Large motor rotor magnet yoke groove repairing device

Abstract

The utility model relates to a large motor rotor magnet yoke groove repairing device which is of a main shaft box side hanging type structure, two linear guide rails are arranged on a stand column, and a power milling head device moves up and down on the guide rails of the stand column and is a Y-axis stroke. The stand column and the base are connected and fixed through bolts, four rolling sliding block bearings are installed at the bottom of the stand column base and move on the arc THK guide rail to form an X-axis stroke, a machine tool moves around the motor rotor along the arc THK guide rail, and repairing machining of the whole motor rotor magnet yoke is completed. The power milling head device is transversely adjustable, and the milling head main shaft rotates left and right on the milling head seat in the horizontal plane, so that the tool setting adjustment of the formed milling cutter on the magnet yoke groove is realized, the movement of the tool in the X, Y and Z coordinate axis directions is realized, and the cutting requirements of different positions and angles are met.

Description

Technical Field

[0001] This utility model belongs to the field of large motor maintenance technology, specifically a large motor rotor magnetic yoke groove repair device. Background Technology

[0002] In the field of large motor maintenance, especially in the repair and processing of rotor yoke slots, numerous technical challenges are faced. The rotor yoke of a large motor plays a crucial role in motor operation, including constructing the magnetic circuit, providing rotational inertia, and stabilizing the magnetic poles. Its typical structural features include a large yoke diameter, often reaching 8-10 meters, and a height exceeding 4 meters. The yoke is composed of 3-5 mm thick fan-shaped laminations stacked in an alternating circular pattern, secured as a single unit by upper and lower pressure plates and tensioning screws. The connection between the yoke and the rotor support and magnetic poles is achieved through yoke keys and dovetail slots, respectively. The inner circle is fixed to the rotor support by the yoke keys, while the outer circle has dovetail slots for installing the magnetic poles. During long-term operation, factors such as centrifugal force, torque, and temperature changes cause relative displacement between the yoke laminations, resulting in lamination misalignment. This situation severely affects the flatness of the two sides of the dovetail slots, impacting the stability of the magnetic pole installation and motor performance. Therefore, reshaping the dovetail slots of the yoke becomes a necessary operation. Because large generator units are installed inside the mountains of hydroelectric power stations, during unit maintenance, it is necessary to lift out the generator rotor, remove the rotor magnetic poles and accessories, and then smooth out the misaligned areas of the yoke's pigeon-tail grooves. However, the size and weight of large hydroelectric generator rotors far exceed transportation restrictions, making it impossible to transport them back to the processing plant for processing. On-site repair becomes the only feasible approach. Traditional manual grinding and shaping methods are not only inefficient and labor-intensive when dealing with high-strength, low-alloy steel yoke laminations, but also have extremely limited effect on improving the flatness of the pigeon-tail grooves. This makes it difficult to meet the requirements of efficient operation and precise maintenance of modern large generators, prompting the industry to seek more efficient, reliable, and on-site-suitable magnetic yoke groove repair and processing technologies. Summary of the Invention

[0003] This utility model relates to a large-scale motor rotor magnetic yoke slot repair device. It employs an innovative processing technology, comprehensively utilizing advanced mechanical devices and intelligent control methods to achieve high-precision repair of the magnetic yoke slots. Its features include: an arc-shaped guide rail base plate, a circular arc THK guide rail, a base, a column, a milling head holder, and a power milling head device, wherein:

[0004] The column base of the large motor rotor yoke slot repair device can move on an arc-shaped THK guide rail. Two linear guide rails and one ball screw are installed on the front and rear sides of the column, enabling the milling head operating platform to move up and down. The column base is fixed to the lower end of the column with bolts. Four rolling slider bearings are installed at the bottom of the column base. The arc-shaped THK guide rail is designed and manufactured according to the diameter of the motor rotor being repaired. The entire machine tool moves around the motor rotor along the arc-shaped THK guide rail to complete the repair processing of the entire motor rotor yoke.

[0005] The milling head operating platform of the large motor rotor yoke groove repair device moves up and down via a ball screw and is balanced by a counterweight. The spindle of the power milling head device can extend and retract. The forming tool of the large motor rotor yoke groove repair device matches the size and shape of the yoke tail to be processed, and the cutting tool is a carbide-coated indexable insert.

[0006] The large motor rotor yoke slot repair device uses an arc-shaped THK guide rail mounted on a 40mm thick steel plate base. The track is formed by splicing two arc-shaped guide rails to create a quarter circle, which can be alternately spliced ​​forward. This allows the column base to rotate around the rotor once along the track, completing the repair of all the rotor's yoke slots.

[0007] The column of the large motor rotor magnetic yoke slot repair device has two linear rolling guide rails. A rolling slider is installed on the milling head seat, which moves up and down along the linear rolling guide rails on the column to achieve the up and down feed motion. A ball screw is installed on the milling head seat, and the motor drives the ball screw to drag the milling head seat up and down to achieve the cutting feed motion.

[0008] The power milling head unit is mounted on a milling head holder. The power milling head unit is laterally adjustable with a stroke of 200mm, and the milling head spindle can rotate left and right in the horizontal plane on the milling head holder, enabling the forming milling cutter to adjust the magnetic yoke groove. The milling head holder can be moved up and down, the power milling head unit itself can rotate and move left and right, and the spindle can move back and forth for tool feed.

[0009] The power milling head unit has an 11KW motor with a speed range of six speeds: 112rpm, 158rpm, 218rpm, 322rpm, 450rpm, and 630rpm.

[0010] The counterweight of the large motor rotor magnetic yoke groove repair device balances the milling head seat and the power milling head device by gravity, so that the ball screw only bears the cutting resistance.

[0011] Device Design

[0012] Magnetic Yoke Groove Repair Processing Device: This project develops a specialized milling machine for repairing magnetic yoke grooves on large motor rotors. Utilizing machining methods, it efficiently and precisely repairs misaligned and deformed magnetic yoke grooves. The cutting tool is designed and manufactured as a forming milling cutter based on the pigeon-tail groove contour of the magnetic yoke groove. The inserts are made of high-strength cemented carbide, possessing excellent wear resistance and impact resistance, enabling one-pass machining of complex curved surfaces. The tool holder is equipped with multi-degree-of-freedom adjustment, allowing for precise tool movement along the X, Y, and Z axes to meet cutting requirements at different positions and angles. The movement accuracy reaches ±0.02 mm, ensuring high precision in machining. Attached Figure Description

[0013] Figure 1 Front view structural diagram

[0014] Figure 2 Column threaded rod layout;

[0015] Figure 3 Column structure

[0016] Figure 4 Column slide

[0017] Figure 5 Arc-shaped THK guide rail Detailed Implementation

[0018] A large motor rotor yoke slot repair device includes a column 1, a milling head seat 2, a power milling head 3, and a column base 4. The base 4 is bolted to the lower end of the column 2. Four rolling slider bearings are installed at the bottom of the column base 4, allowing it to move around the rotor along an arc-shaped THK guide rail. The arc-shaped THK guide rail is mounted on a 40mm thick steel plate base plate and is formed by splicing two arc-shaped guide rails to create a quarter circle. These sections can be alternately spliced ​​forward, allowing the column base to move around the rotor once along the arc-shaped THK guide rail, completing the repair of all the yoke slots on the rotor.

[0019] Preliminary preparation: The large generator rotor to be repaired is hoisted to a specially designed repair work platform, which has high strength and high precision leveling function.

[0020] Machining: Based on the damage condition and repair requirements of the magnetic yoke groove, machining parameters are set, including tool path, cutting speed, and depth of cut. The machining mechanism is activated, and special tools, precisely driven by a multi-degree-of-freedom tool holder, automatically machine the magnetic yoke dovetail groove according to the preset path. During machining, cutting parameters are dynamically adjusted based on feedback information to ensure machining accuracy and quality. For example, if excessive depth of cut is detected in a certain area, the tool feed rate is automatically reduced or the tool angle is adjusted to ensure that the flatness of the two sides of the dovetail groove meets the standard requirements.

[0021] Precision Inspection and Adjustment: After the initial cutting process, the magnetic yoke dovetail groove is comprehensively inspected again using measuring instruments, and the measurement results are carefully compared with the standard parameters. If any local flatness or dimensional deviations are found to exceed the allowable range, the cutting mechanism is driven to perform precise compensation cutting on the corresponding area based on the deviation data until all indicators of the magnetic yoke groove fully meet the design standards.

[0022] Surface treatment and protection: After the magnetic yoke groove repair and processing reaches the required precision, a special anti-corrosion coating material is sprayed onto the surface of the magnetic yoke groove to form a protective film with uniform thickness and strong adhesion, which effectively enhances the corrosion resistance of the magnetic yoke groove, extends its service life, and ensures that it can maintain good performance in complex and harsh operating environments.

Claims

1. A large electric machine rotor yoke slot repair device, characterized in that, It comprises: arc-shaped guide rail bottom plate, circular arc THK guide rail, base, column, milling head seat and power milling head device, wherein: The column base of the large motor rotor yoke slot repairing device can move on the circular arc THK guide rail, two linear guide rails and one ball screw are arranged on the front side and the rear side of the column, the milling head seat operation platform is realized to move up and down, the column base is fixedly connected with the lower end of the column through bolts, four rolling block bearings are installed on the bottom of the column base, the circular arc THK guide rail is designed and manufactured according to the diameter of the repaired motor rotor, the whole machine tool moves along the circular arc THK guide rail around the motor rotor, and the repairing and machining of the whole motor rotor yoke is completed, The milling head seat operation platform of the large motor rotor yoke slot repairing device is driven to move up and down through the ball screw, and is balanced with a counterweight, the spindle of the power milling head device can be extended and retracted, the forming tool of the large motor rotor yoke slot repairing device is matched with the size and shape of the machined yoke dovetail, and the blade is selected to be a hard alloy coated machine clamp blade, The circular arc THK guide rail of the large motor rotor yoke slot repairing device is installed on the track bottom plate made of a 40mm thick steel plate, the track is composed of two circular arc guide rails to form a quarter of a circle, and can be alternatively spliced forward, so that the column base can move along the track around the rotor to complete the repairing and machining of all the yoke slots of the rotor, The two guide rails of the column of the large motor rotor yoke slot repairing device are linear rolling guide rails, rolling blocks are installed on the milling head seat to realize the up and down feeding motion along the linear rolling guide rails on the column, the ball screw is installed on the milling head seat, and the milling head seat is driven to move up and down by the ball screw driven by the motor, thereby realizing the cutting feeding motion, The power milling head device is installed on the milling head seat, the power milling head device is transversely adjustable with a stroke of 200mm, the milling head spindle can rotate left and right in the horizontal plane on the milling head seat, the tool setting of the forming milling cutter to the yoke slot is realized, the milling head seat can be moved up and down by operation, the power milling head device can be rotated, moved left and right and the spindle can be moved forward and backward for feeding, The motor power of the power milling head device is 11KW, and the speed range is six speeds of 112rpm, 158rpm, 218rpm, 322rpm, 450rpm and 630rpm, The counterweight of the large motor rotor yoke slot repairing device is gravitationally balanced with the milling head seat and the power milling head device, so that the ball screw only bears the cutting resistance.

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