Polishing tool and polishing method for rotor slip ring of AC variable frequency synchronous motor

Abstract

This invention belongs to the field of motor manufacturing technology and discloses a grinding fixture for the outer diameter of the rotor slip ring of an AC variable frequency synchronous motor. The fixture includes support feet, an upper crossbeam, a lower crossbeam, two supports, and a support spacing adjustment mechanism. The lower end of the upper crossbeam has an upper crossbeam guide rail groove; the upper end of the lower crossbeam is movably disposed within the upper crossbeam guide rail groove, and the lower end of the lower crossbeam has a lower crossbeam guide rail groove; the upper end of each support is movably disposed within the lower crossbeam guide rail groove, and the two supports are symmetrically distributed at 180° to the left and right; a polishing wooden frame is fixed to the lower end of the vertical part of each support; the support spacing adjustment mechanism is used to adjust the distance between the two supports. This invention changes the grinding process from unilateral force application to symmetrical 180° force application, avoiding slip ring deformation due to unilateral force application, improving processing quality, and enhancing the motor's operating performance and service life. This invention also discloses a method for grinding the outer diameter of the slip ring using the above-mentioned grinding fixture.

Description

Technical Field

[0001] This invention belongs to the field of motor manufacturing technology, specifically relating to a grinding fixture and grinding method for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor used for driving mine hoists. Background Technology

[0002] Please see Figure 1 The winding hoist unit used in mines is mainly used to lift materials from a low place to a high place. It has the characteristics of high efficiency and stability and generally consists of two parts: the left part is the hoist 100 for transportation; the right part is the motor 200 for drive. Currently, the commonly used drive methods for the main motor of the hoist are AC variable frequency motors, permanent magnet synchronous motors, and DC motors, among which AC variable frequency motors are a high-efficiency and energy-saving drive method. AC variable frequency motors are divided into AC synchronous motors and AC asynchronous motors. This application relates to AC variable frequency synchronous motors.

[0003] The hoist 100 mainly consists of a wire rope 101, a drum 102, a shaft 103, and bearings 104. The wire rope 101 is used to lift materials, the drum 102 is used to wind the wire rope to raise and lower it, the shaft 103 is used to fix the drum, and the bearings 104 are mounted on the base frame 105 to support the weight of the shaft and drum, as well as the tension of the wire rope. The hoist itself does not operate and requires external driving force. Therefore, the rotor of a motor is suspended at one end of the hoist's shaft 103, and the motor provides the driving force. The motor itself has no shaft and is coaxial with the hoist. Currently, the excitation of the rotor poles of AC variable frequency synchronous motors generally adopts an external excitation structure, that is, external DC power is supplied to the rotor poles through the rotor's slip rings. Since the motor rotor has no shaft, the slip rings are generally fixed to the rotor's magnetic yoke. Furthermore, due to the technical requirement that the outer circle of the slip ring and the inner circle of the rotor yoke must be coaxial, in order to ensure the machining accuracy of the form and position tolerances, the process involves assembling the slip ring and yoke, and then machining the outer circle of the slip ring using the inner circle of the rotor yoke as a reference. Details are as follows: Please see Figure 2 The AC variable frequency synchronous motor mainly consists of a base frame 203, a stator 202, and a rotor 201. The rotor 201 is suspended on the shaft 103 of the hoist, and the rotation of the motor's rotor 201 will drive the hoist to rotate together.

[0004] Please see Figure 3a and Figure 3b The rotor of the AC variable frequency synchronous motor is mainly composed of a magnetic yoke 2011, magnetic poles 2012 and slip rings 2013. The magnetic poles 2012 are fixed to the outer circle of the magnetic yoke 2011 with screws and nuts; the slip rings 2013 are fixed to the end face of the magnetic yoke 2011 with bolts and tapered pins.

[0005] Please see Figure 4The rotor's magnetic yoke 2011 is welded together from a sleeve 2111, a web plate 2112, and a cylinder 2113, or it can be cast from cast steel. The inner circle, outer circle, and stop all have technical requirements for coaxiality, dimensional requirements, tolerance requirements, and surface roughness requirements.

[0006] Please see Figure 5a and Figure 5b The rotor's slip ring 2013 mainly consists of a slip ring bracket 2131, a support plate 2132, two slip ring bodies 2133, a screw 2134, a nut 2135, an insulating washer 2136, an insulating pad, and an insulating block. The support plate 2132 is welded to the slip ring bracket 2131. The screw 2134 is installed on the support plate 2132. The insulating washer 2136, insulating pad, slip ring body 2133, insulating pad, insulating block, insulating pad, slip ring body 2133, insulating washer 2136, washer, and nut 2135 are then sequentially placed on the slip ring body 2133. Corresponding conductive screws are screwed onto the two slip ring bodies 2133, connecting them to a conductive busbar to form a complete slip ring. A machining allowance is left on the outer circumference of the slip ring for secondary machining.

[0007] Please see Figure 6 The existing machining method for the rotor's magnetic yoke is as follows: First, place the magnetic yoke 2011 with the end where the slip ring needs to be installed facing upwards. Then, place the magnetic yoke on the pre-placed pad 302 on the vertical lathe faceplate 301. Use the machine tool chuck 303 and jack to adjust the coaxiality and perpendicularity of the magnetic yoke with the machine tool. Then, clamp the magnetic yoke 2011 with the machine tool chuck 303. In this way, the inner circle, outer circle, stop, and plane can be machined by the cutting tool on the tool post 305 on the slide ram 304. Two adjustment positions are machined at the upper and lower ends of the inner circle of the magnetic yoke to facilitate adjustment after flipping.

[0008] Please see Figure 7 In existing technology, the machining method for slip rings is as follows: after machining the upper end of the magnetic yoke 2011, the yoke remains stationary, maintaining its original machining state. Then, the slip ring 2013 is directly installed onto the magnetic yoke 2011. Since the magnetic yoke 2011 and slip ring 2013 rotate together around the axis centerline, the runout of the slip ring's outer circle can only meet the technical requirements when the coaxiality of the slip ring's outer circle and the magnetic yoke's inner circle meets the requirements for normal motor operation. Therefore, the machining of the slip ring's outer circle adopts a process technology that matches the machining of the magnetic yoke's inner circle. This eliminates the cumulative error of the slip ring and magnetic yoke's fit. At the same time, the coaxiality of the magnetic yoke's inner circle and the slip ring's outer circle is guaranteed by the precision of the machining tool, ultimately ensuring the product's machining quality.

[0009] First, use a 306 lathe tool to machine away the excess material on the outer diameter of the slip ring, making the outer diameter as smooth as possible. However, directly machining the outer diameter of the slip ring with a 306 lathe tool is unreasonable because the tool marks left by the lathe tool follow a regular spiral trajectory. The vertical lathe operates at a low speed, resulting in a low cutting linear velocity. Therefore, it is difficult to achieve the required surface roughness of Ra 0.8 or higher, which will accelerate carbon brush wear. To solve this technical problem, grinding is usually used to improve the surface roughness of the slip ring's outer diameter. Please see Figure 8 To improve the surface roughness of the outer circle of the slip ring, a grinding method is used. Specifically, a grinding fixture 307 is installed on the tool post 305 of the machine tool. Abrasive is clamped at the top of the grinding fixture 307. The tool post is moved to slowly bring the abrasive closer to the outer circle of the slip ring. To achieve the grinding effect, after the abrasive comes close to the outer circle of the slip ring, the tool post continues to move a certain amount towards the slip ring so that the abrasive has a certain pressure and is pressed tightly against the outer circle of the slip ring. At the same time, an appropriate amount of machine oil is dripped between the contact surface of the abrasive and the slip ring to lubricate and cool, thereby improving the roughness of the machined surface.

[0010] While grinding can effectively improve the roughness of the slip ring's outer diameter, it also introduces problems with the slip ring's roundness and coaxiality. Through extensive verification and technical analysis, it was found that the slip ring body is fixed to the support plate by insulating washers, insulating pads, insulating blocks, screws, and nuts. The slip ring body is only supported and fixed by a few screws, resulting in poor rigidity. When the slip ring's outer diameter is subjected to unilateral pressure from the sandpaper, it will deform. During this unilateral grinding process, the stressed side of the slip ring will tilt towards the unstressed side. Over time, this will cause the slip ring to deform, resulting in a decrease in the roundness of the slip ring's outer diameter and a decrease in the coaxiality between the slip ring's outer diameter and the inner diameter of the magnetic yoke. In severe cases, this can lead to deviations from tolerances, substandard processing quality, and affect the overall quality of the motor. Summary of the Invention

[0011] The purpose of this invention is to overcome the defects of the prior art and provide a grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor. This fixture eliminates the problem of easy deformation due to unilateral stress during grinding of the outer circle of the slip ring, effectively ensuring the coaxiality of the inner circle of the rotor yoke and the outer circle of the slip ring. This significantly improves product quality, enhances the safety and reliability of motor operation, extends the service life of the motor, and reduces operating costs.

[0012] Another objective of this invention is to provide a method for grinding the outer circle of the rotor slip ring of an AC variable frequency synchronous motor, wherein the grinding fixture described above is used to grind the outer circle of the rotor slip ring.

[0013] One technical solution to achieve the above objective is: a grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor, comprising support feet, an upper crossbeam, a lower crossbeam, two supports, and a support spacing adjustment mechanism, wherein: The support leg is fixed to the top of the upper crossbeam; The lower end of the upper crossbeam is provided with an upper crossbeam dovetail guide rail groove; The upper end of the lower crossbeam is movably mounted in the upper crossbeam dovetail guide groove, and the lower end of the lower crossbeam is provided with a lower crossbeam dovetail guide groove. Each bracket has an inverted L-shaped structure consisting of a horizontal section and a vertical section. The upper dovetail guide rail of the horizontal section of each bracket is movably set in the dovetail guide rail groove of the lower crossbeam, and the two brackets are symmetrically distributed at 180° to the left and right. An adjustment screw mounting hole is opened in the middle of the vertical section of each bracket. A polished wooden frame is fixed at the lower end of the vertical section of each bracket. The bracket spacing adjustment mechanism includes an adjusting screw, an adjusting nut, a flat tenon, a clamping spring, a ring, a cam wrench, and a pressure adjusting nut. The left end of the adjusting screw has a small-diameter threaded section, the middle part has a large-diameter threaded section, and the right end is a crank handle. The adjusting nut is composed of a left cylindrical section, a middle flange, and a right cylindrical section connected in sequence. The left cylindrical section of the adjusting nut is threaded to the outside of the right side of the large-diameter threaded section of the adjusting screw, and the left cylindrical section of the adjusting nut passes through the adjusting screw mounting hole of the right bracket. The small-diameter threaded section is connected to the adjusting screw mounting hole of the left bracket through a washer and a double nut. The middle part of the adjusting screw is fitted with a middle sleeve and two spring-loaded springs, and the two spring-loaded springs are distributed... On both sides of the intermediate sleeve; the flat tenon is movably fitted outside the right cylindrical section of the adjusting nut; the cam wrench includes a cam and a handle connected thereto, the cam of the cam wrench is fitted outside the flat tenon, and the cam and the flat tenon are fixed together by screws, the cam wrench and the flat tenon form an eccentric device; the ring is movably fitted on the right cylindrical section of the adjusting nut and is located on the right side of the flat tenon; the compression spring is fitted on the right cylindrical section of the adjusting nut and is located between the flat tenon and the ring; the pressure adjusting nut is threadedly connected to the right cylindrical section of the adjusting nut and is connected to the right side of the ring, the pressure adjusting nut is used to adjust the pressure of the compression spring between the flat tenon and the ring; The support feet of the grinding fixture are mounted on the tool post of the vertical lathe, and the polishing wooden frames on the two supports are close to the outer circles of the slip ring.

[0014] The aforementioned grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor includes a U-shaped groove at the upper part of the support foot, the size of which is adapted to the size of the clamping part of the tool post of a vertical lathe; a support foot mounting groove is provided in the middle of the top of the upper crossbeam, the lower part of the support foot is disposed in the support foot mounting groove, the support foot is connected to the top of the upper crossbeam by bolts, and a stop bolt mounting hole is provided at the center of the support foot and the center of the upper crossbeam respectively.

[0015] The above-mentioned grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor, wherein the upper crossbeam guide rail groove and the lower crossbeam guide rail groove are respectively adopted as dovetail-shaped guide rail grooves; The upper end of the lower crossbeam has a dovetail structure that matches the guide rail groove of the upper crossbeam. A keyway for the lower crossbeam is provided at the middle position of the upper surface of the dovetail guide rail at the upper end of the lower crossbeam. A screw hole for the lower crossbeam is machined on each side of the keyway. A first stop bolt is installed in the stop bolt mounting hole of the support foot and the upper crossbeam, and the bottom end of the first stop bolt is located in the keyway of the lower crossbeam. The first stop bolt is used to prevent the lower crossbeam from sliding out of the guide rail groove of the upper crossbeam. The upper end of the horizontal part of the bracket has a dovetail structure that matches the lower crossbeam guide rail groove. A bracket keyway is provided at the middle position of the upper surface of the upper dovetail guide rail of the horizontal part of the bracket. A second stop bolt is installed in the lower crossbeam screw hole on both sides of the lower crossbeam keyway. The lower ends of the two second stop bolts are respectively located in the bracket keyway of the two brackets. The second stop bolts are used to prevent the corresponding brackets from sliding out of the lower crossbeam guide rail groove.

[0016] The above-mentioned polishing fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor, wherein the polishing wooden frame consists of a tool holder and a polishing head connected thereto; Each bracket has a T-slot at the lower end of its vertical section. The handle of the polishing wooden frame is fixed in the T-slot, and thin steel plates are provided on the two force-bearing surfaces of the handle. The polishing head of the polishing frame is arc-shaped, and a sandpaper is provided on the outside of the polishing head. A wool felt pad is provided between the sandpaper and the polishing head. The sandpaper and wool felt pad are fixed to both sides of the grinding head by bolts, and a pad is provided between each bolt and the corresponding sandpaper contact surface. The grinding head has a wedge angle machined at each end of its arc.

[0017] The above-mentioned grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor includes an intermediate sleeve that is hollow and cylindrical. Both ends of the intermediate sleeve are provided with annular stops, which are used to connect a spring-loaded spring.

[0018] The aforementioned grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor comprises the following: the inner circle of the left cylindrical section of the adjusting nut is an internal thread adapted to the adjusting screw, and a left keyway is formed on the outer circle along its axial direction; the inner circle of the right cylindrical section of the adjusting nut is a countersunk hole, and a right keyway is formed on the outer circle along its axial direction, with a right external thread machined on the right side of the outer circle; the left and right keyways are distributed at 90 degrees; a left limiting guide key is fitted into the left keyway; and a right limiting guide key is fitted into the right keyway. The bracket on the right side has a bracket guide keyway in the mounting hole of the adjusting screw. The left limit guide key is inserted into the bracket guide keyway with clearance fit. The bracket guide keyway moves along the left limit guide key to move the adjusting nut in the corresponding adjusting screw mounting hole. When the adjusting screw rotates, the cooperation between the bracket guide keyway and the left limit guide key prevents the adjusting nut from rotating with the adjusting screw. The flat tenon has a cylindrical structure with an inner circle and an outer square, and the inner circle of the flat tenon has a flat tenon keyway along its axial direction. The right limiting guide key is inserted into the flat tenon keyway with clearance fit. The flat tenon keyway moves along the right limiting guide key to realize the movement of the flat tenon along the adjusting nut. The right end face of the flat tenon and the left end face of the ring are respectively provided with compression spring mounting grooves, and the two ends of the compression spring are respectively inserted into the corresponding compression spring mounting grooves. The pressure regulating nut is threaded onto the external thread on the right side.

[0019] The above-mentioned grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor includes a flat tenon with through holes on the upper and lower end faces of the flat tenon, and a cam screw hole on the upper and lower end faces of the cam of the cam wrench. The flat tenon is set in the cam, and the flat tenon through holes and the corresponding cam screw holes are fixed together by screws. The screws act as a central axis, and the cam rotates around the screws.

[0020] The aforementioned grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor includes a locking pin device installed on the upper end of the cam of the cam wrench. The locking pin device includes a locking pin and a connecting rod connected thereto. After the cam wrench is rotated to the correct position, it has a self-locking function. When unlocking is required, the connecting rod is pressed down to lift the locking pin and unlock it. Then, the cam wrench is rotated in the opposite direction to relieve pressure.

[0021] The aforementioned grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor includes a balance block installed on the left side of the left-side bracket.

[0022] This invention also provides a method for grinding the outer circle of the rotor slip ring of an AC variable frequency synchronous motor. The grinding method uses the above-mentioned grinding fixture to grind the outer circle of the slip ring, and includes the following steps: S1. Place the grinding fixture on the faceplate of the vertical lathe, adjust its position, lower the tool post of the vertical lathe, align the support leg of the grinding fixture with the tool post, insert the clamping part of the tool post into the U-shaped groove of the support leg, tighten the fastening bolts on the tool post, and fix the support leg and the tool post together. S2, lift the tool post and grinding fixture of the vertical lathe. The support legs and upper crossbeam of the grinding fixture are fixed, while the lower crossbeam, with its bracket and polishing wooden frame, slides in the guide groove of the upper crossbeam. S3. Install the slip ring to be machined on the vertical lathe. According to the diameter of the outer circle of the slip ring, rotate the crank handle of the adjusting screw by hand so that the distance between the two polishing wooden frames is greater than the diameter of the outer circle of the slip ring. Move the tool post slide of the vertical lathe to the middle position and slowly lower the tool post slide. When the polishing wooden frame is visually positioned in the middle of the slip ring, lock the tool post slide. Rotate the crank handle by hand until the sandpaper on the grinding heads of the two polishing wooden frames is close to the outer circle of the slip ring. Then press down the cam wrench to give the sandpaper a preload on the outer circle of the slip ring. The sandpaper on the grinding heads of the two polishing wooden frames exerts equal pressure on both sides of the outer circle of the slip ring in opposite directions. The entire lower crossbeam, support and polishing wooden frame form a combined whole, suspended in the guide groove of the upper crossbeam, and is not subject to external forces. It forms a symmetrical double-sided force on the outer circle of the slip ring. S4, start the vertical lathe, the faceplate rotates together with the magnetic yoke and slip ring, and the polishing head of the polishing wooden frame polishes the outer circle of the slip ring.

[0023] The technical solution of the grinding fixture and method for the outer circle of the rotor slip ring of the AC variable frequency synchronous motor of the present invention changes the slip ring from being subjected to force on one side to being subjected to force on both sides symmetrically at the center during grinding, so as to avoid the problem of deformation of the slip ring due to force on one side. It can effectively ensure the coaxiality of the inner circle of the rotor magnetic yoke and the outer circle of the slip ring, greatly improve the product quality, improve the safety and reliability of motor operation, increase the service life of the motor, and reduce operating costs. Attached Figure Description

[0024] Figure 1 A schematic diagram of a winding hoist unit used in mines; Figure 2 This is a schematic diagram of the structure of an AC variable frequency synchronous motor; Figure 3a This is a schematic diagram of the rotor structure of an AC variable frequency synchronous motor; Figure 3b This is a cross-sectional view of the rotor of an AC variable frequency synchronous motor. Figure 4 This is a schematic diagram of the rotor's magnetic yoke; Figure 5a This is a schematic diagram of the rotor's slip ring structure; Figure 5b This is a cross-sectional view of the rotor's slip rings; Figure 6 This is a schematic diagram of the machining of a magnetic yoke in the prior art; Figure 7 This is a schematic diagram of the machining of slip rings in the prior art; Figure 8 A schematic diagram illustrating the grinding of the outer circle of a slip ring in existing technology; Figure 9 This is a structural diagram of a grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor according to the present invention. Figure 10 This is a structural schematic diagram of a vertical lathe; Figure 11 This is a structural diagram of the supporting leg; Figure 12a This is a structural schematic diagram of the upper crossbeam; Figure 12b This is a sectional view of the upper crossbeam; Figure 13a This is a structural schematic diagram of the lower crossbeam; Figure 13b This is a sectional view of the lower crossbeam; Figure 14a This is a schematic diagram of the support structure; Figure 14b This is a side view of the bracket; Figure 15 This is a schematic diagram of the polishing wooden frame. Figure 16 A schematic diagram of the adjusting screw; Figure 17 This is a schematic diagram of the intermediate sleeve structure; Figure 18a A schematic diagram of the adjusting nut; Figure 18b The left side view shows the adjustment nut; Figure 19a This is a schematic diagram of the flat tenon structure; Figure 19b This is a sectional view of a flat tenon; Figure 20a This is a schematic diagram of the cam wrench structure; Figure 20b This is a top view of the cam wrench; Figure 21 This is a schematic diagram of the structure of a circular ring; Figure 22 This is a schematic diagram of the pressure regulating nut. Figure 23a This is a schematic diagram showing the installation of the support legs and the upper crossbeam. Figure 23b A schematic sectional view showing the installation of the support legs and the upper crossbeam; Figure 24a This is a schematic diagram of the installation of the lower crossbeam and the bracket; Figure 24b This is a schematic sectional view showing the installation of the lower crossbeam and the bracket; Figure 25a This is a schematic diagram of the installation of the upper and lower crossbeams; Figure 25b A schematic sectional view showing the installation of the upper and lower crossbeams; Figure 26 This is a schematic diagram of the installation of the bracket spacing adjustment mechanism; Figure 27This is a schematic diagram showing the installation of the bracket and polished wooden frame; Figure 28 This is a diagram showing the usage state of the grinding fixture of the present invention. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solution of the present invention, its specific embodiments are described in detail below with reference to the accompanying drawings: Please see Figures 9 to 28 According to an embodiment of the present invention, a grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor includes a support foot 1, an upper crossbeam 2, a lower crossbeam 3, two brackets 4, and a bracket spacing adjustment mechanism.

[0026] Support foot 1 is fixed to the top of upper crossbeam 2; upper crossbeam guide rail groove 21 is opened at the lower end of upper crossbeam 2; upper end of lower crossbeam 3 is movably set in upper crossbeam guide rail groove 21, and lower end of lower crossbeam 3 is opened in lower crossbeam guide rail groove 31; each bracket 4 is an inverted L-shaped structure composed of a horizontal part and a vertical part, and the upper end of the horizontal part of each bracket is movably set in lower crossbeam guide rail groove 31, and the two brackets 4 are symmetrically distributed at 180° to the left and right; an adjustment screw mounting hole 41 is opened in the middle of the vertical part of each bracket 4; a polished wooden frame 5 is fixed at the lower end of the vertical part of each bracket 4.

[0027] The bracket spacing adjustment mechanism includes an adjusting screw 6, an adjusting nut 8, a flat tenon 9, a clamping spring 10, a circular ring 14, a cam wrench 15, and a pressure adjusting nut 16. The bracket spacing adjustment mechanism is used to adjust the spacing between the two brackets 4, and consequently, the spacing between the two polishing wooden frames 5. The support feet 1 of the grinding fixture are mounted on the tool post 305 of the vertical lathe, and the polishing wooden frames 5 on the two brackets 4 are close to the outer sides of the slip ring 2013.

[0028] The grinding fixture of this invention aims to solve the problem of unilateral force on the outer circle of the slip ring. Instead, it allows the slip ring to be subjected to force at two corresponding positions at 180° angles on its outer circle. The force must be equal in magnitude and opposite in direction to achieve force balance. Based on this design concept, the slip ring is prevented from deforming due to uneven force.

[0029] Please see Figure 10The vertical lathe mainly consists of a faceplate 301, chucks 303, column 308, crossbeam 309, tool post slide 304, and tool post 305. The faceplate 301 rotates around the center. The column 308 supports the crossbeam 309, which can move up and down along the guide rails of the column 308. The tool post slide 304 can move horizontally left and right along the crossbeam 309. Some tool post slides 304 can cross the center, while others cannot. The tool post slide 304 can also move vertically up and down. Therefore, the tool post 305, fixed to the lower end of the tool post slide 304, can move up, down, left, and right.

[0030] The grinding fixture of the present invention is installed on the tool post 305 of a vertical lathe. When the lathe is started, the faceplate 301 rotates together with the magnetic yoke 2011 and the slip ring 2103. The coaxiality of the inner circle of the magnetic yoke and the outer circle of the slip ring is guaranteed by the accuracy of the lathe faceplate rotation. The accuracy of a normal lathe is very high, which fully meets the machining requirements of the outer circle of the slip ring.

[0031] The structure, function, and working principle of the main components of the grinding fixture of the present invention will be introduced one by one below.

[0032] Please see again Figure 11 The support leg 1 is a component used to connect with the tool post 305 of the vertical lathe. The upper part of the support leg 1 is a U-shaped groove 11, the size of which is adapted to the size of the clamping part of the tool post 305 of the vertical lathe. A stop bolt mounting hole 12 is provided at the center of the support leg 1 so that the first stop bolt can pass through. A screw hole 13 is machined on both sides of the stop bolt mounting hole 12 for connecting the upper crossbeam 2.

[0033] Please see Figure 12a and Figure 12b The upper crossbeam 2 is a flat beam. A support foot mounting groove 22 is provided in the middle of the top of the upper crossbeam 2. A through hole countersunk hole 23 is machined on the left and right sides of the support foot mounting groove 22. A stop bolt mounting screw hole 24 with a countersunk hole is machined in the center of the support foot mounting groove 22.

[0034] Please see Figure 23a and Figure 23b The lower part of the support leg 1 is set in the support leg mounting groove 22. Bolts 25 are inserted into the screw hole 13 and the through hole countersunk hole 23 to connect the support leg 1 and the upper crossbeam 2 into one piece. The first stop bolt 26 is screwed into the stop bolt mounting hole 12 and the stop bolt mounting screw hole 24. The upper crossbeam guide rail groove 21 adopts a dovetail-shaped guide rail groove for suspending the lower crossbeam 3. The lower crossbeam 3 can move freely and flexibly within the upper crossbeam guide rail groove 21. The stop bolt 26 can prevent the lower crossbeam 3 from sliding out of the dovetail groove guide rail, thus providing protection. The upper crossbeam 2 is a key component. Its upper end is fixedly connected to the support leg 1, and its lower end is movably connected to the lower crossbeam 3, playing a connecting role between the upper and lower parts. Please see Figure 13a and Figure 13b The upper end of the lower crossbeam 3 has a dovetail structure that matches the upper crossbeam guide rail groove 21. A lower crossbeam keyway 33 is provided at the middle position of the upper surface of the upper dovetail guide rail 32 of the lower crossbeam 3. The bottom end of the first stop bolt 26 is located in the lower crossbeam keyway 33. In this way, the movement range of the lower crossbeam 3 is limited by the lower crossbeam keyway 33. The first stop bolt 26 can be used to prevent the lower crossbeam 3 from sliding out of the upper crossbeam guide rail groove 21.

[0035] A lower crossbeam screw hole 34 is machined on each side of the lower crossbeam keyway 33. The lower crossbeam screw hole 34 is used to install the second stop bolt, which can prevent the bracket 4 from sliding out of the lower crossbeam guide rail groove 31 and play a protective role. The lower crossbeam guide rail groove 31 also adopts a dovetail-shaped guide rail groove.

[0036] The lower crossbeam 3 is a key component connecting the upper crossbeam 2 and the bracket 4. The dovetail guide rail 32 at the upper end of the lower crossbeam 3 cooperates with the upper crossbeam guide rail groove 21 below the upper crossbeam, allowing the lower crossbeam 3 to move freely back and forth within the upper crossbeam guide rail groove 21. The lower crossbeam guide rail groove 31 is used to suspend the bracket 4, allowing the bracket 4 to move freely and flexibly within the lower crossbeam guide rail groove 31.

[0037] Please see Figure 14a and Figure 14b The bracket 4 has an inverted L-shaped structure. The upper end of the horizontal part of the bracket 4 has a dovetail structure that matches the lower crossbeam guide rail groove. A bracket keyway 43 is provided in the middle of the upper surface of the dovetail guide rail 42 at the upper end of the horizontal part of the bracket 4. A second stop bolt 35 is installed in each of the two lower crossbeam screw holes 34. The lower ends of the two second stop bolts 35 are located in the bracket keyways 43 of the two brackets respectively. In this way, the movement range of each bracket 4 is limited by the corresponding bracket keyway 43. The second stop bolts 35 can be used to prevent the corresponding bracket 4 from sliding out of the lower crossbeam guide rail groove 31.

[0038] The bracket 4 is a key component connecting the lower crossbeam 3 and the polishing frame 5. The upper dovetail guide rail 42 of the bracket mates with the lower crossbeam guide rail groove 31, allowing the bracket 4 to move freely back and forth within the lower crossbeam guide rail groove 31. Each bracket 4 has a T-slot 44 at its lower vertical end, with screw holes machined on its side. The T-slot 44 is used to install the polishing frame 5, and fixing bolts are screwed into the screw holes on the side of the T-slot 44 to secure the polishing frame 5.

[0039] Please see Figure 15The polishing frame 5 consists of a tool holder 51 and a grinding head 52 connected to it. The tool holder 51 is rectangular and is fixed to the T-slot 44 at the lower end of the bracket 4 by bolts. The grinding head 52 is arc-shaped, with a screw hole machined on each side for mounting bolts 55 for fixing the felt pad 53 and sandpaper 54. Since the polishing frame 5 is close to the outer circle of the slip ring, it is inevitable that it will bump or rub against the slip ring during processing. To avoid damaging the slip ring, the polishing frame 5 is made of high-strength epoxy fiberglass cloth 3240, which has a lower hardness than metal. A felt pad 53 is placed between the sandpaper 54 and the grinding head and fixed with bolts 55. To ensure that the felt pad 53 and sandpaper 54 are installed snugly, a pad 56 is placed between each bolt 55 and the corresponding sandpaper 54 contact surface. The pad 56 is made of high-strength epoxy fiberglass cloth 3240.

[0040] The tool holder 51 of the polishing frame is frequently subjected to clamping force, and the clamping surface is easily damaged. To improve the service life of the tool holder, a thin steel plate 57 is added to each of the two force-bearing surfaces of the tool holder. The grinding head 52 is made into an arc shape to increase the envelope angle with the outer circle of the slip ring and the grinding area, thereby improving the grinding effect. To ensure a smoother grinding process and avoid vibration, a wedge angle is machined at each end of the arc of the grinding head.

[0041] Please see Figure 16 The adjusting screw 6 has a small-diameter threaded section 61 on its left end, a large-diameter threaded section 62 in the middle, and a crank handle 63 on its right end. The adjusting screw 6 is used to adjust the distance between the two supports. First, screw the adjusting nut 8 into the middle of the adjusting screw 6. Then, insert the adjusting screw 6 and the adjusting nut 8 into the adjusting screw mounting hole 41 of the right-side support. Next, insert the left end of the adjusting screw 6 into the adjusting screw mounting hole 41 of the left-side support. Place a washer on the left end of the adjusting screw 6 and secure it with a double nut. At this point, it is essential to ensure that the adjusting screw 6 can rotate freely within the adjusting screw mounting hole 41. Gently rotate the crank handle 63 by hand to adjust the distance between the two supports. Adjust the distance between the two supports to the appropriate position according to the outer diameter of the slip ring.

[0042] Please see Figure 17 An intermediate sleeve 71 and two spring-loaded springs 72 are fitted into the middle of the adjusting screw 6, with the two spring-loaded springs 72 distributed on both sides of the intermediate sleeve 71, allowing the bracket to extend and retract freely. The intermediate sleeve 71 is a hollow cylinder with annular stops 73 machined at both ends for mounting the spring-loaded springs 72. The intermediate sleeve 71 is fitted onto the adjusting screw 6. Because the distance between the two brackets 4 is relatively large, the intermediate sleeve 71 between the two brackets 4 can shorten the total length of the spring-loaded springs 72.

[0043] Please see Figure 18a and Figure 18bThe adjusting nut 8 is composed of a left cylindrical section 81, a middle flange 82, and a right cylindrical section 83 connected in sequence. The inner circle of the left cylindrical section 81 of the adjusting nut has an internal thread that matches the adjusting screw, and a left keyway 84 is formed on its outer circle along its axial direction. The inner circle of the right cylindrical section 82 of the adjusting nut is a countersunk hole, and a right keyway 85 is formed on its outer circle along its axial direction. The right side of the outer circle is machined with a right external thread. The left keyway 84 and the right keyway 85 are distributed at 90 degrees. A left limit guide key is installed in the left keyway 84 with a transition fit. A right limit guide key is installed in the right keyway 85 with a transition fit.

[0044] The left cylindrical section 81 of the adjusting nut is threaded onto the outside of the right side of the large-diameter threaded section 62 of the adjusting screw 6, and the left cylindrical section 81 of the adjusting nut passes through the adjusting screw mounting hole 41 of the right bracket. Specifically, the adjusting screw mounting hole 41 of the right bracket is provided with a bracket guide keyway, and the left limit guide key is inserted into the bracket guide keyway with clearance fit. The bracket guide keyway moves along the left limit guide key to realize the movement of the adjusting nut 8 in the corresponding adjusting screw 6 mounting hole. When the adjusting screw 6 rotates, the adjustment nut 8 does not rotate with the adjusting screw 6 due to the cooperation of the bracket guide keyway and the left limit guide key. That is, when the crank handle 63 is turned, only the adjusting screw 6 rotates. When the adjusting screw 6 rotates, the two brackets 4 can move inward or outward with the rotation of the adjusting screw 6.

[0045] The adjusting nut 8 is used in conjunction with the adjusting screw 6 to adjust the distance between the two supports 4. The right cylindrical section 83 is the position for installing the flat tenon 9, the pressure spring 10, and the ring 14; the flat tenon 9 and the ring 14 can move freely left and right. The external thread on the right side is used to install the pressure adjusting nut 16. Please see Figure 19a and Figure 19b The flat tenon 9 is movably fitted onto the right cylindrical section 83 of the adjusting nut 8. The main structure of the flat tenon 9 is a hollow cylindrical structure with an inner circle and an outer square, and its shape is machined into a regular quadrilateral. The inner circle of the flat tenon 9 has a flat tenon keyway 91 along its axial direction. The right limiting guide key is inserted into the flat tenon keyway 91 with clearance fit. The flat tenon keyway 91 moves along the right limiting guide key to realize the movement of the flat tenon 9 along the adjusting nut 8. The flat tenon 9 can move freely left and right on the outer circle of the adjusting nut 8. A compression spring mounting groove 92 is opened on the right end face of the flat tenon 9 to connect the left end of the compression spring 10, which serves to support the compression spring 10 and can provide a constant pressure to the bracket 4.

[0046] Please see Figure 20a and Figure 20bThe cam wrench 15 includes a cam 151 and a handle 152 connected thereto. The cam 151 of the cam wrench 15 is fitted onto the outside of the flat tenon 9, and the cam 151 and the flat tenon 9 are fixed together by screws. Specifically, the upper and lower end faces of the flat tenon 9 are respectively provided with flat tenon through holes 93, and the upper and lower end faces of the cam of the cam wrench are respectively provided with cam screw holes 153. The flat tenon 9 is set inside the cam 151, and the flat tenon through holes 93 and the corresponding cam screw holes 153 are fixed together by screws. After the cam wrench 15 and the flat tenon 9 are combined into one unit, they form an eccentric device. A locking pin device is installed on the upper end of the cam 151 of the cam wrench 15. The locking pin device includes a locking pin 154 and a connecting rod 155 connected thereto.

[0047] The purpose of the cam wrench 15 is to provide a constant clamping force to the two supports 4. After the cam wrench 15 rotates in a specified direction, the cam eccentricity naturally increases or decreases. The difference in this eccentricity is the distance of the clamping spring 10. According to Hooke's law, the clamping spring 10 will generate a rebound force. This force acts on the support 4 and is then transmitted to the polishing wooden frame 5 and sandpaper 54 mounted on the support 4. The sandpaper 54 exerts pressure on the outer circle of the slip ring. Since the two supports are symmetrically distributed at 180°, the pressure of the sandpaper 54 on the polishing wooden frame 5 on both sides of the slip ring is equal in magnitude and opposite in direction, thus achieving force balance and preventing the slip ring from tilting to one side. After the cam wrench 15 is rotated to its position, it has a self-locking function, and pressure release is also very convenient. When unlocking is required, the lower connecting rod 155 is pressed down to lift the locking pin 154 and unlock it. Then, the cam wrench 15 is rotated in the opposite direction to release the pressure.

[0048] Please see Figure 21 The main structure of the ring 14 is a hollow cylinder. A compression spring mounting groove 141 is provided on the left end face of the ring 14 for connecting the right end of the compression spring 10.

[0049] The ring 14 is fitted with a clearance fit on the outer circle of the right cylindrical section 83 of the adjusting nut 8. The ring 14 can move freely left and right on the adjusting nut 8. The ring 14 is located on the right side of the flat tenon 9. The compression spring is located between the flat tenon 9 and the ring 14.

[0050] Please see Figure 22 The pressure adjusting nut 16 is ring-shaped with knurled patterns on the outer circumference and four notches, making it easy to rotate the pressure adjusting nut 16 with a hook wrench.

[0051] The pressure adjusting nut 16 is threaded onto the right external thread of the adjusting nut 8 and connected to the right side of the ring 14. Since the eccentricity of the cam wrench 15 is fixed, the cam cannot adjust the pressure. Therefore, the pressure of the clamping spring 10 between the flat tenon 9 and the ring 14 needs to be adjusted via the pressure adjusting nut 16. When the pressure adjusting nut 16 is tightened with the hook wrench, the pressure of the clamping spring 10 increases, and vice versa.

[0052] Please see Figures 23a to 27 The assembly process of the grinding fixture for the outer circle of the rotor slip ring of the AC variable frequency synchronous motor of the present invention is as follows: (1) First, bolt the support leg 1 to the upper crossbeam 2 to form a whole. The support leg 1 must be inserted into the support leg mounting groove 22 on the upper crossbeam 2 (see Figure 23a and 23b The bottom surface of the support leg 1 is in close contact with the bottom surface of the support leg mounting groove 22. This structure allows the side of the support leg 1 to cooperate with the groove wall of the support leg mounting groove 22, enabling the upper crossbeam 2 to withstand a large torque.

[0053] (2) Then assemble the bracket 4 and the lower crossbeam 3 together. Please refer to [link / reference]. Figure 24a and Figure 24b The upper dovetail guide rails 42 of the two brackets 4 are inserted into the lower crossbeam guide rail grooves 31 respectively. The second stop bolts 35 are then screwed into the lower crossbeam screw holes 34. At this point, the lower end of the second stop bolts 35 is precisely engaged in the bracket keyway 43 at the upper end of the bracket 4, while maintaining a gap with the side and bottom surfaces of the bracket keyway 43. The bracket 4 can move freely within the lower crossbeam guide rail grooves 31, with the range of motion being the length of the bracket keyway 43. Because this bracket keyway 43 is a closed groove, when the second stop bolts 35 approach both ends of the bracket keyway 43, the bracket 4 can no longer move. This prevents the bracket 4 from sliding out of the lower crossbeam guide rail grooves 31 and falling, thus providing protection.

[0054] (3) Then assemble the upper crossbeam 3 and the lower crossbeam 2 together, see [link to relevant documentation]. Figure 25a and Figure 25b Insert the upper dovetail guide rail 32 of the lower crossbeam 3 into the upper crossbeam guide rail groove 21. Screw the first stop bolt 26 into the stop bolt mounting hole 12 of the support leg 1 and the stop bolt mounting screw hole 24 of the upper crossbeam 2. At this time, the lower end of the first stop bolt 26 is just stuck in the lower crossbeam keyway 33 at the upper end of the lower crossbeam, but maintains a gap with the side and bottom surface of the lower crossbeam keyway 33. The lower crossbeam 3 can move freely in the upper crossbeam guide rail groove 21, and the range of movement is the length of the lower crossbeam keyway 33. Since this lower crossbeam keyway 33 is a closed groove, when the stop bolt approaches both ends of the lower crossbeam keyway 33, the lower crossbeam 3 can no longer move. This prevents the lower crossbeam 3 from sliding out of the upper crossbeam guide rail groove 21 and falling, thus providing protection.

[0055] (4) Next, assemble the bracket spacing adjustment mechanism with the bracket. Please refer to [link / reference]. Figure 26 An adjusting nut 8, a flat tenon 9, a clamping spring 10, a ring 14, a cam wrench 15, and a pressure adjusting nut 16 are pre-installed on the adjusting screw 6 to form an adjusting screw assembly. The adjusting screw assembly is then passed through the adjusting screw mounting hole of the right-side bracket 4. Next, a middle sleeve 71 and two spring-loaded springs 72 are inserted into the middle of the adjusting screw 6. Then, the small-diameter threaded section 61 of the adjusting screw 6 is inserted into the adjusting screw mounting hole of the left-side bracket 4. External force is used to bring the two brackets 4 as close together as possible. A washer is placed on the left end of the adjusting screw 6, the nut is tightened, and the retaining washer is flipped over for safety. The external force is then removed, allowing the two brackets 4 to spring open naturally under the action of the spring-loaded springs 72. At this point, rotating the crank handle 63 by hand can reduce or increase the distance between the two brackets.

[0056] (5) Install polishing wooden frame 5, please refer to Figure 27 The polishing wooden frame 5 is installed in the T-slot 44 at the lower end of the two supports 4 and fixed with bolts. The new polishing fixture is now fully installed and can be machined on a lathe.

[0057] The present invention relates to a grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor. The opening size of the left and right side brackets 4 of the grinding fixture is adjusted by the adjusting screw 6. There are two spring springs 72 between the brackets 4 to open the brackets 4. When adjusting the opening size of the two side supports 4 by rotating the adjusting screw 6, the clamping spring 10 has no effect. When the adjusting screw 6 is adjusted until the polishing wooden frame 5 is close to the outer circle of the slip ring, the pressure of the sandpaper 54 on the outer circle of the slip ring is very small. After the cam wrench 15 is turned, the cam protrusion is only close to the right side of the right support 4. Since the support 4 is supported by the slip ring, the support 4 cannot move, forcing the flat tenon 9 to move to the right. The amount of movement is the eccentricity of the cam. According to Hooke's theorem, the pressure of the clamping spring 10 is all applied to the cam, and the cam then transmits the force to the support 4. The support 4, along with the sandpaper 54 of the polishing wooden frame 5, acts on the outer circle of the slip ring. This achieves the problem of symmetrical force. The spring force of the clamping spring 10 is greater than the spring force of the release spring 72. The difference between the two forces is the force of the sandpaper acting on the outer circle of the slip ring. Originally, the support 4 and the lower crossbeam 3 were movable. However, due to the clamping force, according to the lever principle, the support 4 is automatically locked in the lower crossbeam guide rail groove 31 and cannot move. At this time, the polishing wooden frame 5, the support 4, and the lower crossbeam 3 form a stable assembly. Since the upper dovetail guide rail 32 of the lower crossbeam 3 is inserted into the upper crossbeam guide rail groove 21, the lower crossbeam 3 can still move freely within the upper crossbeam guide rail groove 21. Therefore, even if there is a deviation between the rotation center of the fixed grinding fixture tool holder 305 and the slip ring, the grinding fixture has a floating self-aligning function, which will not affect the clamping force of the sandpaper on both sides of the grinding fixture, thus achieving the fixture design requirements.

[0058] Please see Figure 28 The present invention discloses a grinding method for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor, which uses the above-mentioned grinding fixture to grind the outer circle of the slip ring, and includes the following steps: S1. Place the grinding fixture 400 on the faceplate 301 of the vertical lathe, adjust the placement position, lower the tool post 305 of the vertical lathe, align the support leg 1 of the grinding fixture with the tool post 305, insert the clamping part of the tool post 305 into the U-shaped groove 11 of the support leg, tighten the fastening bolts on the tool post, and fix the support leg 1 and the tool post 305 together. S2, raise the tool post 305 and grinding fixture of the vertical lathe to a suitable height. The support foot 1 and upper crossbeam 2 of the grinding fixture are fixed in place. The lower crossbeam 3, with the bracket 4 and polishing wooden frame 5, can move smoothly left and right in the guide rail groove 21 of the upper crossbeam without being restricted. This is very important. S3. Install the slip ring 2013 to be machined on the vertical lathe. According to the outer diameter of the slip ring 2013, manually rotate the crank handle 63 of the adjusting screw 6 so that the distance between the two polishing wooden frames 5 is greater than the outer diameter of the slip ring 2013. Move the tool post slide 304 of the vertical lathe to the middle position and slowly lower the tool post slide 304. When the polishing wooden frame 5 is visually positioned in the middle of the slip ring 2013, lock the tool post slide 304. Manually rotate the crank handle 63 until the two polishing wooden frames 5 are in the middle position of the slip ring 2013. The sandpaper 54 on the grinding head 52 of the polishing frame 5 is pressed tightly against the outer circle of the slip ring 2013. Then the cam wrench 15 is pressed down to give the sandpaper 54 a pre-pressure on the outer circle of the slip ring 2013. The sandpaper 54 on the grinding heads 52 of the two polishing frames 5 exert equal pressure on both sides of the outer circle of the slip ring, and the pressure is opposite in direction. The entire lower crossbeam 3, bracket 4 and polishing frame 5 form a combined whole, which is suspended in the upper crossbeam guide groove 21 and is not subject to external force. It forms a symmetrical double-sided force on the outer circle of the slip ring. S4, start the vertical lathe, the faceplate 301 rotates together with the magnetic yoke 2011 and the slip ring 2013, and the polishing head 52 of the polishing frame 5 polishes the outer circle of the slip ring.

[0059] Except for the adjusting screw assembly, all components of the grinding fixture are symmetrically distributed. Since the adjusting screw assembly has a cam wrench 15, a clamping device (composed of a flat tenon 9, a clamping spring 10, a ring 14, and a pressure adjusting nut 16) and a crank handle 63 installed on the right side, the right side of the grinding fixture is heavier than the left side. To ensure the balance of the left and right weights and to prevent the fixture from vibrating when grinding the outer circle of the slip ring, thus affecting the processing quality, a balance block 27 is installed on the left side of the left support.

[0060] In summary, the grinding fixture and grinding method for the outer circle of the rotor slip ring of the AC variable frequency synchronous motor of the present invention change the slip ring from being subjected to force on one side to being subjected to force on both sides symmetrically at the center during grinding. This avoids the problem of deformation of the slip ring due to force on one side, effectively ensures the coaxiality of the inner circle of the rotor yoke and the outer circle of the slip ring, greatly improves product quality, enhances the safety and reliability of motor operation, extends the service life of the motor, and reduces operating costs.

[0061] 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 grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor, characterized in that, Includes support feet, upper crossbeam, lower crossbeam, two brackets, and bracket spacing adjustment mechanism, wherein: The support leg is fixed to the top of the upper crossbeam; The lower end of the upper crossbeam is provided with an upper crossbeam guide rail groove; The upper end of the lower crossbeam is movably mounted in the upper crossbeam guide rail groove, and the lower end of the lower crossbeam is provided with a lower crossbeam guide rail groove. Each bracket has an inverted L-shaped structure consisting of a horizontal section and a vertical section. The upper dovetail guide rail of the horizontal section of each bracket can be movably set in the guide rail groove of the lower crossbeam, and the two brackets are symmetrically distributed at 180° to the left and right. An adjustment screw mounting hole is opened in the middle of the vertical section of each bracket. A polished wooden frame is fixed at the lower end of the vertical section of each bracket. The bracket spacing adjustment mechanism includes an adjusting screw, an adjusting nut, a flat tenon, a clamping spring, a ring, a cam wrench, and a pressure adjusting nut. The left end of the adjusting screw has a small-diameter threaded section, the middle part has a large-diameter threaded section, and the right end is a crank handle. The adjusting nut is composed of a left cylindrical section, a middle flange, and a right cylindrical section connected in sequence. The left cylindrical section of the adjusting nut is threaded to the outside of the right side of the large-diameter threaded section of the adjusting screw, and the left cylindrical section of the adjusting nut passes through the adjusting screw mounting hole of the right bracket. The small-diameter threaded section is connected to the adjusting screw mounting hole of the left bracket through a washer and a double nut. The middle part of the adjusting screw is fitted with a middle sleeve and two spring-loaded springs, and the two spring-loaded springs are distributed... On both sides of the intermediate sleeve; the flat tenon is movably fitted outside the right cylindrical section of the adjusting nut; the cam wrench includes a cam and a handle connected thereto, the cam of the cam wrench is fitted outside the flat tenon, and the cam and the flat tenon are fixed together by screws, the cam wrench and the flat tenon form an eccentric device; the ring is movably fitted on the right cylindrical section of the adjusting nut and is located on the right side of the flat tenon; the compression spring is fitted on the right cylindrical section of the adjusting nut and is located between the flat tenon and the ring; the pressure adjusting nut is threadedly connected to the right cylindrical section of the adjusting nut and is connected to the right side of the ring, the pressure adjusting nut is used to adjust the pressure of the compression spring between the flat tenon and the ring; The support feet of the grinding fixture are mounted on the tool post of the vertical lathe, and the polishing wooden frames on the two supports are close to the outer circles of the slip ring.

2. The grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor as described in claim 1, characterized in that, The upper part of the support leg is U-shaped groove, the size of which is adapted to the size of the clamping part of the tool post of the vertical lathe; a support leg mounting groove is opened in the middle of the top of the upper crossbeam, the lower part of the support leg is set in the support leg mounting groove, the support leg is connected to the top of the upper crossbeam by bolts, and a stop bolt mounting hole is opened at the center of the support leg and the center of the upper crossbeam respectively.

3. The grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor as described in claim 2, characterized in that, The upper crossbeam guide rail groove and the lower crossbeam guide rail groove are respectively adopted as dovetail-shaped guide rail grooves; The upper dovetail guide rail of the lower crossbeam has a dovetail structure that matches the guide rail groove of the upper crossbeam. A lower crossbeam keyway is provided at the middle position of the upper surface of the upper dovetail guide rail of the lower crossbeam. A lower crossbeam screw hole is machined on both sides of the lower crossbeam keyway. A first stop bolt is installed in the stop bolt mounting hole of the support foot and the upper crossbeam, and the bottom end of the first stop bolt is located in the lower crossbeam keyway. The first stop bolt is used to prevent the lower crossbeam from sliding out of the upper crossbeam guide rail groove. The upper dovetail guide rail of the horizontal part of the bracket has a dovetail structure that matches the lower crossbeam guide rail groove. A bracket keyway is provided at the middle position of the upper surface of the upper dovetail guide rail of the horizontal part of the bracket. A second stop bolt is installed in the lower crossbeam screw hole on both sides of the lower crossbeam keyway. The lower ends of the two second stop bolts are respectively located in the bracket keyway of the two brackets. The second stop bolts are used to prevent the corresponding brackets from sliding out of the lower crossbeam guide rail groove.

4. The grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor as described in claim 1, characterized in that, The polishing frame consists of a handle and a polishing head connected thereto; Each bracket has a T-slot at the lower end of its vertical section. The handle of the polishing wooden frame is fixed in the T-slot, and thin steel plates are provided on the two force-bearing surfaces of the handle. The polishing head of the polishing frame is arc-shaped, and a sandpaper is provided on the outside of the polishing head. A wool felt pad is provided between the sandpaper and the polishing head. The sandpaper and wool felt pad are fixed to both sides of the grinding head by bolts, and a pad is provided between each bolt and the corresponding sandpaper contact surface. The grinding head has a wedge angle machined at each end of its arc.

5. The grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor as described in claim 1, characterized in that, The intermediate sleeve is a hollow cylinder, and annular stops are provided at both ends of the intermediate sleeve. The annular stops are used to connect the spring.

6. The grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor as described in claim 1, characterized in that, The inner circle of the left cylindrical section of the adjusting nut is an internal thread adapted to the adjusting screw, and a left keyway is formed on the outer circle along its axial direction; the inner circle of the right cylindrical section of the adjusting nut is a countersunk hole, and a right keyway is formed on the outer circle along its axial direction, with a right external thread machined on the right side of the outer circle; the left and right keyways are distributed at 90 degrees; a left limit guide key is fitted in the left keyway; a right limit guide key is fitted in the right keyway. The bracket on the right side has a bracket guide keyway in the mounting hole of the adjusting screw. The left limit guide key is inserted into the bracket guide keyway with clearance fit. The bracket guide keyway moves along the left limit guide key to move the adjusting nut in the corresponding adjusting screw mounting hole. When the adjusting screw rotates, the cooperation between the bracket guide keyway and the left limit guide key prevents the adjusting nut from rotating with the adjusting screw. The flat tenon has a cylindrical structure with an inner circle and an outer square, and the inner circle of the flat tenon has a flat tenon keyway along its axial direction. The right limiting guide key is inserted into the flat tenon keyway with clearance fit. The flat tenon keyway moves along the right limiting guide key to realize the movement of the flat tenon along the adjusting nut. The right end face of the flat tenon and the left end face of the ring are respectively provided with compression spring mounting grooves, and the two ends of the compression spring are respectively inserted into the corresponding compression spring mounting grooves. The pressure regulating nut is threaded onto the external thread on the right side of the adjusting nut.

7. The grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor as described in claim 1, characterized in that, The upper and lower end faces of the flat tenon are respectively provided with flat tenon through holes, and the upper and lower end faces of the cam of the cam wrench are respectively provided with cam screw holes. The flat tenon is set in the cam, and the flat tenon through holes and the corresponding cam screw holes are fixed together by screws. The screws act as a central axis, and the cam rotates around the screws.

8. The grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor as described in claim 1, characterized in that, The upper end of the cam of the cam wrench is equipped with a locking pin device, which includes a locking pin and a connecting rod connected thereto. After the cam wrench is rotated to the correct position, it has a self-locking function. When it needs to be unlocked, the connecting rod is pressed down to lift the locking pin and unlock it. Then, the cam wrench is rotated in the opposite direction to relieve pressure.

9. The grinding fixture for the outer circle of the rotor slip ring of an AC variable frequency synchronous motor as described in claim 1, characterized in that, A balance weight is installed on the left side of the support on the left.

10. A method for grinding the outer circle of the rotor slip ring of an AC variable frequency synchronous motor, characterized in that, Grinding the outer diameter of a slip ring using the grinding fixture described in any one of claims 1 to 9 includes the following steps: S1. Place the grinding fixture on the faceplate of the vertical lathe, adjust its position, lower the tool post of the vertical lathe, align the support leg of the grinding fixture with the tool post, insert the clamping part of the tool post into the U-shaped groove of the support leg, tighten the fastening bolts on the tool post, and fix the support leg and the tool post together. S2, lift the tool post and grinding fixture of the vertical lathe. The support legs and upper crossbeam of the grinding fixture are fixed, while the lower crossbeam, with its bracket and polishing wooden frame, slides in the guide groove of the upper crossbeam. S3. Install the slip ring to be machined on the vertical lathe. According to the diameter of the outer circle of the slip ring, rotate the crank handle of the adjusting screw by hand so that the distance between the two polishing wooden frames is greater than the diameter of the outer circle of the slip ring. Move the tool post slide of the vertical lathe to the middle position and slowly lower the tool post slide. When the polishing wooden frame is visually positioned in the middle of the slip ring, lock the tool post slide. Rotate the crank handle by hand until the sandpaper on the grinding heads of the two polishing wooden frames is close to the outer circle of the slip ring. Then press down the cam wrench to give the sandpaper a preload on the outer circle of the slip ring. The pressure of the sandpaper on both sides of the outer circle of the slip ring is equal in magnitude and opposite in direction. The entire lower crossbeam, support and polishing wooden frame form a combined whole, suspended in the guide groove of the upper crossbeam, and is not subject to external forces. It forms a symmetrical double-sided force on the outer circle of the slip ring. S4, start the vertical lathe, the faceplate rotates together with the magnetic yoke and slip ring to grind the outer circle of the slip ring.

Images