Multi-specification applicable spindle motor shaft polishing device and method thereof

Abstract

The present application relates to the field of machining and automation manufacturing, in particular to a multi-specification applicable spindle motor shaft polishing device; it comprises a machine tool bed body, a spindle, a tailstock, a support, a polishing mechanism and a controller arranged thereon; the system tightens the center hole of the workpiece end through an internal expanding chuck, realizes positioning of both ends by cooperating with a pneumatic center, and uses a servo-driven V-shaped support block to resist the outer circle of the workpiece radially; the core is to adopt an internal fixed clamping mode, which does not block the outer circle surface of the motor shaft, leaving sufficient grinding space for the profiled grinding wheel; the present application overcomes the defect of traditional fixed center frame type changing complexity, and can adapt to motor shafts of different outer diameters and lengths without frequent manual replacement of support parts, effectively improving the adaptability of multi-specification machining.

Description

Technical Field

[0001] This invention relates to the field of machining and automated manufacturing, specifically to a multi-specification applicable spindle motor shaft grinding device and method. Background Technology

[0002] In the current environment of external cylindrical grinding of spindle motor shafts, workpieces often exhibit multiple specifications and significant variations in length and outer diameter. Simultaneously, the grinding operation continuously generates radial cutting forces, causing slender shafts to undergo bending deformation. To achieve workpiece positioning and grinding, existing solutions generally employ a traditional mechanical structure with external cylindrical clamping and a fixed center rest support. This means that when faced with workpieces of different specifications, the machine is manually stopped to replace the center rest support with one matching the specific outer diameter, and the tailstock span is readjusted. Meanwhile, independently deployed optical or contact measuring devices are used to obtain the outer diameter and machining allowance. Although this method… While the solution possesses a certain processing capability in single-specification batch processing scenarios, it relies heavily on manual physical shape change and offline debugging. Furthermore, the fixed support components cannot maintain real-time fit as the outer diameter of the workpiece decreases during material removal, and cannot actively compensate for instantaneous stress deformation caused by grinding load fluctuations. In addition, the independently external measuring elements are easily interfered with or even fail in harsh processing areas filled with grinding fluid, abrasive particles, and metal dust, resulting in cumbersome multi-specification processing switching steps, lack of dynamic stress support response, and difficulty in maintaining dimensional control accuracy under complex working conditions.

[0003] Therefore, improving the accuracy of adaptive identification of outer diameter and the real-time performance of dynamic support compensation in the grinding of multi-specification motor shafts 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 multi-specification applicable spindle motor shaft grinding device and method. Specifically, the technical solution of the present invention is as follows: A multi-specification applicable spindle motor shaft grinding device, including: The machine tool bed that provides basic support; The spindle mechanism located on the upper left side of the machine tool bed includes a spindle box, a rotary spindle supported in the spindle box, and an internal expansion chuck connected to the right end face of the rotary spindle. The tailstock mechanism located on the upper right side of the machine tool bed includes a tailstock slidably connected to the machine tool bed and a pneumatic center installed inside it. The pneumatic center is coaxial with the rotary spindle and works with an internal expansion chuck to position both ends of the motor shaft. The support mechanism located in the middle and rear part of the machine tool bed includes a support servo motor fixed to the machine tool bed, a ball screw connected to the motor, a support slide slidably connected to the machine tool bed and connected to the nut seat of the ball screw, and a V-shaped support block fixed to the support slide. The V-shaped support block has an opening facing the axis of the rotary spindle and radially abuts against the outer cylindrical surface of the motor shaft. The grinding mechanism located in front of the machine tool bed includes a cross slide driven by a feed servo motor, a grinding wheel spindle box connected to the cross slide, and a forming grinding wheel mounted thereon. The controller connects to and controls the operation of the spindle mechanism, tailstock mechanism, support mechanism, and grinding mechanism.

[0005] In one possible implementation, the internal expansion chuck includes a tapered tie rod and a slotted expansion sleeve, and the spindle mechanism further includes a cylinder connected to the tapered tie rod, wherein the cylinder pushes the tapered tie rod to move axially, causing the slotted expansion sleeve to expand radially to tighten the inner wall of the central hole at the end of the motor shaft.

[0006] In one possible implementation, a pair of angular contact ball bearings are provided inside the spindle box, and the rotary spindle is supported inside the spindle box by the angular contact ball bearings.

[0007] In one possible implementation, the machine tool bed is provided with a dovetail guide rail, and the tailstock is slidably connected to the machine tool bed through the dovetail guide rail.

[0008] In one possible implementation, a linear guide rail is provided at the rear of the middle section of the machine tool bed, and the support slide is slidably connected to the machine tool bed via the linear guide rail.

[0009] In one possible implementation, the support mechanism further includes a swivel coupling, through which the support servo motor is directly connected to the ball screw.

[0010] In one possible implementation, the V-shaped support block is made of polyurethane.

[0011] Grinding methods for motor shafts of multi-specification applicable spindle motors include: S1. Control the internal expansion chuck to support the center hole at the left end of the motor shaft, and control the pneumatic tip to extend and press against the center hole at the right end of the motor shaft; S2. Control the support servo motor to drive the ball screw to rotate, thereby moving the V-shaped support block towards the motor shaft, and monitor the drive current of the support servo motor. S3. When the driving current is less than or equal to the support no-load current threshold, control the support servo motor to continue driving; when the driving current is greater than the support no-load current threshold, control the support servo motor to stop moving and calculate the actual outer diameter of the current motor shaft. S4. Control the rotary spindle to drive the motor shaft to rotate, and control the feed servo motor to drive the forming grinding wheel to feed towards the motor shaft to start grinding; S5. Monitor the current fluctuation of the feed servo motor in real time, calculate the estimated radial deformation of the motor shaft, and control the support servo motor to drive the V-shaped support block forward to perform compensating feed in real time to offset the deformation caused by the radial grinding force. S6. As the grinding proceeds, the V-shaped support block is controlled to continuously move forward while maintaining a constant contact current, and the real-time following displacement of the V-shaped support block is recorded. S7. Calculate the real-time outer diameter of the motor shaft. When the real-time outer diameter is greater than the target machining outer diameter, control the feed servo motor to continue driving. When the real-time outer diameter is less than or equal to the target machining outer diameter, control the feed servo motor to drive the forming grinding wheel to retreat quickly, and control the support servo motor to drive the V-shaped support block to return to the initial position.

[0012] In one possible implementation, the method for calculating the actual outer diameter of the current motor shaft in step S3 includes: reading the number of rotation pulses of the support servo motor from the initial position to the current position; multiplying the number of rotation pulses by the lead conversion factor of the ball screw to obtain the linear displacement; subtracting the linear displacement from the preset maximum stroke, and then multiplying by the trigonometric function conversion factor related to the opening angle of the V-shaped support block to calculate the actual outer diameter of the current motor shaft.

[0013] In one possible implementation, the method for calculating the radial deformation estimate of the motor shaft in step S5 includes: when the current of the feed servo motor is greater than the feed no-load current, taking the difference between the real-time current of the feed servo motor and the feed no-load current as the current increase, multiplying it by the stiffness conversion factor to obtain the radial deformation estimate of the motor shaft; converting the radial deformation estimate into the number of compensation pulses of the support servo motor to control the support servo motor to drive the V-shaped support block to advance slightly forward.

[0014] The present invention has the following beneficial effects: 1. This device uses an internal expansion chuck to support the center hole at the end of the motor shaft, and uses a pneumatic center to achieve positioning at both ends. This clamping method is fixed from the inside and does not obstruct the outer surface of the motor shaft, leaving sufficient grinding space for the forming grinding wheel. At the same time, combined with the tailstock that is slidably connected to the machine tool bed and the V-shaped support block driven by the support servo motor, the equipment can adapt to workpieces with different outer diameters and lengths without frequent manual replacement of support components, effectively overcoming the shortcomings of the traditional fixed center rest which is cumbersome to change. 2. This method monitors the drive current of the support servo motor and stops the movement when the drive current exceeds the support no-load current threshold. It also uses the number of rotation pulses read to accurately calculate the actual outer diameter. In addition, it calculates the radial deformation estimate by monitoring the current fluctuation of the feed servo motor in real time, and then controls the V-shaped support block to perform compensating feed forward to dynamically offset the radial elastic deformation caused by the grinding force. This avoids misjudging the radial stress deformation as material removal, thereby ensuring stable machining accuracy. 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 main shaft mechanism of the device; Figure 3 This is a schematic diagram of the device's support mechanism. Figure 4 This is a flowchart of the method of the present invention.

[0016] In the diagram: 1. Machine tool bed; 2. Spindle mechanism; 3. Spindle box; 4. Rotary spindle; 5. Internal expansion chuck; 6. Tailstock mechanism; 7. Tailstock; 8. Pneumatic center; 9. Support mechanism; 10. Support slide; 11. Support servo motor; 12. Ball screw; 13. V-shaped support block; 14. Grinding mechanism; 15. Cross slide; 16. Grinding wheel spindle box; 17. Forming grinding wheel; 18. Feed servo motor; 19. Controller; 20. Tapered tie rod; 21. Slotted expansion sleeve; 22. Cylinder; 23. Angular contact ball bearing; 24. Dovetail guide rail; 25. Linear guide rail; 26. Plum blossom coupling; 27. Ball screw nut seat. 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 multi-specification applicable spindle motor shaft grinding device, including: like Figure 1 As shown, the machine tool bed 1 serves as the basic support; The spindle mechanism 2, located on the upper left of the machine tool bed 1, includes a spindle box 3, a rotary spindle 4 supported in the spindle box 3, and an internal expansion chuck 5 connected to the right end face of the rotary spindle 4. The tailstock mechanism 6 located on the upper right side of the machine tool bed 1 includes a tailstock 7 slidably connected to the machine tool bed 1 and a pneumatic center 8 installed inside it. The pneumatic center 8 is coaxial with the rotary spindle 4 and works with the internal expansion chuck 5 to position both ends of the motor shaft. The support mechanism 9 located at the rear of the machine tool bed 1 includes a support servo motor 11 fixed to the machine tool bed 1, a ball screw 12 connected to the motor, a support slide 10 slidably connected to the machine tool bed 1 and connected to the nut seat 27 of the ball screw 12, and a V-shaped support block 13 fixed to the support slide 10. The V-shaped support block 13 has its opening facing the axis of the rotary spindle 4 and radially abuts against the outer cylindrical surface of the motor shaft. The grinding mechanism 14 located in front of the machine tool bed 1 includes a cross slide 15 driven by a feed servo motor 18, a grinding wheel spindle box 16 connected to the cross slide 15, and a forming grinding wheel 17 mounted thereon. Controller 19 connects to and controls the operation of spindle mechanism 2, tailstock mechanism 6, support mechanism 9 and grinding mechanism 14; The machine tool bed 1 is made of cast iron or welded annealed steel structure, and its length can be 1500mm to 3000mm. The upper surface of the bed forms the installation area of ​​the spindle mechanism 2 and the moving area of ​​the tailstock mechanism 6. The middle rear of the bed forms the installation area of ​​the support mechanism 9, and the front of the bed forms the installation area of ​​the grinding mechanism 14, so as to ensure that after the motor shaft is clamped, the support position is on the opposite side of the direction of the grinding wheel force. The spindle box 3 in the spindle mechanism 2 is fixed to the mounting surface on the left side of the machine tool bed 1 by bolts. The rotary spindle 4 can be driven to rotate by a servo spindle motor or a frequency converter motor. The speed can be set from 500 r / min to 6000 r / min to adapt to the grinding linear speed requirements of motor shafts with different diameters. The internal expansion chuck 5 is installed on the right end face of the rotary spindle 4 and is used to clamp the center hole of the left end of the motor shaft within the size range of the outer circumference of the motor shaft end face, thereby leaving working space for the radial cutting of the forming grinding wheel 17. The tailstock mechanism 6 is located on the right side of the machine tool bed 1. The tailstock 7 can be adjusted along the length of the bed. The pneumatic center 8 is installed inside the tailstock 7. After the pneumatic center 8 extends out, it forms a two-end positioning with the internal expansion chuck 5. The positioning reference is the center holes at both ends of the motor shaft. Therefore, the axis of the motor shaft is consistent with the axis of the rotary spindle 4. The support slide 10 in the support mechanism 9 moves in the front-to-back direction. The support servo motor 11 drives the V-shaped support block 13 to approach or move away from the outer cylindrical surface of the motor shaft through the ball screw 12. The opening of the V-shaped support block 13 faces the axis of the rotary spindle 4, so that its two inclined surfaces can simultaneously contact the outer cylindrical surface of the motor shaft and generate stable radial support. Compared with the fixed center support, the support mechanism 9 not only serves as a machining support but also identifies the outer diameter of motor shafts of different specifications, reducing the need to replace different support components when changing models; the grinding mechanism 14 is located in front of the machine tool bed 1, the cross slide 15 provides the grinding wheel spindle box 16 with radial and axial movement freedom, and the feed servo motor 18 drives the cross slide 15 to move the forming grinding wheel 17 close to the motor shaft for grinding; The controller 19 can be a combination of a programmable logic controller and a motion control card, or a combination of an industrial computer and a servo driver bus. The controller 19 is connected to the actuators and current acquisition units of the spindle mechanism 2, tailstock mechanism 6, support mechanism 9 and grinding mechanism 14 respectively. The current acquisition unit is set inside the driver of the corresponding servo motor, or is connected in series as an independent sensor in the power supply circuit of the support servo motor 11 and the feed servo motor 18. It receives information such as the current of the support servo motor 11, the current of the feed servo motor 18, the pulse position, and the pneumatic execution status, and controls clamping, support, grinding, compensation, and tool retraction according to the preset program. This structure allows the same equipment to accommodate spindle motor shafts with different shaft diameters and lengths, effectively improving the equipment's versatility and adaptability.

[0019] like Figure 2 As shown, the internal expansion chuck 5 includes a tapered tie rod 20 and a slotted expansion sleeve 21. The main spindle mechanism 2 also includes a cylinder 22, which is connected to the tapered tie rod 20. The cylinder 22 pushes the tapered tie rod 20 to move axially, causing the slotted expansion sleeve 21 to expand radially to tighten the inner wall of the center hole at the end of the motor shaft. The tapered tie rod 20 in the internal expansion chuck 5 is axially arranged along the rotary spindle 4, and its front end forms a tapered surface. The slotted expansion sleeve 21 is sleeved on the outside of the tapered tie rod 20 and located in the mounting hole at the right end of the rotary spindle 4. The slotted expansion sleeve 21 has 3 to 8 axial slots evenly distributed in the circumferential direction, so that it has controllable radial elastic deformation capability. The cylinder 22 can be a double-acting cylinder 22 with a cylinder diameter of 32mm to 80mm and a stroke of 10mm to 40mm. The cylinder 22 is connected to the rear end of the tapered tie rod 20 via a connecting rod. In specific operation, the working air pressure of the cylinder 22 can be set to 0.4MPa to 0.6MPa to output an axial tensile force of about 300N to 1500N. After being amplified by the tapered surface, this axial tensile force can generate sufficient radial clamping force on the inner wall of the center hole of the motor shaft by the slotted expansion sleeve 21, ensuring that the workpiece does not circumferentially slip or axially move under grinding stress. When the cylinder 22 outputs axial tension or thrust, the tapered tie rod 20 generates axial displacement relative to the slotted expansion sleeve 21, and the tapered surface cooperates with the inner tapered hole of the slotted expansion sleeve 21, causing the outer circle of the slotted expansion sleeve 21 to expand radially and form an interference clamp with the inner wall of the central hole at the end of the motor shaft. Since the clamping part is located inside the center hole of the motor shaft, the outer surface of the motor shaft is not blocked by the clamping element, and the forming grinding wheel 17 can complete the grinding at a preset position near the shaft end; the cone angle of the tapered tie rod 20 can be set from 6° to 16°. When the cone angle approaches the lower limit of the set range, the self-locking effect is enhanced; when the cone angle approaches the upper limit of the set range, the release response time is shortened. It can be matched and selected according to the target clamping force and the set action response time. The outer circular surface of the slotted expansion sleeve 21 can be hardened or plated to reduce wear caused by repeated clamping. When this clamping method is used in conjunction with the pneumatic center 8 of the tailstock 7, only the position of the tailstock 7 needs to be adjusted for motor shafts of different lengths without the need to replace the outer chuck jaws, thus achieving adaptive clamping of workpieces of different lengths.

[0020] An angular contact ball bearing 23 is installed inside the spindle box 3, and the rotary spindle 4 is supported inside the spindle box 3 by the angular contact ball bearing 23; The angular contact ball bearings 23 in the spindle box 3 are used to bear the radial and axial loads on the rotating spindle 4 during the grinding process. The angular contact ball bearings 23 can be arranged in pairs back to back or face to face. The back to back arrangement is suitable for improving the spindle support span and overturning stiffness. To reduce radial runout at the spindle end, the angular contact ball bearing 23 can be a precision bearing with a contact angle of 15°, 25° or 40°, and the bearing preload can be set by preloading with a spacer or locking nut; the preload amount can be set according to the spindle speed and heat generation, usually keeping the radial runout at the front end of the rotary spindle 4 within 0.005mm; The rotary spindle 4 is positioned in the spindle box 3 through the shaft shoulder, lock nut and bearing seat hole. The spindle box 3 can also be provided with a grease cavity or oil-air lubrication channel to maintain the stability of bearing operation. The function of the angular contact ball bearing 23 support structure is not only to realize the spindle rotation, but also to ensure that the spatial position of the motor shaft rotation axis relative to the forming grinding wheel 17 is stable after the internal expansion chuck 5 clamps the motor shaft, so that the contact identification position of the V-shaped support block 13 and the actual grinding position are maintained in a corresponding relationship. If the spindle support stiffness is insufficient, the mechanical state reflected by the current of the support servo motor 11 and the current of the feed servo motor 18 will deviate, and the accuracy of dimension recognition and support compensation will decrease. Therefore, this bearing support form is the basic condition for realizing the reliability of subsequent current monitoring and displacement conversion.

[0021] The machine tool bed 1 is equipped with a dovetail guide rail 24, and the tailstock 7 is slidably connected to the machine tool bed 1 through the dovetail guide rail 24; The dovetail guide rail 24 on the machine tool bed 1 extends along the motor shaft axis. The bottom of the tailstock 7 forms a guide surface that mates with the dovetail guide rail 24. Strips can be installed between the guide surfaces to adjust the mating clearance and maintain smooth movement. The guide angle of the dovetail guide rail 24 can be 45° to 60°, which ensures that the tailstock 7 is not prone to lateral displacement when subjected to clamping force, and facilitates manual or mechanical adjustment of the tailstock 7 position. The length of the tailstock 7 can be roughly adjusted according to the motor shaft specifications and fixed in the required position by locking bolts or hydraulic locking devices; For motor shafts with lengths from 200mm to 1200mm, the movement of the tailstock 7 on the dovetail guide rail 24 can cover the above range, and the extension of the pneumatic center 8 can be set from 10mm to 30mm to absorb different workpiece length errors and clamping tolerances. The use of dovetail guide rail 24 for sliding connection instead of fixed tailstock 7 allows one set of equipment to process motor shafts of various lengths. On the other hand, the surface contact form of dovetail guide rail 24 improves the vibration resistance of the support system, and the tailstock 7 is less prone to local deformation common in point contact guides when under stress. The axial movement of the pneumatic center 8 within the tailstock 7 is coordinated with the length adjustment of the tailstock 7 on the dovetail guide rail 24, forming a variable-pitch end-positioning structure between the internal expansion chuck 5 and the pneumatic center 8, which is beneficial for achieving stable clamping and positioning of motor shafts of different lengths.

[0022] A linear guide rail 25 is provided at the rear of the middle part of the machine tool bed 1, and the support slide 10 is slidably connected to the machine tool bed 1 through the linear guide rail 25. The linear guide rail 25 at the rear of the middle part of the machine tool bed 1 is arranged in a direction perpendicular to the motor shaft axis, preferably in the front-to-back direction. The support slide 10 cooperates with the linear guide rail 25 through the guide rail slider, so that the V-shaped support block 13 can perform high repeatability linear movement between near the motor shaft and far from the motor shaft. The linear guide 25 can be made of two parallel roller guides or ball guides. The distance between the guide sliders is determined according to the length of the support slide 10, and can be from 120mm to 300mm, so as to improve the ability of the support mechanism 9 to resist grinding reaction force. The total stroke of the support slide 10 on the linear guide 25 can be set from 30mm to 120mm to cover the support and measurement displacement requirements of motor shafts with different outer diameters. The direction of movement is consistent with the center line of the opening of the V-shaped support block 13. Therefore, the linear displacement driven by the ball screw 12 can be directly converted into the contact displacement of the V-shaped support block 13 on the motor shaft and the following displacement generated by grinding. Since the support slide 10 and the machine tool bed 1 use 25 pairs of standardized linear guides, the guiding friction resistance is relatively stable. The no-load current threshold of the support servo motor 11 can be calibrated during the equipment debugging stage. Subsequently, by monitoring the rise of the current, it can be determined whether the V-shaped support block 13 contacts the outer cylindrical surface of the motor shaft. If a regular sliding guide is used, the fluctuation of friction will exceed the preset range, and the stability of the current threshold judgment will be reduced. Therefore, the linear guide 25 is directly related to the accuracy of outer diameter recognition and the sensitivity of compensation control.

[0023] like Figure 3 As shown, the support mechanism 9 also includes a plum blossom coupling 26, through which the support servo motor 11 is directly connected to the ball screw 12. The plum blossom coupling 26 in the support mechanism 9 is installed between the output shaft of the support servo motor 11 and the input end of the ball screw 12. The plum blossom coupling 26 includes two metal claw discs and an elastic body located in the middle. The elastic body transmits torque and compensates for radial, angular and axial installation errors within a preset range between the shaft of the support servo motor 11 and the shaft of the ball screw 12. The servo motor 11 and the ball screw 12 are directly connected without a gear reduction mechanism or belt drive mechanism. The rotational pulses output by the servo motor 11 directly correspond to the rotational angular displacement of the ball screw 12 and directly correspond to the linear displacement of the V-shaped support block 13. Taking a ball screw with a lead of 12mm / r and a servo motor encoder with a resolution of 10000p / r as an example, the single-pulse linear displacement resolution can reach 0.0005mm, which makes it easy to convert the contact recognition displacement and support compensation displacement into calculable dimensional quantities. Compared with rigid couplings, plum blossom couplings 26 can reduce the impact of installation deviations on the additional load of bearings, and compared with belt drives, they can reduce elastic hysteresis and slippage risks. Therefore, they are more suitable for establishing a stable correspondence between the current changes of the supporting servo motor 11 and the actual mechanical contact state. This transmission structure enables the V-shaped support block 13 to perform both large-stroke specification identification displacement and micro-pulse-level compensation feed, thus ensuring the calculability of the support displacement.

[0024] V-shaped support block 13 is made of polyurethane material; The V-shaped support block 13 is made of polyurethane material. In this device, polyurethane material refers to a polymer support material with a certain elastic modulus, wear resistance and cutting fluid resistance. Its Shore hardness can be 80A to 98A. The included angle of the V-groove of the V-shaped support block 13 can be set to 60°, 90° or 120°. The 90° structure facilitates the establishment of a stable geometric conversion relationship between the displacement and the change in workpiece diameter. When polyurethane material comes into contact with the outer cylindrical surface of the steel motor shaft, it can form a surface contact tendency under contact stress below the preset yield strength, reducing the risk of local indentation and scratches, and is suitable for continuous contact support of the motor shaft in the rotating state; compared with metal roller support, polyurethane V-type support block 13 does not need to be equipped with independent rotating bearings, the structure is simplified, and in the presence of grinding fluid, abrasive particles and metal powder, it is not easy for the support to fail due to roller jamming; The slight elastic deformation of polyurethane material can also filter out some high-frequency vibrations, making the current signal of the supporting servo motor 11 more stable, which makes it easier to judge the contact state and maintain the fit by setting a threshold. To reduce wear, the working surface of the V-shaped support block 13 can adopt a replaceable insert structure. The insert can be replaced after it wears to the set limit, without affecting the repeatability of the ball screw 12 nut seat 27 and the support slide 10.

[0025] Example 2: like Figure 4 As shown, the grinding method for the motor shaft of a multi-specification applicable spindle motor includes: S1. Control the internal expansion chuck 5 to support the center hole at the left end of the motor shaft, and control the pneumatic center 8 to extend and press against the center hole at the right end of the motor shaft; S2. Control the support servo motor 11 to drive the ball screw 12 to rotate, thereby moving the V-shaped support block 13 towards the motor shaft, and monitor the drive current of the support servo motor 11. S3. When the driving current is less than or equal to the support no-load current threshold, control the support servo motor 11 to continue driving; when the driving current is greater than the support no-load current threshold, control the support servo motor 11 to stop moving and calculate the actual outer diameter of the current motor shaft. S4. Control the rotary spindle 4 to drive the motor shaft to rotate, and control the feed servo motor 18 to drive the forming grinding wheel 17 to feed towards the motor shaft to start grinding; S5. Monitor the current fluctuation of the feed servo motor 18 in real time, calculate the estimated radial deformation of the motor shaft, and control the support servo motor 11 to drive the V-shaped support block 13 forward to perform compensating feed in real time to offset the deformation caused by the radial grinding force. S6. As grinding proceeds, the V-shaped support block 13 is controlled to continuously move forward while maintaining a constant contact current, and the real-time displacement of the V-shaped support block 13 is recorded. S7. Calculate the real-time outer diameter of the motor shaft. When the real-time outer diameter is greater than the target machining outer diameter, control the feed servo motor 18 to continue driving. When the real-time outer diameter is less than or equal to the target machining outer diameter, control the feed servo motor 18 to drive the forming grinding wheel 17 to retreat quickly, and control the support servo motor 11 to drive the V-shaped support block 13 to return to the initial position. This grinding method is applicable to the above-mentioned device for automatically identifying and grinding spindle motor shafts with different outer diameters and lengths. In S1, the controller 19 sends a clamping command to the cylinder 22 of the spindle mechanism 2, so that the slotted expansion sleeve 21 of the internal expansion chuck 5 supports the center hole at the left end of the motor shaft. At the same time, it sends an extension command to the pneumatic tip 8 of the tailstock mechanism 6, so that the pneumatic tip 8 is pressed into the center hole at the right end of the motor shaft and forms an axial positioning force. The axial positioning force can be controlled within the range of 100N to 800N. In S2, the support servo motor 11 drives the ball screw 12 to rotate at a low speed, which can be selected from 10r / min to 100r / min. The purpose is to reduce the impact at the moment of contact and improve the accuracy of current threshold judgment. The controller 19 collects the current value fed back by the driver of the support servo motor 11 in real time. In S3, when the current value is not higher than the support no-load current threshold, it indicates that the V-shaped support block 13 has not yet made reliable contact with the motor shaft, and the controller 19 continues to output displacement pulses; when the current value is higher than the no-load current threshold, it indicates that the V-shaped support block 13 has made contact with the outer cylindrical surface of the motor shaft or the contact resistance has reached the set level, and the controller 19 immediately stops supporting the servo motor 11, calculates the current actual outer diameter of the motor shaft based on the recorded displacement data, and then subtracts it from the target machining outer diameter in the process database to obtain the total grinding allowance; the process database is pre-stored in the memory of the controller 19, and contains the target machining outer diameter, target surface roughness and corresponding feed speed parameters for motor shafts of different specifications; In S4, the rotary spindle 4 starts to rotate, and the rotation speed is selected according to the motor shaft material and the target surface roughness. The forming grinding wheel 17 is driven by the feed servo motor 18 to feed radially toward the motor shaft and begin grinding. In practice, for annealed steel motor shafts with diameters of 20mm to 50mm, the rotational speed of the spindle 4 can be set to 1500r / min to 3000r / min, the roughing feed speed of the forming grinding wheel 17 can be set to 0.5mm / min to 1.5mm / min, the fine grinding feed speed can be set to 0.05mm / min to 0.2mm / min, and the grinding depth is usually controlled between 0.01mm and 0.1mm to ensure the stability of the grinding process and avoid workpiece surface burns. In S5, the controller 19 continuously acquires the current fluctuation of the feed servo motor 18 and compares it with the no-load or light-contact current reference to obtain the current increase reflecting the increase in cutting resistance. The light-contact current reference refers to the drive current value when the forming grinding wheel 17 just contacts the workpiece but does not generate radial extrusion exceeding the preset deformation threshold. This value is calibrated by the controller 19 by identifying abrupt changes in the preset current fluctuation range that is slightly greater than the feed no-load current. The estimated radial deformation of the motor shaft is then calculated according to the established conversion relationship. The controller 19 calculates the compensation displacement of the support servo motor 11 based on the estimated value and drives the V-shaped support block 13 to feed forward slightly, so that the support force is adjusted according to the grinding force. In S6, as the forming grinding wheel 17 removes material, the outer diameter of the motor shaft continuously decreases. The controller 19 maintains the support servo motor 11 working near the contact threshold, so that the V-shaped support block 13 continuously fits the outer cylindrical surface of the motor shaft, and records the real-time follow-up displacement from the identified contact position to the current support position. In S7, the controller 19 subtracts the diameter reduction corresponding to the follow-up displacement from the initial outer diameter to obtain the real-time outer diameter of the motor shaft. When the real-time outer diameter is still greater than the target machining outer diameter, the feed servo motor 18 maintains the grinding feed. When the real-time outer diameter reaches the target machining outer diameter, the controller 19 issues a retraction command, the forming grinding wheel 17 retracts rapidly in the radial direction, the support servo motor 11 drives the V-shaped support block 13 to return to the initial position, the internal expansion chuck 5 and the pneumatic center 8 are released, and the single-piece machining is completed. This method uses the support displacement, support current, feed current and dimension calculation together to enable the support to have both specification recognition and grinding tracking functions, which is suitable for continuous switching of processing of workpieces of multiple specifications; among them, the support no-load current threshold is used to characterize the boundary current value of the support mechanism 9 when it changes from no-load motion state to contact judgment state. This value represents the upper limit of the reference current required for the support slide 10, ball screw 12 and V-shaped support block 13 to overcome transmission friction, guide rail resistance and coupling elastic deformation when not in contact with the workpiece; The threshold is preferably determined during the equipment debugging stage. The determination process is as follows: with no workpiece on the spindle, the tailstock 7 retracted, and the V-shaped support block 13 reciprocating at the same speed as the actual identification for no less than 5 times, record the current in the stable segment of each movement; take the maximum value of the current in each stable segment as the no-load reference value, and then add a safety margin of 5% to 20% to obtain the support no-load current threshold. In S2 and S3, the controller 19 compares the real-time current with the threshold to determine whether a state transition from no-load movement to outer circle contact has occurred. The constant contact current is used to characterize the target current level at which the V-shaped support block 13 has formed a continuous contact with the outer cylindrical surface of the motor shaft but has not generated radial compression exceeding the allowable deformation range. This current level is used as a closed-loop adjustment target in S6 so that the support block neither detaches from the workpiece nor generates pressure exceeding the set threshold. The constant contact current can be determined in the following way: first, make the V-shaped support block 13 lightly touch the standard cylindrical bar, then feed it step by step with a preset single-step pulse equivalent, and record the current range when the contact can be maintained stably and no indentation is left on the surface of the standard cylindrical bar; the controller 19 takes the midpoint or near the lower limit of the current range as the constant contact current. During the grinding process, when the real-time support current is lower than this value, the controller 19 outputs a forward compensation pulse; when the real-time support current is higher than this value and exceeds the allowable bandwidth, the controller 19 reduces the compensation amount or stops advancing, thereby maintaining stable contact. The processing flow from S2 to S7 can be broken down as follows: read the encoder pulse of the support servo motor 11, the real-time current of the support servo motor 11, and the real-time current of the feed servo motor 18; convert the position of the V-shaped support block 13 from the pulse of the support servo motor 11, and perform contact recognition using the real-time current of the support servo motor 11; after the contact is recognized, record the contact start position as the initial outer diameter calculation reference. During grinding, the controller 19 estimates the amount of deformation under force based on the change in current of the feed servo motor 18, and corrects the current position of the support block based on the deviation between the current of the support servo motor 11 and the constant contact current. It compares the contact start position, real-time tracking displacement and target machining outer diameter, and outputs a command to continue grinding or retract the tool. Therefore, S3 outputs the initial outer diameter and total grinding allowance, S5 outputs the instantaneous compensation displacement, S6 outputs the cumulative follow-up displacement, and S7 outputs the real-time outer diameter and the machining end judgment result. The dimension recognition and compensation control process in the above method is as follows: the controller 19 determines whether the V-shaped support block 13 is in contact with the outer circle of the workpiece based on the current of the support servo motor 11 and the support displacement information, so as to determine the starting reference; based on the contact start position, the opening angle of the V-shaped support block 13 and the subsequent cumulative follow-up displacement, the mechanical displacement is converted into the initial outer diameter, the real-time outer diameter and the total grinding allowance. During the grinding process, based on the change in current of the feed servo motor 18 and the current workpiece specification information, a compensation displacement is output to counteract the elastic yielding tendency caused by the radial grinding force, so as to continuously correct the support position; by comparing the real-time outer diameter and the target machining outer diameter, the control result of continuing grinding or retracting the tool is output. The data flow between the above four parts is as follows: first, the contact recognition module determines the starting reference; then, the size conversion module establishes the current size of the workpiece; the load compensation module continuously corrects the support position during the grinding process; and the endpoint determination module makes a judgment on the end of processing. The overall control process characterizes the linkage between the reduction of the workpiece outer diameter, the change of grinding load and the adjustment of the support position. That is, because grinding removes material, the outer diameter will be reduced and the grinding force will cause elastic deformation of the slender shaft, so the controller 19 simultaneously uses displacement information for size tracking and current information for force compensation, so that the determination of the grinding end point is consistent with the real-time support state. The diameter reduction corresponding to the follow-up displacement in S7 is not simply equivalent to the displacement of the V-shaped support block 13 along the support direction, but refers to the diameter change after converting the follow-up displacement according to the geometric relationship of the opening angle of the V-shaped support block 13. When the V-shaped support block 13 has an instantaneous compensation displacement to offset the grinding force, the controller 19 preferably first separates the instantaneous compensation component caused by the load change from the current position, and then performs diameter conversion on the cumulative follow-up component that reflects the actual reduction of the outer diameter of the workpiece, so as to avoid misjudging the elastic deformation under force as a dimensional change in which the material has been ground away. Therefore, the calculation logic of the real-time outer diameter and the calculation logic of the initial outer diameter maintain the same geometric reference, and the causal relationship between the steps is more consistent; the data interaction between the above four modules adopts a fixed-cycle real-time bus communication protocol, and the communication cycle can be set from 1ms to 4ms. The contact recognition module sends a contact status signal to the size conversion module in each communication cycle, where 0 indicates no contact and 1 indicates contact, and simultaneously sends position pulse data; the load compensation module obtains the current of the feed servo motor 18 through the current acquisition unit at a sampling rate of not less than 1kHz, and sends the current increase value to the processing unit of the controller 19 after digital filtering; the execution core is the microprocessor unit inside the controller 19 responsible for processing motion trajectory planning and servo axis linkage command issuance; The endpoint determination module compares the real-time floating-point outer diameter with the target machining outer diameter in each cycle. When the difference is less than or equal to 0, it sends a high-level interrupt signal to the main control program to trigger the tool retraction action. The controller 19 performs grinding control and real-time compensation through the above high-frequency cycle interaction mechanism.

[0026] The method for calculating the actual outer diameter of the current motor shaft in step S3 includes: reading the number of rotation pulses of the support servo motor 11 from the initial position to the current position; Multiply the number of rotational pulses by the ball screw lead conversion factor of 12 to obtain the linear displacement. Subtract the linear displacement from the preset maximum stroke, and then multiply by the trigonometric function conversion coefficient related to the opening angle of the V-shaped support block 13 to calculate the actual outer diameter of the current motor shaft. The calculation of the actual outer diameter of the current motor shaft in step S3 is based on the geometric relationship of the V-shaped support block 13 and the pulse displacement relationship of the support servo motor 11. The support servo motor 11 starts moving from the preset initial position, and the controller 19 records the cumulative number of rotation pulses P. If the lead of the ball screw 12 is Lmm / r and the number of pulses per revolution of the encoder of the support servo motor 11 is N, then the lead conversion factor of the ball screw 12 is L divided by N, and the linear displacement is P multiplied by L divided by N. The preset maximum stroke refers to the upper limit of the support displacement corresponding to the theoretical distance between the initial position vertex of the V-shaped support block 13 and the axis of the rotary spindle 4. This value is measured by a standard bar during equipment installation and calibration and can be stored in the parameter table of the controller 19. The controller 19 subtracts the linear displacement from the preset maximum stroke to obtain the current distance between the vertex of the V-shaped support block 13 and the axis of the rotary spindle 4. If the included angle of the opening of the V-shaped support block 13 is θ, then the included angle between the single-sided inclined plane and the center line of symmetry is half of θ. The geometric conversion between the motor shaft radius and the current distance can be expressed as the current distance multiplied by the trigonometric function conversion coefficient related to θ. For the case of using a 90° V-groove, the trigonometric function conversion coefficient can be determined according to the standard trigonometric function relationship, the motor shaft radius can be obtained, and then converted into the actual outer diameter. Taking a preset maximum stroke of 50mm, ball screw lead of 12mm / r, encoder of 10000p / r, and recorded pulse count of 30000 as an example, the linear displacement is 15mm, the current distance is 35mm, and the outer diameter of the motor shaft can be calculated by combining the V-groove angle. This method does not rely on external optical measuring devices, but uses the contact position and mechanical geometry to complete the size recognition. The measurement stability is high when grinding fluid, dust and reflective surfaces are present. To improve calculation accuracy, multiple standard cylindrical bars can be used to establish a correction table during the equipment commissioning phase to compensate for geometric errors, polyurethane compression, and installation deviations for different diameter segments. The controller 19 outputs outer diameter data that is closer to the actual value according to the correction table. The physical meaning of the preset maximum stroke is: when the V-shaped support block 13 is located at the known initial zero position, the reference distance from the theoretical vertex of its V-groove to the axis of the rotary spindle 4; this parameter is not a real-time quantity that changes with the workpiece, but a structural parameter that is pre-calibrated and stored for a long time after the equipment is installed. During calibration, a standard cylindrical bar can be clamped between the main spindle mechanism 2 and the tailstock mechanism 6, so that the axis of the standard cylindrical bar coincides with the axis of the rotary main spindle 4; then drive the V-shaped support block 13 to slowly approach the standard cylindrical bar, record the number of pulses of the support servo motor 11 at the moment of contact, and back-calculate the reference distance by combining the known outer diameter of the standard cylindrical bar; repeat this process with no less than 3 standard cylindrical bars of known diameter and take the average value or segmented correction value as the source of the preset maximum stroke and its correction table; The logical order of outer diameter calculation in step S3 is as follows: The first step is for the controller 19 to read the cumulative number of pulses from the initial zero position to the contact position and convert it into the actual linear displacement of the V-shaped support block 13 along the support direction. The second step is to subtract the actual linear displacement from the preset maximum stroke to obtain the current distance from the vertex of the V-shaped support block 13 to the axis of the rotary spindle 4. The third step is to convert the current distance into the motor shaft radius based on the opening angle of the V-shaped support block 13. The fourth step is to multiply the radius by 2 to obtain the actual outer diameter of the current motor shaft; Fifth step: If the controller 19 contains correction tables for different diameter segments, then the result of the fourth step is sent to the correction table for the corresponding diameter segment, and the corrected actual outer diameter is output. Therefore, the input sources are the pulse count of the supporting servo motor 11, the lead of the ball screw 12, the encoder resolution, the preset maximum stroke, and the opening angle of the V-shaped support block 13. The output result is the actual outer diameter of the current motor shaft, which is further directed to the total grinding allowance calculation module. When the V-shaped support block 13 adopts a 90° V-groove, the outer diameter of the motor shaft can be calculated using the following formula: Where D is the outer diameter of the motor shaft, d is the current distance, and sin is the sign of the sine function; for 60° or 120° V-groove, the same geometric decomposition approach can be used, only replacing 45° with the corresponding half angle; if the polyurethane material has repeatable elastic compression, the compression amount can be treated as the compensation value in the correction table without changing the aforementioned basic calculation process. The trigonometric function conversion coefficient related to the opening angle of the V-shaped support block 13 is intended to convert the mechanical distance measured along the symmetrical center line of the V-groove into the actual outer diameter of the workpiece, so as to avoid introducing geometric errors by directly treating the displacement in the support direction as the diameter change. The specific conversion process is as follows: the current position of the V-shaped support block 13 along the support direction is obtained by the pulse of the support servo motor 11 and the lead of the ball screw 12; the current position displacement is subtracted from the preset maximum stroke to obtain the current distance from the theoretical vertex of the V-groove to the workpiece axis; the current distance is converted into the workpiece radius according to the half angle of the V-groove to obtain the outer diameter of the workpiece. The physical relationship it represents is as follows: when the outer circle of the workpiece is in contact with the two inclined surfaces of the V-groove at the same time, the center of the workpiece is located in the direction of the angle bisector of the V-groove, and the radius of the workpiece is determined by the vertical distance from the center to either inclined surface. Therefore, the change of the opening angle of the V-groove will directly affect the outer diameter value corresponding to the same support displacement. To avoid the increase in error of a single theoretical coefficient across the entire diameter range due to compression of the polyurethane working surface, assembly deviation, or contact recognition delay, the correction table is preferably established according to the diameter interval; after completing the above theoretical conversion, the controller 19 first calls the corresponding correction value according to the interval in which the theoretical outer diameter falls, and then outputs the final actual outer diameter. After completing the theoretical conversion using the above geometric relationships, and then combining the correction table to compensate for material elasticity and installation errors, the accurate actual outer diameter is output.

[0027] The method for calculating the estimated radial deformation of the motor shaft in step S5 includes: When the current of the feed servo motor 18 is greater than the feed no-load current, the difference between the real-time current and the feed no-load current of the feed servo motor 18 is taken as the current increase, multiplied by the stiffness conversion factor, to obtain the estimated radial deformation of the motor shaft; the calculation model is as follows: if the real-time current is The feed no-load current is The increase in current Radial deformation estimate: in, The stiffness conversion factor is used to convert the radial deformation estimate into the number of compensation pulses for the support servo motor 11, so as to control the support servo motor 11 to drive the V-shaped support block 13 forward. The calculation of the estimated radial deformation of the motor shaft in step S5 corresponds to the increase in current of the feed servo motor 18 with the elastic yielding trend of the motor shaft caused by the grinding force; the feed servo motor 18 has a feed idle current I0 when running unloaded or when the grinding wheel has not cut into the workpiece, and the real-time current is I after grinding begins. Greater than The increase in current ; Controller 19 will Multiply by stiffness conversion factor The estimated radial deformation of the motor shaft is obtained. ,in, The unit can be mm / A or μm / A; stiffness conversion factor K can be obtained through calibration. The calibration method is to select a motor shaft of known specifications, record the current change of the feed servo motor 18 under different grinding depths and feed conditions, and at the same time use a contact displacement sensor or standard gauge block to measure the corresponding radial elastic displacement. Then, K value is obtained by linear fitting or piecewise fitting. Specifically, the linear fitting process is as follows: within the set grinding depth range, select no less than 5 test points, record the increase in current of the feed servo motor 18 and the corresponding radial elastic displacement, construct a scatter plot with the increase in current as the abscissa and the radial elastic displacement as the ordinate, and calculate a fitting line that minimizes the sum of the squares of the distances from all data points to the line using the least squares method. The slope of the fitting line is the stiffness conversion coefficient K of the motor shaft of the corresponding specification. For piecewise fitting, the grinding depth range is divided into light load and heavy load segments, and the above-mentioned least squares linear fitting is performed in each segment to obtain multiple K values ​​corresponding to different load ranges, so as to further improve the accuracy of deformation prediction. If the stiffness difference of motor shafts of different lengths and diameters exceeds the preset stiffness tolerance threshold, the controller 19 can call the K values ​​corresponding to different specification ranges based on the actual outer diameter calculated in step S3 and the workpiece overhang length corresponding to the tailstock 7 position. Seek Then, the controller 19 calculates the number of compensation pulses for the supporting servo motor 11 based on the lead of the ball screw 12 and the encoder resolution. : Single pulse corresponding linear displacement The compensation pulse count is then output to the support servo motor 11 to cause the V-shaped support block 13 to move forward by the corresponding displacement. The compensation displacement and the follow-up displacement in step S6 can be executed in combination. The compensation displacement is used to counteract the instantaneous bending tendency caused by the force, and the follow-up displacement is used to compensate for the change in geometric clearance caused by the reduction of the outer diameter of the motor shaft due to grinding. By incorporating the increase in current of the feed servo motor 18 into the displacement calculation, the movement of the support mechanism 9 no longer depends solely on the preset program position, but is associated with the current grinding load, thereby enabling the slender motor shaft to obtain a support position adjustment that matches load changes during grinding; Among them, the feed no-load current is the reference current of the feed servo motor 18 when the grinding wheel has not cut into the workpiece and the cross slide 15 is running at the set speed. This value represents the basic current level required for the feed transmission chain to overcome the friction of the lead screw, the resistance of the guide rail and the resistance of the grinding wheel idling. The parameter is preferably pre-calibrated under the same grinding wheel speed, the same feed speed and the same lubrication conditions. During calibration, the forming grinding wheel 17 is kept in a gap with the workpiece, and the current of the feed servo motor 18 is continuously collected over a period of time. The average value of the stable section or the maximum value of the stable section plus the safety margin is taken as the feed no-load current. In S5, the controller 19 compares the real-time feed servo motor 18 current with the feed no-load current to identify whether there is an actual grinding load and the magnitude of the load increment. Among them, the stiffness conversion coefficient is used to establish the correspondence between the increase in current of the feed servo motor 18 and the radial elastic relief of the motor shaft. Its logical function is to convert the grinding force change that is difficult to measure directly into an executable support compensation displacement. The stiffness conversion factor can be a single factor or a segmented factor table established according to the workpiece diameter range, workpiece length range and grinding condition range. Preferably, the controller 19 first determines the workpiece diameter range based on the actual outer diameter obtained in S3, and then determines the workpiece length range based on the position of the tailstock 7 or the positioning distance between the two ends, and calls the stiffness conversion coefficient of the corresponding range to avoid workpieces with different slenderness ratios sharing the same coefficient, which would lead to excessive or insufficient compensation. The processing flow of step S5 can be broken down as follows: The first step is to collect the real-time current of the feed servo motor 18 and subtract the feed no-load current to obtain the current increase. The second step is to determine whether the increase in current exceeds the noise filtering bandwidth. If it does not exceed the bandwidth, it is determined that the change in grinding load is insufficient to trigger compensation, and the V-shaped support block 13 is controlled to maintain its current position. The third step is to read the stiffness conversion factor corresponding to the current workpiece specification when the bandwidth is exceeded, and convert the current increase into the radial deformation estimate. The fourth step is to convert the estimated radial deformation into the number of compensation pulses based on the ball screw lead of 12 and the encoder resolution. Fifth step: Control the support servo motor 11 to advance according to the number of compensation pulses; The sixth step is to repeat the above steps in the next sampling cycle, thereby forming a compensation closed loop that is updated in real time with the grinding load; The input sources for this process are the real-time current of the feed servo motor 18, the feed no-load current, the workpiece specification information, the lead of the ball screw 12 and the encoder resolution. The output is the number of compensation pulses for the support servo motor 11, which directly affects the micro-advance control of the V-shaped support block 13. To avoid overcompensation caused by instantaneous current spikes, the controller 19 can also perform a moving average of the current increase over multiple consecutive sampling periods or perform compensation only after two or more consecutive over-limits. The noise filtering bandwidth can be set to 2% to 10% of the feed no-load current. Its function is to filter out short-term fluctuations caused by driver sampling jitter, abrasive impact, and local non-roundness of the grinding wheel, so that the compensation action mainly responds to the actual grinding load change rather than random disturbance. The stiffness conversion factor is not a simple mathematical constant, but a control parameter used to characterize the actual correspondence between the grinding load change, the workpiece elastic yielding trend and the support compensation displacement. The purpose of this model is to indirectly estimate the radial elastic deformation trend of the workpiece under the current grinding state by using the easily acquired current change of the feed servo motor 18 without directly arranging the workpiece online displacement sensor, and to give the support compensation amount accordingly. The specific process is as follows: calculate the difference between the real-time current of the feed servo motor 18 and the feed no-load current to obtain the current increase reflecting the additional load of grinding; calculate the estimated radial deformation of the workpiece based on the current increase and the stiffness conversion coefficient called according to the workpiece specifications; and calculate the number of compensation pulses for the supporting servo motor 11 by combining the estimated radial deformation, the lead of the ball screw 12 and the encoder resolution. To avoid interference from instantaneous fluctuations, the controller 19 sets a compensation trigger condition: only when the increase in current continuously meets the condition of exceeding the noise filtering bandwidth, the corresponding stiffness conversion coefficient is called according to the current workpiece specifications and a compensation pulse is output. The above control algorithm as a whole represents the following actual machining relationship: as the grinding force increases, the load of the feed transmission chain increases accordingly and causes the drive current to rise. The slender motor shaft will produce more obvious elastic yielding under the action of greater grinding force. Therefore, the current increment can be used as an indirect representation of the change in grinding force. After calibration, the conversion relationship is transformed into support compensation displacement. To avoid mistaking current peaks with durations shorter than a preset period caused by localized grinding wheel out-of-roundness, cutting fluid impact, or instantaneous friction fluctuations in the transmission chain for actual workpiece deformation, controller 19 preferably divides compensation control into two levels: trigger determination and compensation execution. In the trigger determination level, the load change is considered continuous only when the current increase continuously exceeds the noise filtering bandwidth. In the compensation execution level, the corresponding stiffness conversion coefficient is called according to the current workpiece specifications, and a compensation pulse is output. The reason for this setup is that the previous level is responsible for eliminating random disturbances, while the next level is responsible for converting changes in effective load into support actions. This allows for a more direct and stable causal relationship between the compensation behavior and the actual stress state of the workpiece. In order to accurately determine the noise filtering bandwidth and clarify the data processing process of the control algorithm, the controller 19 uses a sliding window averaging algorithm to preprocess the collected current. Specifically, the window length is set to 10 sampling periods. In each period, the controller 19 removes the earliest current data and adds the latest data, and calculates the average value of the data in the window as the current effective current increment. If the effective current increment is greater than 5% of the feed no-load current for 3 consecutive windows, it is determined to be an effective load change. Let's illustrate this with a specific quantitative derivation example: Assume the feed servo motor's feed no-load current is... The stiffness conversion factor used for the current workpiece specifications is calibrated as follows: The lead of the ball screw 12 is The encoder resolution is That is, the linear displacement corresponding to a single pulse. ; At a certain grinding stage, the effective feed current after sliding window filtering is: The increase in current The controller 19 calculates the radial deformation estimate based on the calculation rules. ; The controller 19 converts the deformation into the number of compensation pulses, i.e., 6.0μm divided by 0.5μm per pulse, resulting in 12 pulses; the controller 19 then sends these 12 pulse commands to the support servo driver, driving the V-shaped support block 13 to move forward by 6.0μm; through the above process, precise closed-loop control from current acquisition to mechanical displacement compensation is realized.

[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 multi-specification applicable spindle motor shaft grinding device, used for clamping and grinding motor shafts, characterized in that, include: The machine tool bed that serves as the basic support (1); The spindle mechanism (2) located on the upper left of the machine tool bed (1) includes a spindle box (3), a rotary spindle (4) supported in the spindle box (3), and an internal expansion chuck (5) connected to the right end face of the rotary spindle (4). The support mechanism (9) located at the rear of the machine tool bed (1) includes a support servo motor (11) fixed to the machine tool bed (1), a ball screw (12) connected to the motor, a support slide (10) slidably connected to the machine tool bed (1) and connected to the nut seat (27) of the ball screw (12), and a V-shaped support block (13) fixed to the support slide (10). The V-shaped support block (13) has its opening facing the axis of the rotary spindle (4) and radially abuts against the outer cylindrical surface of the motor shaft. The grinding mechanism (14) located in front of the machine tool bed (1) includes a cross slide (15) driven by a feed servo motor (18), a grinding wheel spindle box (16) connected to the cross slide (15), and a forming grinding wheel (17) mounted thereon. The controller (19) connects to and controls the operation of the spindle mechanism (2), tailstock mechanism (6), support mechanism (9) and grinding mechanism (14).

2. The multi-specification applicable spindle motor shaft grinding device according to claim 1, characterized in that, The internal expansion chuck (5) includes a tapered tie rod (20) and a slotted expansion sleeve (21). The main shaft mechanism (2) also includes a cylinder (22), which is connected to the tapered tie rod (20). The cylinder (22) pushes the tapered tie rod (20) to move axially, causing the slotted expansion sleeve (21) to expand radially to tighten the inner wall of the center hole at the end of the motor shaft.

3. The multi-specification applicable spindle motor shaft grinding device according to claim 1, characterized in that, The spindle box (3) is provided with a pair of angular contact ball bearings (23), and the rotary spindle (4) is supported in the spindle box (3) by the angular contact ball bearings (23).

4. The multi-specification applicable spindle motor shaft grinding device according to claim 1, characterized in that, The machine tool bed (1) is provided with a dovetail guide rail (24), and the tailstock (7) is slidably connected to the machine tool bed (1) through the dovetail guide rail (24).

5. The multi-specification applicable spindle motor shaft grinding device according to claim 1, characterized in that, A linear guide rail (25) is provided at the rear of the middle part of the machine tool bed (1), and the support slide (10) is slidably connected to the machine tool bed (1) through the linear guide rail (25).

6. The multi-specification applicable spindle motor shaft grinding device according to claim 1, characterized in that, The support mechanism (9) also includes a plum blossom coupling (26), and the support servo motor (11) is directly connected to the ball screw (12) through the plum blossom coupling (26).

7. The multi-specification applicable spindle motor shaft grinding device according to claim 1, characterized in that, The V-shaped support block (13) is made of polyurethane.

8. A grinding method, applied to the multi-specification applicable spindle motor shaft grinding device according to any one of claims 1 to 7, characterized in that, include: S1. Control the internal expansion chuck (5) to tighten the center hole at the left end of the motor shaft, and control the pneumatic tip (8) to extend and press against the center hole at the right end of the motor shaft; S2. Control the support servo motor (11) to drive the ball screw (12) to rotate, thereby moving the V-shaped support block (13) towards the motor shaft, and monitor the drive current of the support servo motor (11); S3. When the driving current is less than or equal to the support no-load current threshold, control the support servo motor (11) to continue driving; when the driving current is greater than the support no-load current threshold, control the support servo motor (11) to stop moving and calculate the actual outer diameter of the current motor shaft. S4. Control the rotary spindle (4) to drive the motor shaft to rotate, and control the feed servo motor (18) to drive the forming grinding wheel (17) to feed towards the motor shaft to start grinding; S5. Monitor the current fluctuation of the feed servo motor (18) in real time, calculate the estimated radial deformation of the motor shaft, and control the support servo motor (11) to drive the V-shaped support block (13) to perform compensating feed forward to offset the deformation caused by the radial grinding force in real time. S6. As the grinding proceeds, the V-shaped support block (13) is controlled to continuously move forward while maintaining a constant contact current, and the real-time following displacement of the V-shaped support block (13) is recorded. S7. Calculate the real-time outer diameter of the motor shaft. When the real-time outer diameter is greater than the target machining outer diameter, control the feed servo motor (18) to continue driving. When the real-time outer diameter is less than or equal to the target machining outer diameter, control the feed servo motor (18) to drive the forming grinding wheel (17) to retreat quickly, and control the support servo motor (11) to drive the V-shaped support block (13) to return to the initial position.

9. The polishing method according to claim 8, characterized in that, In step S3, the method for calculating the actual outer diameter of the current motor shaft includes: Read the number of rotation pulses of the support servo motor (11) from the initial position to the current position; multiply the number of rotation pulses by the lead conversion factor of the ball screw (12) to obtain the linear displacement; Subtract the linear displacement from the preset maximum stroke, and then multiply by the trigonometric function conversion coefficient related to the opening angle of the V-shaped support block (13) to calculate the actual outer diameter of the current motor shaft.

10. The polishing method according to claim 8, characterized in that, In step S5, the method for calculating the estimated radial deformation of the motor shaft includes: When the current of the feed servo motor (18) is greater than the feed no-load current, the difference between the real-time current of the feed servo motor (18) and the feed no-load current is used as the current increase, multiplied by the stiffness conversion factor, to obtain the estimated radial deformation of the motor shaft. The radial deformation estimate is converted into the number of compensation pulses of the support servo motor (11) to control the support servo motor (11) to drive the V-shaped support block (13) to advance slightly forward.

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