A machining fixture and method for the stator core of a large Y-series asynchronous motor

Abstract

This invention relates to a machining fixture and method for a large Y-series asynchronous motor stator core, comprising a lifting bolt, a fastening nut, a T-bolt, a positioning rod, and support blocks or jacks. The upper end of the lifting bolt is connected to the threaded hole of the lower pressure ring of the stator core, and the lower end is connected to the T-bolt via the fastening nut. The lower end of the T-bolt is connected to the faceplate of a vertical lathe. Support blocks or jacks are placed between the lower pressure ring of the stator core and the faceplate of the vertical lathe. The height and tension of the stator core are adjusted by adjusting the central fastening nut in conjunction with the support blocks or jacks on both sides, thus fixing the stator core on the faceplate of the vertical lathe. This fixture and method are used to machine the upper and lower pressure rings of the stator core, the outer circle of the arc plate, and the outer circle stop of the upper pressure ring. The fixture and method of this invention can complete machining in one setup, improving machining quality, increasing work efficiency, shortening the production cycle, and reducing energy consumption.

Description

Technical Field

[0001] This invention relates to a machining fixture for a large motor stator core, and more particularly to a machining fixture for a large Y-series asynchronous motor stator core. Background Technology

[0002] Stator structure of large Y-series asynchronous motors, such as Figure 1 As shown, the stator mainly consists of a frame, a core, and windings. The stator uses an externally press-fitted core. After the stator core is fitted with the coil windings and undergoes VPI impregnation, the stator core is placed into the frame and welded to it as a whole. The outer circle of the stator core and the inner circle of the frame have dimensional accuracy requirements. Therefore, after the stator core press-fitting is completed, the outer circle of the stator core and the positioning stop need to be machined.

[0003] The stator of a large Y-series asynchronous motor typically uses an externally press-fitted core. After the stator core has been fitted with the coil windings and subjected to VPI (Vehicle Impregnation) treatment, it is then fitted into the frame. The outer diameter of the stator core and the inner diameter of the frame have specific dimensional accuracy requirements. Therefore, after the stator core is press-fitted, the outer diameter and locating stop of the stator core need to be machined to ensure proper fit with the inner diameter of the stator frame.

[0004] Generally, the outer diameter of the pressure rings and the locating stops at both ends of the stator core require machining, such as... Figure 2 As shown, the most common machining method is to use a vertical lathe, which is the simplest and most convenient. The key is that during machining, the vertical lathe's fixture must clamp the outer circle of the lower end of the stator core's pressure ring. This allows the stator core to rotate together with the lathe's faceplate, completing the machining of the stator core. This method involves using the vertical lathe's own fixture to clamp the outer circle of the lower end of the stator core's pressure ring, and then machining the outer circle of the upper pressure ring, the stop, and the outer circle of the curved plate, as shown... Figure 3 As shown, after these parts are machined, the stator core is removed from the machine tool, rotated 180°, and then mounted on a vertical lathe to machine the outer diameter of the other end's pressure ring. Because the outer diameter of the lower end's pressure ring is clamped by the lathe fixture, the outer diameter of the upper stator core's pressure ring, the locating stop, and the arc plate can be machined in one setup. However, the outer diameter of the lower pressure ring requires a 180° rotation and re-clamping before machining. This machining process is complex, risky, and time-consuming. The coaxiality of the machined outer diameter is difficult to guarantee, resulting in a large workload, high labor intensity, high energy consumption, and high manufacturing costs, thus limiting the expansion of production capacity.

[0005] The above method uses a vertical lathe fixture for clamping. The advantages of this traditional machining method are: it can process without other auxiliary tooling and is simple to operate; however, its disadvantages are: the machining process is complex, the processing cycle is long, the workload is large, the labor intensity is high, the risk is also high, the energy consumption is high, the cost is high, and the coaxiality of the machined outer diameter is difficult to guarantee, thus restricting the expansion of production capacity. Therefore, it is necessary to improve this machining method.

[0006] To avoid the need for overturning during stator core outer diameter machining, existing technology employed a set of lathe fixture base plates. The method involved bolting the stator core to the base plate, with the lathe fixture clamping the outer diameter of the base plate. This allowed adjustment of the coaxiality between the stator core's inner diameter and the lathe facet's rotation center. Adjusting the height of the jacks between the facet and the base plate adjusted the perpendicularity of the stator core's inner diameter. Once the stator core was properly adjusted, the upper and lower end pressure rings, the outer diameter of the arc plate, and the outer diameter stop of the upper pressure ring could be machined in a single setup. Figure 4 As shown.

[0007] The above method uses a lathe fixture base plate clamping method. The advantage of this processing method is that it can solve the problem of one-time clamping and processing of stator core and improve the processing quality. The disadvantage is that the lathe fixture base plate is relatively troublesome to install, requiring multiple people to cooperate in the installation. The fixing bolts need to be tightened from the bottom of the lathe fixture base plate upwards, which is difficult to operate in practice and also poses certain safety hazards. The effect of use is not ideal and it has no value for widespread use.

[0008] To enable the stator core to be machined in a single setup and machining operation, existing technology has also employed the method of machining 4-Φ36 evenly distributed process holes on the lower pressure ring. These process holes are used to install tension screws, thereby fixing the stator core onto the faceplate of a vertical lathe. This allows for the simultaneous machining of the upper and lower pressure rings, the outer diameter of the arc plate, and the outer diameter stop of the upper pressure ring in a single setup. Figure 5 As shown.

[0009] The above method employs a clamping technique with added process holes. The advantage of this approach is that the stator core can be machined in a single clamping operation, which is effective for machining. However, the disadvantages include: extended machining routes, increased machining cycles, higher manufacturing costs, and technical, managerial, and product quality issues. It solves one old problem but creates several new ones. To address these new problems, a special production process is required each time the stator core is machined, which only provides temporary relief and does not fundamentally solve the problem. Therefore, this clamping method has no value for widespread adoption.

[0010] In summary, modifying the process fixing holes on all Y-series stator core drawings to meet the technical requirement of one-time clamping and machining would be extremely labor-intensive, exceeding the capacity of current manpower and resources. So, how can we achieve one-time clamping and machining of stator cores without modifying the drawings? This is a difficult problem facing process engineers. After a comprehensive and in-depth analysis and research of the stator core machining process, process engineers boldly proposed a new type of clamping tool. Without modifying the drawings, the tooling should be easy to install, lightweight, and have low labor intensity. The stator core should be easy to mount, quick and accurate in positioning, securely fixed, easy to adjust, highly efficient, have a short processing cycle, low production cost, and be safe and environmentally friendly.

[0011] Therefore, the main problem in enabling the machining of all surfaces of the stator core to be completed in a single clamping operation is solving the clamping issue. To this end, a new type of machining fixture needs to be designed to achieve better clamping results. Summary of the Invention

[0012] The present invention provides a machining fixture and method for the stator core of a large Y-series asynchronous motor, enabling the machining of the stator core to be completed in a single setup.

[0013] To achieve the above objectives, the present invention provides a machining fixture for the stator core of a large Y-series asynchronous motor, comprising a lifting bolt, a fastening nut, a T-bolt, a positioning rod, and a support pad or jack. The upper end of the lifting bolt is connected to the screw hole of the lower pressure ring of the stator core, and the lower end is connected to the T-bolt via the fastening nut. The lower end of the T-bolt is connected to the faceplate of a vertical lathe. A support pad or jack is placed between the lower pressure ring of the stator core and the faceplate of the vertical lathe. The height and tension of the stator core are adjusted by adjusting the fastening nut in the middle in conjunction with the support pads or jacks on both sides, thereby fixing the stator core on the faceplate of the vertical lathe. This fixture is used to machine the upper and lower pressure rings of the stator core, the outer circle of the arc plate, and the outer circle stop of the upper pressure ring.

[0014] Next, the fastening nut is first put onto the lifting bolt, the lifting bolt is screwed into the threaded hole of the stator core lower pressure ring, and the T-bolt is inserted into the T-slot of the lathe faceplate. When the lifting bolt and the T-bolt are aligned, the fastening nut is screwed into the T-bolt and tightened.

[0015] Furthermore, the upper end of the lifting bolt is a threaded part, and the thread size corresponds to the thread hole size on the pressure ring; a retaining ring is added at the root of the thread, and the retaining ring is welded to the lifting bolt as a whole; the middle part is a regular hexagonal prism, which makes it easy to install the lifting bolt on the pressure ring or remove it from the pressure ring with a wrench; the lower end is a flange edge, which is used to fasten the fastening nut and play a connecting role.

[0016] Furthermore, the fastening nut is shaped like a regular hexagonal prism, with a skirt added to the lower outer end to prevent the wrench from falling off after it is secured to the fastening nut; there is a countersunk hole in the middle for the flange of the lifting bolt to pass through, and a through hole is opened at the top center of the countersunk hole for the central cylinder of the lifting bolt to pass through. At the same time, a flange edge is formed at the top of the countersunk hole of the fastening nut to lock the flange edge of the lifting bolt; the lower part of the countersunk hole has a thread that mates with the T-bolt, and the thread is a left-hand helical thread.

[0017] Furthermore, the upper part of the T-bolt has a thread that mates with the fastening nut. The thread is a left-hand helical thread. The neck of the T-bolt is flat, and the lower end is divided into a T-shaped boss that matches the T-slot on the lathe faceplate.

[0018] Furthermore, the positioning rod is used for circumferential positioning when the stator core is mounted on a lathe. The upper thread is consistent with the size of the screw hole on the lower pressure ring of the stator core. The lower part of the thread is in the shape of a regular hexagonal prism, and the lower part of the regular hexagonal prism is machined into a cylindrical shape. Its diameter is 1mm smaller than the neck groove of the T-slot of the lathe faceplate, so as to facilitate the insertion of the positioning rod into the T-slot and positioning. The length from the flange plane at the root of the positioning rod thread to the cylindrical end face is H+20~40mm, where: H is the height distance from the upper end face of the lathe faceplate to the lower end face of the lower pressure ring.

[0019] A method for machining the stator core of a large Y-series asynchronous motor, using a machining fixture for the stator core of a large Y-series asynchronous motor, comprises the following steps: First, two positioning rods are installed in two screw holes distributed at 180° intervals on the lower pressure ring of the stator. Then, two tightening bolts are installed in two screw holes distributed at another 180° intervals after rotating the stator core 90°. When the stator core is mounted on the lathe, the two positioning rods are first inserted into the T-slots of the lathe faceplate to position the stator core circumferentially, ensuring that the two pressure ring screw holes are precisely positioned in the T-slots of the lathe faceplate. Then, the stator core is adjusted relative to the faceplate. To ensure the coaxiality of the stator core, align the centers of the two installed lifting bolts with the corresponding centers of the T-slots. Then, remove the positioning rod, replace it with the lifting bolts, insert the T-bolts into the T-slots of the lathe facet, move them directly below the lifting bolts, lower the fastening nuts, and tighten them to secure the stator core. Adjust the height of the support pads or jacks below the stator core and the position of the lathe fixture to adjust the coaxiality and perpendicularity of the stator core. After adjustment, remove the lathe fixture to complete the machining of all surfaces of the stator core in one setup.

[0020] The beneficial effects of this invention are:

[0021] The advantages of the new type of car fixture using the present invention are: no need to modify the drawings, the tooling is small and lightweight, easy to install, low labor intensity, the stator core has a self-positioning function, fast and accurate positioning speed, reliable fixation, easy adjustment, high efficiency, short processing cycle, low production cost, and safety and environmental protection.

[0022] This invention presents a novel machining fixture that truly achieves complete machining in a single setup, improving machining quality, increasing work efficiency, shortening production cycles, and reducing energy consumption. Because this novel machining fixture is versatile and can be used for a long time, cost reduction can be sustained in the long term, resulting in substantial economic benefits. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the stator structure;

[0024] Figure 2 This is a schematic diagram of the stator core structure;

[0025] Figure 3 This is a schematic diagram of lathe fixture clamping;

[0026] Figure 4 This is a schematic diagram of the clamping of the car fixture base plate;

[0027] Figure 5 This is a schematic diagram of the tensioning screw being inserted into the process hole for clamping;

[0028] Figure 6 This is a schematic diagram of the stator core pressing ring;

[0029] Figure 7 yes Figure 6 Left sectional view;

[0030] Figure 8 This is a schematic diagram of the novel vehicle clamping device of the present invention;

[0031] Figure 9 This is a schematic diagram of the novel vehicle clamp structure of the present invention;

[0032] Figure 10 This is a schematic diagram of the cross T-slot of a vertical lathe faceplate;

[0033] Figure 11 This is a diagram of the lifting bolts;

[0034] Figure 12 yes Figure 11 Sectional view of BB;

[0035] Figure 13 This is a diagram of a fastening nut;

[0036] Figure 14 yes Figure 13 Sectional view of CC;

[0037] Figure 15 This is a schematic diagram of a T-bolt;

[0038] Figure 16 yes Figure 15 Sectional view of DD;

[0039] Figure 17 This is a schematic diagram of the positioning rod;

[0040] Figure 18 yes Figure 17 Sectional view of EE;

[0041] Figure 19 This is a schematic diagram showing the gap between the lifting bolt and the T-bolt;

[0042] Figure 20 This is a diagram showing the upward position of the fastening nut;

[0043] Figure 21 This is a diagram illustrating the positioning of the positioning rod;

[0044] Figure 22 This is a stress analysis diagram of the stator core underpinning ring. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0046] like Figures 8 to 21 As shown, the large Y-series asynchronous motor stator core machining fixture 10 of the present invention mainly consists of a lifting bolt 12, a fastening nut 13, a T-bolt 14, and a positioning rod 15. The fastening nut 13 is first fitted onto the lifting bolt 12, and then a retaining ring 12-1 is fitted on top and welded to the lifting bolt 12. The lifting bolt 12 is screwed into the threaded hole of the stator core lower pressure ring 3. The T-bolt 14 is inserted into the T-slot 4-1 of the lathe faceplate 4. When the lifting bolt 12 and the T-bolt 14 are aligned, the fastening nut 13 is screwed into the T-bolt 14. The tighter the fastening nut 13 is tightened, the more the lower pressure ring 3 of the stator core is pulled downwards, and this pulling force is used to fix the stator core. To prevent the lower pressure ring 3 from deforming due to the downward pulling force and to provide support force to the lower pressure ring 3, support pads or jacks 11 should be placed on both sides of the new machining fixture 10. The T-slots 4-1 of the faceplate 4 on a typical vertical lathe are arranged in a cross shape. Therefore, the screw holes on the pressure ring 3 should also be arranged in a cross shape, and their positions must match.

[0047] The novel vehicle clamping method of the present invention fully utilizes the existing screw holes on the lower pressure ring 3 for lifting and support, such as... Figure 6 and Figure 7 As shown. The new type of lathe fixture 10 uses the existing screw holes on the lower pressure ring 3 to fix the stator core on the lathe faceplate 4, so as to complete the stator core machining in one clamping.

[0048] The new stator core car clamp has a clamping method of 10 clamping. Figure 8As shown, the upper end of the new lathe fixture 10 is connected to the screw hole of the lower pressure ring 3 of the stator core, and the lower end of the new lathe fixture 10 is connected to the faceplate 4 of the vertical lathe. By adjusting the fastening nut 13 in the middle of the new lathe fixture 10 and combining it with the support pads or jacks 11 on both sides, the height and tension of the stator core can be adjusted, firmly fixing the stator core on the faceplate 4 of the vertical lathe. After the coaxiality and perpendicularity of the stator core and the faceplate 4 of the vertical lathe meet the technical requirements, the upper pressure ring 1, lower pressure ring 3, outer circle of the arc plate 2, and outer circle stop of the upper pressure ring 1 can be machined. Because there is no lathe fixture to clamp the outer circle of the lower pressure ring 3, the upper pressure ring 1, lower pressure ring 3, outer circle of the arc plate 2, and outer circle stop of the upper pressure ring 1 can be machined in one clamping of the stator core, meeting the technical requirements of our initial design of the new lathe fixture 10, and has been promoted and used.

[0049] The stator core of Y-series motors generally adopts an externally press-fit stator core. This structure offers obvious advantages in production organization: the stator core, stator coils, and frame can be produced simultaneously without interference, shortening the production cycle and improving efficiency. Furthermore, after the stator core is wound, it undergoes VPI vacuum pressure impregnation. Since the stator windings do not have a frame, they are small and lightweight, allowing for the use of smaller impregnation tanks, reducing the amount of insulating varnish used, lowering equipment requirements, lowering production costs, and shortening the manufacturing cycle. This structure also has its specific requirements. The outer circle of the stator core and the inner circle of the frame require precise fit, and axial position control is necessary to ensure the magnetic center of the stator and rotor cores are aligned. Therefore, the machining precision control of the stator core's outer circle and the stop surface is crucial. While meeting dimensional accuracy requirements, it is also desirable that the coaxiality and perpendicularity of the machined outer circle and stop surface with the inner circle of the stator core meet technical requirements. Using a new type of machining fixture 10 allows for the completion of machining on all surfaces of the stator core in a single clamping operation, ensuring dimensional and positional tolerances.

[0050] The main function of the new lathe fixture 10 is to stably fix the stator core onto the faceplate 4 of the vertical lathe, such as... Figure 8 As shown. How does the new type of vehicle clamp 10 connect to the stator core? This is an important question. Solving this problem makes other problems easier to solve. After a detailed analysis of the stator core's structure, it was found that the existing screw holes on the upper pressure ring 1 and lower pressure ring 3 at both ends of the stator core, used for lifting and support, can be fully utilized. Figure 6As shown, it was decided to fix the new machining fixture 10 onto the screw holes of the lower pressure ring 3. Because there are many specifications of Y-series motors, the size, number, position distribution, and pitch circle of the screw holes on the lower pressure ring 3 vary. Designing a separate fixture for each specification would result in a huge number of fixtures, which is clearly unreasonable. Since the screw holes on the lower pressure ring 3 are chosen as the connection point to the new machining fixture 10, and each lower pressure ring 3 has screw holes—this is a common feature—only the size of the screw holes needs to be considered. Ignoring other factors, this reduces the large number of motor specifications to a few screw hole sizes, significantly decreasing the number of fixtures to design and manufacture. It also facilitates fixture use and production management, which is a win-win situation. Currently, the most commonly used screw hole specifications on the lower pressure ring 3 are: M16, M20, M24, M30, M36, M42, and M48. Manufacturing only seven sets of the new machining fixture 10 can meet the technical requirement of completing the machining of various stator core specifications in a single clamping operation. The T-slots 4-1 on the faceplate 4 of a vertical lathe are generally distributed in a central cross shape, such as... Figure 10 As shown. In the design of the new lathe fixture 10, the T-slot 4-1 on the lathe faceplate 4 is fully utilized to design a special T-bolt 14. The lower end of the T-bolt 14 is inserted into the T-slot 4-1 on the faceplate 4, and the upper end is connected to the fastening nut 13. The fastening nut 13 is connected to the upper lifting bolt 12. By rotating the fastening nut 13, the stator core is fixed on the faceplate 4, so that the faceplate 4 rotates with the stator core. In this way, the stator core can be machined very well.

[0051] How can the stator core be reliably fixed on the faceplate 4? When placing the stator core on the faceplate 4, a shim (or jack) 11 should be placed underneath. When tightening the fastening nut 13, the lower pressure ring 3 will be pulled down, which may deform it. To avoid this, a shim (or jack) 11 should be placed on each side of the new type of machine tool clamp 10. Figure 8 As shown. The new type of car clamp 10 rotates and tightens the stator core by rotating the fastening nut 13. The stator core can be fixed and metal cutting can be performed by the tightening force of the new type of car clamp 10 and the friction between the pad (or jack) 11 and the face plate 4 and the lower pressure ring 3.

[0052] The fixture height of a vertical lathe is fixed. When adjusting the stator core on the lathe, the fixture of the vertical lathe must be used. The lathe fixture only needs to be able to clamp the outer circle of the lower pressure ring 3. To ensure that the external connection dimensions of the newly designed fixture 10 are consistent and uniform, and to have interchangeability, the distance from the lower end face of the stator core lower pressure ring 3 to the upper plane of the faceplate 4 is specified as H. This also determines that the height of the pad (or jack) 11 is of one specification. Figure 8 As shown.

[0053] After determining the dimension H (height from the upper end face of the lathe facet 4 to the lower end face of the lower pressure ring 3), the first step is to design the lifting bolt 12, such as... Figure 11 As shown in Figure 12, the upper end is a threaded section, with the thread size corresponding to the threaded hole size on the lower pressure ring 3; the middle part is a regular hexagonal prism, facilitating the installation or removal of the lifting bolt 12 from the lower pressure ring 3 using a wrench; the lower end is a flange edge, used to fasten the fastening nut 13, serving a connecting function. Because the lifting bolt 12 needs to pass through the fastening nut 13, the diameter of the middle part of the lifting bolt 12 cannot be too large, otherwise the flange stop will be too shallow, and the flange stop strength will be weakened; however, it cannot be too thin either, otherwise the strength will be weakened, and a comprehensive consideration is necessary. The flange face at the root of the thread is relatively small, making it easy to create indentations after the lifting bolt 12 is screwed into the lower pressure ring 3, and the flange face is also easily damaged. Therefore, a retaining ring 12-1 is added at the root of the thread, and the retaining ring 12-1 is welded to the lifting bolt 12 as a whole. The retaining ring 12-1 also has another function, which is to prevent the fastening nut 13 from separating after it is put into the lifting bolt 12, and also facilitates the installation and storage of the tooling.

[0054] The fastening nut 13 is shaped like a regular hexagonal prism. Because it needs to fit inside the lifting bolt 12, a slightly larger circular hole than the center of the lifting bolt 12 is machined in the center. The fastening nut 13 must pass through the flange of the lifting bolt 12; therefore, a countersunk hole must also be machined in the fastening nut 13. The diameter of this hole must be slightly larger than the outer diameter of the lower flange of the lifting bolt 12. The fastening nut 13 will form an inner flange edge, which must withstand tensile force when fixing the stator core. Therefore, the inner flange edge must have a certain thickness and width to ensure sufficient mechanical strength. The fastening nut 13 is to be connected to the T-bolt 14; the inner circle of the countersunk hole also needs to be machined with internal threads. Because the thread at the upper end of the lifting bolt 12 is right-hand thread, if the fastening nut 13 also uses a right-hand thread, then when the fastening nut 13 is tightened on the lifting bolt 12, a frictional torque will be generated, and its rotation direction will be left-hand thread. This could potentially loosen the lifting bolt 12. To prevent this from happening, the thread of the fastening nut 13 is a left-hand thread. Because the nominal diameter of the thread of the fastening nut 13 is relatively large, the required tightening torque is also relatively large, and correspondingly, the wrench used will also be larger and heavier. To reduce the labor intensity of the operator, a skirt is added to the lower outer side of the fastening nut 13. After the wrench is locked onto the fastening nut 13, it can prevent the wrench from falling off. Figure 13 and Figure 14 As shown.

[0055] T-bolt 14 structure as follows Figure 15As shown in Figure 16, the lower part is designed according to the dimensions of the T-slot 4-1 on the lathe faceplate 4. The T-slot size should be slightly smaller than the T-slot 4-1 on the lathe faceplate 4 to facilitate disassembly and assembly. The upper part is the thread that mates with the fastening nut 13, and the thread should also be a left-hand helical thread. The neck of the T-bolt 14 is made into a flat shape so that the T-bolt 14 will not rotate with the fastening nut 13 when tightening or loosening, making disassembly and assembly easier.

[0056] The positioning rod 15 is used for circumferential positioning of the stator core when it is mounted on a lathe. The threaded upper end matches the threaded hole size of the new type of lathe fixture 10 mounted on the lower pressure ring 3 of the stator core. Since the positioning rod 15 also needs to be disassembled and reassembled, it is machined into a regular hexagonal prism shape below the threaded end, and then into a cylindrical shape below the hexagonal prism. Its diameter should be 1mm smaller than the neck groove width of the T-slot 4-1 of the lathe faceplate 4, so that the positioning rod 15 can be inserted into the T-slot 4-1 and positioned. Figure 17 As shown in Figure 18, the length of the positioning rod 15 from the flange plane at the thread root to the cylindrical end face is approximately H + (20~40) mm. When mounting the stator core on the lathe, the positioning rod 15 should first be inserted into the T-slot 4-1 for positioning. Alternatively, the two positioning rods 15 can be installed in the two threaded holes of the stator lower pressure ring 3, distributed at 180°, thus achieving circumferential positioning.

[0057] Method of using the novel car clamp 10 of the present invention:

[0058] Depend on Figure 10 It can be seen that the T-slots 4-1 on the vertical lathe faceplate 4 are distributed in a cross shape. In order to use the cross-shaped T-slots 4-1 to fix the stator core, four evenly distributed cross-shaped screw holes are also used on the lower pressure ring 3, such as... Figure 6 As shown in Figure 7.

[0059] The key structural feature of the new type of vehicle clamp 10 is that after the stator core is placed on the pad (or jack) 11, the lower end face of the tightening bolt 12 should not touch the upper end face of the T-bolt 14, and a gap should be left between them. Figure 19 As shown. After the stator core is initially placed and positioned, the T-bolt 14 can be moved unimpeded below the tightening bolt 12, making it convenient to connect with the fastening nut 13.

[0060] The fastening nut 13 is fitted onto the lifting bolt 12 and can move freely up and down and rotate. When the fastening nut 13 is raised to its highest position, the lower end face of the fastening nut 13 should be flush with or slightly higher than the lower end face of the lifting bolt 12. This will not interfere with the normal movement of the T-bolt 14 below the lifting bolt 12. After the lifting bolt 12 and the T-bolt 14 are aligned, the fastening nut 13 is lowered and the T-bolt 14 is screwed in, completing the pre-assembly of the new type of vehicle clamp 10. Figure 20 As shown.

[0061] First, install two positioning rods 15 in the two screw holes distributed at 180° on the lower pressure ring 3 of the stator core. Then, rotate 90° to the other two screw holes distributed at 180° and install two sets of lifting bolts 12 of the new lathe fixture 10. When the stator core is mounted on the lathe, the two positioning rods 15 are first inserted into the T-slot 4-1 of the lathe faceplate 4. This makes it easy to position the stator core circumferentially. The two screw holes of the pressure ring for installing the positioning rods 15 are exactly at the position of the T-slot 4-1 of the lathe faceplate 4. Figure 21 As shown. By simply adjusting the coaxiality of the stator core and the faceplate 4 using the lathe fixture, the center position of the lifting bolts 12 of the two sets of new lathe fixtures 10 installed can be aligned with the center position of the corresponding T-slots 4-1. Then, remove the positioning rod 15 and replace it with the lifting bolts 12 of the new lathe fixture 10. Insert the T-bolts 14 into the T-slots 4-1 of the lathe faceplate 4, move them directly below the lifting bolts 12, lower the fastening nuts 13, and tighten them to fix the stator core. By adjusting the height of the pads (or jacks) 11 below the stator core and the position of the lathe fixture, the coaxiality and perpendicularity of the stator core and the faceplate can be adjusted. After adjustment, the lathe fixture can be removed, and all machined surfaces of the stator core can be completed in one setup.

[0062] When the new type of car clamp 10 tightens the fastening nut 13, it will generate a downward tension force, which is calculated according to the following empirical formula (1):

[0063] F = M10 3 / Kd (1)

[0064] In the formula

[0065] F...Tightening force of the new type of car clamp 10

[0066] M……Tightening torque of fastening nut 13

[0067] K……constant

[0068] D...Nominal thread diameter of T-bolt 14

[0069] Depend on Figure 9 As shown, the tension of this new type of car clamp 10 is borne by the pads (or jacks) 11 on both sides. If the tangential distance between each pad (or jack) 11 and the new type of car clamp 10 is equal, then the pressure borne by each pad 11 is F / 2, where the weight of the iron core is negligible. The two ends of the pad (or jack) 11 are in contact with the end face of the lower pressure ring 3 of the stator iron core and the plane of the face plate 4, respectively. The tangential friction force of the contact surface is calculated according to the following formula (2):

[0070] f=μF / 2 (2)

[0071] In the formula

[0072] f……tangential friction force

[0073] μ...coefficient of friction

[0074] F...Tightening force of the new type of car clamp 10

[0075] The stator core experiences the greatest tangential torque during rotational start-up, shutdown, and machining. The stator core is fixed using 8 pads (or jacks) 11. The tangential torque generated by friction is calculated by the following formula (3):

[0076] m = fr * 8 (3)

[0077] In the formula

[0078] m……tangential friction torque

[0079] f……tangential friction force

[0080] r……radius from the center of pad 11 to the center of rotation of flower plate 4

[0081] Eight pads (or jacks) 11 and four sets of new machine tool clamps 10 form a stable plane, ensuring excellent stability of the stator core installation. In actual use, the tangential friction torque generated by the new machine tool clamps 10 fully meets the requirements of stator core machining, ensuring reliability and safety.

[0082] Stress analysis of stator core underpinning ring 3 as follows Figure 22 As shown.

Claims

1. A machining fixture for the stator core of a large Y-series asynchronous motor, characterized in that: This system includes a lifting bolt, a fastening nut, a T-bolt, a positioning rod, and support blocks or jacks. The upper end of the lifting bolt connects to the threaded hole of the stator core lower pressure ring, and the lower end connects to the T-bolt via the fastening nut. The lower end of the T-bolt connects to the vertical lathe faceplate. Support blocks or jacks are placed between the stator core lower pressure ring and the vertical lathe faceplate. The height and tension of the stator core are adjusted by adjusting the central fastening nut in conjunction with the support blocks or jacks on both sides, thus fixing the stator core onto the vertical lathe faceplate. This system is used for machining the stator core upper pressure ring, the stator core lower pressure ring, the outer circle of the arc plate, and the outer circle stop of the stator core upper pressure ring. The upper end of the lifting bolt is threaded, and the thread size corresponds to the threaded hole size on the stator core upper and lower pressure rings. A retaining ring is added at the root of the thread. The retaining ring and the lifting bolt are welded together; the middle part is a regular hexagonal prism, which facilitates the installation and removal of the lifting bolt from the stator core upper and lower pressure rings using a wrench; the lower end is a flange edge, used to fasten the fastening nut, serving as a connection; the fastening nut is in the shape of a regular hexagonal prism, with a skirt added to the lower outer side of the fastening nut to prevent the wrench from falling after it is locked onto the fastening nut; the fastening nut has a countersunk hole in the middle for the flange of the lifting bolt to pass through, and a through hole is opened at the top center of the countersunk hole for the central cylinder of the lifting bolt to pass through, while a flange edge is formed at the top of the countersunk hole of the fastening nut for fastening the flange edge of the lifting bolt; the lower part of the countersunk hole has a thread for mating with a T-bolt, and the thread is a left-hand helical thread.

2. The large Y-series asynchronous motor stator core machining fixture according to claim 1, characterized in that: First, put the fastening nut onto the lifting bolt, then screw the lifting bolt into the threaded hole of the stator core lower pressure ring. Insert the T-bolt into the T-slot of the vertical lathe faceplate. Once the lifting bolt and the T-bolt are aligned, screw the fastening nut into the T-bolt and tighten it.

3. The large Y-series asynchronous motor stator core machining fixture according to claim 1, characterized in that: The upper part of the T-bolt has a thread that mates with the fastening nut. The thread is a left-hand helical thread. The neck of the T-bolt is flat. The lower end is divided into a T-shaped boss that matches the T-slot on the faceplate of the vertical lathe.

4. The large Y-series asynchronous motor stator core machining fixture according to claim 1, characterized in that: The positioning rod is used for circumferential positioning of the stator core when it is mounted on a vertical lathe. The upper thread is consistent with the size of the screw hole on the lower pressure ring of the stator core. The lower part of the thread is a regular hexagonal prism, and the lower part of the regular hexagonal prism is machined into a cylinder. Its diameter is 1mm smaller than the neck groove width of the T-slot of the vertical lathe faceplate, so as to facilitate the insertion of the positioning rod into the T-slot and positioning. The length from the flange plane at the root of the positioning rod thread to the cylindrical end face is H+20~40mm, where: H is the height distance from the upper end face of the vertical lathe faceplate to the lower end face of the lower pressure ring of the stator core.

5. A method for machining the stator core of a large Y-series asynchronous motor, using the machining fixture for the stator core of a large Y-series asynchronous motor as described in any one of claims 1-4, characterized in that, The steps are as follows: First, install two positioning rods in the two screw holes distributed 180º on the lower pressure ring of the stator core. Then, rotate 90º to the other two screw holes distributed 180º and install two lifting bolts. When the stator core is mounted on the lathe, the two positioning rods are first inserted into the T-slots of the vertical lathe faceplate to position the stator core circumferentially, ensuring that the screw holes of the upper and lower pressure rings of the stator core are exactly in the T-slots of the vertical lathe faceplate. Then, adjust the coaxiality of the stator core and the vertical lathe faceplate, and finally, install the two positioning rods... The center position of each tightening bolt is located at the center position of the corresponding T-slot. Then, remove the positioning rod, replace it with the tightening bolt, install the T-bolt in the T-slot of the vertical lathe faceplate, move it directly below the tightening bolt, lower the fastening nut and tighten it to fix the stator core. Adjust the height of the support pad or jack under the stator core and the position of the lathe fixture to adjust the coaxiality and perpendicularity of the stator core. After adjustment, remove the lathe fixture to complete the machining of all surfaces of the stator core in one clamping operation.

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