CN204103739U - A kind of soft start permanent magnet eddy current coupling - Google Patents

Abstract

The utility model discloses a soft-start permanent magnet eddy current coupling, which comprises a conductor disk rotor and a permanent magnet rotor; the conductor disk rotor is a driving end connected with a motor shaft, and the expansion sleeve structure is used to realize quick installation and quick disassembly; The disc rotor surrounds the permanent magnet rotor, and the adjacent parts are separated by an air gap; the permanent magnet rotor is the driven end, which is connected with the load shaft; the connecting rod slider mechanism inside the permanent magnet rotor has the function of adjusting the air gap, so as to control The transmitted torque and speed; the four main drive pins inside the permanent magnet rotor provide a bridge for torque transmission and also provide guidance for the movement of the permanent magnet carrier; the centrifugal arm in the permanent magnet rotor ensures the change of the air gap during the start-up process Value, to achieve a better soft start effect; the utility model has the basic function of the permanent magnetic coupling, but also integrates the functions of soft start and overload protection, simple and compact in structure, and has great practical value.

Description

A soft start permanent magnet eddy current coupling

technical field

The utility model relates to a permanent magnet eddy current shaft coupling, which controls the change of the air gap between the permanent magnet and the conductor disk through components, realizes the soft start of the motor, and realizes the overload protection under the overload condition. Especially the soft start permanent magnet eddy current coupling with overload protection.

Background technique

In the existing mechanical transmission, most of the motor and the load are directly connected by the mechanical structure. Mechanical couplings have parts in contact with each other, and vibration transmission is unavoidable. Even flexible couplings have relatively low elasticity, so there are the following problems during use: During installation, the drive shaft It requires high alignment with the driven shaft, high installation accuracy, and increases installation difficulty and machining accuracy. What is transmitted in the transmission is not only the torque, but also the vibration effect of the load on the motor. The vibration in the working process will seriously damage the motor, transmission mechanism and load equipment, which will greatly reduce the life of the equipment.

The mechanism related to variable speed and variable torque in transmission, such as the use of frequency converter and hydraulic coupling for soft start and speed regulation. The frequency converter has harmonic pollution to the power system, the transmission efficiency of the hydraulic coupling is low, and the requirements for the use environment are relatively high.

The unique structure of the permanent magnet coupling makes it irreplaceable in use. There are various types of permanent magnet couplings, such as speed regulating type, practical type, soft start type, etc., and they have been used in petroleum, chemical, electric power and other industrial fields at this stage. While realizing the basic functions of the permanent magnet coupling and transmitting torque, it also has many advantages such as low installation accuracy, overload protection, soft start, and speed regulation. For example, in the transmission process, the active part and the driven part are separated by an air gap, so that the vibration will not affect each other. Eliminating the existence of vibration in the transmission process not only improves the transmission efficiency, saves energy, but also improves the service life of the equipment. The existence of the air gap makes it possible to avoid high centering during the installation process, reduce the installation accuracy and meet the requirements of use, reduce installation costs, save installation time, and improve installation efficiency.

The principle of the permanent magnet eddy current coupling is that the conductor disk cuts the magnetic field generated by the permanent magnet to generate eddy current, and the anti-magnetic field generated by the eddy current interacts with the original magnetic field to generate force. In the rotating state, the effect of torque is produced; in the linear state, the effect of force is produced in the direction of motion. Due to the existence of eddy currents, eddy current losses exist. Smaller speed difference will result in smaller eddy current loss. It is necessary to obtain the maximum torque with the smallest speed difference and the maximum magnetic induction intensity with a certain permanent magnet volume. The core components of permanent magnet eddy current couplings are permanent magnets and conductors. Due to its complex internal structure and relatively large rotational speed in the transmission, with the wide application, the problem of realizing dynamic balance with a simple structure is highlighted. While generating the torque, the huge axial force produced by the guide disk and the permanent magnet also needs to be eliminated urgently.

The current soft start coupling has room for improvement because the start process cannot take into account the functions of soft start and overload protection. And the internal structure is too complicated, which can be simplified by a new structure. The linkage of permanent magnets in a symmetrical structure has many disadvantages such as slow response or high friction. The form of the magnet in the coupling is too simple, and the shape and size of the permanent magnet need to be improved, so that a relatively large torque can be transmitted by a permanent magnet with a small volume, and a cost advantage can be obtained.

Utility model content

The purpose of this utility model is to overcome the deficiencies of the above-mentioned technologies, provide a permanent magnet coupling with a simple structure, and realize the functions of soft start and overload protection at the same time.

The coupling consists of two parts, the conductor disc rotor and the permanent magnet rotor. The conductor disc rotor is the driving end and is connected with the motor shaft. The permanent magnet rotor is the driven end and is connected to the load shaft. The connection of both uses the expansion sleeve flange structure to realize the function of quick installation and quick disassembly. The conductor disc cuts the magnetic induction lines produced by the permanent magnet, generates eddy current, forms an anti-magnetic field, and interacts with the original magnetic field to produce the effect of torque. The conductor disk rotor is outside, and the permanent magnet rotor is inside; the adjustment of the air gap is realized by changing the axial distance between two permanent magnet carriers in the permanent magnet rotor.

The conductor disc rotor is the driving end. The low-carbon steel with better magnetic conductivity is used as the carrier, and the ring-shaped copper plate with better conductivity is connected to it by screws; due to the left and right sides, the overall structure is a cylindrical cage, and the low-carbon steel plate is the left and right bottom surfaces , the copper plate is attached inside; the left and right low-carbon steel plates are connected by connecting plates and fixed by bolts and nuts. The flange connected to the motor shaft is connected to the low-carbon steel plate by screws, and the flange is fastened on the motor shaft by an expansion sleeve.

The permanent magnet rotor is the driven end, the permanent magnet is the excitation source, and the axial movement of the two permanent magnet carrier disks realizes the function of adjusting the air gap. The load shaft is connected to the driven end through the fastening flange of the expansion sleeve. Due to the heavy weight of the permanent magnet rotor and the long overhang length, the flange is connected to the central axis of the permanent magnet rotor through bolts and nuts. The permanent magnet is in the shape of a trapezoid, and its position is fixed by being embedded in the permanent magnet carrier with holes. The size and number of holes in the permanent magnet carrier are the same as that of the permanent magnet, and the circumference is evenly arranged; for the magnetic circuit circulation of the permanent magnet, and the coupling In order to ensure the structural strength of the device, a carrier liner is attached to the back of each permanent magnet carrier. The material is low-carbon steel. Two slotted strip steel plates are welded on the carrier liner to serve as a connecting rod to connect the two plates. part, and increase the stress area through the slider. The connecting rod is rectangular, with holes punched at both ends, and the carrier liner is connected by hexagonal shoulder bolts. A hole is punched in the middle of the connecting rod, and it is fixed on the fixed block by a shoulder bolt. There are four holes in the four corners of the fixed block to install four guide shafts, and they are fastened with jacking screws. The guide shafts pass through the permanent magnet carrier to make it move smoothly. The fixed block is fixed on the central shaft, and the axial position is positioned by the end cover fastened on the central shaft by screws, and the radial position is positioned by two keys. One of the carrier liners is equipped with upper and lower centrifugal arms, which are connected by a pin shaft, and a coil spring is installed on the pin shaft to make the centrifugal arm return when it is started.

The connection between the two conductor carrier plates uses a connecting plate with a shallow groove in the middle. While ensuring the width, the groove on the back also increases the internal space, improves the utilization of space, and reduces weight at the same time. The two ends of the connection plate are wide and the middle is narrow, so that the torque transmitted by the connection plate with a small area is improved. Four connecting plates make the cylindrical surface of the overall structure have a large gap, and the temperature can be stabilized during the operation of the coupling, and the rotation of the connecting plates can also drive the flow of air, so that the heat exchange between the inside and outside of the coupling Speed up; for larger power couplings, heat dissipation fins or water cooling systems can be added to the outer conductor carrier disk. The conductor carrier plate and the flange plate are connected by screws, which makes the installation more convenient and convenient.

The linkage of the two permanent magnet carriers uses two symmetrical connecting rods up and down. The connecting rod installed on the fixed block makes the axial forces in the opposite direction inside the coupling cancel each other and eliminate the influence on the outside. The connection between the connecting rod and the liner is a hexagon shoulder bolt and a slider. Because of the relative rotation, there must be a pin. In the sliding groove, the slider is used to increase the contact area; make the force surface more uniform, Reduce friction and prolong service life.

Four guide shafts fixed on the fixed blocks have a guiding effect on the movement of the two permanent magnet carriers. Due to the guiding movement, there is friction between the contact surfaces. A guide sleeve is added in the hole of the permanent magnet carrier to make the friction smaller, the movement response is faster, and the service life is long.

The use of the centrifugal arm ensures that the torque is stable during the starting process, that is, the function of soft starting can be realized. When the load suddenly increases, the air gap becomes larger, and the centrifugal arm is vertical to provide conditions for overload protection. In order to ensure that the centrifugal arm returns to its position when it is started, and it is vertical during overload protection (providing a larger space), a coil spring is added to the rotation pin of the centrifugal arm; the design of this coil spring has two symmetrical parts. The protruding parts at both ends use the reserved holes on the liner to provide reverse force.

The shape of the permanent magnet adopts a trapezoidal shape to obtain the maximum torque at the minimum cost. The permanent magnets are evenly distributed on the circumference, and the N and S poles are arranged alternately, and the total number is an even number.

The central fixed block is in the shape of a rectangle, with better processing technology, and in use, there are two centrifugal arms on one pair of sides, and two connecting rods on the other opposite side. The symmetrical structure design is adopted to ensure dynamic balance.

The connection between the central shaft and the load flange uses bolts and nuts to increase the structural strength. The central shaft is a section of hollow structure, which provides space for the load shaft, which is relatively simplified in structure, reduces weight, and increases structural strength.

Both the driving end and the driven end of the coupling use flanges and expansion sleeves, and the driving end is connected by screws, and the driven end is connected by bolts and nuts; the two realize the quick assembly and fast assembly of the coupling and equipment. dismantle. This feature improves assembly efficiency during use and saves time during maintenance.

This practical patent not only realizes the basic function of the permanent magnet eddy current coupling, which transmits torque; it also realizes soft start and soft connection during the transmission process, and realizes the protection function when overloaded. Compared with other types of couplings, it is not only powerful, but also simple in structure, light in weight, long in life, convenient and efficient in use. It can be widely used in petroleum, chemical industry, electric power and other industries, and has broad prospects.

Description of drawings

Fig. 1 is the main structure diagram of the utility model.

Fig. 2 is a schematic diagram of the permanent magnet distribution and the connecting plate in the conductor disk rotor.

Figure 3 is a schematic diagram of a conductor disk rotor.

Fig. 4 is a schematic diagram of a permanent magnet rotor.

Fig. 5 is a schematic diagram of the connecting rod slider mechanism for adjusting the air gap by the permanent magnet rotor.

Figure 6 is a schematic diagram of the guide and bronze sleeve of the main drive pin.

Fig. 7 is a schematic structural view of the state of the fixed block and the centrifugal arm.

Among them, 1. Motor shaft flange; 2. Expansion sleeve; 3. Hexagon socket screw one; ;9. Bolt 1; 10. Nut 1; 11. Load flange; 12. Bolt 2; 13. Nut 2; 14. Central shaft; 15. Key; 16. Fixed block; 17. Shaft positioning sleeve; 18. Center Shaft end cover; 19. Inner hexagon screw 2; 20. Permanent magnet; 21. Permanent magnet left carrier; 22. Left carrier lining; 23. Right carrier lining; 24. Permanent magnet right carrier; 25. Inner hexagon shoulder Bolt 1; 26. Gasket; 27. Connecting rod; 28. Hexagon socket shoulder bolt 2; 29. Nut 3; 30. Slider; 31. Bronze sleeve; 32. Main drive pin; 33. Jacking screw; 34. Centrifugal arm pin; 35. Centrifugal arm; 36. Coil spring; 37. Air gap.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

As shown in FIG. 1 , the soft-start permanent magnet eddy current coupling includes a conductor disk rotor 50 and a permanent magnet rotor 60 . The conductor disc rotor 50 is connected to the motor shaft, fixed by the expansion sleeve 2 to fasten the motor shaft flange 1, and installed on the coaxial line. The torque and rotational speed of the motor are transmitted to the conductor disk rotor 50, both of which are the same size front and back. The permanent magnet rotor 60 is mounted coaxially inside the conductor disk rotor 50, allowing a general difference. There is an air gap 37 between the copper disk 6 and the permanent magnet 20 in the axial direction, and there is a difference in rotational speed. The inside of the permanent magnet rotor 60 can change the air gap 37 through the swing of the connecting rod 27 . The permanent magnet rotor 60 is connected with the load shaft, installed coaxially, and fixed by fastening the load flange 11 through the expansion sleeve 2, and the torque and speed of the two are the same.

As shown in FIG. 3 , the conductor disc rotor 50 is composed of expansion sleeve 2 , motor shaft flange 1 , conductor carrier left and right discs 4 , 8 , copper disc 6 and connecting plate 7 . The motor shaft flange 1 is connected to the left disk 4 of the conductor carrier through an inner hexagonal screw-3. The copper disk 6 is ring-shaped, and is tightly abutted on the left and right disks 4 and 8 of the conductor carrier through the screws 5 with alternate inner and outer diameters of the ring. The left and right disks 4, 8 of the conductor carrier are connected by a connecting plate 7, and fastened by a bolt 9 and a nut 10.

As shown in Figure 4, the permanent magnet rotor 60 is composed of a central shaft 14, a fixed block 16, a permanent magnet 20, a permanent magnet left 21 and a right 24 carrier, a left 22 and a right 23 carrier liner, upper and lower connecting rods 27, front and rear centrifugal arms 35 , an expansion sleeve 2 and a load flange 11; The fixed block 16 is fixed on the central shaft 14; in the axial direction, the right end utilizes the shoulder of the central shaft 14 to locate the fixed block 16, and the left end uses the shaft positioning sleeve 17 and is fastened to the central shaft by two hexagon socket screws 19 The central shaft end cover 18 on the upper part is used to position the fixed block 16; in the radial direction, two keys 15 are used to transmit torque.

The permanent magnet 20 is embedded on the left and right permanent magnet carriers 21, 24, and the left and right carrier lining plates 22, 23 are arranged on the back of the left and right permanent magnet carriers 21, 24, which are fixed on the above by screws. As shown in FIG. 5 , the hole in the middle of the connecting rod 27 is fixed on the fixed block 16 through a hexagonal shoulder bolt 1 25, and a gasket 26 is added on the contacting surface to reduce friction. There are two holes at both ends of the connecting rod 27, through which hexagonal shoulder bolts 228 are connected with the left and right carrier liners 22, 23. The second hexagonal shoulder bolt 28 acts as a pin and is used in conjunction with the third nut 29. A slide block 30 is added to the part where the second hexagonal shoulder bolt 28 is in contact with the left and right carrier liners 22, 23. As shown in Figure 6, the motion guides of the left and right carriers 21, 24 of the permanent magnets are four main drive pin shafts 32 fixed on the fixed block 16, and the main drive pin shafts 32 are connected to the fixed block 16 by jacking screws 33. connect. The four main drive pin shafts 32 slide relative to the left and right carriers 21, 24 of the permanent magnets, and bronze sleeves 31 are added to the left and right carrier liners 22, 23. The maximum value of the change of the air gap 37, the limit position of the permanent magnet carrier 21, 24 movement is positioned by the shoulder of the central shaft 14, and the outer ring of the end cover 18 also has a positioning effect. As shown in Figure 7, the centrifugal arm 35 is installed on the liner, which is connected with the left and right carrier liners 22, 23 through the pin shaft 34, and the symmetrical coil spring 36 is installed on the pin shaft 34, so that the centrifugal arm 35 reaches a predetermined s position.

As shown in Figures 2 and 3, the connecting plate 7 has a shallow groove in the middle, which increases the internal space while ensuring the strength, and the structure with wide ends and narrow middle increases the maximum value of the transmitted torque. The structure of four connecting plates 7 provides a large enough contact space for the inside of the conductor disc rotor 50 and the outside air, so that the internal temperature is stable. stable conditions.

As shown in FIGS. 2 and 4 , the size, quantity and installation size of the permanent magnets 20 are determined according to design requirements, and the quantity is an even number. The inner and outer diameters of the copper disc 6 are determined according to the maximum inner and outer diameters of the permanent magnet 20; the connecting rod 27 is two up and down, installed crosswise, and can achieve dynamic balance after rotation; The length of the arm 35 varies according to the actuation requirements.

As shown in Figures 3 and 4, the expansion sleeve 2 can be quickly installed and disassembled. The inner hexagon screw 3 can be installed directly, providing conditions for quick assembly and quick release. The second bolt 12 and the nut 13 provide structural strength for the overhanging part of the permanent magnet rotor 60, and together with the expansion sleeve 2 and the hexagon socket head cap screw 3, realize quick assembly and quick disassembly of the coupling.

The left and right disks 4, 8 of the conductor carrier and the left and right carrier liners 22, 23 are all low-carbon steel with good magnetic conductivity, and have high strength, which provides sufficient strength for transmitting torque and rotating speed, and also provides paths for magnetic induction lines, so that The region of the copper plate 6 has a strong magnetic induction.

As shown in Figure 5, the use of the slider 30 in the linkage mechanism changes the line contact to the surface contact, which increases the contact area, reduces friction, and prolongs the service life.

As shown in FIG. 6 , the main transmission pin shaft 32 not only has the function of transmission torque, but also has the function of guiding. The bronze sleeve 31 makes the internal structure have less friction during movement, which speeds up the response and prolongs the service life.

As shown in FIG. 4 at rest, due to the attraction force of the permanent magnets 20 to the conductor carriers 4, 8 in the conductor rotor, the air gap 37 is kept at a minimum, the solid line state of the centrifugal arm 35 in FIG. 4 . After the motor starts, the conductor rotor part 50 and the motor start simultaneously at the same speed; the permanent magnet rotor 60 lags behind, and the relative speed difference is very large, and the copper disc 6 cuts the magnetic field lines produced by the permanent magnet 20 with the maximum speed difference. Due to the large difference in speed, the generated torque is not only the largest, but also the repulsive force is the largest. When the repulsive force generated is greater than the attraction force of the permanent magnet 20 to the copper disc carriers 4, 8, the two permanent magnet carriers 21, 24 begin to approach , because the received forces are mutually symmetrical, the interior cancels each other out, and has no influence on the outside. And the centrifugal arm 35 is in the straight state, as shown in the dotted line state of the centrifugal arm 35 in Figure 4, the size of the air gap 37 is not very large; the permanent magnet rotor 60 begins to accelerate, and while accelerating, the conductor disc rotor 50 and the permanent magnet rotor 60 The relative rotational speed begins to decrease; when the repulsive force produced by the rotational speed difference is less than the attraction force of the permanent magnet 20 to the conductor carrier left and right disks 4, 8, the two permanent magnet left and right carriers 21, 24 in the permanent magnet rotor 60 are separated. Because of the existence of the rotational speed difference, the permanent magnet rotor 60 is always accelerating. When the air gap 37 is reduced to the minimum and the rotational speed difference is reduced enough to provide the torque required by the load, the start-up is completed. During start-up, the centrifugal arm 35 in the permanent magnet rotor 60 rotates faster, and when the moment generated by the centrifugal force is greater than the torque of the coil spring 36 to it, the centrifugal arm 35 leans against the left carrier liner 22 .

Since the starting process is a slow acceleration, a soft start is realized and the peak current of the motor is avoided. In normal operation, when encountering a sudden stuck or suddenly loaded state, the speed difference increases rapidly, and the repulsive force generated is suddenly greater than the attraction force of the permanent magnet 20 to the left and right disks 4 and 8 of the conductor carrier. Two of the permanent magnet rotors 60 The left and right carriers 21, 24 of the permanent magnet move closer quickly, and the centrifugal arm 35 is not yet straightened because of the lag, so the left and right carriers 21, 24 of the permanent magnet can move closer, so that the air gap 37 is the largest, and the magnetic induction intensity in the copper plate 6 area is small, which can transmit The torque is almost zero, achieving the effect of overload protection.

Claims (5)

1. A soft-start permanent magnet eddy current coupling, including two parts, the conductor disc rotor and the permanent magnet rotor; the conductor disc rotor is the driving end, which is connected to the motor shaft; the permanent magnet rotor is the driven end, which is connected to the load shaft The two connections use the expansion sleeve flange structure to realize the quick installation and quick disassembly function; the conductor disc cuts the magnetic induction line generated by the permanent magnet, generates eddy current, forms a repulsive magnetic field, interacts with the original magnetic field, and generates a rotational The effect of torque; the conductor disk rotor is outside, and the permanent magnet rotor is inside; the adjustment of the air gap is realized by changing the axial distance of the two permanent magnet carriers in the permanent magnet rotor. 2. A kind of soft-start permanent magnet eddy current coupling as claimed in claim 1, characterized in that, the connection of two conductor carrier discs in the conductor disc rotor uses a connecting plate with a shallow groove in the middle, and when the width is guaranteed At the same time, the slots on the back also increase the internal space, reduce weight, and improve the utilization of space; the two ends of the connecting plate are wide and the middle is narrow, so that the torque transmitted by the connecting plate with a small area is improved; the four connecting plates make The cylindrical surface of the overall structure has a large gap, the temperature can be stabilized during the operation of the coupling, and the rotation of the connecting plate can also drive the flow of air, so that the heat exchange between the inside and outside of the coupling is accelerated. 3. A kind of soft-start permanent magnet eddy current coupling as claimed in claim 1, characterized in that, the shape of the permanent magnet adopts a trapezoidal shape to obtain the maximum torque at a minimum cost; the permanent magnets are evenly distributed on the circumference, The N and S poles are arranged alternately, and the total number is an even number. 4. A kind of soft-start permanent magnet eddy current coupling as claimed in claim 1, characterized in that, the linkage of two permanent magnet carriers uses two symmetrical connecting rods up and down; the connecting rod installed on the fixed block, The axial forces in the opposite direction inside the coupling cancel each other out and eliminate the influence on the outside world; the upper and lower symmetry ensure the dynamic balance; the connecting rod and the liner are connected by hexagonal shoulder bolts and sliders, because they need to rotate relative to each other. There must be the use of pins. In the sliding groove, the slider is used to increase the contact area; to make the force-bearing surface more uniform, reduce friction, and prolong the service life. 5. A soft-start permanent magnet eddy current coupling as claimed in claim 1, characterized in that four guide shafts fixed on the fixed block have a guiding effect on the motion of the two permanent magnet carriers; due to the guide movement, the contact surface There is friction between them, and a guide sleeve is added in the hole of the permanent magnet carrier plate, so that the friction becomes smaller, the motion response is faster, and the service life is long.