed on the inner wall surface to below 0.1 micrometers.

[0068] To isolate the impact of ground vibrations on ultra-precision machining, the cast iron base 1 is supported on six active vibration damping pads 28. Each pad integrates an air spring and a large-stroke electromagnetic vibrator, forming an active vibration isolation system. A triaxial accelerometer mounted on the bottom surface of the base monitors micro-vibrations from the factory floor in real time. The control unit calculates the compensation vector and drives the electromagnetic vibrator to generate a force with opposite phase, reducing the transmittance of external interference to less than three percent.

[0069] The automation level of this device is also reflected in its efficient tool changing mechanism. The dressing head 14 is replaced using a standard HSK-A63 interface, and the tool changing robot 29 can complete the tool grabbing and locking within fifteen seconds. The disc-type tool magazine is equipped with dedicated dressing tools for different materials (such as aluminum alloy, stainless steel, and cast iron). Each tool holder has an electronic tag at the bottom that stores the tool's geometric offset, the number of workpieces already processed, and the expected wear trend. In addition, an optical roughness sensor 30 is installed on the auxiliary measuring arm next to the spindle. Before the dressing task is completed, the sensor uses the reflection and scattering principle of helium-neon laser to complete a non-contact measurement of the Ra value of the key area of ​​the inner wall within ten seconds, directly generating a final quality inspection report.

[0070] Furthermore, in terms of electrical control, this device adopts a distributed control architecture based on Gigabit Ethernet. The underlying servo controller communicates with the core processor in the main control cabinet 6 via a high-speed bus, with a sampling period controlled at the microsecond level. The system has a built-in expert database for different materials and can automatically handle irregularly shaped motor housings with keyways or complex bosses through preset machining path interpolation models. When handling intermittent cutting at the edge of the keyway, the system effectively prevents edge chipping by monitoring the current loop fluctuation of the motor in real time and adjusting the cutting force of the spindle accordingly.

[0071] To demonstrate the superior performance of the present invention through experimental data, a set of specific implementation schemes and comparative tests are provided.

[0072] Example 1: The motor housing inner wall trimming device described in this invention is used. The workpiece material is a thin-walled aluminum alloy shell with an outer diameter of 220 mm, a length of 450 mm, and a wall thickness of 3.5 mm. The machining parameters are set as follows: spindle speed 18,000 rpm, feed rate 150 mm / min, and trimming depth 0.02 mm. The flexible centering clamping mechanism is activated, and the clamping force is set to 500 Newtons. The piezoelectric ceramic dynamic compensation and circulating chip removal system is activated, and the chip removal air pressure is set to 0.55 MPa.

[0073] Comparative Example 1: Dressing was performed using a traditional horizontal precision boring machine with a standard three-jaw chuck. The workpiece material, specifications, and nominal machining parameters (speed, feed, depth) were consistent with those in Example 1. Traditional cutting fluid spray cooling was used.

[0074] The experimental test indicators included: inner wall roundness error (μm), surface roughness Ra (μm), maximum temperature rise of the workpiece during processing (°C), and residual debris density (mg / cm²). The test results are shown in Table 1.

[0075] Table 1: Comparison of Processing Performance between Embodiments of the Invention and Traditional Comparative Examples

[0076] Test metrics Example 1 Comparative Example 1 Performance improvement Inner wall roundness error (μm) 2.1 12.8 83.6% Surface roughness Ra (μm) 0.28 1.15 75.7% Maximum temperature rise of the workpiece (°C) 3.2 18.5 82.7% Residual debris density (mg / cm²) 0.04 2.30 98.3% Coaxiality error (μm) 3.5 15.0 76.7%

[0077] Analysis of the data in Table 1 shows that Embodiment 1 of the present invention significantly outperforms Comparative Example 1 in all key accuracy indicators. In particular, the inner wall roundness error is reduced from 12.8 micrometers to 2.1 micrometers, directly demonstrating the remarkable effectiveness of the flexible centering clamping mechanism and piezoelectric ceramic micro-displacement compensation in suppressing thin-wall deformation and compensating for mechanical system errors. Simultaneously, the extremely low temperature rise reflects the effectiveness of the thermal balance control module and the circulating cooling system, while the negligible residual debris density verifies the excellent chip removal capability of the annular air curtain and negative pressure dust collection system.

[0078] In the specific operation process, the operator first inputs the material parameters and tolerance requirements of the motor housing through the human-machine interface of the main control cabinet 6. The laser interferometer measurement module 23 automatically performs a pre-scanning task to obtain the initial geometric model of the blank. The flexible centering clamping mechanism 7 automatically adjusts the position of the jaws 9 according to the blank size, and applies a preset clamping load based on the feedback from the pressure sensor array 10 without causing plastic deformation of the housing. The spindle dressing execution system 3 starts feeding according to the generated optimized path. At this time, the acoustic emission sensor 24 monitors the cutting frequency in real time. If the system detects high-frequency vibration caused by insufficient stiffness in the thin-walled section, it immediately adjusts the magnetohydrodynamic viscosity through the multi-degree-of-freedom support mechanism 25 to achieve dynamic damping enhancement.

[0079] During the operation of the dressing head 14, a mixture of diamond micron powder and cubic boron nitride abrasive performs micro-cutting on the inner wall. The generated heat is quickly dissipated by a constant-temperature cooling cycle within the spindle, while splashed debris is trapped by an annular air curtain and removed by a centrifugal vacuum cleaner 22. When the laser interferometer measurement module 23 reports that the current dimension is close to the target tolerance limit, the system automatically switches to the finishing mode, and the piezoelectric ceramic micro-displacement actuator 15 enters a high-frequency closed-loop state to perform point-to-point dynamic compensation for the measured minute shape errors. Finally, through final inspection by the optical roughness sensor 30, it is confirmed that the inner wall roughness meets the industrial limit requirement of Ra 0.4 micrometers or less, and the clamping mechanism automatically releases, completing the entire process cycle.

[0080] The lubrication system of this device also employs meticulous management. The high-speed electric spindle 13 integrates an oil mist lubrication module, which atomizes precision spindle oil into particles of 0.3 to 0.5 micrometers using a micro-pump, and delivers it into the bearing cavity along with clean compressed air. Lubricant consumption is precisely controlled to 0.2 ml per hour, ensuring reliable lubrication of the bearings at high speeds of 30,000 RPM while preventing excess grease from splashing and contaminating the machining surface. All sliding guideways are covered with retractable polymer protective covers made of oil-resistant, wear-resistant, and chemically corrosion-resistant materials, ensuring long-term precision even in harsh metal grinding environments.

[0081] In terms of the engineering implementation of the structural layout, this invention fully considers the needs of modular maintenance. All electrical connectors use aerospace-grade quick-lock connectors, which have extremely high vibration resistance and electromagnetic shielding capabilities. The filter element replacement process of the circulating chip removal system is designed to be tool-free, greatly reducing equipment downtime for maintenance. The heavy-duty design of the cast iron base 1 makes its center of gravity lower than the spindle centerline. This "low center of gravity, high rigidity" physical configuration fundamentally ensures the stability of the device under high-speed dynamic operation.

[0082] It should be noted that the above embodiments are merely preferred embodiments of the present invention. Those skilled in the art can make various minor adjustments and improvements without departing from the inventive concept. For example, the geometry of the grippers can be adjusted for shells with specific outer diameters, or the abrasive ratio can be adjusted for special alloy materials. These should all be covered within the scope of protection of the present invention. All physical parameters and performance indicators of the device described in this invention have undergone rigorous engineering verification and experimental testing, demonstrating strong industrial applicability and technological advancement.

Claims

1. A device for trimming the inner wall of a motor housing, characterized in that, The device includes: a cast iron base (1), which is made of HT300 ductile iron with high damping characteristics and has an asymmetrical rib structure inside. The top surface of the cast iron base (1) serves as the mounting reference plane, and its static flatness error is controlled within 0.01 mm per meter; a workpiece positioning and clamping system (2), which is set at one end of the cast iron base (1) and is used to perform radial centering and stress-controlled mechanical clamping on the motor housing to be processed; and a spindle dressing execution system (3), which is installed above the cast iron base (1) through a suspension beam (12). The spindle dressing execution system (3) has a multi-axis linkage displacement function and is used to drive the dressing head (1) with self-compensation function. 4) Perform excess material removal operation on the inner wall of the motor housing; a dynamic monitoring and feedback system (4) includes multiple sensor modules distributed on the spindle dressing execution system (3) and the cast iron base (1) for real-time acquisition of geometric deviation signals, vibration stress wave signals and surface quality parameters during the machining process, and realize closed-loop correction of the machining trajectory; a circulating chip removal and cooling system (5) is connected to the gas-liquid channel of the spindle dressing execution system (3), and performs synchronous chip removal and thermal control on the machining area through a controlled directional air field and a small amount of lubricating medium; a main control cabinet (6) establishes an electrical signal connection with the above systems through a distributed control architecture, and is used to coordinate the logical actions of each actuator according to the preset expert system database.

2. The device for trimming the inner wall of a motor housing according to claim 1, characterized in that, The workpiece positioning and clamping system (2) includes a flexible centering clamping mechanism (7) disposed at one end of the cast iron base (1); the flexible centering clamping mechanism (7) includes a central base (8) with three jaws moving synchronously, the central base (8) being radially extended and retracted by a precision ball screw driven by a servo motor; a pressure sensor array (10) is integrated on the inner side of each jaw (9), the pressure sensor array (10) being a thin-film piezoresistive structure, used to sense the distribution of clamping force on the outer wall of the motor housing in real time; a layer of polyurethane elastic buffer pad (11) with a thickness of 2mm and a Shore hardness of A70 is attached to the contact surface between the jaw (9) and the motor housing, used to absorb the local stress concentration generated during the clamping process; the effective working radius of the jaw (9) is continuously adjustable between 80mm and 350mm.

3. The device for trimming the inner wall of a motor housing according to claim 1, characterized in that, The core kinetic energy component of the spindle dressing execution system (3) is mounted on a suspension beam (12) that can move in three dimensions along the guide rail of the cast iron base (1). The suspension beam (12) is made of carbon fiber reinforced composite material with a modulus of 230 GPa or more. The spindle dressing execution system (3) integrates a high-speed electric spindle (13), which is supported by ceramic ball bearings and has a maximum speed of 30,000 rpm and a radial runout of less than 1 μm. At the front end of the high-speed electric spindle (13), a dressing head (14) is connected through an HSK-A63 interface. The dressing head (14) integrates a piezoelectric ceramic micro-displacement actuator (15), which is connected to the grinding wheel through a flexible hinge amplification mechanism. It can achieve displacement compensation within a range of 10 μm in both axial and radial directions, and its compensation response time is less than 5 ms.

4. The device for trimming the inner wall of a motor housing according to claim 3, characterized in that, The grinding surface of the dressing head (14) is made of a ceramic matrix composite material formed by sintering diamond micro powder and cubic boron nitride, and the abrasive particle size is distributed between 800 mesh and 1200 mesh. At the geometric center of the dressing head (14), a through-hole is opened, which is connected to the hollow channel inside the high-speed electric spindle (13). The surface of the hollow channel is coated with a Teflon anti-friction layer. Inside the high-speed electric spindle (13), an auxiliary dynamic balancing device based on magnetic levitation support is also installed. The auxiliary dynamic balancing device includes an electromagnet pair installed at the end of the spindle and a displacement monitoring system, which is used to counteract the unbalanced vibration of the spindle caused by the wear of the grinding wheel in real time during rotation by magnetic pull.

5. The device for trimming the inner wall of a motor housing according to claim 1, characterized in that, The spindle dressing execution system (3) also integrates a thermal balance control module (16); the thermal balance control module (16) includes a spiral cooling pipe (17) surrounding the housing of the high-speed electric spindle (13), and a constant temperature coolant circulates in the spiral cooling pipe (17); a first platinum resistance thermometer (18) and a second platinum resistance thermometer (19) are respectively installed at the inlet and outlet of the spiral cooling pipe (17); the control unit in the main control cabinet (6) automatically adjusts the compressor power of the refrigeration unit according to the temperature difference between the first platinum resistance thermometer (18) and the second platinum resistance thermometer (19) to ensure that the temperature rise of the high-speed electric spindle (13) under continuous operation does not exceed 5 degrees Celsius.

6. The device for trimming the inner wall of a motor housing according to claim 1, characterized in that, The circulating chip removal and cooling system (5) includes an annular air curtain generator (20) disposed on the outer edge of the dressing head (14); the annular air curtain generator (20) consists of a set of evenly distributed Laval nozzles, the axis of the nozzles forming an angle of 30 to 45 degrees with the machining surface, used to spray high-pressure dry air with a pressure of 0.6 MPa into the machining area to form a conical flow field surrounding the grinding point; a collection hood (21) is disposed behind the dressing head (14), the collection hood (21) is connected to a centrifugal vacuum cleaner (22) through a large-diameter corrugated pipe, the centrifugal vacuum cleaner (22) has a three-stage filtration structure, including a cyclone separator, a stainless steel wire mesh filter and a high-efficiency particulate air (HEPA) filter, and the centrifugal vacuum cleaner (22) is equipped with an automatic pulse back-blowing mechanism.

7. The device for trimming the inner wall of a motor housing according to claim 1, characterized in that, The dynamic monitoring and feedback system (4) includes a laser interferometer measurement module (23) mounted on the spindle seat and an acoustic emission sensor (24) mounted on the cast iron base (1). The laser interferometer measurement module (23) adopts the frequency division heterodyne interference principle. Its measurement optical path is equipped with a gas flow stabilizing tube filled with a micro-flow dry nitrogen gas, which is used to obtain the diameter error and shape deviation of the inner wall in real time. The frequency response range of the acoustic emission sensor (24) is between 50kHz and 800kHz, which is used to collect high-frequency vibration signals during the cutting process to identify the wear state of the grinding wheel. The dynamic monitoring and feedback system (4) also includes an optical roughness sensor (30) mounted on the auxiliary measuring arm on the side of the spindle. The optical roughness sensor (30) uses a helium-neon laser with a wavelength of 633nm to reflect speckle signals and perform online measurement of the Ra value of the machined surface.

8. The device for trimming the inner wall of a motor housing according to claim 1, characterized in that, The device also includes a multi-degree-of-freedom support mechanism (25), which is located in the middle section of the motor housing. The multi-degree-of-freedom support mechanism (25) includes an annular bracket (26) and four magnetofluid variable stiffness support heads (27) symmetrically arranged inside the annular bracket (26). Each magnetofluid variable stiffness support head (27) is filled with magnetofluid and has an excitation coil inside. By adjusting the current of the excitation coil, the viscosity of the magnetofluid is changed, thereby realizing the dynamic adjustment of the radial stiffness of the motor housing to suppress resonance during the processing of thin-walled housing.

9. The device for trimming the inner wall of a motor housing according to claim 1, characterized in that, Six active vibration damping pads (28) are installed below the cast iron base (1). Each active vibration damping pad (28) integrates an air spring and an electromagnetic vibrator. A triaxial accelerometer is installed on the bottom surface of the cast iron base (1) to sense ground vibration interference and drive the electromagnetic vibrator to generate a force with opposite phase to cancel the interference. At the connection interface between the spindle dressing execution system (3) and the suspension beam (12), a layer of polymer viscoelastic damping material is also provided to absorb the high-frequency harmonics generated by the high-speed rotation of the spindle.

10. The device for trimming the inner wall of a motor housing according to claim 1, characterized in that, All motion axes of the device are equipped with a high-precision grating feedback system. The displacement sensor of the grating feedback system is connected to the moving parts through an indium steel rod. A disc-type tool magazine is provided on the side of the spindle dressing execution system (3). The disc-type tool magazine works with the tool changing robot (29) to perform automatic tool changing based on the HSK-A63 interface. Each dressing tool has an electronic tag embedded in its shank that records tool life and size information. The control system in the main control cabinet (6) is configured with a distributed architecture based on gigabit industrial Ethernet and introduces speed feedforward control and gravity compensation algorithm for the vertical installation embodiment to counteract the influence of the spindle assembly's own weight on the axial feed trajectory.

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