Electric motor having non-contact magnetic braking device and electric hoist

Abstract

Provided are an electric motor having a non-contact magnetic braking device and an electric hoist, belonging to the technical field of electric motor braking. The electric motor comprises a rotating shaft (1), an electric motor housing (2), a magnetic braking mechanism (3), a limiting member (4) and a reset mechanism (5), wherein the magnetic braking mechanism (3) consists of a static magnetic assembly (31) and a dynamic magnetic assembly (32), which have opposite magnetic polarities and are arranged opposite each other, achieving braking in a non-contact manner; the dynamic magnetic assembly (32) is threadedly connected to the rotating shaft (1) and can rotate away from the static magnetic assembly (31) along with the rotating shaft (1), and when the rotating shaft (1) stops, the reset mechanism (5) drives the dynamic magnetic assembly (32) to reset. The electric motor further comprises a stator assembly (7) and a rotor assembly (8). The braking device is mounted in a braking chamber (22) of the electric motor housing (2), achieving separation of the power transmission function and the braking function, and thereby reducing friction and wear, improving braking efficiency and reliability, and facilitating maintenance and upgrades.

Description

A motor and electric hoist with a non-contact magnetic braking device Technical Field

[0001] This invention belongs to the technical field of motor braking devices, and particularly relates to a motor and an electric hoist with a non-contact magnetic braking device. Background Technology

[0002] Electric motors, as a widely used power source in modern industry and daily life, are indispensable in various equipment. Motor start-stop control is a basic requirement in motor applications, especially in heavy lifting equipment such as cranes and winches, where effective braking of the motor is of great significance for ensuring operational safety and preventing equipment damage.

[0003] In heavy lifting equipment, the motor shaft is in operation when the motor is running and lifting the load. After hoisting a heavy object, the lack of a reliable braking system to limit the movement of the motor shaft poses a significant safety hazard and could even damage the motor. Therefore, the design of the braking system is crucial; it must ensure that the equipment can stop quickly and smoothly when needed, while preventing unnecessary rotation of the motor shaft.

[0004] Currently, a common method of motor braking is through mechanical brakes. For example, Chinese invention patent application number 2020221472408 discloses such a motor brake. This brake includes components such as a housing, a contact plate, an electromagnet, an armature, and an adjusting device. The armature is fixedly mounted on the contact plate, and the adjusting device adjusts the position of the contact plate using an adjusting rod and an adjusting nut. When the motor is de-energized, the electromagnet is also de-energized, releasing the attraction force on the armature. At this time, under the action of the spring, the contact plate comes into contact with the friction pad, achieving the braking effect.

[0005] However, this mechanical braking method has significant drawbacks. Due to the frequent physical contact between the contact plate and the friction pads during braking, wear is inevitable. Over time, this wear gradually intensifies, affecting braking efficiency and service life. This not only reduces the reliability of the brake but may also pose safety hazards.

[0006] To address this issue, invention patent application number 2020221472408 proposes a solution: compensating for the decrease in the clamping force between the contact plate and friction pad due to wear by adjusting the nut. However, while this method can extend the service life of the brake to some extent, it does not fundamentally solve the problem of brake performance degradation caused by frictional losses. Therefore, a more effective and reliable motor braking solution is still needed to ensure the safe operation of the equipment and the long-term stability of the motor. Technical issues

[0007] This disclosure aims to address at least one of the technical problems existing in the prior art or related technologies.

[0008] To this end, the first aspect of this disclosure proposes a motor with a non-contact magnetic braking device. Through the innovative magnetic braking principle, it eliminates the need for physical contact, effectively solving the wear problem caused by friction in traditional braking methods, and providing a new and more reliable solution for motor braking.

[0009] The second aspect of this disclosure proposes an electric hoist. Technical solutions

[0010] The objective of this invention can be achieved through the following technical solutions:

[0011] A motor with a non-contact magnetic braking device includes a rotating shaft, a motor housing, a magnetic braking mechanism, a limiting member, and a reset mechanism. The magnetic braking mechanism includes a static magnetic component and a moving magnetic component, which have opposite magnetic properties and are arranged opposite to each other. The static magnetic component is fixedly mounted on the motor housing. The limiting member is disposed between the static magnetic component and the moving magnetic component to form a gap between them. The moving magnetic component is threadedly connected to the rotating shaft. When the rotating shaft is working, rotation can drive the moving magnetic component to move away from the static magnetic component, thereby increasing the gap between them. The reset mechanism includes an elastic element and a first bearing. The first bearing is mounted on the motor housing and has an interference fit with one end of the rotating shaft. The two ends of the elastic element abut against the moving magnetic component and the first bearing, respectively, and can rotate with the rotating shaft. When the rotating shaft stops working, the reset mechanism can drive the moving magnetic component to move closer to the static magnetic component until it is reset.

[0012] Preferably, the static magnetic force assembly includes a static magnetic yoke and a static magnet fixedly mounted on the static magnetic yoke, the static magnetic yoke being fixedly mounted on the motor housing, and the moving magnetic force assembly includes a moving magnetic yoke and a moving magnet fixedly mounted on the moving magnetic yoke, the moving magnetic yoke being threadedly connected to the shaft, and the static magnet and the moving magnet having opposite magnetic properties and being arranged opposite to each other.

[0013] Preferably, a screw is fixedly mounted on the rotating shaft, and the moving magnetic yoke is threadedly connected to the screw.

[0014] Preferably, a second bearing is fixedly installed on the static magnetic yoke to support the rotating shaft, and the limiting member is sleeved outside the rotating shaft and fixedly connected to the static magnetic yoke. The limiting member is located between the static magnetic yoke and the moving magnetic yoke.

[0015] Preferably, the static magnetic yoke, the dynamic magnetic yoke, and the limiting component are all made of non-magnetic stainless steel.

[0016] Preferably, the end of the moving magnetic yoke opposite to the stationary magnetic yoke is disc-shaped, and a number of moving magnets are evenly arranged circumferentially on the end face opposite to the moving magnetic yoke and the stationary magnetic yoke, with a number of stationary magnets and a number of moving magnets corresponding to each other.

[0017] An electric hoist includes a motor with a non-contact magnetic braking device. The motor with the non-contact magnetic braking device further includes a stator assembly and a rotor assembly. The static magnetic yoke divides the interior of the motor housing into a power chamber and a braking chamber. The stator assembly is fixedly installed in the power chamber. The rotor assembly is located in the stator assembly for mounting the rotating shaft. The non-contact magnetic braking device is installed in the braking chamber.

[0018] Preferably, a cooling fan is installed on the rotating shaft, and the cooling fan is located on the side of the power cavity away from the non-contact motor magnetic braking device. Beneficial effects

[0019] Compared with existing technologies, the motor with this non-contact magnetic braking device exhibits significantly improved magnetic braking effect. It achieves non-contact magnetic braking, reducing wear caused by friction in traditional braking methods, improving braking efficiency and response speed, extending the service life of the braking device, optimizing the magnetic field distribution, and achieving precise control of the axial position of the moving magnetic force component, preventing overtravel and significantly enhancing the reliability and stability of the device. The motor incorporating this magnetic braking device also shows effective improvements in braking effect, structural stability, position control, impact prevention, wear reduction, space utilization, maintenance and upgrades, and heat dissipation. Attached Figure Description

[0020] Figure 1 is a schematic diagram of the overall structure of the magnetic braking device of this motor.

[0021] Figure 2 is a schematic diagram of the overall structure of the motor.

[0022] Figure 3 is a schematic diagram of the overall cross-sectional structure of the motor and braking device under the working state of the rotating shaft.

[0023] Figure 4 is a schematic diagram of the overall cross-sectional structure of the motor and braking device in the standby state of the rotating shaft.

[0024] Figure 5 is a schematic diagram of the end face structure of the static magnetic force component and the moving magnetic force component.

[0025] Figure 6 shows the usage status of this motor in an electric hoist.

[0026] In the diagram, 1. Shaft; 11. Screw; 2. Motor housing; 21. Power chamber; 22. Braking chamber; 3. Magnetic braking mechanism; 31. Static magnetic force assembly; 311. Static magnetic yoke; 312. Static magnet; 32. Moving magnetic force assembly; 321. Moving magnetic yoke; 322. Moving magnet; 4. Limiting component; 5. Reset mechanism; 51. Elastic component; 52. First bearing; 6. Second bearing; 7. Stator assembly; 8. Rotor assembly; 9. Cooling fan. Embodiments of the present invention

[0027] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments. Example

[0028] As shown in Figures 1 to 4, a motor with a non-contact magnetic braking device includes a rotating shaft 1 and a motor housing 2, and further includes a magnetic braking mechanism 3, a limiting member 4, and a reset mechanism 5. The magnetic braking mechanism 3 includes a static magnetic component 31 and a moving magnetic component 32, which have opposite magnetic properties and are arranged opposite to each other. The static magnetic component 31 is fixedly installed on the motor housing 2. The limiting member 4 is disposed between the static magnetic component 31 and the moving magnetic component 32 to form a gap between them. The moving magnetic component 32 is threadedly connected to the rotating shaft 1. When the rotating shaft 1 is working, it is connected to the rotating shaft 1. The rotation can drive the moving magnetic force component 32 to move away from the static magnetic force component 31, thereby increasing the gap between them. The reset mechanism 5 includes an elastic element 51 and a first bearing 52. The first bearing 52 is mounted on the motor housing 2 and is press-fitted to one end of the rotating shaft 1. The two ends of the elastic element 51 abut against the moving magnetic force component 32 and the first bearing 52 respectively and can rotate with the rotating shaft 1. When the rotating shaft 1 stops working, the reset mechanism 5 can drive the moving magnetic force component 32 to move closer to the static magnetic force component 31 until it is reset.

[0029] In this embodiment, the principle of magnetic braking can be summarized as follows:

[0030] The moving magnetic force component 32 and the stationary magnetic force component 31 have opposite magnetic properties and are arranged opposite to each other, thereby generating a magnetic attraction between them. When the motor shaft 1 attempts to rotate, the position of the moving magnetic force component 32 relative to the stationary magnetic force component 31 changes, causing the direction of the magnetic attraction to form an angle with the rotation direction of the shaft 1. This angle causes the magnetic attraction to generate a component perpendicular to the axis of the shaft 1. This component generates a resistance torque around the motor shaft 1 that is opposite to the rotation direction. This resistance torque effectively slows down or prevents the rotation of the shaft 1 through non-contact magnetic force, thereby achieving the effect of magnetic braking.

[0031] In short, the principle of magnetic braking is to use the magnetic attraction between the moving magnetic force component 32 and the stationary magnetic force component 31 to generate a resistance torque opposite to the direction of rotation when the rotating shaft 1 rotates, thereby achieving the braking function.

[0032] Referring to Figure 4, when the rotating shaft 1 is in normal operating condition, the threaded connection between the rotating shaft 1 and the moving magnetic component 32 allows the moving magnetic component 32 to overcome the magnetic attraction between itself and the stationary magnetic component 31, as well as the frictional force between the threaded connections, thus converting the motion into linear motion. During this process, the elastic element 51 is continuously compressed, applying a resistance to the moving magnetic component 32. This resistance is in the same direction as the magnetic attraction between the moving magnetic component 32 and the stationary magnetic component 31, and opposite to the thrust applied by the rotating shaft 1 to the moving magnetic component 32. When the sum of the resistance and the magnetic attraction equals the thrust, the axial movement of the moving magnetic component 32 stops, and it rotates with the rotating shaft 1. Through the combined action of the elastic element 51 and the magnetic force, this device achieves precise control of the axial position of the moving magnetic component 32, preventing overtravel and significantly improving the reliability and stability of the device.

[0033] It is worth mentioning that, in this embodiment, the elastic element 51 may have a certain torque, such as a spring or a rubber support. This torque can restrict the degree of freedom of the moving magnetic force component 32 in the rotation direction, so that the moving magnetic force component 32 is linearly displaced along the thread in a direction away from the static magnetic force component 31, thereby increasing the gap between the two.

[0034] It should also be noted that the moving magnetic force assembly 32 is allowed to undergo a certain degree of torsion within the torque range of the elastic element 51. The spacing and angle of the threads determine the distance and direction of movement of the moving magnetic force assembly 32 during rotation. Power and torque are transmitted through the threaded pair, which has high rigidity and load-bearing capacity.

[0035] Referring to Figure 3, when the motor shaft 1 stops working, the outward force applied to the moving magnetic force assembly 32 by the threaded connection disappears. At an appropriate distance, the moving magnetic force assembly 32 and the stationary magnetic force assembly 31 maintain a magnetic attraction. This attraction becomes particularly significant when the shaft 1 stops rotating. Driven by the elastic element 51, the moving magnetic force assembly 32 moves closer to the stationary magnetic force assembly 31, and the magnetic attraction between them increases as the distance decreases. If the motor shaft 1 tends to rotate abnormally, this magnetic attraction will be converted into a resistance torque opposite to the direction of rotation of the shaft 1, effectively achieving an automatic braking effect when the motor stops and preventing unexpected rotation.

[0036] The setting of the limiting member 4 creates a gap between the static magnetic force component 31 and the moving magnetic force component 32, while preventing the moving magnetic force component 32 from directly contacting the static magnetic force component 31. Under high-speed rotation or high load conditions, direct impact may generate huge impact force, causing serious damage to the device. The addition of the limiting member 4 provides additional protection for the device.

[0037] Further, referring to Figure 5, the static magnetic force assembly 31 includes a static magnetic yoke 311 and a static magnet 312 fixedly mounted on the static magnetic yoke 311. The static magnetic yoke 311 is fixedly mounted on the motor housing 2. The moving magnetic force assembly 32 includes a moving magnetic yoke 321 and a moving magnet 322 fixedly mounted on the moving magnetic yoke 321. The moving magnetic yoke 321 is threadedly connected to the rotating shaft 1. The static magnet 312 and the moving magnet 322 have opposite magnetic properties and are arranged opposite to each other.

[0038] The static magnetic yoke 311 and the moving magnetic yoke 321 not only provide a stable support for the static magnet 312 and the moving magnet 322, but also ensure their stability and reliability during operation. The static magnetic yoke 311 and the moving magnetic yoke 321 help guide and concentrate the magnetic field and have a certain magnetic permeability, making the magnetic attraction force more concentrated and efficient. This helps to enhance the braking effect, improve braking efficiency and response speed.

[0039] Furthermore, a screw 11 is fixedly installed on the rotating shaft 1, and the moving magnetic yoke 321 is threadedly connected to the screw 11. In heavy lifting equipment such as cranes and winches, the main function of the rotating shaft 1 is to efficiently and stably transmit power and torque, ensuring the normal operation of the entire mechanical system. The threaded connection between the screw 11 and the moving magnetic yoke 321 effectively avoids direct contact between the rotating shaft 1 and the moving magnetic yoke 321, thereby reducing wear caused by friction. This not only protects the surface quality of the rotating shaft 1 and extends its service life, but also reduces maintenance costs. Moreover, the threaded connection has self-locking properties, which can resist the influence of external loads and vibrations to a certain extent, preventing positional changes caused by vibration and other reasons, ensuring a stable and reliable connection between the rotating shaft and the moving magnetic yoke, and reducing mechanical noise.

[0040] In this embodiment, referring to Figures 1 and 3, a second bearing 6 is fixedly installed on the static magnetic yoke 311 to rotate and support the rotating shaft 1. The limiting member 4 is sleeved on the outside of the rotating shaft 1 and fixedly connected to the static magnetic yoke 311. The limiting member 4 is located between the static magnetic yoke 311 and the moving magnetic yoke 321.

[0041] By adopting a dual-bearing support system, the non-contact motor magnetic braking device achieves effective rotational support and axial restriction of the rotating shaft 1 through the cooperation of the second bearing 6 and the limiting member 4 on the static magnetic yoke 311, as well as the synergistic effect with the first bearing 52, ensuring the stability and smoothness of the rotating shaft 1 during rotation.

[0042] The static magnetic yoke 311, the moving magnetic yoke 321, and the limiting member 4 are all made of non-magnetic stainless steel. Non-magnetic stainless steel cannot be magnetized and has the characteristic of avoiding magnetic interference, ensuring the stability of the motor's magnetic field and the accurate operation of the braking device.

[0043] Non-magnetic stainless steel exhibits excellent corrosion resistance, resisting the attack of corrosive substances such as oxidation, acids, and alkalis. In the magnetic braking device of an electric motor, the static magnetic yoke 311 and the limiting component 4 may come into contact with various environmental media, such as oil, water, and dust. Using non-magnetic stainless steel can improve the corrosion resistance of these components, extend their service life, and reduce the frequency of maintenance and replacement.

[0044] In this embodiment, referring to Figure 5, the end of the moving magnetic yoke 321 opposite to the stationary magnetic yoke 311 is disc-shaped. A plurality of moving magnets 322 are circumferentially and evenly arranged on the end faces of the moving magnetic yoke 321 and the stationary magnetic yoke 311. A plurality of stationary magnets 312 are correspondingly arranged opposite to the plurality of moving magnets 322. The disc-shaped end of the moving magnetic yoke 321 opposite to the stationary magnetic yoke 311, and the circumferentially even arrangement of the moving magnets 322 and the stationary magnets 312 on their respective end faces, ensures a more uniform distribution of the magnetic field throughout the braking device, reducing local concentrations or deficiencies in the magnetic field. This improves the stability and consistency of the braking effect, enabling the braking device to achieve the required braking effect in a shorter time.

[0045] Furthermore, the uniform magnetic field distribution reduces the risk of component wear and damage caused by uneven magnetic field, thereby improving the reliability and service life of the braking device.

[0046] The disc-shaped moving magnetic yoke 321 and stationary magnetic yoke 311, along with the circumferentially evenly arranged magnets, can make more efficient use of the space inside the motor housing 2. This design allows the braking device to maintain high performance while having a smaller size and lighter weight, making it easier to install and maintain. Example

[0047] Figure 6 shows an electric hoist, also known as a lifting machine. The electric hoist includes a sprocket, a gearbox, and a motor with a non-contact magnetic braking device. The motor is the power source of the electric hoist, responsible for providing sufficient power to drive the entire machine. In the electric hoist, the motor drives the rotation of the sprocket and chain to achieve the lifting and transport of materials.

[0048] As shown in Figures 2-4, in this embodiment, an electric hoist is provided, including a motor with a non-contact magnetic braking device. The motor with the non-contact magnetic braking device also includes a stator assembly 7 and a rotor assembly 8. The static magnetic yoke 311 divides the interior of the motor housing 2 into a power chamber 21 and a braking chamber 22. The stator assembly 7 is fixedly installed in the power chamber 21. The rotor assembly 8 is located in the stator assembly 7 for mounting the rotating shaft 1. The non-contact magnetic braking device of the motor is installed in the braking chamber 22.

[0049] By dividing the interior of the motor housing 2 into a power chamber 21 and a braking chamber 22, the physical separation of the motor's power transmission and braking functions is achieved. This design allows the motor's power transmission components (stator assembly 7 and rotor assembly 8) and braking components (non-contact magnetic braking device) to operate independently without interference, thereby improving the overall performance and stability of the motor.

[0050] The internal layout of the motor is optimized, with the static magnetic yoke 311 acting as a separator, which not only separates the power chamber 21 and the braking chamber 22 but also improves the internal space layout of the motor. This design allows the various components of the motor to be installed compactly together, reducing the size and weight of the motor and improving space utilization.

[0051] The efficiency and reliability of the motor are improved. Due to the separation of the power transmission and braking components, and the use of non-contact braking, the overall efficiency and reliability of the motor are significantly enhanced. The power transmission component can convert electrical energy and mechanical energy more efficiently, while the braking component can quickly and accurately provide braking force when needed, thereby ensuring the stable operation of the motor.

[0052] This motor is easy to maintain and upgrade. Because the various parts of the motor are relatively independent, maintenance and upgrades are more convenient. For example, if it is necessary to replace the braking device or adjust the braking performance, only the components inside the brake chamber 22 need to be operated, without affecting the operation of the power transmission part.

[0053] Furthermore, a cooling fan 9 is installed on the rotating shaft 1, and the cooling fan 9 is located in the power cavity 21 on the side away from the non-contact motor magnetic braking device.

[0054] The cooling fan 9 effectively removes heat generated within the power chamber 21, reducing the motor's operating temperature. Because the cooling fan 9 is located on one side of the non-contact motor magnetic braking device, it is unaffected by any additional heat generated during braking. It also avoids interference from magnetic fields or mechanical vibrations that may occur during braking. The cooling fan 9 is mounted on the shaft 1 and positioned in a relatively independent location within the power chamber 21, making installation and maintenance more convenient. If replacement or repair of the cooling fan 9 is required, it can be easily removed from the power chamber 21 without affecting the operation of other components.

[0055] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A motor with a non-contact magnetic braking device, comprising a rotating shaft (1) and a motor housing (2), characterized in that, It also includes a magnetic braking mechanism (3), a limiting member (4), and a reset mechanism (5). The magnetic braking mechanism (3) includes a static magnetic force component (31) and a moving magnetic force component (32), which have opposite magnetic properties and are arranged opposite to each other. The static magnetic force component (31) is fixedly installed on the motor housing (2). The limiting member (4) is arranged between the static magnetic force component (31) and the moving magnetic force component (32) to form a gap between them. The moving magnetic force component (32) is threadedly connected to the rotating shaft (1). When the rotating shaft (1) is working, it can drive the moving magnetic force component (32) away from the static magnetic force component by rotating. The force component (31) is displaced in a direction to increase the gap between the two. The reset mechanism (5) includes an elastic element (51) and a first bearing (52). The first bearing (52) is mounted on the motor housing (2) and is interference-fitted with one end of the rotating shaft (1). The two ends of the elastic element (51) abut against the moving magnetic force component (32) and the first bearing (52) respectively and can rotate with the rotating shaft (1). The reset mechanism (5) can drive the moving magnetic force component (32) to move towards the stationary magnetic force component (31) until it is reset when the rotating shaft (1) stops working.

2. A motor with a non-contact magnetic braking device according to claim 1, characterized in that, The static magnetic force assembly (31) includes a static magnetic yoke (311) and a static magnet (312) fixedly mounted on the static magnetic yoke (311). The static magnetic yoke (311) is fixedly mounted on the motor housing (2). The moving magnetic force assembly (32) includes a moving magnetic yoke (321) and a moving magnet (322) fixedly mounted on the moving magnetic yoke (321). The moving magnetic yoke (322) is threadedly connected to the rotating shaft (1). The static magnet (312) and the moving magnet (322) have opposite magnetic properties and are arranged opposite to each other.

3. A motor with a non-contact magnetic braking device according to claim 2, characterized in that, A screw (11) is fixedly installed on the rotating shaft (1), and the moving magnetic yoke (321) is threadedly connected to the screw (11).

4. A motor with a non-contact magnetic braking device according to claim 2, characterized in that, A second bearing (6) is fixedly installed on the static magnetic yoke (311) and rotates in cooperation with the rotating shaft (1) to support the rotating shaft (1). The limiting member (4) is sleeved outside the rotating shaft (1) and fixedly connected to the static magnetic yoke (311). The limiting member (4) is located between the static magnetic yoke (311) and the moving magnetic yoke (321).

5. A motor with a non-contact magnetic braking device according to claim 4, characterized in that, The static magnetic yoke (311), the moving magnetic yoke (321), and the limiting member (4) are all made of non-magnetic stainless steel.

6. A motor with a non-contact magnetic braking device according to claim 2, characterized in that, The end of the moving magnetic yoke (321) opposite to the stationary magnetic yoke (311) is disc-shaped. A number of moving magnets (322) are evenly arranged circumferentially on the end face opposite to the moving magnetic yoke (321) and the stationary magnetic yoke (311). A number of stationary magnets (312) and a number of moving magnets (322) are arranged in a one-to-one correspondence.

7. An electric hoist, characterized in that, The motor includes a non-contact magnetic braking device as described in any one of claims 1-6, and the motor further includes a stator assembly (7) and a rotor assembly (8). The static magnetic yoke (311) divides the interior of the motor housing (2) into a power chamber (21) and a braking chamber (22). The stator assembly (7) is fixedly installed in the power chamber (21). The rotor assembly (8) is located in the stator assembly (7) for mounting the rotating shaft (1). The non-contact magnetic braking device of the motor is installed in the braking chamber (22).

8. An electric hoist according to claim 7, characterized in that, A cooling fan (9) is installed on the rotating shaft (1), and the cooling fan (9) is located in the power cavity (21) on the side away from the non-contact motor magnetic braking device.

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