Welding device for machining of a main shaft motor housing and method thereof

Abstract

The present application relates to the field of machining and welding equipment, in particular to a welding device for machining of a main shaft motor shell and a method thereof; the device comprises a positioning base operation table, a centering cantilever main shaft, a push-pull core rod, a centering driving core and a supporting suspension tile; the system realizes electromagnetic dynamic adjustment of contact stiffness by combining excitation coils and magnetorheological elastomers outside the tile; the core is to use micro-guiding flow pipes and liquid silicon oil to communicate with the opposite blind hole, and when the heated tile retreats, the pressure is automatically transmitted to force the opposite push-pulling plunger to extend and compensate; the present application breaks through the limitation of single rigid expansion sleeve, and can complete mechanical redistribution in a narrow high-temperature space without external sensors, effectively taking into account the geometric avoidance of local thermal deformation and the overall coaxiality maintenance, and avoiding high constraint stress and out-of-round deformation.

Description

Technical Field

[0001] This invention relates to the field of machining and welding equipment, specifically to a welding apparatus and method for machining spindle motor housings. Background Technology

[0002] When the thin-walled sleeve housing of the spindle motor is in the machining process, the welding process introduces concentrated heat input, causing local thermal expansion of the housing material and subsequent cooling contraction. To ensure the assembly clearance, machining accuracy, and structural integrity of the motor, reliable centering support is required inside the housing during machining. To achieve internal centering support, existing solutions generally use a single rigid expansion sleeve or an integral rigid fixture as clamping tooling. This solution mainly uses a mechanical transmission structure to radially support the clamping components, forming a strong static mechanical constraint on the inner wall of the housing, thereby resisting structural collapse during welding and maintaining the basic coaxiality of the workpiece. While this solution provides basic centering and anti-collapse capabilities in static clamping scenarios at room temperature, its completely rigid mechanical structure lacks local stiffness adjustment and counter-pressure compensation mechanisms. During actual continuous circumferential welding, the heated area of ​​the shell will be locally squeezed inward and undergo severe thermal shrinkage after welding. Since the rigid fixture cannot adaptively avoid geometric deformation or absorb local thermal deformation, the high-heat area cannot obtain retreat space. This mechanical interference forces the weld and heat-affected zone to bear extremely high residual constraint stress, which can easily cause permanent indentations, overall out-of-roundness deformation, and even induce micro-cracks on the surface of the thin-walled shell. In addition, due to the limited physical space inside such sleeves and the high temperature, strong arc light, and spatter during welding, traditional external displacement probes or temperature sensors are difficult to place effectively, making conventional dynamic control methods impossible to implement.

[0003] Therefore, how to maintain high-precision centering of the base axis while dynamically absorbing and releasing clamping stress caused by local thermal deformation under welding conditions with limited internal space, and avoid dimensional and positional defects caused by rigid constraint overload, has become an urgent technical problem to be solved. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a welding apparatus and method for machining a spindle motor housing. Specifically, the technical solution of the present invention is as follows: A welding apparatus for machining the spindle motor housing, comprising: Position the basic operating platform; A centering cantilever spindle is suspended and fixedly connected to the positioning base operating table. The centering cantilever spindle has a central through hole inside and four rectangular guide slots are arranged circumferentially on the outside of the centering cantilever spindle. The push-pull core rod is slidably disposed in the central through hole of the centering cantilever main shaft, and the push-pull core rod is connected to an external push-pull servo main motor; A centering drive core is connected to the end of the push-pull core rod. The centering drive core is provided with four blind holes and four pressure-transmitting push plungers. Four supporting suspension blocks are respectively disposed in the four rectangular guide slots to perform radial sliding, and the supporting suspension blocks are pressed across the upper part of the pressure-transmitting push plunger; an electromagnetic variable stiffness component for adjusting the contact stiffness is attached to the supporting suspension blocks. The controller is electrically connected to the push-pull servo main motor and the electromagnetic variable stiffness component to perform control.

[0005] In one possible implementation, the bottoms of the two accommodating blind holes corresponding to the 0° and 180° positions are connected by a first micro-guide tube, and the bottoms of the two accommodating blind holes corresponding to the 90° and 270° positions are connected by a second micro-guide tube.

[0006] In one possible implementation, the bottom gaps of the first micro-guide tube, the second micro-guide tube, and the four accommodating blind holes are filled with liquid silicone oil, and the four pressure-transmitting push plungers are slidably disposed on the upper ends of the four accommodating blind holes, with the outer ends of the pressure-transmitting push plungers having a downward tilt plane.

[0007] In one possible implementation, the bottom arc surface inside the supporting suspension block has an upward tilt sliding surface that matches the downward tilt plane of the pressure-transmitting push plunger.

[0008] In one possible implementation, the outer surface of the supporting suspended tile is provided with a low-carbon magnetic pure iron sheet, and an excitation copper coil bundle connected to and controlled by the controller is wound in the groove of the edge of the low-carbon magnetic pure iron sheet.

[0009] In one possible implementation, the excitation copper conductor coil bundle and the low-carbon magnetic pure iron sheet are externally coated with a magnetorheological elastomer doped with iron powder, and the magnetorheological elastomer is covered with a non-magnetic austenitic stainless steel protective layer.

[0010] Welding control methods for machining the spindle motor housing include: S1. Control the push-pull servo main motor to drive the push-pull core rod to move, and push the supporting suspended tile outward through the centering drive core and the pressure transmission push plunger to form an initial forced shaping support and center locking. S2. Obtain the compressive force on the supporting suspended tile. When the compressive force reaches full load, the controller outputs a continuous high-frequency DC modulated current square wave to the excitation copper conductor coil bundle. S3. Real-time acquisition of the phase hysteresis angle on the excitation copper conductor coil bundle; S4. Calculate the radial compression deformation of the spatial thickness based on the phase hysteresis angle. S5. The local maximum compressive force is obtained by converting the radial compression deformation and the equivalent stiffness resistance coefficient.

[0011] In one possible implementation, step S5 is followed by: S601. Compare the local maximum compressive force with the yield stress safety threshold curve; S602. Determine whether the local maximum compressive force corresponding to a certain supporting suspension tile reaches the yield stress safety threshold curve; if yes, define the area corresponding to the supporting suspension tile as a local overheating area, and control the pulse duty cycle of the excitation copper conductor coil bundle in the local overheating area to be reduced to a preset width limit ratio; if no, maintain the high stiffness of the corresponding area. S603. By reducing the pulse duty cycle, the magnetorheological elastomer in the locally overheated region is transformed into a compliant rheological state with low shear modulus.

[0012] In one possible implementation, step S603 is followed by: S701. Obtain the back pressure displacement of the pressure-transmitting push plunger caused by the internal pressure of the housing after the magnetorheological elastomer in the corresponding region is converted into a low shear modulus. S702, The pressure is transmitted to the pressure-transmitting push plunger opposite to the high-rigidity support area through the liquid silicone oil in the first micro-guide tube or the second micro-guide tube; S703. The pressure transmitted in the opposite direction forces the opposing pressure-transmitting plunger to extend outward, forming a reverse support force to counteract the eccentric offset caused by unilateral deformation.

[0013] In one possible implementation, in step S2, the controller drives the duty cycle to a value of 90%, triggering magnetic field lines that penetrate the low-carbon magnetic pure iron sheet, causing the iron powder in the magnetorheological elastic body to oriented along the direction of the magnetic field lines to form a chain-like load-bearing structure.

[0014] The present invention has the following beneficial effects: 1. This invention overcomes the limitations of a single rigid expansion sleeve by combining a composite excitation copper conductor coil bundle and a magnetorheological elastomer on the outside of the supporting suspension tile, achieving electromagnetic dynamic adjustment of contact stiffness on the basis of mechanical centering; at the same time, by using micro-guiding tubes and liquid silicone oil to connect the opposing receiving blind holes, when the heated tile retracts and presses the pressure-transmitting plunger, the pressure is automatically transmitted, forcing the opposing pushing plunger to extend outward; this mechanism can complete mechanical redistribution in a confined high-temperature space without external sensors, effectively taking into account both the geometric avoidance of local thermal deformation and the maintenance of overall coaxiality, avoiding high constraint stress and out-of-round deformation; 2. This control method innovatively obtains the phase hysteresis angle on the excitation copper conductor coil bundle and implicitly inverts to calculate the radial compression deformation and local maximum extrusion pressure, overcoming the difficulty of placing external probes under harsh welding conditions. When the local maximum extrusion pressure touches the yield stress safety threshold curve, the pulse duty cycle of a specific local overheated area is actively reduced, causing the magnetorheological elastomer at that location to quickly transform into a compliant rheological state with low shear modulus. This precisely releases the local residual constraint stress, fundamentally preventing the thin-walled shell from developing permanent indentations and microcracks. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the device; Figure 2 This is a schematic diagram of the cross-sectional structure of the centering cantilever spindle of the device; Figure 3 This is a schematic diagram of the centering drive core structure of the device; Figure 4 This is a schematic diagram of the device supporting the suspended tile structure; Figure 5 This is a flowchart of the method of the present invention.

[0016] In the diagram: 1. Positioning base operating table; 2. Centering cantilever spindle; 3. Central through hole; 4. Rectangular guide slot; 5. Push-pull core rod; 6. Push-pull servo main motor; 7. Centering drive core; 8. Accommodating blind hole; 9. Pressure transmission push plunger; 10. Supporting suspension block; 11. Controller; 12. First micro-guide tube; 13. Second micro-guide tube; 14. Liquid silicone oil; 15. Descending tilt plane; 16. Rising tilt sliding surface; 17. Low-carbon magnetic pure iron sheet; 18. Excitation copper conductor coil bundle; 19. Magnetorheological elastomer; 20. Non-magnetic austenitic stainless steel protective layer. Detailed Implementation

[0017] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0018] Example 1: A welding apparatus for machining the spindle motor housing, comprising: Combination Figure 1 Position the basic operating platform 1; The centering cantilever spindle 2 is suspended and fixedly connected to the positioning base operating table 1. The centering cantilever spindle 2 has a central through hole 3 inside and four rectangular guide slots 4 are arranged circumferentially on the outside of the centering cantilever spindle 2. Combination Figure 2 The push-pull core rod 5 is slidably installed in the central through hole 3 of the centering cantilever spindle 2, and the push-pull core rod 5 is connected to the external push-pull servo main motor 6; Combination Figure 3 The centering drive core 7 is connected to the end of the push-pull core rod 5. The centering drive core 7 is provided with four blind holes 8 and four pressure-transmitting push plungers 9. Four supporting suspension blocks 10 are respectively set in four rectangular guide slots 4 to perform radial sliding, and the supporting suspension blocks 10 press against the upper part of the pressure transmission push plunger 9; the supporting suspension blocks 10 are combined with an electromagnetic variable stiffness component for adjusting the contact stiffness. Controller 11 is electrically connected to push-pull servo main motor 6 and electromagnetic variable stiffness assembly to perform control; To address the issue of needing internal centering support while avoiding high residual constraint stress caused by welding thermal shrinkage during the welding process of the thin-walled sleeve housing of the spindle motor, a positioning base operating table 1 is set up as the load-bearing foundation for the entire welding device. The positioning base operating platform 1 can be a welded steel structure platform or an integral casting platform, preferably a steel platform with a thickness of 30mm to 80mm, and is fixed to the ground foundation with four M20 to M24 anchor bolts to ensure the stability of the equipment axis position; The centering cantilever spindle 2 is fixed to the front end of the positioning base operating table 1 and extends into the housing to be processed. The centering cantilever spindle 2 can be formed by machining 45 steel or 40Cr steel. The outer cylindrical surface is coaxial with the axis of the housing to be supported. The central through hole 3 inside is used to accommodate the push-pull core rod 5 to make axial linear movement. The four rectangular guide slots 4 are arranged at 90-degree intervals along the circumference to limit the four supporting suspension blocks 10 to only make radial movement and avoid circumferential movement that affects the centering accuracy. The push-pull core rod 5 is preferably a cylindrical rod with surface hardening and precision grinding. The rod diameter can be selected from 20mm to 60mm according to the inner diameter of the shell. One end of the push-pull core rod 5 is connected to the external push-pull servo main motor 6 for transmission, and the other end is connected to the centering drive core 7. The axial advance and retreat of the centering drive core 7 is realized by means of the forward and reverse rotation and displacement control of the servo motor. The centering drive core 7 is located in the front end area of ​​the centering cantilever spindle 2. Four blind holes 8 are provided on its outer periphery. Four pressure-transmitting push plungers 9 are respectively installed in the four blind holes 8 to convert the axial drive into the radial support of the suspended pad 10. Four supporting suspension blocks 10 are respectively embedded in four rectangular guide slots 4. The outer arc surfaces of the blocks together form a supporting circumference that matches the inner circle of the spindle motor housing. They form a force transmission relationship by pressing across the upper part of the pressure transmission push plunger 9. The controller 11 can be an industrial programmable logic controller, motion controller or embedded control board. Its output is connected to the excitation execution unit related to the push-pull servo main motor 6 and each support suspension tile 10, respectively, to control clamping, holding, partial retraction and restoration of support state. Compared with existing single rigid expansion sleeves, this structure not only has basic centering and anti-collapse capabilities, but also provides a unified mechanical basis for subsequent local stiffness adjustment and counter-pressure compensation. Therefore, it can simultaneously maintain the axis and absorb local thermal deformation during the shell welding process.

[0019] The bottoms of the two blind holes 8 corresponding to the 0° and 180° positions are connected by the first micro-guide tube 12, and the bottoms of the two blind holes 8 corresponding to the 90° and 270° positions are connected by the second micro-guide tube 13. To ensure that when a local support point retracts due to thermal expansion during welding, the stress change can be transmitted to the opposite non-heated support point without delay, a cross-type hydraulic transmission channel is provided inside the centering drive core 7; the bottoms of the two accommodating blind holes 8 corresponding to the 0° and 180° positions are connected by the first micro-guide tube 12, and the bottoms of the two accommodating blind holes 8 corresponding to the 90° and 270° positions are connected by the second micro-guide tube 13; 0°, 180°, 90° and 270° are all defined as circumferential angles based on the central axis of the device; among them, the starting reference for the 0° position is set as the vertical radius line directly above the section of the centering cantilever main shaft 2 as the 0° reference direction, and the other angles are calculated sequentially along the same predetermined rotation direction; The first micro-guided drainage tube 12 and the second micro-guided drainage tube 13 are preferably formed by drilling an inner hole with a diameter of 1 mm to 4 mm, or they can be formed by pre-embedded pressure-resistant metal tubes. Their axes are located inside the solid metal of the centering drive core 7. The two are arranged in layers or staggered in space to ensure that they are not connected to each other. The technical consideration for adopting the above-mentioned opposing pairing connection method, instead of connecting all four blind holes 8 in one go, is that if the four holes are connected in a common cavity, the liquid pressure after local pressure will spread in all directions, resulting in overall loosening, which is not conducive to maintaining the central axis. After adopting the opposite pair connection, when the support tile corresponding to the heated area retracts, its bottom pressure is mainly transmitted to the opposite tile, forming a pair compensation relationship of one set of pressure-receding and the other set of pressure-enhancing, so that local geometric avoidance and overall coaxiality are maintained at the same time. This opposing pressure transmission structure does not rely on additional sensors or external actuators. It utilizes the internal fluid pressure to complete the mechanical redistribution, making it suitable for applications with limited space, high temperature, and a lot of spatter in the welding area.

[0020] Liquid silicone oil 14 is filled in the bottom gap of the first micro-guide tube 12, the second micro-guide tube 13 and the four accommodating blind holes 8. Four pressure-transmitting push plungers 9 are slidably disposed on the upper end of the four accommodating blind holes 8 respectively. The outer end of the pressure-transmitting push plunger 9 has a downward tilt plane 15. To ensure that the pressure transmission passage has low compressibility, good temperature stability and long-term sealing, the first micro-guide tube 12, the second micro-guide tube 13 and the bottom gap of the four blind holes 8 are filled with liquid silicone oil 14; the liquid silicone oil 14 is preferably dimethyl silicone oil with a kinematic viscosity of 1000 cSt to 3000 cSt, more preferably about 2000 cSt, so as to balance pressure transmission sensitivity and flow stability at high temperature. A clearance of 0.01mm to 0.05mm is provided between the diameter of the blind hole 8 and the outer diameter of the pressure-transmitting push plunger 9, so that the pressure-transmitting push plunger 9 can slide at the upper end of the blind hole without significant jamming; an oil-resistant sealing ring or a metal labyrinth seal can be provided at the opening of the blind hole, and the bottom of the blind hole is sealed with a copper expansion plug, a cone plug or laser welding after oil filling to ensure long-term fluid sealing; The near-axial ends of the four pressure-transmitting push plungers 9 are in direct contact with the liquid silicone oil 14. Therefore, when any plunger is subjected to external force back pressure, the pressure inside the liquid silicone oil 14 increases and is transmitted to the opposing blind hole connected to it. The outer end of the pressure-transmitting push plunger 9 is machined into a downward tilt plane 15. The downward tilt plane 15 forms a wedge surface relative to the radial direction. The tilt angle is preferably 10° to 20°, and more preferably 15°. The purpose of using the descending angle plane 15 is to convert the axial displacement of the centering drive core 7 and the axial micro-displacement of the hydraulic plunger into the radial displacement of the supporting suspension pad 10, and to realize the bidirectional transmission of displacement and force when the supporting suspension pad 10 is subjected to back pressure from the inner wall. Compared with the flat-head plunger, the inclined plunger can output a stable radial support force within the preset stroke, and at the same time facilitates the formation of controllable local clearance.

[0021] The bottom arc surface inside the supporting suspension block 10 has an upward tilt sliding surface 16, which matches the cross pressure on the downward tilt plane 15 of the pressure transmission push plunger 9. In order to convert the displacement of the pressure-transmitting push plunger 9 into pure radial sliding of the supporting suspension pad 10, the inner bottom arc surface of each supporting suspension pad 10 is machined with an upward tilt sliding surface 16, which is in contact with the downward tilt plane 15 of the corresponding pressure-transmitting push plunger 9; the matching includes both tilt matching and contact length and contact width matching. The supporting suspension pad 10 is preferably made of high-strength alloy steel, tempered steel or surface-hardened stainless steel. Its outer arc radius is determined according to the inner diameter of the spindle motor housing to be welded. The inner sliding surface is precision milled or ground, and the surface roughness is preferably controlled between Ra0.8μm and Ra1.6μm to reduce the frictional resistance of the inclined surface. The four supporting suspended tiles 10 are constrained by the sidewalls of the rectangular guide groove 4, allowing them to slide only radially. Therefore, when the push-pull servo main motor 6 drives the push-pull core rod 5 and the centering drive core 7 to move axially, the pressure-transmitting push plunger 9 follows and generates axial displacement, pushing the supporting suspended tiles 10 to expand outward under the action of the wedge-shaped inclined surface. When the local outer shell is heated and pushes back a certain supporting suspension tile 10, the tile retracts radially in the opposite direction. With the help of the matching inclined surface, the back pressure is converted into the axial pressing displacement of the corresponding pressure-transmitting push plunger 9, and further squeezes the liquid silicone oil 14. Therefore, the relationship between the supporting suspension block 10 and the pressure-transmitting pusher 9 is not a simple push-together relationship, but an inclined plane cooperation relationship with mechanical force amplification and displacement conversion functions. Through this structure, while maintaining a single support direction and a clear motion trajectory, a clamping force that meets the preset threshold and a matching pressure response can be obtained.

[0022] Combination Figure 4 The outer surface of the supporting suspension tile 10 is provided with a low-carbon magnetic pure iron sheet 17, and an excitation copper conductor coil bundle 18 connected to and controlled by the controller 11 is wound in the groove of the edge of the low-carbon magnetic pure iron sheet 17. To ensure that the supporting suspension tile 10 has adjustable contact stiffness during the welding process, a low-carbon magnetically conductive pure iron sheet 17 is provided on the outer surface of the supporting suspension tile 10. The low-carbon magnetically conductive pure iron sheet 17 serves as a magnetic circuit pole plate, used to form a magnetic flux channel passing through the subsequent magnetorheological elastomer 19 during excitation. The low-carbon magnetically conductive pure iron sheet 17 can be made of industrial pure iron sheet, low-carbon steel laminate, or silicon steel sheet laminate, and the thickness is preferably 2mm to 8mm. The purpose of using a laminated form is to reduce eddy current losses under alternating excitation conditions, thereby reducing local self-heating; the edge of the pure iron sheet is machined with annular or semi-annular grooves, and an excitation copper conductor coil bundle 18 is wound in the grooves. The copper conductor can be enameled copper wire with a temperature resistance of 180℃ or higher, the wire diameter is preferably 0.3mm to 1.0mm, the number of turns is preferably 300 to 800 turns, and more preferably about 600 turns; The excitation copper conductor coil bundle 18 is connected to the power output terminal of the controller 11. The controller 11 can independently adjust the driving current, voltage, square wave frequency and duty cycle of the coil corresponding to each supporting suspension tile 10. By combining the low-carbon magnetic pure iron sheet 17 with the excitation copper conductor coil bundle 18, each supporting suspended tile 10 forms an independent and controllable local magnetic field generating unit; when the controller 11 outputs a drive signal, the pure iron sheet guides the magnetic field to its outer surface, causing the functional layer material between the supporting tile and the inner wall of the shell to produce a magnetostrictive stiffening effect. This setup differs from traditional rigid fixtures in that the supporting base is still borne by mechanical components, while the stiffness of the contact surface is adjusted by electromagnetic means according to the region. Therefore, it is possible to implement local yield control for the welding heat-affected zone without reducing the overall centering capability.

[0023] The excitation copper conductor coil bundle 18 and the low carbon magnetic pure iron sheet 17 are coated with a magnetorheological elastomer 19 doped with iron powder. The magnetorheological elastomer 19 is covered with a non-magnetic austenitic stainless steel protective layer 20. To form a contact medium that can both bear load and be flexible between the supporting suspension block 10 and the inner wall of the main spindle motor housing, the excitation copper conductor coil bundle 18 and the low-carbon magnetic pure iron sheet 17 are coated with a magnetorheological elastomer 19 doped with iron powder. The magnetorheological elastomer 19 refers to a composite material that exhibits a low shear modulus under no magnetic field conditions and whose internal magnetic particles are aligned along the direction of the magnetic field lines under the action of a magnetic field, thereby increasing the overall modulus. The material can be made of silicone rubber matrix, polyurethane matrix or high temperature resistant elastic resin matrix, and internally doped with carbonyl iron powder, soft magnetic powder or carbon-based coated iron powder, with a mass fraction preferably of 10% to 35%, more preferably 20% to 25%; the casting thickness is preferably 5mm to 15mm, more preferably about 10mm. In order to prevent the magnetorheological elastomer 19 from being burned by welding spatter when it directly bears the pressure of the inner wall of the shell, and to keep the contact surface clean, a non-magnetic austenitic stainless steel protective layer 20 is covered on its surface; the non-magnetic austenitic stainless steel protective layer 20 can be made of 304, 316 or 310S thin stainless steel sheet, with a thickness preferably from 0.3mm to 1.5mm, more preferably about 1mm. The outer membrane is fixed to the outer surface of the supporting suspension tile 10 by heat-resistant adhesive, edge covering or local spot welding; due to the low magnetic permeability of austenitic stainless steel, the outer membrane has little disturbance to the magnetic circuit, so the magnetic field can still penetrate the outer membrane and act on the internal magnetorheological elastomer 19. During this process, the magnetic field lines penetrating the magnetorheological elastomer 19 further enter the inner wall of the spindle motor housing to be processed, and use the magnetically conductive housing itself as a magnetic medium to make the magnetic field lines fold back and pass through the other pole of the low-carbon magnetically conductive pure iron sheet 17, thereby forming a complete closed magnetic return path; when the housing to be processed is a non-magnetic material, the magnetic field lines are folded back by using the centering drive core 7 or adding a special magnetically conductive inner liner as a magnetic medium, thereby forming a complete closed magnetic return path; With this composite layer structure, the surface of the supporting suspended tile 10 is no longer a single hard metal surface, but a structure in which a metal protective layer, a magnetorheological elastic layer, a magnetic pole plate, and a mechanical tile substrate are stacked in sequence. The mechanical tile is responsible for load bearing and guidance, the magnetic pole plate and coil are responsible for adjusting the magnetic field, the magnetorheological elastic body 19 is responsible for stiffness changes and absorbing local thermal extrusion, and the non-magnetic austenitic stainless steel protective layer 20 is responsible for heat insulation, anti-splashing, and direct contact with the inner wall of the shell. This multi-layer combination can reduce local indentation and stress concentration during the welding process.

[0024] Example 2: Combination Figure 5 Welding methods for machining spindle motor housings include: S1. Control the push-pull servo main motor 6 to drive the push-pull core rod 5 to move, and push the supporting suspended tile block 10 to be pushed outward through the centering drive core body 7 and the pressure transmission push plunger 9 to form an initial strong fixed shape support and center lock. S2. Obtain the compressive force on the supporting suspended tile 10. When the compressive force reaches full load, the controller 11 outputs a continuous high-frequency DC modulated current square wave to the excitation copper conductor coil bundle 18. S3. Real-time acquisition of the phase hysteresis angle on the excitation copper conductor coil bundle 18; S4. Calculate the radial compression deformation of the spatial thickness based on the phase hysteresis angle; S5. The local maximum compressive force is obtained by converting the radial compression deformation and the equivalent stiffness resistance coefficient. This control method is used to achieve implicit identification of local thermal deformation and active adjustment of support stiffness during welding. In S1, the controller 11 sends a displacement command to the push-pull servo main motor 6. The push-pull servo main motor 6 drives the push-pull core rod 5 to move axially along the central through hole 3, which in turn drives the centering drive core 7 to move. The centering drive core 7 pushes the four pressure-transmitting push plungers 9 to generate a wedge displacement relative to the supporting suspension block 10. The supporting suspension block 10 is pushed outward along the rectangular guide groove 4 and abuts against the inner wall of the thin-walled sleeve of the main spindle motor, thereby establishing a predetermined clamping state. This predetermined clamping state can be determined by the servo motor torque threshold, the core rod displacement, or an independent pressure detection device. In S2, the compressive force on the supporting suspended tile 10 can be obtained in two ways. One way is to convert the current and displacement of the push-pull servo main motor 6 into the output pressure of the tile. The other way is to set strain gauges, thin film pressure sensors or piezoelectric elements in the pressure transmission push plunger 9, the supporting suspended tile 10 or the servo drive chain to obtain the compressive force. When the compressive force reaches the preset full load value, the controller 11 outputs a continuous high-frequency DC modulated current square wave to the excitation copper conductor coil bundle 18, so that the magnetorheological elastomer 19 enters a high-stiffness working state. In S3, the controller 11 collects the voltage and current waveforms of the excitation copper conductor coil bundle 18 in real time and calculates the phase hysteresis angle of the voltage phase relative to the current phase. This phase hysteresis angle reflects the change in coil reactance, and the change in coil reactance is related to the air gap of the magnetic circuit, the magnetic flux density, and the degree of compression of the support contact layer. In S4, the radial compression deformation is calculated based on the functional relationship between the phase hysteresis angle and the spatial thickness obtained from the calibration. The radial compression deformation refers to the compression formed by the magnetorheological elastomer 19 and its outer skin film on the outside of the supporting suspension tile 10 under the pressure of the inner wall of the shell. It also corresponds to the reduction in the contact layer thickness caused by the inward bulging of the heated area of ​​the shell. This conversion relationship can be established by using standard gauge blocks, known compression displacement and corresponding phase angle data to establish a lookup table model or fitting model during the equipment factory calibration stage. In S5, the local maximum compressive force is obtained by converting the radial compression deformation and the equivalent stiffness resistance coefficient. The equivalent stiffness resistance coefficient can be understood as the equivalent stiffness coefficient of magnetorheological elastomer 19 under the current excitation conditions and contact state. Its value can be determined by material compression test, temperature correction and excitation level calibration. The unit can be N / mm or MPa / mm. To ensure the uniformity of the dimensions of the product operation in the control logic and that the final output of the local maximum compressive force is an absolute force value, the unit of the equivalent stiffness resistance coefficient is fixed at N / mm to truly match the equivalent stiffness mapping relationship between force and displacement. The controller 11 multiplies the radial compression deformation with the equivalent stiffness resistance coefficient to obtain the local maximum extrusion force when the heated shell is pushed back to the support surface, which is used to determine whether it has entered the yield risk zone. Using the above method, it is not necessary to place an independent displacement probe or temperature probe near the welding torch. The deformation information of the inner wall can be obtained through the inductive response of the excitation coil itself. It is suitable for welding conditions with strong arc light, limited space and spatter. To ensure that the control logic from S2 to S5 is repeatable, the extrusion pressure reaches full load when the corresponding support suspension tile 10 has reached the upper limit load of the preset clamping working area. This state is not the material failure limit, but the reference state for subsequent magnetic stiffness adjustment and phase detection. The full load value can be determined as follows: First, under normal temperature and no welding conditions, the shell to be welded is installed into the device and the displacement of the push-pull core rod 5 is gradually increased; then, the tile extrusion pressure is recorded when the shell is stably fitted without obvious out-of-roundness; this pressure is multiplied by the process amplification amount of 1.05 to 1.20 and used as the full load threshold stored in the controller 11. For housings of the same specification, the full load threshold can also be determined by any one or a combination of two of the following: the drive current threshold of the servo main motor, the core rod displacement threshold, and the independent pressure sensor value, in order to avoid misjudgment caused by a single signal drift. The physical meaning of the phase hysteresis angle is the change in voltage and current phase difference caused by the change in effective magnetic reluctance of the magnetic circuit under a given modulation frequency and duty cycle. The preferred processing flow is: first, the controller 11 synchronously samples the driving voltage waveform and loop current waveform of each excitation copper conductor coil bundle 18. Then, the fundamental AC component in the voltage and current waveforms within the same period is extracted by fast Fourier transform, and the voltage zero-crossing time and current zero-crossing time of the fundamental component are extracted to obtain the instantaneous phase difference; or the rising edge triggering time of the voltage square wave and the lag time of the current rising to the preset steady-state threshold are extracted and converted into instantaneous phase difference. The inputs to the process are the original coil voltage, current sampling signal, and the internal clock of the controller 11. The output of the process is a set of real-time phase hysteresis angle values ​​corresponding to each supporting suspension tile 10. This output is simultaneously sent to the radial compression deformation calculation module and the abnormal fluctuation elimination module. The abnormal fluctuation elimination module uses a Kalman filter algorithm or a moving average window to eliminate millisecond-level high-frequency phase spike data caused by strong electromagnetic interference from the welding arc, ensuring that the output phase hysteresis angle is smooth and stable. The optimal calculation logic for S4 is to perform step-by-step conversion according to the calibration table: The first step involves applying multiple known compression displacements (e.g., 0.02mm, 0.05mm, 0.10mm to 1.00mm) to each support unit during the equipment manufacturing process, recording the corresponding phase hysteresis angle values, and establishing a one-to-one calibration table. The second step involves the controller 11 reading the real-time phase hysteresis angle values ​​during the welding operation. The third step involves directly reading the corresponding compression amount if the value falls on a node in the calibration table. The fourth step involves calculating the current compression amount by linear interpolation between adjacent nodes if the value lies between two calibration nodes. The fifth step involves outputting this compression amount as the radial compression deformation of the spatial thickness. Through the above steps, the radial compression deformation was quantitatively obtained; the role of the equivalent stiffness drag coefficient in the control logic is to convert the displacement obtained by phase change inversion into an equivalent stiffness factor of the local compression degree. The preferred method for determining this is as follows: under different excitation duty cycles, different temperature ranges, and different skin film thicknesses, a compression test is performed on the magnetorheological elastomer 19 composite layer to obtain the relationship between compression displacement and reaction force; then, the test slopes under the same duty cycle and the same temperature range are stored as a coefficient table; during welding, the controller 11 retrieves the corresponding coefficients according to the current duty cycle setting and temperature correction setting. If no independent temperature sensor is set, an approximate correction can be made using a process temperature rise table corresponding to the welding current level and the duration of energization. The process temperature rise table is a two-dimensional discrete mapping table pre-stored in the controller 11. Its horizontal axis index is the nominal level of welding current, and its vertical axis index is the cumulative energizing duration. The output value stored in the table is the corresponding temperature rise compensation coefficient. When the controller 11 is running, it extracts the real-time temperature rise compensation coefficient from the table through a bilinear interpolation algorithm to correct the equivalent stiffness resistance coefficient. The logical function of the local maximum compressive force is to serve as the input for determining whether the subsequent local stiffness reduction control is triggered. The larger the value, the stronger the tendency of the inner wall of the heated shell to press back towards the support surface. The output of S5 is preferably generated point by point according to the support unit, rather than just generating the overall average value; the controller 11 can calculate the local maximum extrusion pressure for each of the four support suspension tiles 10, and use the maximum value as the risk criterion at the current moment; it can also weight the peak values ​​of two adjacent support units in combination with the current position of the welding gun when the circumferential weld moves along the circumference to improve the correspondence with the moving heat source. Thus, S1 to S5 form a clear data flow: mechanical clamping establishes the reference state, the excitation circuit collects phase information, the calibration table calculates the radial compression deformation, the radial compression deformation is then combined with the equivalent stiffness coefficient to convert it into the local maximum extrusion force, and this peak value is input into the subsequent threshold comparison and local yield control steps. The above-mentioned processing logic for inverting the compression amount from the phase hysteresis angle and further converting it into the local maximum extrusion pressure can be collectively referred to as the contact layer compression identification model. The purpose of this model is to identify the degree of compression of the support contact layer by using the change in the electrical signal of the excitation circuit itself, under the condition that it is inconvenient to place displacement probes and temperature probes near the welding torch, and to judge the local pressure risk of the welding area accordingly. The model logically comprises three sequentially connected sub-units: The first sub-unit is the phase extraction unit, which receives the coil voltage waveform, current waveform and controller 11 clock as input, and outputs the real-time phase hysteresis angle of each support unit. The second subunit is the compression conversion unit, which receives the real-time phase hysteresis angle and the factory calibration table of the corresponding support unit as input, and outputs the radial compression deformation. The third sub-unit is the peak pressure conversion unit, which receives the radial compression deformation and the equivalent stiffness resistance coefficient called according to the excitation level and process temperature rise conditions, and outputs the local maximum extrusion pressure. The model as a whole represents the following physical relationship: the inner wall of the heated shell presses closer to the supporting surface, which will compress the magnetorheological elastomer 19 composite layer and change the effective magnetic reluctance of the magnetic circuit; the change in magnetic reluctance will cause the equivalent inductive reactance of the coil to change, forming a measurable phase difference change between the driving voltage and the circuit current; after the controller 11 calibrates and converts this change, it can obtain the amount of reduction in the contact layer thickness and the corresponding local pressure strength. The model adopts a structure that first calibrates, then looks up a table, and then selects the equivalent stiffness coefficient according to the working conditions, which corresponds to the execution process of S1 to S5. Specifically, the process for calculating the radial compression deformation and local maximum compressive force of the spatial thickness is as follows: The high-speed analog-to-digital converter module of controller 11 acquires the voltage signal and loop current signal at the two ends of the coil at a sampling rate of 10kHz to 50kHz, and extracts the zero-crossing time difference of the voltage and current through a digital filtering algorithm, multiplies it by the driving square wave frequency, and further multiplies it by 360° to obtain the instantaneous phase difference. Then, the instantaneous phase difference is subtracted from the reference phase difference to obtain the phase hysteresis angle; the above calculation formula is: In the formula, The phase hysteresis angle, The zero-crossing time difference between voltage and current. To drive the square wave frequency, The reference phase difference; Taking a certain quantization simulation as an example, if the reference phase difference is 15° and the current detected phase difference is 18.5°, then the phase hysteresis angle is 3.5°; the controller 11 calls the calibration mapping table in the non-volatile memory. If 3.5° corresponds to a compression amount of 0.15mm in the mapping table, then the 0.15mm is the radial compression deformation amount used as the output data. The controller 11 sends the 0.15mm to the arithmetic logic unit and retrieves the equivalent stiffness resistance coefficient from the register according to the current heat input level; the controller 11 performs a product operation: 0.15mm multiplied by 400N / mm equals 60N, and this 60N is the local maximum extrusion force output at the current moment; The above steps enable complete data calculation from analog electrical signals to digital phase angles, then to physical displacements and the final peak force.

[0025] The steps following S5 include: S601. Compare the local maximum compressive force with the yield stress safety threshold curve; S602. Determine whether the local maximum compressive force corresponding to a certain support suspension tile 10 reaches the yield stress safety threshold curve; if yes, define the area corresponding to the support suspension tile 10 as a local overheating area, and control the pulse duty cycle of the excitation copper conductor coil bundle 18 in the local overheating area to be reduced to the preset width limit ratio; if no, maintain the high stiffness of the corresponding area. S603. By reducing the pulse duty cycle, the magnetorheological elastomer 19 in the local overheated region is transformed into a compliant rheological state with low shear modulus. To release the constraint in a timely manner when the contact stress in the local heated area is detected to be close to the yield limit of the shell material, local yield control should be implemented after S5. In S601, the controller 11 compares the local maximum compressive stress with the yield stress safety threshold curve. The yield stress safety threshold curve is a preset safety limit based on the spindle motor housing material grade, housing wall thickness, current welding heat input, and allowable deformation. It can be stored in the controller 11 in the form of a piecewise function, a lookup table threshold, or a temperature correction threshold. For example, for magnetic steel or martensitic stainless steel sleeves with a wall thickness of 1.5 mm to 4 mm, the safety threshold of the local maximum compressive stress can be set to 50% to 85% of the material's high-temperature yield stress. In S602, when the local maximum compressive force reaches or exceeds the threshold, the controller 11 identifies the area of ​​the support suspension tile 10 corresponding to the peak value and reduces the pulse duty cycle of the excitation copper conductor coil bundle 18 in that area from the high stiffness holding value to the preset tolerance ratio; the preset tolerance ratio is preferably 10% to 30%, more preferably about 15%; since each support suspension tile 10 can be controlled independently, the duty cycle is reduced only in the local overheated area, and the stiffness is not uniformly reduced for all support points; In S603, as the pulse duty cycle decreases, the effective magnetic flux provided by the low-carbon magnetic pure iron sheet 17 to the magnetorheological elastomer 19 decreases, the internal iron powder chain structure changes from dense arrangement to sparse arrangement, and the shear modulus and compressive modulus of the magnetorheological elastomer 19 decrease simultaneously, exhibiting a compliant absorption state with low shear resistance. The transformation to a compliant rheological state with low shear modulus here refers to the material's equivalent mechanical behavior changing from a high-modulus state to a low-modulus state, not becoming a completely free liquid. Through this local stiffness reduction measure, the shell area that expands inward when heated can obtain additional clearance space at the corresponding support points, reducing the risk of permanent indentations, out-of-roundness, and cracks caused by welding thermal shrinkage. The innovation in this step is that the control signal is not directly fed back from external thermal imaging or displacement probes, but is determined by the local stress value derived from the coil phase hysteresis angle, and the yield is limited to the local support unit corresponding to the high fire point, thereby reducing the axial drift caused by the decrease in overall clamping stiffness. The role of the yield stress safety threshold curve in the control process is as the trigger boundary for switching from the monitoring stage to the yielding stage; it is not a single fixed value, but a set of safety criteria that vary with shell material, wall thickness and welding conditions. The preferred steps for determining the yield strength are as follows: First, the room temperature yield strength and high temperature yield attenuation curves are obtained based on the shell material grade; then, the current heat input level is determined based on the current, voltage, welding speed, and interpass temperature in the welding process; the allowable stress in the corresponding temperature range is selected according to the heat input level; then, the actual trigger threshold is obtained by multiplying by a safety factor of 0.50 to 0.85; the controller 11 can pre-write the above thresholds into the parameter table according to different workpiece specifications, and the operator can call the corresponding process number before welding. The specific calculation logic within controller 11 for this step is as follows: Assuming controller 11 retrieves a local yield stress of 150 MPa for the material in the current high-temperature range, and based on the contact state of the inner wall to be clamped, the effective bearing contact area is 400 square mm; controller 11 performs a product operation through its built-in arithmetic logic module to obtain the theoretical yield strength bearing capacity of 60000 N, using the following formula: In the formula, For theoretical yield strength, For local yield stress, To effectively bear the contact area; The controller 11 uses a conservative safety reduction factor of 0.6 from the preset process library to calculate the effective safe bearing capacity as 36000N. The formula is as follows: In the formula, For effective and safe load-bearing capacity, This is a conservative safety reduction factor; this value is directly stored in the threshold comparison register as a parameter of the yield stress safety threshold curve, and is continuously compared with the calculated real-time local maximum compressive force at high frequency. The local overheated area refers to the local support area among the four supporting suspended tiles 10 that corresponds to the maximum local extrusion pressure at the current moment, or the area that is closest to the current circumferential position of the welding torch and simultaneously shows an increase in the phase hysteresis angle. The preferred identification logic is as follows: the controller 11 first compares the local maximum extrusion pressure of the four support units; if the maximum value exceeds the set threshold of the other three, the unit is directly identified as a local overheating area; if the peak values ​​of two adjacent units are close, the current position of the welding torch or the direction of movement of the weld heat source is combined to define one or both of them as a local overheating area. The data on the current position of the welding torch or the direction of movement of the weld heat source are synchronously acquired by the controller 11 through the industrial communication bus by reading the encoder axis coordinate data of the external welding robot or the external tooling rotary table in real time; this can avoid misjudgment when the heat source is located between two support units. The preferred control process of S602 is to reduce the duty cycle in stages, rather than reducing it to the lowest preset grace ratio all at once. In the first stage, when the local maximum extrusion pressure reaches 100% of the threshold force line, the duty cycle of that area is reduced from the high stiffness maintenance value to 40% to 60%, and the phase hysteresis angle is observed to see if it continues to increase. In the second stage, if the peak value continues to rise within the preset observation time window, it is further reduced to 20% to 30%. In the third stage, if it still exceeds the safety line, it is reduced to the preset tolerance ratio. The observation time window is preferably 20ms to 200ms to take into account both the rate of change of welding heat input and the execution response speed. Using graded stiffness reduction can reduce sudden overall retreat and avoid one-time instability of the support surface. The physical meaning of the preset tolerance ratio is to ensure that the magnetorheological elastomer 19 retains the minimum guiding support capacity without completely losing its constraint in a low-stiffness working position. This tolerance ratio can be determined according to the following principle: gradually reduce the duty cycle under test conditions and record the reaction force change of the magnetorheological elastomer 19 composite layer under the same compressive displacement; when its reaction force drops to a range that allows for local yielding without causing the supporting suspension tile 10 to lose its basic following ability, the corresponding duty cycle is taken as the tolerance ratio. For magnetorheological elastomers 19 with different formulations, this value can be calibrated and stored separately; thus, through steps S601 to S603, the conditions and degree of implementation for reducing the duty cycle after reaching the threshold are clarified. The above S601 to S603 can be summarized as a local yield judgment and execution model. The purpose of this model is to reduce the contact stiffness only at local support points that are close to the risk of yielding, while maintaining the overall centering, so that the welding heat-induced internal pressure has a controlled release path, rather than indiscriminately weakening the support on the entire circumference. The model logically comprises three sequentially connected stages: the risk comparison stage receives the local maximum extrusion pressure of each support unit output by S5 and the threshold force line parameters corresponding to the current workpiece, and outputs whether the limit is exceeded and the number of the unit that exceeds the limit; the area locking stage receives the number of the unit that exceeds the limit, the peak distribution of adjacent units and the current position of the welding torch, and outputs the local overheated area that needs to have its stiffness reduced; the duty cycle execution stage receives the number of the local overheated area and the preset tolerance table, and outputs the graded duty cycle reduction command for the corresponding coil. The physical relationship represented by this model is as follows: the more concentrated the local heat input, the more obvious the inward back pressure tendency of the shell, and the higher the peak pressure of the support contact layer; when this peak value approaches the safe boundary that the material can withstand under the current thermal state, if the high stiffness support continues to be maintained, the risk of residual constraint stress and indentation after welding will increase; if the modulus of magnetorheological elastomer 19 is moderately reduced only in the corresponding area, the heated area can obtain a limited yield space, thereby reducing stress concentration without damaging the centering support of other areas; Therefore, the causal chain of this model can be clearly stated as follows: because the local maximum compressive force is close to the threshold force line, the duty cycle of the corresponding region is reduced; because the decrease in duty cycle leads to the weakening of the magnetic chain structure inside the magnetorheological elastomer 19, the stiffness of the contact layer in this region decreases and allows the heated area to compliantly absorb deformation; because the yielding action is limited to the local overheated area, the overall axial stability is still maintained by the other high-stiffness support units. Specifically, when executing S602 and S603, the internal data flow and underlying interaction process are as follows: After the microprocessor core of controller 11 determines that the local maximum extrusion pressure has reached the threshold, it generates a derating instruction data packet; the data packet contains the channel address of the target support unit and the target duty cycle; The instruction is transmitted to the pulse width modulation timer peripheral module via the internal high-speed bus. The pulse width modulation timer immediately updates the comparison register value of the corresponding channel, thereby changing the square wave duty cycle output to the power drive circuit. The power drive circuit adjusts the average current flowing through the excitation copper conductor coil bundle 18 according to the updated pulse width modulation signal, causing the magnetic field strength in the magnetorheological elastomer 19 to weaken within milliseconds, thus realizing the transformation into a compliant rheological state with low shear modulus. Through the flow of the aforementioned data and control signals, data interaction and communication between the modules in the system are realized, and the corresponding hardware execution actions are completed.

[0026] Following the steps in S603 are: S701. After the magnetorheological elastomer 19 in the corresponding region is converted into a low shear modulus, the back pressure displacement of the pressure-transmitting plunger 9 caused by the internal pressure of the shell is obtained. S702, The pressure is transmitted to the pressure-transmitting plunger 9 located in the high-rigidity support area through the liquid silicone oil 14 in the first micro-guide tube 12 or the second micro-guide tube 13. S703. The pressure transmitted in the opposite direction forces the pressure-transmitting plunger 9 to extend outward, forming a reverse support force to counteract the eccentric offset caused by unilateral deformation. To prevent the centering cantilever spindle 2 from becoming unbalanced after the stiffness of the local support unit decreases and yields, a counter-hydraulic compensation structure should be used for synchronous support reinforcement after the local yield occurs. In S701, the controller 11 acquires the back pressure displacement of the pressure-transmitting push plunger 9 caused by a significant decrease in local contact stiffness. The back pressure displacement can be obtained in several ways: it can be indirectly calculated by the further change in the phase hysteresis angle of the corresponding excitation unit, or it can be measured by the displacement sensing element set at the end of the push-pull core rod 5, inside the centering drive core 7, or at the end of the plunger. The displacement resolution is preferably 0.01mm to 0.05mm. Since the local support suspension tile 10 is more likely to retract inward after the stiffness of the magnetorheological elastomer 19 decreases, this retraction will be converted into the displacement of the pressure-transmitting push plunger 9 being pressed into the blind hole along the wedge-shaped inclined surface. In S702, after the pressure-transmitting push plunger 9 is pressed in, the liquid silicone oil 14 at the bottom of the blind hole is pressurized. The pressure is transmitted through the first micro-guide tube 12 or the second micro-guide tube 13 to the other pressure-transmitting push plunger 9 in the opposite high-rigidity state. Because the volume compression of the liquid silicone oil 14 is small and the flow path is short, the pressure can quickly reach the opposite blind hole. In S703, after the pressure at the bottom of the opposing blind hole increases, the opposing pressure transmission pusher 9 extends outward and lifts the opposing support suspension tile 10 through its descending inclination plane 15, thereby increasing the radial support force of the opposing support point. Since the duty cycle of the opposing region is not reduced, the magnetorheological elastomer 19 still maintains a high modulus, so the opposing support point can provide a more stable reaction force. In this way, the local overheated area gains room to retreat, while the support points of the opposite non-heated area are simultaneously strengthened, forming a force balance correction along the transverse direction of the workpiece; after adopting this step, local thermal deformation is allowed to be released in the heated area, but the resulting spindle offset tendency is offset by the opposing mechanical hydraulic support, thereby keeping the overall machining baseline position from drifting significantly. The synergy between this structure and method is that the controller 11 is only responsible for identifying and triggering local stiffness reduction, while the pressure redistribution is completed by the internal micro-guide tube and liquid silicone oil 14. Therefore, the response path is short and the number of execution units is small, making it suitable for the heating position that changes continuously along the circumference during continuous circumferential welding. The significant decrease in local contact stiffness in S701 refers to the fact that due to the stiffness reduction operation after S603, the equivalent compressive modulus of the magnetorheological elastomer 19 composite layer in that region decreases significantly, and the inner wall of the shell continues to be pressed inward, causing the supporting suspension tile 10 to produce a detectable retraction state. The judgment criteria are preferably at least one of the following: the duty cycle of the corresponding unit has dropped to the preset tolerance ratio; the phase hysteresis angle of the corresponding unit continues to increase rapidly; the pusher piston of the corresponding unit generates back pressure displacement exceeding the minimum displacement threshold; the minimum displacement threshold is preferably 0.01mm to 0.10mm, used to eliminate small spurious changes caused by vibration noise and thermal disturbance; The preferred procedure for obtaining back pressure displacement in S701 is as follows: first, record the reference position of the piston before the support unit retracts; then, after executing S603, continuously collect the current position of the piston or its corresponding phase-converted displacement. Subtracting the current position from the reference position yields the actual back pressure displacement of the plunger pressing into the blind hole. If this displacement is greater than the minimum displacement threshold for multiple consecutive sampling periods, it is determined that local retraction has actually occurred, and this displacement value is used as the input of S702. The output of the process is the plunger back pressure displacement data used to characterize the degree of local retraction, which is sent to the opposing compensation judgment module. In S702, the pressure is transmitted to the pressure-transmitting push plunger 9, which is located in the high-rigidity support area, through liquid silicone oil 14. The physical meaning of this is to direct the back pressure released from the heated area to the non-heated area support unit that is 180° opposite to it in the circumferential direction, rather than spreading it to all support points. The so-called high stiffness working area refers to the opposing support area that has not been subjected to the duty cycle reduction operation and still maintains a high stiffness value or is at least higher than the preset tolerance ratio; the controller 11 can simultaneously latch the current duty cycle state of each unit after executing S602, so it can clearly determine which pair of opposing units is in a high stiffness state that can bear compensation. If a certain opposing unit is also in a state of reduced stiffness, the controller 11 may delay performing compensation judgment in that direction until it recovers to the load-bearing level, or transfer the auxiliary stabilization task to another pair of circumferential support units. The formation of reverse support force in S703 to counteract the eccentric offset caused by unilateral deformation means that after the opposing plunger pushes outward under the action of hydraulic transmission, the axial pushing displacement is converted into the radial outward displacement of the opposing support suspension block 10 through the wedge-shaped inclined plane relationship, so that the eccentric trend originally formed on the cross section of the workpiece due to unilateral retreat is counteracted by the opposing reinforcement support. The preferred processing logic is as follows: when the controller 11 confirms that a certain unit has experienced back pressure displacement, it reads the status of the opposing unit connected to it; if the opposing unit is in a high stiffness state, it allows the hydraulic spontaneous compensation to take effect and continues to monitor whether the overall phase distribution has returned to balance; if the local maximum extrusion pressure falls below the threshold after recovery, it maintains the current compensation state; if it still has not recovered, it can continue to reduce the duty cycle of the heated zone or finely adjust the total tension of the push-pull core rod 5. Thus, S701 to S703 realize the transmission and judgment of pressure and the adjustment of subsequent centering control; the above S701 to S703 can be summarized as the opposing compensation centering model; the purpose of this model is to use an internal closed hydraulic circuit to transfer the back pressure caused by the retreat to the opposing support unit that still maintains high stiffness after a certain local support unit is allowed to retreat due to active stiffness reduction, so as to counteract the eccentricity trend caused by unilateral retreat. The model logically includes three sequentially connected processing parts: the yield identification part receives back pressure displacement data, duty cycle status and phase hysteresis angle changes, and outputs whether a real local yield has occurred and the yield unit number; the pressure transmission part receives the yield unit number and its corresponding pair connection relationship, determines whether the first micro-guide tube 12 or the second micro-guide tube 13 should participate in pressure transmission, and outputs the opposite compensation direction. The compensation active part receives the opposite compensation direction, the current high stiffness state of the opposite unit, and the phase distribution changes obtained from continuous monitoring, and outputs whether to maintain the current compensation, whether to continue to reduce stiffness, or to fine-tune the total tension. The physical relationship represented by the model is as follows: the retraction of the heated zone support tile will press into the corresponding plunger, and the pressing into the plunger will increase the pressure of the liquid silicone oil 14 at its bottom; since the liquid silicone oil 14 is approximately incompressible and only connected in paired channels, this pressure is mainly transmitted to the opposing plungers at 180°. The opposing plungers extend outward under hydraulic pressure and convert the axial micro-displacement into radial outward force through wedge contact; therefore, the opposing region is supported and the heated region is allowed to retreat, and the tendency of the cross-sectional center to shift is mutually canceled. Therefore, the causal chain of the model can be clearly stated as follows: because the local yielding causes back pressure on the piston on this side, directional pressure transmission is formed in the hydraulic channel; because the directional pressure transmission only acts on the opposing high stiffness unit, it will not cause full-circumference loosening; because the opposing unit obtains additional external support, the eccentricity caused by the single-sided yielding is compensated, and the overall stable state is maintained. Specifically, during the execution of S701 to S703, the quantitative deduction logic of data flow and physical feedback forming a closed loop is as follows: the controller 11 continuously reads the current position data of the pressure-transmitting push plunger 9 from the displacement sensor or phase inversion module, and performs a difference operation between it and the reference position data latched in memory in the digital comparator. For a specific example, if the calculated back pressure displacement is 0.08 mm, which is greater than the set minimum displacement threshold of 0.05 mm, the controller 11 will confirm that a significant decrease in local contact stiffness has occurred; at this time, the liquid silicone oil 14 at the physical level will passively transmit the pressure to the opposite blind hole. The controller 11 simultaneously reads the duty cycle status flag of the opposing channel. If it is confirmed that the channel is in a high-rigidity support state, the software logic does not intervene in the passive hydraulic compensation, but switches to the monitoring mode to collect the overall phase distribution data in real time. If the phase hysteresis fluctuation rate of the opposing support unit is detected to be lower than the preset value... If the overall eccentricity calculation value is less than the preset safety tolerance, then it is determined that the eccentricity offset caused by unilateral thermal deformation is successfully eliminated through the counter-reaction force compensation; this process realizes the coordinated control between software monitoring data and physical hydraulic transmission, and completes the data mapping in the judgment process.

[0027] In step S2, the controller 11 drives the duty cycle to a value of 90%, which triggers the magnetic field lines that penetrate the low-carbon magnetic pure iron sheet 17, causing the iron powder in the magnetorheological elastomer 19 to be oriented along the direction of the magnetic field lines to form a chain-like load-bearing structure. In step S2, in order to ensure that the supporting suspension tile 10 has sufficient initial compressive strength after clamping is established, the controller 11 adjusts the duty cycle of the driving square wave of the excitation copper conductor coil bundle 18 to about 90%. It should be noted that the magnetic field lines mentioned later are physically passing through the magnetic field of the low-carbon magnetic pure iron sheet. The approximately 90% here can be set in the range of 80% to 95% according to the coil resistance, supply voltage, thermal balance capability and target stiffness. The driving signal is preferably a high-frequency DC modulated square wave with a frequency of 200Hz to 5000Hz, more preferably 500Hz to 2000Hz, to balance magnetic response speed and coil heating control. When a high duty cycle excitation signal is applied to the excitation copper conductor coil bundle 18, the low-carbon magnetic pure iron sheet 17 forms a stable magnetic circuit, and the magnetic lines of force pass through the magnetorheological elastic body 19 region on its outer side, so that the internal iron powder is arranged along the magnetic field direction and forms a chain-like, columnar or mesh-like connection structure. This internal structural change increases the equivalent compressive modulus and shear modulus of the magnetorheological elastomer 19, causing the support surface to transition from a low-stiffness contact state to a high-stiffness load-bearing state. In this state, the non-magnetic austenitic stainless steel protective layer 20 on the outer surface of the supporting suspension tile 10 can more stably bear the load on the inner wall of the spindle motor housing, reducing the displacement of the housing under cold clamping and mechanical disturbance of the welding torch. To ensure that the internal wires and filling materials under high duty cycle do not age due to overheating and overload, the controller 11 uses a coil temperature rise model to limit the maximum continuous energization time. The determination mechanism of this coil temperature rise model does not rely on conventional empirical estimation, but rather establishes a clear quantitative flow path through parameter logic decomposition at the bottom layer of the controller 11: During the execution of the controller 11, the voltage of the drive link, the actual feedback current, and the equivalent impedance value extracted from the phase angle are extracted first to determine the instantaneous input active power of the coil per unit time; its calculation formula is as follows: In the formula, To input active power in real time, For the voltage of the drive link, This is the actual feedback current. The absolute phase difference between voltage and current, determined by the zero-crossing time difference, is... Its relative phase hysteresis angle compared to the aforementioned angle used to reflect the amount of deformation It has a mapping relationship, and at the same time, it uses a timer interrupt to record the cumulative integral duration of the channel when it enters a 90% duty cycle; Let's take a quantitative simulation as an example: Suppose the system arithmetic analysis shows that the coil input power consumption is 20W, while the cumulative timing shows that it has been continuously powered on for 150 seconds. The arithmetic unit determines that the heat reserve of the injected coil reaches 3000J based on the multiplication calculation. The controller 11 uses the pre-installed comprehensive heat dissipation coefficient in the program table. This coefficient, defined in W / ℃, characterizes the overall thermal conductivity attenuation capability that incorporates the effective heat dissipation area parameter. Multiplying this by the current temperature difference between the coil and the environment, and the cumulative energizing time, the controller calculates the environmental energy loss. The result is then converted to absolute Joules and subtracted, yielding a net accumulated heat of 2500J. The general calculation formula for the coil temperature rise logic is: In the formula, For net heat accumulation, Provide the instantaneous power consumption value for the coil input. To calculate the total power-on time, To consider the overall heat dissipation coefficient, The current temperature difference between the coil and the environment; if the real-time calculated value of 2500J approaches or exceeds the system's configured temperature aging safety threshold, the digital trigger will immediately lower the relevant pulse width modulation duty cycle to implement rapid cooling and downsizing, or swap and replace the four support elements, so that other load-bearing tiles located on the opposite side or adjacent area of ​​the unaffected area are immediately raised to 90% duty cycle to take over their supporting role, while the tile that is overheating will safely fall back and ensure that the centering axis does not drift radially; The above control system enables safe fuse control of coil temperature rise; the high-stiffness initial support established by this high duty cycle excitation step is the basis for subsequent phase hysteresis angle detection and local stiffness reduction, because the conversion relationship between radial compression deformation and stress peak value is stable only when the support layer has a clear reference modulus.

[0028] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A welding device for machining a spindle motor housing, characterized in that, include: Positioning the basic operating console (1); The centering cantilever spindle (2) is suspended and fixedly connected to the positioning base operating table (1). The centering cantilever spindle (2) has a central through hole (3) inside and four rectangular guide slots (4) are provided on the outside of the centering cantilever spindle (2) along the circumferential direction. The push-pull core rod (5) slides through the central through hole (3) of the centering cantilever spindle (2), and the push-pull core rod (5) is connected to an external push-pull servo motor (6). The centering drive core (7) is connected to the end of the push-pull core rod (5). The centering drive core (7) is provided with four blind holes (8) and four pressure-transmitting push plungers (9). Four supporting suspension blocks (10) are respectively set in the four rectangular guide slots (4) to perform radial sliding, and the supporting suspension blocks (10) press against the upper part of the pressure transmission push plunger (9); The supporting suspension tile (10) is equipped with an electromagnetic variable stiffness component for adjusting the contact stiffness. The controller (11) is electrically connected to the push-pull servo main motor (6) and the electromagnetic variable stiffness assembly to perform control.

2. The welding device for machining a spindle motor housing according to claim 1, characterized in that, The bottoms of the two accommodating blind holes (8) corresponding to the 0° and 180° positions are connected by a first micro-guide tube (12), and the bottoms of the two accommodating blind holes (8) corresponding to the 90° and 270° positions are connected by a second micro-guide tube (13).

3. The welding apparatus for machining a spindle motor housing according to claim 2, characterized in that, Liquid silicone oil (14) is filled in the bottom gap of the first micro-guide tube (12), the second micro-guide tube (13) and the four accommodating blind holes (8). The four pressure-transmitting push plungers (9) are respectively slidably disposed on the upper end of the four accommodating blind holes (8). The end of the pressure-transmitting push plunger (9) facing outward has a downward tilt plane (15).

4. The welding apparatus for machining a spindle motor housing according to claim 3, characterized in that, The bottom arc surface inside the supporting suspension block (10) has an upward tilt sliding surface (16), which matches the pressure across the downward tilt plane (15) of the pressure transmission push plunger (9).

5. The welding apparatus for machining a spindle motor housing according to any one of claims 1 to 4, characterized in that, The outer surface of the supporting suspension tile (10) is provided with a low-carbon magnetic pure iron sheet (17), and an excitation copper conductor coil bundle (18) connected to and controlled by the controller (11) is wound in the groove of the edge of the low-carbon magnetic pure iron sheet (17).

6. The welding apparatus for machining a spindle motor housing according to claim 5, characterized in that, The excitation copper conductor coil bundle (18) and the low-carbon magnetic pure iron sheet (17) are coated with a magnetorheological elastomer (19) doped with iron powder. The magnetorheological elastomer (19) is covered with a non-magnetic austenitic stainless steel protective layer (20).

7. A welding control method for machining a spindle motor housing, applied to the welding apparatus for machining a spindle motor housing as described in claim 6, characterized in that, include: S1. Control the push-pull servo main motor (6) to drive the push-pull core rod (5) to move, and push the supporting suspension tile (10) outward through the centering drive core (7) and the pressure transmission push plunger (9) to form an initial forced shaping support and center locking; S2. Obtain the compressive force on the supporting suspended tile (10). When the compressive force reaches full load, the controller (11) outputs a continuous high-frequency DC modulated current square wave to the excitation copper conductor coil bundle (18). S3. Real-time acquisition of the phase hysteresis angle on the excitation copper conductor coil bundle (18); S4. Calculate the radial compression deformation of the spatial thickness based on the phase hysteresis angle. S5. The local maximum compressive force is obtained by converting the radial compression deformation and the equivalent stiffness resistance coefficient.

8. The control method according to claim 7, characterized in that, The step S5 is followed by: S601. Compare the local maximum compressive force with the yield stress safety threshold curve; S602. Determine whether the local maximum compressive force corresponding to a certain supporting suspension tile (10) reaches the yield stress safety threshold curve; if yes, define the area corresponding to the supporting suspension tile (10) as a local overheating area, and control the pulse duty cycle of the excitation copper conductor coil bundle (18) in the local overheating area to be reduced to a preset width limit ratio; if no, maintain the high stiffness of the corresponding area. S603. By reducing the pulse duty cycle, the magnetorheological elastomer (19) in the locally overheated region is transformed into a compliant rheological state with low shear modulus.

9. The control method according to claim 8, characterized in that, The step S603 is followed by: S701. Obtain the back pressure displacement of the pressure-transmitting plunger (9) caused by the internal pressure of the housing after the magnetorheological elastomer (19) in the corresponding region is converted into a low shear modulus. S702, The pressure is transmitted to the pressure-transmitting plunger (9) opposite to the high-rigidity support area through the liquid silicone oil (14) in the first micro-guide tube (12) or the second micro-guide tube (13). S703. The opposing pressure is forced to push the opposing pressure-transmitting plunger (9) outward, forming a reverse support force to counteract the eccentric offset caused by unilateral deformation.

10. The control method according to claim 7, characterized in that, In step S2, the controller (11) drives the duty cycle to a value of 90%, which triggers the magnetic field lines that penetrate the low-carbon magnetic pure iron sheet (17), causing the iron powder in the magnetorheological elastomer (19) to be oriented along the direction of the magnetic field lines to form a chain-like bearing structure.

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