Large-length-diameter-ratio rotor core vertical lathe inner hole finishing combined tooling and method

Abstract

The application discloses a large-length-diameter-ratio rotor core vertical lathe inner hole finishing combined tool, which comprises a spliced thickened bottom plate, a middle-section adjustable auxiliary support clamp, an arc-shaped tensioning pressing plate assembly, a lengthened damping vibration reduction tool row assembly and a dry air cooling gas supply assembly, the spliced thickened bottom plate is used for vertically fixing the rotor core, the middle-section adjustable auxiliary support clamp is used for abutting and supporting the middle section of the outer circle of the rotor core, the arc-shaped tensioning pressing plate assembly comprises vertical tensioning screws arranged along the ventilation holes of the rotor core and arc-shaped pressing plates matched with the end portions of the vertical tensioning screws, and the lengthened damping vibration reduction tool row assembly comprises a lengthened tool row mounted on a vertical tool rest of the vertical lathe and a reinforced damping vibration reduction tool rod mounted on the lengthened tool row. The vertical lathe can finish the inner holes of the whole length of the rotor core through single clamping, and is suitable for batch manufacturing of various large-length-diameter-ratio shaftless hollow motor rotor cores. The application further discloses a large-length-diameter-ratio rotor core vertical lathe inner hole finishing method.

Description

Technical Field

[0001] This invention belongs to the field of mechanical manufacturing and processing technology of motor rotor cores, and relates to a combination tooling and method for precision machining of the inner hole of a vertical lathe for a rotor core with a large length-to-diameter ratio. It is particularly suitable for the scenario of precision machining of the inner hole of a hollow rotor core with a large length-to-diameter ratio on a vertical lathe for marine pod propulsion motors. Background Technology

[0002] The 15MW polar ice-area pod propulsion motor rotor core features a completely new structural design. The core's silicon steel laminations are stacked for 2700mm, and the total length after assembling end rings at both ends is 3030mm. The nominal inner diameter is Φ1000.12mm, and the workpiece weighs 43 tons. It is a typical hollow rotor core with a large length-to-diameter ratio. Currently, there is no mature vertical lathe machining process for the inner hole of shaftless hollow cores.

[0003] The existing industry machining solution is: a vertical lathe (referred to as vertical lathe) with two-stage flipping and clamping for machining internal holes. Please refer to [link / reference]. Figure 1 An extended tool post 2' is added to the original tool post 1' of the vertical lathe 8'. A conventional tool 3' is installed on the extended tool post 2'. The vertical lathe chuck 7' has a flat bottom mold 6' and four jaws 5'. The four jaws 5' are used to clamp the bottom pressure ring / end ring of the rotor core 4'. After machining the inner hole of the upper half, the core is lifted and turned over. The four jaws 5' are used to clamp the bottom pressure ring / end ring of the core for a second time to machine the inner hole of the lower half.

[0004] The existing technical solution has the following drawbacks: (1) Insufficient positioning and clamping rigidity makes it difficult to guarantee form and position tolerances: The 3030mm ultra-long iron core is suspended in the middle section with only a single-point clamping at the bottom, resulting in large deflection vibration during rotation; without auxiliary support in the middle section and vertical tensioning reinforcement structure, the iron core shakes during machining, and the roundness of the inner hole and the coaxiality with the pressure ring are prone to exceeding the tolerance. The root cause is the lack of a combination of segmented support and vertical clamping tooling to constrain the deformation of the workpiece.

[0005] (2) Large deviation in accuracy between two turning and clamping: Turning processing requires two alignment of the reference, and the error of manual adjustment is superimposed. The inner hole has a tool-connecting step, and the radial runout is difficult to control within 0.1mm; there is a risk of overturning and collision when turning and hoisting heavy iron cores.

[0006] (3) Long-stroke internal hole machining tools have poor rigidity, severe vibration, and low surface roughness: The CK5263×45 / 63Q vertical lathe's original tool post 1' has a stroke of only 2200mm, which cannot cover the 2700mm machining length of silicon steel sheets; the ordinary extended tool post 2' has no vibration damping structure, resulting in obvious chatter during deep cavity cutting; the silicon steel sheets are thin stacked and cut intermittently, causing conventional tools to wear out quickly and have a short service life.

[0007] (4) Coolant cannot be used, and there is no suitable cooling solution for damping and vibration reduction cutting tool holders: water ingress into the silicon steel sheet interlayer is prone to rusting of the iron core, and the industry prohibits the spraying of cutting fluid; standard damping and vibration reduction tool holders rely on liquid cooling temperature control and have no dry air cooling adaptation structure, so they cannot stably exert the vibration reduction cutting effect.

[0008] (5) The manufacturing cost and cycle of tooling are difficult to control: the procurement cycle of the solid steel plate base plate with a thickness of 200mm is long and the unit price is high; the tooling has no modular adjustable support structure, and the single specification iron core is dedicated to poor versatility. Summary of the Invention

[0009] The purpose of this invention is to address the shortcomings of existing machining processes for large aspect ratio hollow rotor cores without a mandrel, such as insufficient tooling rigidity, poor accuracy due to double-turning clamping, vibration during long internal hole machining, rapid tool wear, and high tooling costs. This invention provides a combined tooling solution for finishing the internal holes of large aspect ratio rotor cores on a vertical lathe. This solution enables single-clamping positioning of large aspect ratio hollow rotor cores on a vertical lathe, eliminating the need for turning over, reducing secondary clamping datum errors, and improving the coaxiality and roundness accuracy of the internal holes. It also solves the problems of large deflection and rotational sway in the suspended middle section of ultra-long cores, enhancing workpiece machining rigidity and mitigating the risk of tipping over. Furthermore, it addresses the problem of insufficient stroke of the original tool rack on the vertical lathe, while suppressing vibration defects in deep cavity cutting with extended tool racks. It is suitable for dry cutting conditions of silicon steel sheets, providing a damped and vibration-reducing compressed air cooling solution for the tool holder, extending tool life. Finally, it simplifies the tooling structure, reducing the manufacturing cost and procurement cycle of the base plate.

[0010] Another objective of this invention is to provide a method for precision machining of the inner hole of a rotor core with a large length-to-diameter ratio on a vertical lathe.

[0011] One technical solution to achieve the above objective is: a combination tooling for precision machining of the inner hole of a vertical lathe with a large length-to-diameter ratio rotor core, comprising: The assembled thickened base plate is formed by the lower base plate and the upper base plate through the positioning stop and the fasteners. The assembled thickened base plate has a base plate mounting hole that matches the screw hole for connecting the pressure ring of the non-driving end of the rotor core, which is used to vertically fix the rotor core to the assembled thickened base plate. The adjustable auxiliary support fixture in the middle section includes four triangular support brackets arranged in a cross shape on the table of the vertical car chuck. Each triangular support bracket has a telescopically adjustable tightening bolt at its top. The end of the tightening bolt is equipped with a V-shaped soft pad support head for fitting and supporting the middle section of the outer circle of the rotor core. The arc-shaped tensioning plate assembly includes a vertical tensioning screw arranged along the ventilation holes of the rotor core and an arc-shaped pressure plate at the end, which, together with the bottom tensioning nut of the assembled thickened base plate, forms a bidirectional vertical constraint. The extended damping and vibration damping tool bar assembly includes an extended tool bar mounted on a vertical tool post of a vertical lathe and a reinforced damping and vibration damping tool bar mounted on the extended tool bar. The damping and vibration damping tool bar has a built-in damping and vibration damping module. A lathe tool head is mounted on the head of the damping and vibration damping tool bar. A cooling interface is reserved on the damping and vibration damping tool bar. The dry air-cooled air supply assembly includes a compressed air pipeline and a pressure regulating valve installed thereon. One end of the compressed air pipeline is connected to a compressed air source via a quick connector, and the other end is connected to the cooling interface of the damping and vibration-damping tool bar, so as to continuously supply compressed air to cool the damping and vibration-damping tool bar during the processing.

[0012] The above-mentioned combination tooling for precision machining of the inner hole of a vertical lathe for a large length-to-diameter ratio rotor core includes a prefabricated thickened base plate consisting of two 100mm thick steel plates fitted together with a small gap and bolted together, with a total thickness equivalent to 200mm. The prefabricated thickened base plate has eight mounting holes to match the eight sets of connecting bolt holes of the non-drive end pressure ring of the rotor core. The flatness of the mounting plane of the prefabricated thickened base plate is controlled to be ≤0.05mm.

[0013] The above-mentioned combination tooling for precision machining of the inner hole of a vertical lathe with a large length-to-diameter ratio rotor core includes a triangular support bracket whose bottom end is fixed to a T-slot on the chuck table of the vertical lathe by bolts. The V-shaped structure of the V-shaped soft pad support head matches the outer diameter of the patented iron core, and the V-shaped soft pad support head can be replaced to adapt to rotor cores of different diameters.

[0014] The above-mentioned combination tooling for precision machining of the inner hole of a vertical lathe for a rotor core with a large length-to-diameter ratio includes an arc-shaped tensioning plate assembly that is offset from the original tensioning screw position of the rotor core pressure ring. Four sets of a total of eight vertical tensioning screws are arranged along the ventilation holes of the rotor core. Every two vertical tensioning screws press one of the arc-shaped pressure plates onto the drive end of the rotor core. The arc-shaped pressure plate increases the contact area with the end face of the rotor core to disperse the clamping stress.

[0015] The above-mentioned combination tooling for finishing the inner hole of a vertical lathe with a large length-to-diameter ratio rotor core includes a 93° positive lathe tool head and cubic boron nitride inserts.

[0016] The above-mentioned combination tooling for precision machining of the inner hole of a vertical lathe for a rotor core with a large length-to-diameter ratio includes a dry air-cooled air supply assembly that introduces ambient temperature compressed air into the damping and vibration-damping tool holder. The temperature of the damping and vibration-damping tool holder is controlled to be ≤100℃ throughout the process, which meets the requirements for the use of the damping and vibration-damping tool holder. No cutting fluid is required, thus avoiding corrosion of the silicon steel sheet interlayer of the rotor core.

[0017] This invention also provides a method for finishing the inner hole of a rotor core with a large length-to-diameter ratio on a vertical lathe. The method uses the aforementioned machining fixture to finish the inner hole of the rotor core and includes the following steps: S1. On the boring and milling machining center, the rotor core is horizontally hoisted onto the V-shaped shelf. The coaxiality of the inner holes of the pressure rings at both ends of the rotor core is adjusted using a rotary indexing table. The non-drive end pressure ring contact plane is milled by a face milling cutter as the reference plane. S2, place the assembled thickened base plate on the support and level the mounting surface of the assembled thickened base plate. Hoist the rotor core to the upper plane of the assembled thickened base plate, align the non-drive end pressure ring contact plane of the rotor core with the mounting hole of the base plate, and install the fastening bolts and tighten them to the standard torque. Arrange the arc-shaped tensioning plate assembly through the ventilation hole of the rotor core, and form a two-way vertical constraint with the bottom tensioning nut of the assembled thickened base plate. S3, Install the flat bottom mold on the vertical car chuck according to the size of the assembled thickened bottom plate and match it with the car; hoist the rotor core assembled in step S2 onto the flat bottom mold of the vertical car; install the middle adjustable auxiliary support fixture and tighten it in the cross direction to the outer circle of the middle section of the rotor core; calibrate the reference twice and adjust the coaxiality of the inner holes of the pressure rings at both ends of the rotor core. S4, after the vertical lathe is clamped in one operation, the inner hole of the rotor core is machined in three sections in sequence: upper, middle, and lower. Specifically: First, install the cutting tool head on the vertical tool post of the vertical lathe and turn the upper section of the inner hole of the rotor core; Then, install an extended tool bar on the vertical tool post of the vertical lathe, and then install a cutting tool head on the extended tool bar to turn the inner hole of the middle section of the rotor core. Finally, an extended tool bar is added to the vertical tool post of the vertical lathe, and then a reinforced damping and vibration-damping tool bar and a cutting tool head are installed. The cooling interface of the damping and vibration-damping tool bar is connected to the compressed air pipeline of the dry air cooling air supply assembly. The compressed air is turned on to continuously cool the damping and vibration-damping tool bar, and the lower section of the inner hole of the rotor core is turned.

[0018] In the above-mentioned method for finishing the inner hole of a large length-to-diameter ratio hollow rotor core on a vertical lathe, in step S1, the coaxiality of the inner holes of the end rings of the rotor core is calibrated to ≤0.1mm, and the flatness of the mating plane of the non-drive end ring is milled to ≤0.03mm.

[0019] In the above-mentioned method for finishing the inner hole of a hollow rotor core on a vertical lathe with a large length-to-diameter ratio, in step S3, the two calibration benchmarks are: first, calibrate the inner circle runout of the non-drive end pressure ring to ≤0.05mm, then calibrate the inner circle runout of the drive end pressure ring to ≤0.05mm, and finally recalibrate the coaxiality of the inner holes of the pressure rings at both ends to ≤0.05mm.

[0020] In the above-mentioned method for finishing the inner hole of a hollow rotor core on a vertical lathe with a large length-to-diameter ratio, in step S4, the tool misalignment of the upper, middle, and lower sections of the inner hole is controlled to be ≤0.02mm.

[0021] The technical solution of the present invention, which is a combination tooling and machining method for finishing the inner hole of a rotor core on a vertical lathe with a large length-to-diameter ratio, has the following technical advantages compared with existing turning machining and simple single-point clamping tooling solutions: (1) Single clamping without flipping, significantly improving machining accuracy: By using a modular base plate + adjustable auxiliary support fixture in the middle section + arc-shaped tensioning plate tooling, the iron core can be hoisted and positioned in one go to complete the machining of the entire inner hole, eliminating the reference error of two flipping clamping. The dial indicator measured the maximum coaxiality of the iron core inner hole to be Φ0.075mm and the roundness to be 0.036mm, both of which are lower than the requirement of 0.1mm in the drawing. There is no tool-jointing step, the inner hole taper is ≤0.01mm, and the form and position tolerance qualification rate is 100%.

[0022] (2) The clamping rigidity is significantly enhanced, eliminating vibration and shaking defects: The adjustable support fixture in the middle section constrains the radial displacement of the middle section of the iron core, and the upper and lower arc-shaped tensioning plates are vertically tightened, solving the problems of large rotational deflection and upper machining vibration of ultra-long iron cores. The matching damping vibration reduction tool rod + compressed air dry cooling completely solves the problem of vibration in deep cavity cutting of extended tool racks. The roughness of the inner hole of the upper, middle and lower sections of the iron core is uniformly and stably in Ra2.0~Ra2.2, meeting the Ra3.2 drawing requirements.

[0023] (3) Low tooling cost and short manufacturing cycle: The thickened base plate is assembled from two 100mm general-purpose steel plates, which reduces material procurement costs and shortens the supply cycle compared to a 200mm whole plate. The adjustable auxiliary support fixtures in the middle section all adopt a modular and universal structure. Only the support blocks need to be replaced to adapt to hollow rotor cores of different diameters in the same series. It has strong reusability and does not require single-piece special tooling.

[0024] (4) Improved processing safety, reduced working time, and controllable delivery cycle: The 43-ton heavy iron core turning and hoisting process is eliminated, avoiding the safety risks of workpiece overturning and collision. The secondary alignment and repeated milling of the reference process are eliminated, reducing the total processing time for a single iron core. The company's existing boring and milling and vertical lathe equipment are fully utilized, eliminating the need for additional heavy machine tools and resulting in zero equipment investment costs.

[0025] (5) Dry cutting adapted to core protection: The compressed air cooling scheme does not use cutting fluid at all, avoiding water ingress and corrosion of silicon steel sheet interlayer, and improving the quality of rotor core finished product.

[0026] (6) High versatility and can be replicated and promoted in batches: The complete set of tooling and processing methods are compatible with various large length-to-diameter ratio shaftless hollow motor rotor cores, providing a mature technical solution for the domestic mass production of 15MW, 12.5MW and 8.8MW marine pod motor rotor cores. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the machining tooling for a neutral lathe in the existing technology.

[0028] Figure 2 This is a structural diagram of a combined tooling for precision machining of the inner hole of a vertical lathe with a large length-to-diameter ratio rotor core, according to the present invention. Figure 3 This is a structural diagram of a modular thickened base plate; Figure 4 for Figure 3 Sectional view along axis AA; Figure 5 This is the front view of the adjustable auxiliary support fixture in the middle section; Figure 6 Top view of the adjustable auxiliary support fixture in the middle section Figure 7 A schematic diagram of the V-shaped soft pad support head of the adjustable auxiliary support clamp in the middle section; Figure 8 This is a schematic diagram of the arc-shaped pressure plate. Figure 9 This is a schematic diagram of the vertical tension screw. Figure 10 A schematic diagram of the extended damping and vibration reduction knife bar assembly; Figure 11 A schematic diagram of a dry air-cooled air supply assembly; Figure 12 Schematic diagram of milling pressure ring assembly for boring and milling machining center; Figure 13 This is a schematic diagram of the rotor core and base plate assembly. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solution of the present invention, its specific embodiments will be described in detail below with reference to the accompanying drawings.

[0030] Example 1: Please see Figures 2 to 11 This embodiment provides a combination tooling for precision machining of the inner hole of a vertical lathe with a large length-to-diameter ratio rotor core, including a modular thickened base plate 8, a mid-section adjustable auxiliary support fixture 4, an arc-shaped tensioning pressure plate assembly 10, an extended damping and vibration-damping tool assembly 2, and a dry air-cooled air supply assembly 1.

[0031] Please see again Figure 3 and Figure 4 The assembled thickened base plate 8 is formed by the lower base plate 83 and the upper base plate 84 through the positioning stop and fasteners. The assembled thickened base plate 8 has a base plate mounting hole 82 that matches the screw hole for connecting the non-drive end pressure ring of the rotor core, which is used to vertically fix the rotor core 3 to the assembled thickened base plate.

[0032] The assembled thickened base plate 8 is made of two 100mm thick Q355ND steel plates with a small gap positioning stop. The lower base plate 83 and the upper base plate 84 are assembled with four M56 bolts 81, with a total thickness equivalent to 200mm, avoiding the problems of long procurement cycle and high unit price of 200mm whole plates. The assembled thickened base plate 8 has 8 φ60mm base plate mounting holes 82, which match the 8 sets of M56 connecting screw holes of the non-drive end pressure ring of the rotor core. The flatness of the mounting plane of the assembled thickened base plate 8 is controlled within ≤0.05mm to ensure that the core is installed vertically without clamping deformation. The overall load-bearing capacity of the assembled thickened base plate 8 meets the load-bearing requirements of a 43-ton core. After assembly, it is directly placed on the flat bottom mold 5 after the vertical car is assembled for integrated calibration.

[0033] Please see again Figure 5 , Figure 6 and Figure 7 The adjustable auxiliary support fixture 4 includes four triangular support brackets 41 arranged in a cross shape on the table of the vertical chuck 6. Each triangular support bracket 41 is provided with a telescopically adjustable tightening bolt 45 at its top. The end of the tightening bolt 45 is equipped with a V-shaped soft pad support head 44 for fitting and supporting the middle section of the outer circle of the rotor core 3.

[0034] The bottom end of the triangular support bracket 41 is fixed to the T-slot on the table surface of the vertical lathe chuck 6 by bolts; the top end of the triangular support bracket 41 is provided with a telescopic adjustable tightening bolt 45, and the bolt end is equipped with a V-shaped soft pad support head 4, which fits against the middle section of the outer circle of the rotor core; the V-shape of the V-shaped soft pad support head 44 matches the outer diameter of the core, and the part of the V-shaped soft pad support head 44 that fits against the outer circle of the rotor core is provided with a soft pad 43, which can prevent the outer circle of the rotor core from being squeezed and damaged; by simply replacing the V-shaped soft pad support head 44, it can be adapted to rotor cores of different diameters, and during processing, it constrains the radial wobble of the middle section of the core and reduces rotational deflection.

[0035] Please see again Figure 8 and Figure 9 The arc-shaped tensioning plate assembly 10 includes a vertical tensioning screw 102 arranged along the ventilation hole of the rotor core and an arc-shaped pressure plate 101 at the end, which, together with the bottom tensioning nut of the assembled thickened base plate 8, forms a bidirectional vertical constraint.

[0036] The arc-shaped tensioning plate assembly 10 is staggered from the original tensioning screw position of the pressure ring, and four sets of eight vertical tensioning screws 102 are arranged along the ventilation holes of the core. An arc-shaped pressure plate 101 is fitted to the top of each vertical tensioning screw 102 to increase the contact area with the core end face and distribute the clamping stress. Every two vertical tensioning screws 102 press one arc-shaped pressure plate 101 onto the drive end of the rotor core. The vertical tensioning screws 102 are tightened to the standard torque. The bottom end of the vertical tensioning screws 102, together with the bottom tensioning nut of the assembled thickened base plate 8, forms a bidirectional vertical constraint, eliminating vibration of the upper part of the rotor core during processing. Two vertical tensioning screws 102 and one arc-shaped pressure plate 101 constitute one set of arc-shaped tensioning plate assemblies 10, and a total of four sets of arc-shaped tensioning plate assemblies 10 are required.

[0037] Please see again Figure 10 The extended damping and vibration-damping tool post assembly 2 includes an extended tool post 21 mounted on the vertical tool post of a vertical lathe and a reinforced damping and vibration-damping tool shank 22 mounted on the extended tool post. The damping and vibration-damping tool shank 22 has a built-in damping and vibration-damping module to suppress chatter during deep cavity cutting. A positive 93° turning tool head 23 is mounted at the head of the damping and vibration-damping tool shank 22. The cutting insert of the turning tool head 23 is a cubic boron nitride insert, which is suitable for intermittent dry cutting of silicon steel sheets. A G3 / 4" standard cooling interface is provided at the tail end of the damping and vibration-damping tool shank 22.

[0038] The extended tool rack 21 is 800mm long, and the reinforced damping and vibration-damping tool bar 22 is 628mm long; the original vertical lathe tool rack has a stroke of 2200mm, and after adding the extended tool rack 21, the total machining stroke covers the total core length of 3000mm.

[0039] Please see again Figure 11 The dry air-cooled air supply assembly 1 includes a compressed air pipeline 11 and a pressure regulating valve 12 installed thereon. One end of the compressed air pipeline 11 is connected to a compressed air source through a quick connector 13, and the other end is connected to the cooling interface of the damping and vibration-damping tool rod 22, so as to continuously supply compressed air to cool the damping and vibration-damping tool rod during the processing.

[0040] The dry air-cooled air supply assembly 1 introduces ambient temperature compressed air into the damping vibration damping tool bar 22, which carries away the heat generated by the damping of the tool bar. The temperature of the damping vibration damping tool bar 22 is controlled to be ≤100℃ throughout the process, which meets the usage requirements of the damping vibration damping tool bar 22. No cutting fluid is required, which avoids corrosion of the silicon steel sheet interlayer of the rotor core.

[0041] Example 2: Please see Figure 2 , Figure 12 and Figure 13 A method for finishing the inner hole of a rotor core with a large length-to-diameter ratio on a vertical lathe, using the machining fixture of this invention for finishing the inner hole of the rotor core, and equipped with a TK6922A boring and milling machining center 305 and CK5263. Two 45 / 63Q CNC double-column vertical lathes are required. The specific steps include: S1, please refer to Figure 12 On the boring and milling machining center 305, the rotor core 3 is horizontally hoisted onto the V-shaped shelf 306. The coaxiality of the inner holes of the two end pressure rings 32 of the rotor core 3 is adjusted to ≤0.1mm using the rotary indexing table 307. The face milling cutter 304 mills the plane of the non-drive end pressure ring pad 33 as the reference plane, with a flatness of ≤0.03mm.

[0042] S2, Assembly Area: Place two 1600×1400×1200mm square boxes 20 (supports) according to the dimensions of the assembled thickened base plate 8; Place the assembled thickened base plate 8 on the two square boxes 20, exposing the base plate mounting holes 82, and level its mounting surface; Hoist the rotor core 3 to the upper plane of the assembled thickened base plate 8, align the reference plane of the non-drive end pressure ring with the base plate mounting hole, install 8 M56 fastening bolts and flat washers, and tighten them to the standard torque to secure the rotor core to the assembled thickened base plate 8, assembling the two into one unit; Arrange the arc-shaped tensioning plate assembly through the rotor core ventilation holes, which, together with the bottom tensioning nut of the assembled thickened base plate, forms a bidirectional vertical constraint.

[0043] S3. Based on the dimensions of the assembled thickened base plate 8, install the four flat bottom molds 5 on the vertical car chuck 6 and assemble them. Hoist the rotor core assembled in step S2 onto the flat bottom mold 5 of the vertical car. Install the adjustable auxiliary support fixture 4 in the middle section, select its support head and soft pad to match the outer diameter of the core, and tighten it in the cross direction to the outer circle of the middle section of the rotor core until it just contacts. Calibrate the reference twice and adjust the coaxiality of the inner holes of the pressure rings at both ends of the rotor core. First, check that the runout of the inner circle of the pressure ring at the non-drive end is ≤0.05mm, then check that the runout of the inner circle of the pressure ring at the drive end is ≤0.05mm, and then check that the coaxiality of the inner holes of the pressure rings at both ends is ≤0.05mm.

[0044] S4, after the vertical lathe is clamped in one operation, the inner hole of the rotor core is machined in three sections in sequence: upper, middle, and lower. Specifically: First, install a standard positive 93° turning tool head on the vertical tool post of the vertical lathe, and turn the upper section of the inner hole of rotor core 3; Then, install the extended tool rack on the vertical tool post of the vertical lathe, and then install the standard positive 93° turning tool head on the extended tool rack to turn the middle section inner hole of the rotor core 3; Finally, install the extended damping and vibration damping tool rack assembly 2: add an extended tool rack 21 to the vertical tool post of the vertical lathe, then install the reinforced damping and vibration damping tool rack 22 and the standard positive 93° turning tool head 23. Connect the G3 / 4" standard cooling interface at the tail end of the damping and vibration damping tool rack 22 to the compressed air pipeline of the dry air cooling supply assembly 1, turn on the compressed air to continuously cool the damping and vibration damping tool rack 22, and turn the lower section of the inner hole of the rotor core.

[0045] The misalignment of the inner hole joints in the upper, middle, and lower sections is controlled to be ≤0.02mm.

[0046] In summary, the present invention provides a combined tooling and machining method for finishing the inner hole of a vertical lathe with a large length-to-diameter ratio rotor core. This allows for the finishing of the entire inner hole of the core in a single clamping operation on the vertical lathe. Single-clamping positioning eliminates the need for flipping the lathe, reducing secondary clamping datum errors and improving the coaxiality and roundness accuracy of the inner hole. It solves the problems of large deflection and rotational sway in the suspended middle section of ultra-long cores, enhancing workpiece machining rigidity and mitigating the risk of tipping over. It also addresses the insufficient stroke of the original tool rack on the vertical lathe while suppressing the vibration defects in deep-cavity cutting with extended tool racks. Furthermore, it is suitable for dry cutting of silicon steel sheets, providing a damped, vibration-reducing compressed air cooling solution for the tool holder, extending tool life. Finally, it simplifies the tooling structure, reducing the manufacturing cost and procurement cycle of the base plate.

[0047] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the spirit and essence of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A combination tooling for precision machining of the inner hole of a vertical lathe with a large length-to-diameter ratio rotor core, characterized in that, include: The assembled thickened base plate is formed by the lower base plate and the upper base plate through the positioning stop and the fasteners. The assembled thickened base plate has a base plate mounting hole that matches the screw hole for connecting the pressure ring of the non-driving end of the rotor core, which is used to vertically fix the rotor core to the assembled thickened base plate. The adjustable auxiliary support fixture in the middle section includes four triangular support brackets arranged in a cross shape on the table of the vertical car chuck. Each triangular support bracket has a telescopically adjustable tightening bolt at its top. The end of the tightening bolt is equipped with a V-shaped soft pad support head for fitting and supporting the middle section of the outer circle of the rotor core. The arc-shaped tensioning plate assembly includes a vertical tensioning screw arranged along the ventilation holes of the rotor core and an arc-shaped pressure plate at the end, which, together with the bottom tensioning nut of the assembled thickened base plate, forms a bidirectional vertical constraint. The extended damping and vibration damping tool bar assembly includes an extended tool bar mounted on a vertical tool post of a vertical lathe and a reinforced damping and vibration damping tool bar mounted on the extended tool bar. The damping and vibration damping tool bar has a built-in damping and vibration damping module. A lathe tool head is mounted on the head of the damping and vibration damping tool bar. A cooling interface is reserved on the damping and vibration damping tool bar. The dry air-cooled air supply assembly includes a compressed air pipeline and a pressure regulating valve installed thereon. One end of the compressed air pipeline is connected to a compressed air source via a quick connector, and the other end is connected to the cooling interface of the damping and vibration-damping tool bar, so as to continuously supply compressed air to cool the damping and vibration-damping tool bar during the processing.

2. The combined tooling for finishing the inner hole of a vertical lathe with a large length-to-diameter ratio rotor core as described in claim 1, characterized in that, The assembled thickened base plate is formed by two 100mm thick steel plates with a small gap positioning stop and bolts, with a total thickness equivalent to 200mm; the assembled thickened base plate has 8 base plate mounting holes, which match the 8 sets of connecting screw holes of the non-drive end pressure ring of the rotor core; the flatness of the mounting plane of the assembled thickened base plate is controlled to ≤0.05mm.

3. The combined tooling for finishing the inner hole of a vertical lathe with a large length-to-diameter ratio rotor core as described in claim 1, characterized in that, The bottom end of the triangular support bracket is fixed to the T-slot on the chuck table of the vertical car by bolts. The V-shaped structure of the V-shaped soft pad support head matches the outer diameter of the patented iron core. By replacing the V-shaped soft pad support head, it can be adapted to rotor iron cores of different diameters.

4. The combined tooling for finishing the inner hole of a vertical lathe with a large length-to-diameter ratio rotor core as described in claim 1, characterized in that, The arc-shaped tensioning plate assembly is offset from the original tensioning screw position of the rotor core pressure ring. Four sets of a total of eight vertical tensioning screws are arranged along the ventilation holes of the rotor core. Every two vertical tensioning screws press one of the arc-shaped pressure plates onto the drive end of the rotor core. The arc-shaped pressure plate increases the contact area with the end face of the rotor core to disperse the clamping stress.

5. The combined tooling for finishing the inner hole of a vertical lathe with a large length-to-diameter ratio rotor core as described in claim 1, characterized in that, The cutting tool head is a positive 93° cutting tool, and the cutting inserts of the cutting tool head are cubic boron nitride inserts.

6. The combined tooling for finishing the inner hole of a vertical lathe with a large length-to-diameter ratio rotor core as described in claim 1, characterized in that, The dry air-cooled air supply assembly introduces ambient temperature compressed air into the damping vibration damping cutter bar, and controls the temperature of the damping vibration damping cutter bar to ≤100℃ throughout the process, which meets the usage requirements of the damping vibration damping cutter bar. No cutting fluid is required, thus avoiding corrosion of the silicon steel sheet interlayer of the rotor core.

7. A method for finishing the inner hole of a rotor core with a large length-to-diameter ratio on a vertical lathe, wherein the inner hole of the rotor core is finished using the machining fixture described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1. On the boring and milling machining center, the rotor core is horizontally hoisted onto the V-shaped shelf. The coaxiality of the inner holes of the pressure rings at both ends of the rotor core is adjusted using a rotary indexing table. The non-drive end pressure ring contact plane is milled by a face milling cutter as the reference plane. S2, place the assembled thickened base plate on the support and level the mounting surface of the assembled thickened base plate. Hoist the rotor core to the upper plane of the assembled thickened base plate, align the non-drive end pressure ring contact plane of the rotor core with the mounting hole of the base plate, and install the fastening bolts and tighten them to the standard torque. Arrange the arc-shaped tensioning plate assembly through the ventilation hole of the rotor core, and form a two-way vertical constraint with the bottom tensioning nut of the assembled thickened base plate. S3, Install the flat bottom mold on the vertical car chuck according to the size of the assembled thickened bottom plate and match it with the car. Hoist the rotor core assembled in step S2 onto the flat bottom mold of the vertical car. Install the adjustable auxiliary support fixture in the middle section and tighten it in the cross direction to the outer circle of the middle section of the rotor core. Calibrate the reference twice and adjust the coaxiality of the inner holes of the pressure rings at both ends of the rotor core. S4, after the vertical lathe is clamped in one operation, the inner hole of the rotor core is machined in three sections in sequence: upper, middle, and lower. Specifically: First, install the cutting tool head on the vertical tool post of the vertical lathe and turn the upper section of the inner hole of the rotor core; Then, install an extended tool bar on the vertical tool post of the vertical lathe, and then install a cutting tool head on the extended tool bar to turn the inner hole of the middle section of the rotor core. Finally, an extended tool bar is added to the vertical tool post of the vertical lathe, and then a reinforced damping and vibration-damping tool bar and a cutting tool head are installed. The cooling interface of the damping and vibration-damping tool bar is connected to the compressed air pipeline of the dry air cooling air supply assembly. The compressed air is turned on to continuously cool the damping and vibration-damping tool bar, and the lower section of the inner hole of the rotor core is turned.

8. The method for finishing the inner hole of a large length-to-diameter ratio hollow rotor core on a vertical lathe according to claim 7, characterized in that, In step S1, the coaxiality of the inner holes of the end rings of the rotor core is calibrated to ≤0.1mm, and the flatness of the mating plane of the non-drive end ring is milled to ≤0.03mm.

9. The method for finishing the inner hole of a large length-to-diameter ratio hollow rotor core on a vertical lathe according to claim 7, characterized in that, In step S3, the two calibration benchmarks are: first, calibrate the runout of the inner circle of the non-driving end pressure ring to ≤0.05mm, then calibrate the runout of the inner circle of the driving end pressure ring to ≤0.05mm, and finally recalibrate the coaxiality of the inner holes of the pressure rings at both ends to ≤0.05mm.

10. The method for finishing the inner hole of a large length-to-diameter ratio hollow rotor core on a vertical lathe according to claim 7, characterized in that, In step S4, the misalignment of the upper, middle and lower sections of the inner hole for tool connection is controlled to be ≤0.02mm.

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