Permanent magnet coupling induction current self-regulating method and device and permanent magnet coupling

Abstract

The application discloses a kind of permanent magnet coupler induction current self-regulating method and device and permanent magnet coupler for realizing soft start and overload torque limiting protection of equipment, and its features are that resistance is connected in series in two lead terminals of induction winding, the centrifugal force that centrifugal slider is received when being installed radially on inner rotor is different at different rotational speed of inner rotor, the resistance value of resistance connected in series in conductive loop including induction winding is automatically regulated, so that the induction current in conductive loop of induction winding is little changed under different induction electromotive force generated by induction winding under different working conditions of permanent magnet coupler, so that the transmission torque of permanent magnet coupler is automatically regulated, and it is changed in a very small range and tends to be constant, realizing soft start and overload torque limiting protection of equipment;The principle of the application is reliable, simple in structure, easy to realize, and can be widely applied to equipment such as belt conveyor, elevator and other equipment that need soft start, and various large inertia equipment such as ball mill, mixer, crusher and other equipment that need to improve starting performance.

Description

Technical Field

[0001] This invention relates to a cylindrical torque-limiting permanent magnet coupler, specifically a method and apparatus for self-adjusting the induced current of a permanent magnet coupler and a permanent magnet coupler, particularly to a method and apparatus for self-adjusting the induced current of a permanent magnet coupler and a permanent magnet coupler for achieving soft start and overload torque-limiting protection of equipment. Background Technology

[0002] Permanent magnet magnetic drive is a new type of transmission developed at the end of the last century, and it is divided into two main categories: synchronous and asynchronous. Synchronous transmission utilizes the attractive (or repulsive) force between permanent magnets to achieve a non-rigid connection, primarily used as a torque-limiting safety coupling. Asynchronous transmission utilizes the magnetic-electric-magnetic induction force between permanent magnets and conductors to achieve a non-rigid connection. Besides its use as a safety coupling, it has recently been used as a transmission element with certain soft-start characteristics and torque-limiting protection. Due to its lack of liquid spray pollution, its ability to tolerate larger installation coaxiality errors during adjustment, and its ease of maintenance, it is widely used as a replacement for hydraulic couplings.

[0003] However, the aforementioned products still have the following drawbacks: First, the so-called "soft" start-up characteristics are extremely limited. Although the torque-limiting permanent magnet coupler is not rigidly connected, and the transmitted torque is zero or close to zero at the initial moment of startup, it is difficult to complete the start-up as the motor speed increases and the load is connected before entering the stable operating range. In other words, the middle and later stages of the motor startup process are actually "rigidly" connected to the load, relying on the driving torque of the motor to perform "rigid" startup on the equipment. Second, the so-called "torque-limiting" protection is actually mostly "torque loss" protection. That is, when the equipment is severely overloaded, causing the driven end of the disc-type permanent magnet coupler to stall, the induced axial thrust formed by the huge speed difference will cause the permanent magnet to suddenly separate from the conductor (induction disc), causing the torque transmitted by the permanent magnet coupler to suddenly disappear or abruptly decrease to a minimum value, presenting a torque cliff-like "protection" state. This cliff-like protection can be very dangerous for certain types of equipment. For example, if the torque-limiting permanent magnet coupler of an inclined belt conveyor or bucket elevator enters the torque loss protection state, the motor will be running and the brake will not be able to brake. If a backstop is not installed or fails, the equipment will cause great trouble or even lead to a serious accident. Summary of the Invention

[0004] The purpose of this invention is to provide a method and device for self-regulating the induced current of a permanent magnet coupler, and a permanent magnet coupler for achieving soft start and overload torque limiting protection of equipment. In the initial stage of equipment startup, only a small transmission torque is generated, enabling the motor to quickly start and reach the rated speed under low load conditions. As the equipment accelerates, the transmission torque of the permanent magnet coupler gradually increases to a constant value, allowing the equipment to accelerate flexibly under constant torque conditions until it completes startup and enters the rated operating condition. Furthermore, when the equipment is severely overloaded and the speed at the load end drops significantly, the permanent magnet coupler automatically limits the increase in its transmission torque to achieve overload torque limiting protection for the motor and transmission system.

[0005] This invention achieves its objective by employing the following technical solution: a resistor is connected in series with the two leads of the induction winding. Utilizing the different centrifugal forces experienced by an object at different rotational speeds, the resistance value of the resistor in the conductive circuit, including the induction winding, is automatically adjusted (i.e., as the centrifugal force gradually increases, the resistance value of the resistor in the conductive circuit gradually decreases; as the centrifugal force gradually decreases, the resistance value of the resistor in the conductive circuit gradually increases). This ensures that the induced current in the conductive circuit of the induction winding does not change significantly under different operating conditions of the permanent magnet coupler, thereby automatically adjusting the torque transmitted by the permanent magnet coupler, which varies within a very small range and tends to remain constant, achieving soft start and overload torque limiting protection for the equipment.

[0006] A method for self-adjusting the induced current of a permanent magnet coupler utilizes the different centrifugal forces experienced by a centrifugal slider radially mounted on the inner rotor at different rotor speeds. The centrifugal slider automatically adjusts the resistance value of the series resistor in the conductive circuit, including the induction winding. Specifically, as the centrifugal force gradually increases, the resistance value in the conductive circuit gradually decreases; conversely, as the centrifugal force gradually decreases, the resistance value in the conductive circuit gradually increases. This causes the induced current in the conductive circuit to vary within a set operating current range, thereby automatically adjusting and stabilizing the transmitted torque of the permanent magnet coupler under different operating conditions, achieving soft start and overload torque limiting protection for the equipment.

[0007] A self-regulating device for the induced current of a permanent magnet coupler includes an inner rotor as the driven end, an iron core mounted on the outer periphery of the inner rotor, an induction winding embedded in the iron core, two leads of the induction winding connected to a U-shaped resistance plate mounted on the inner rotor, a radial guide rail on the inner rotor, and a centrifugal slider sliding on the radial guide rail, the centrifugal slider having two sliding conductive contacts that respectively contact the U-shaped resistance plate, forming a conductive circuit with the induction winding, the U-shaped resistance plate, and the sliding conductive contacts, one end of the centrifugal slider being fitted with a tension spring, the other end of the tension spring being connected to the inner rotor, pulling the centrifugal slider towards the center of the inner rotor. The permanent magnet coupler operates under different conditions by varying the centrifugal force experienced by the centrifugal slider at different rotational speeds of the inner rotor. This changes the contact position between the two sliding conductive contacts on the centrifugal slider and the U-shaped resistance plate, automatically adjusting the resistance value in the conductive circuit. Specifically, as the centrifugal force gradually increases, the resistance value in the conductive circuit gradually decreases, and as the centrifugal force gradually decreases, the resistance value in the conductive circuit gradually increases. This causes the induced current in the conductive circuit to vary within a set operating current range, thereby automatically adjusting and stabilizing the torque transmitted by the permanent magnet coupler under different operating conditions, achieving soft start and overload torque limiting protection for the equipment.

[0008] To ensure that the resistance of the series resistor in the conductive circuit is zero after the equipment has started up and entered the rated operating condition, the two terminals of the induction winding of this invention are connected to the U-shaped resistance plate through two short-circuit contacts respectively. That is, the induction winding, the short-circuit contact, the U-shaped resistance plate, and the sliding conductive contact constitute a conductive circuit.

[0009] To facilitate adjustment of the resistance value of the series resistor in the conductive circuit, a stop block is installed on the inner rotor of this invention, and the tension spring is installed on the stop block through a spring frame; the initial tension of the tension spring and the initial position of the centrifugal slider are adjusted by the installation position of the stop block.

[0010] To facilitate adjustment of the centrifugal force, the centrifugal slider of the present invention is provided with a counterweight adjustment screw to adjust the mass of the centrifugal slider.

[0011] A permanent magnet coupler employing the self-adjusting device for the induced current of the permanent magnet coupler as described above.

[0012] By adopting the above technical solution, the present invention has achieved its purpose well. Its principle is reliable, its structure is simple and easy to implement. It can be widely used in equipment that requires soft start, such as belt conveyors and elevators, as well as various large inertia equipment that requires improved starting performance, such as ball mills, mixers and crushers. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention;

[0014] Figure 2This is a schematic diagram showing the position of the sliding conductive contact when the present invention is in a stationary state;

[0015] Figure 3 This is a schematic diagram showing the position of the sliding conductive contact during the start-up or overload transition state of the present invention.

[0016] Figure 4 This is a schematic diagram of the position of the sliding conductive contact in the rated operating state of the present invention.

[0017] 1. Main coupling 2. Tension spring 3. Spring frame 4. Counterweight adjusting screw 5. Radial guide rail 6. Centrifugal slider 7. Induction winding 8. Outer rotor 9. Permanent magnet 10. Iron core 11. Short-circuit contact 12. Stop block 13. U-shaped resistance plate 14. Sliding conductive contact 15. Slave coupling 16. Inner rotor. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Depend on Figure 1 It is understood that a method for self-adjusting the induced current of a permanent magnet coupler utilizes the different centrifugal forces experienced by the centrifugal slider 6 radially mounted on the inner rotor 16 at different rotational speeds. The centrifugal slider 6 automatically adjusts the resistance value of the resistor connected in series in the conductive circuit, including the induction winding 7. Specifically, as the centrifugal force gradually increases, the resistance value of the resistor connected in series in the conductive circuit gradually decreases; as the centrifugal force gradually decreases, the resistance value of the variable resistor connected in series in the conductive circuit gradually increases; and as the centrifugal force gradually decreases, the resistance value of the resistor connected in series in the conductive circuit gradually increases. This causes the induced current in the conductive circuit to vary within a set operating current range, thereby automatically adjusting and stabilizing the torque transmitted by the permanent magnet coupler under different operating conditions, achieving soft start and overload torque limiting protection for the equipment.

[0020] A self-regulating device for the induced current of a permanent magnet coupler includes an outer rotor 8, which is the active end and connected to a main coupling 1. A permanent magnet 9 is embedded in the circumference of the outer rotor 8. An inner rotor 16, which is the driven end, is connected to a driven coupling 15. An iron core 10 is mounted on the outer circumference of the inner rotor 16, and an induction winding 7 is embedded in the iron core 10. Two leads of the induction winding 7 are respectively connected to a U-shaped resistance plate 13 mounted on the inner rotor 16. A radial guide rail 5 is provided on the inner rotor 16 in the radial direction. A centrifugal slider 6 is mounted on the radial guide rail 5 and slides on it. The centrifugal slider 6 is provided with two sliding conductive contacts 14 that respectively contact the U-shaped resistance plate 13, so that the induction winding 7, the U-shaped resistance plate 13, and the sliding conductive contacts 14 form a conductive circuit. A pull rod is installed at one end of the centrifugal slider 6. The other end of the extension spring 2 is connected to the inner rotor 16, pulling the centrifugal slider 6 towards the center of the inner rotor 16. Under different operating conditions, the centrifugal force on the centrifugal slider 6 at different speeds of the inner rotor 16 changes, altering the contact position between the two sliding conductive contacts 14 on the centrifugal slider 6 and the U-shaped resistance plate 13. This automatically adjusts the resistance value of the series resistor in the conductive circuit. That is, as the centrifugal force gradually increases, the resistance value of the series resistor in the conductive circuit gradually decreases; as the centrifugal force gradually decreases, the resistance value of the series variable resistor in the conductive circuit gradually increases. This causes the induced current in the conductive circuit to change within the set operating current range, thereby automatically adjusting and keeping the torque transmitted by the permanent magnet coupler constant under different operating conditions, achieving soft start and overload torque limiting protection for the equipment.

[0021] To ensure that the resistance of the series resistor in the conductive circuit is zero after the equipment has started up and entered the rated operating condition, the two terminals of the induction winding 7 of this invention are connected to the U-shaped resistance plate 13 through two short-circuit contacts 11 respectively. That is, the induction winding 7, the short-circuit contact 11, the U-shaped resistance plate 13, and the sliding conductive contact 14 constitute a conductive circuit.

[0022] To facilitate adjustment of the resistance value of the series resistor in the conductive circuit, a stop block 12 is installed on the inner rotor 16 of the present invention, and the tension spring 2 is installed on the stop block 12 through the spring frame 3; the initial tension of the tension spring 2 and the initial position of the centrifugal slider 6 are adjusted by the installation position of the stop block 12.

[0023] To facilitate adjustment of the centrifugal force, the centrifugal slider 6 of the present invention is provided with a counterweight adjustment screw 4 for adjusting the mass of the centrifugal slider 6.

[0024] A permanent magnet coupler employing the self-adjusting device for the induced current of the permanent magnet coupler as described above.

[0025] Depend on Figure 2 It can be seen that before the device is started, the centrifugal slider 6 is in its initial position under the tension of the tension spring 2, at which time the resistance of the resistor in the conductive circuit is at its maximum. From Figure 3, Figure 4 As can be seen, when the equipment starts, the motor begins to rotate the outer rotor 8. At this time, a speed difference is generated between the outer rotor 8 and the inner rotor 16, and an induced electromotive force is generated in the induction winding 7. Since the resistance of the series resistor in the conductive circuit is at its maximum at this time, the induced current passing through the conductive circuit is very weak, and the torque generated between the outer rotor 8 and the inner rotor 16 is also extremely small. This allows the motor to quickly accelerate past the peak torque speed and enter the stable operating range to complete the start-up. As the speed difference between the inner rotor 16 and the outer rotor 8 continues to increase, the torque transmitted by the permanent magnet coupler also gradually increases and begins to accelerate, overcoming the initial torque of the equipment. As the inner rotor 16 accelerates its rotation upon equipment startup, the centrifugal slider 6 overcomes the tension of the tension spring 2 under centrifugal force and moves radially outward along the radial guide rail 5. The sliding conductive contact 14 also gradually moves from the U-shaped resistance plate 13 to the short-circuit contact 11, causing the resistance in the conductive circuit to gradually decrease to zero. Although the speed difference between the inner rotor 16 and the outer rotor 8 gradually decreases during this process, and the induced electromotive force generated by the induction winding 7 also decreases accordingly, the change in the induced current in the conductive circuit is small because the resistance in the conductive circuit gradually decreases to zero as the speed of the inner rotor 16 increases. This results in the transmission torque between the inner rotor 16 and the outer rotor 8 varying only within a very small range. After the equipment completes startup and enters its rated operating condition, the speed of the inner rotor 16 reaches its rated speed, and the rated speed difference between the outer rotor 8 and the inner rotor 16 is very small, enabling the permanent magnet coupler of this invention to transmit the rated torque under rated operating conditions.

[0026] When the equipment is overloaded, the speed difference between the inner rotor 16 and the outer rotor 8 of the permanent magnet coupler of this invention increases, thereby increasing the transmission torque to overcome the overload and return to the rated condition. If the overload continues to increase, the speed of the inner rotor 16 continues to decrease, the centrifugal force on the centrifugal slider 6 decreases, and it begins to slide towards the center of the inner rotor 16, causing the resistance of the series resistor in the conductive circuit to gradually increase until it reaches its maximum value. Although the induced electromotive force generated by the induction winding 7 will increase with the increase of the speed difference between the inner rotor 16 and the outer rotor 8, its induced current will not change much due to the increase of the resistance of the series resistor in the conductive circuit. This limits the torque transmitted between the inner rotor 16 and the outer rotor 8 to a certain range, thereby providing good torque limiting protection for the entire transmission system.

[0027] By rationally selecting the resistance value of the U-shaped resistance plate 13, adjusting the stiffness and initial tension of the tension spring 2, and adjusting the mass and initial and final positions of the centrifugal slider 6, this invention can conveniently adjust the starting characteristics of the permanent magnet coupler and the overload coefficient during torque protection according to the power transmitted by the permanent magnet coupler and the equipment's requirements for starting and torque limiting protection.

[0028] This invention generates only a small transmission torque during the initial startup phase, enabling the motor to quickly start and reach rated speed under low load conditions. As the equipment accelerates, the transmission torque of the permanent magnet coupler gradually increases to a constant value, allowing the equipment to accelerate gently under constant torque conditions until startup and rated operating conditions are achieved. Furthermore, when the equipment is severely overloaded and the speed at the load end drops significantly, the permanent magnet coupler automatically limits the increase in its transmission torque to achieve overload torque limiting protection for the motor and transmission system. It can be widely used in equipment requiring soft starts, such as belt conveyors and elevators, as well as various large-inertia equipment requiring improved starting performance, such as ball mills, mixers, and crushers.

Claims

1. A self-regulating device for induced current of a permanent magnet coupler, comprising an inner rotor as the driven end, an iron core mounted on the outer periphery of the inner rotor, and an induction winding embedded in the iron core, characterized in that... Two lead terminals of the induction winding are connected with U-shaped resistance plates installed on the inner rotor, the inner rotor is provided with radial guide rails in the radial direction, the radial guide rails are installed with centrifugal sliding blocks sliding thereon, the centrifugal sliding blocks are provided with two sliding conductive contacts respectively contacting with the U-shaped resistance plates, so that the induction winding, the U-shaped resistance plates and the sliding conductive contacts form a conductive loop, one end of the centrifugal sliding block is installed with a tension spring, the other end of the tension spring is connected with the inner rotor, and the centrifugal sliding block is pulled to the center of the inner rotor; the permanent magnet coupler changes the contact positions of the two sliding conductive contacts on the centrifugal sliding block and the U-shaped resistance plates by different centrifugal forces received by the centrifugal sliding block at different rotating speeds of the inner rotor under different working conditions, automatically adjusts the resistance value of the resistance connected in the conductive loop, that is, the resistance value of the resistance connected in the conductive loop gradually decreases with the gradual increase of the centrifugal force, and the resistance value of the resistance connected in the conductive loop gradually increases with the gradual decrease of the centrifugal force, so that the induction current in the conductive loop changes in the set working current range, thereby the permanent magnet coupler automatically adjusts the transmission torque under different working conditions to be constant, and the soft start and overload torque limiting protection of the equipment are realized.

2. The permanent magnet coupler induction current self-adjusting device according to claim 1, characterized in that two terminals of the induction winding are connected with the U-shaped resistance plates through two short-circuit contacts, that is, the induction winding, the short-circuit contacts, the U-shaped resistance plates and the sliding conductive contacts form a conductive loop.

3. The permanent magnet coupler induced current self-regulating device of claim 1, wherein The inner rotor is installed with a stop block, and the tension spring is installed on the stop block through a spring frame; the initial tension of the tension spring and the initial position of the centrifugal sliding block are adjusted by the installation position of the stop block.

4. The permanent magnet coupler induced current self-regulating device of claim 1, wherein The centrifugal sliding block is provided with a counterweight adjusting screw for adjusting the mass of the centrifugal sliding block.

5. A permanent magnet coupler adopting the permanent magnet coupler induction current self-adjusting device according to claim 1 or 2 or 3 or 4.

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