Shaft current prevention insulation device of variable frequency motor

Abstract

The utility model relates to a shaft current prevention insulation device of a variable frequency motor, and belongs to the technical field of motor insulation, the shaft current prevention insulation device comprises a motor shell, a rotor shaft arranged in the motor shell, a bearing rotatably connected outside the rotor shaft and a fixing disc used for stabilizing a shaft core of the rotor shaft, a grounding device is arranged on one side face of the fixing disc and used for preventing shaft current. According to the shaft current prevention insulation device of the variable frequency motor, the mounting plate and the sliding bin are additionally arranged in the motor shell, the electric brush in contact with the rotor shaft is slidably mounted in the sliding bin, and the electric brush and the motor shell are indirectly conducted through the wire and the conductive frame, so that the motor shell grounded through the power line can be mutually conducted with the rotor shaft; the shaft current formed in the rotor shaft is released in a grounding mode, accumulation of the shaft current is prevented, the device is simple in structure, only a single electric brush is used as a consumable material, and compared with an insulating material, the cost is greatly reduced, and popularization is facilitated.

Description

Technical Field

[0001] This application relates to the technical field of motor insulation, and specifically to an insulation device for preventing shaft current in a variable-frequency motor. Background Art

[0002] An AC asynchronous motor operates under a sinusoidal alternating voltage, and its rotor is in a sinusoidal alternating magnetic field. Due to factors such as the stator and rotor sector punching sheets, lamination of silicon steel sheets, and core slots and ventilation holes of the motor, it is easy to generate unbalanced magnetic resistance. When the magnetic resistance in the circumferential direction of the stator core of the motor is unbalanced, a rotating magnetic flux that intersects the rotating shaft will be generated. As the magnetic poles rotate, an electromotive force is induced at both ends of the rotating shaft, forming a closed loop through the main shaft, bearings, end covers, and machine base, generating shaft current.

[0003] Shaft current may cause overheating, insulation damage, and mechanical wear of the equipment, thereby affecting the performance and lifespan of the motor. To reduce the impact of shaft current, some measures are usually taken, such as using high-quality insulating materials for the rotor and ensuring the integrity of the insulation layer. However, in this way, the cost of the motor increases significantly, which is not conducive to promotion. Therefore, an insulation device for preventing shaft current in a variable-frequency motor is proposed to solve the above-mentioned problems. Utility Model Content

[0004] In view of the deficiencies of the prior art, this application provides an insulation device for preventing shaft current in a variable-frequency motor, which has the advantages of not requiring additional insulation materials and low cost for preventing shaft current.

[0005] To achieve the above object, this application provides the following technical solution: An insulation device for preventing shaft current in a variable-frequency motor, including a motor housing and a rotor shaft disposed inside the motor housing. A bearing and a fixing plate for stabilizing the axis of the rotor shaft are rotatably connected to the outside of the rotor shaft. A grounding device is provided on one side of the fixing plate to prevent shaft current.

[0006] The grounding device includes a connecting plate and a mounting plate fixedly connected to the fixing plate. A sliding chamber is integrally connected to the front end of the mounting plate. A brush for contacting the rotor shaft is slidably installed in the sliding chamber. An extension slot is formed through the front surface of the sliding chamber. A conductive frame extending to the side of the sliding chamber is fixedly installed outside the mounting plate.

[0007] A connector is fixedly installed on the surface of the brush. A wire is connected between the conductive frame and the connector.

[0008] Further, the connecting plate is used to contact the fixing plate. Bolt holes are formed through the mounting plate for screws to pass through to fix the mounting plate and the fixing plate to each other.

[0009] Furthermore, a guide rod for guiding the position of the mounting plate is fixedly installed on one side of the fixed plate facing the connecting plate. A guide hole corresponding to the guide rod is penetrated and opened on the mounting plate, and the guide rod is slidably connected to the guide hole.

[0010] Furthermore, an opening is formed on the side surface of the sliding bin. A conductive rod for inserting the fixed plate is fixedly penetrated on the mounting plate. A reed is fixedly connected to one end of the conductive rod located on the side surface of the sliding bin, and the reed is in contact with the brush.

[0011] Furthermore, one end of the reed is fixed to the conductive rod, and the other end is wound around the conductive rod into a curled shape and attached to the side wall of the brush.

[0012] Furthermore, a compression spring is connected between the brush and the inner top wall of the sliding bin. Both ends of the compression spring are fixedly connected to the inner top wall of the sliding bin and the top end of the brush respectively through two spring seats.

[0013] Furthermore, the sliding bin is a rectangular structure with an open lower end.

[0014] Compared with the prior art, the technical solution of the present application has the following beneficial effects:

[0015] In the insulation device for preventing shaft current of the variable-frequency motor, by adding a mounting plate and a sliding bin inside the motor housing, a brush contacting the rotor shaft is slidably installed in the sliding bin, and the brush and the motor housing are indirectly conducted through a wire and a conductive frame, so that the motor housing grounded through the power cord can be conducted with the rotor shaft, thereby releasing the shaft current formed in the rotor shaft in the form of grounding, and preventing the accumulation of shaft current. Since the device has a simple structure and the consumable material is only a single brush, compared with using insulating materials, the cost is greatly reduced and it is convenient to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is an exploded view of the overall structure of the present application;

[0017] Figure 2 is for the present application Figure 1 is an enlarged view of the structure at A in;

[0018] Figure 3 is a three-dimensional view of the structure of the mounting plate of the present application;

[0019] Figure 4 is a schematic diagram of the structure of the sliding bin of the present application.

[0020] In the figure: 1. Motor housing; 2. Rotor shaft; 3. Bearing; 4. Fixed disk; 5. Mounting plate; 6. Connecting plate; 7. Guide hole; 8. Guide rod; 9. Bolt hole; 10. Sliding chamber; 11. Brush; 12. Compression spring; 13. Conductive frame; 14. Conducting wire; 15. Extension groove; 16. Conductive rod; 17. Reed; 18. Connector; 19. Connector. Specific embodiments

[0021] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0022] Please refer to Figures 1 to 4 , the anti-shaft current insulation device of the variable-frequency motor in this embodiment includes a motor housing 1 and a rotor shaft 2 disposed inside the motor housing 1. A bearing 3 and a fixed disk 4 for stabilizing the axis of the rotor shaft 2 are rotatably connected to the outside of the rotor shaft 2.

[0023] In this embodiment, one side surface of the fixed disk 4 is fixedly connected to one end of the motor housing 1, and a grounding device is provided on the other side surface to prevent shaft current.

[0024] It should be noted that the grounding device includes a connecting plate 6 and a mounting plate 5 fixedly connected to the fixed disk 4. The connecting plate 6 is used to contact the fixed disk 4, and a bolt hole 9 is provided through the mounting plate 5 for a screw to pass through to fix the mounting plate 5 and the fixed disk 4 to each other.

[0025] Preferably, a guide rod 8 for guiding the position of the mounting plate 5 is fixedly installed on one side surface of the fixed disk 4 facing the connecting plate 6. A guide hole 7 corresponding to the guide rod 8 is provided through the mounting plate 5, and the guide rod 8 is slidably connected to the guide hole 7.

[0026] In this embodiment, the front end of the mounting plate 5 is also integrally connected with a sliding chamber 10. The sliding chamber 10 is a rectangular structure with an open lower end. A brush 11 for contacting the rotor shaft 2 is slidably installed in the sliding chamber 10. The brush 11 is used to contact the rotor shaft 2 in a rotating state and lead out the shaft current in the rotor shaft 2.

[0027] In this embodiment, an extension groove 15 is provided through the front surface of the sliding chamber 10. A conductive frame 13 extending to the side surface of the sliding chamber 10 is fixedly installed outside the mounting plate 5. The conductive frame 13 can stably contact the fixed disk 4 when the mounting plate 5 is attached to the fixed disk 4.

[0028] Furthermore, a connector 19 is fixedly installed on the surface of the brush 11, and a wire 14 is connected between the conductive frame 13 and the connector 19 for transporting the shaft current.

[0029] In a specific implementation, since the fixed disk 4 is directly in contact and connected with the motor housing 1, the motor housing 1 can be grounded through the power cord, that is, the rotor shaft 2 can be grounded accordingly to prevent the harm of the shaft current.

[0030] It should be noted that, in order to increase the contact amount, an opening 18 is provided on the side surface of the sliding bin 10, and a conductive rod 16 for inserting and fixing the fixed disk 4 is fixedly penetrated on the mounting plate 5. A reed 17 is fixedly connected to one end of the conductive rod 16 on the side surface of the sliding bin 10, and the reed 17 is in contact with the brush 11.

[0031] Specifically, the reed 17 is made of a conductive metal material, one end is fixed to the conductive rod 16, and the other end is wound around the conductive rod 16 and curled to fit on the side wall of the brush 11.

[0032] With such a design, after the brush 11 slides relative to the sliding bin 10 to change its position, the conductive rod 16 and the brush 11 can maintain good contact.

[0033] Similarly, a compression spring 12 is connected between the brush 11 and the inner top wall of the sliding bin 10 in this embodiment. Both ends of the compression spring 12 are fixedly connected to the inner top wall of the sliding bin 10 and the top end of the brush 11 through two spring seats respectively. Through the compression spring 12, the brush 11 can be pushed into contact with the rotor shaft 2, thereby ensuring the stability of the contact.

[0034] The working principle of the above embodiment is as follows:

[0035] After the variable-frequency motor is connected to the power supply, it starts to work. During the rotation of the rotor shaft 2, a shaft current is generated. At this time, the brush 11 in the sliding bin 10 extends and comes into contact with the rotor shaft 2. The shaft current in the rotor shaft 2 can flow along the brush 11, the wire 14 connected to the brush 11, and the conductive frame 13 to contact with the fixed disk 4. Also, since the fixed disk 4 is in contact with the motor housing 1, the motor housing 1 is grounded through the grounding wire in the three-phase system, so that the rotor shaft 2 is also grounded. Therefore, no shaft current will accumulate in the rotor shaft 2. Compared with using expensive insulating materials, only the consumed brush 11 needs to be replaced regularly to prevent the shaft current.

[0036] It should be noted that, in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0037] Although the embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A variable frequency motor shaft current insulation device, comprising a motor housing (1) and a rotor shaft (2) built into the motor housing (1), characterized in that: The outer portion of the rotor shaft (2) is rotatably connected to a bearing (3) and a fixed disk (4) for stabilizing the core of the rotor shaft (2); a grounding device is provided on one side of the fixed disk (4) for preventing shaft current; The grounding device comprises a connecting plate (6) and a mounting plate (5) fixedly connected to the fixing plate (4); a sliding bin (10) is integrally connected to the front end of the mounting plate (5); a brush (11) for contacting the rotor shaft (2) is slidably mounted in the sliding bin (10); an extension groove (15) is provided through the front of the sliding bin (10); and a conductive frame (13) extending to the side of the sliding bin (10) is fixedly mounted on the outside of the mounting plate (5); A connector (19) is fixedly mounted on the surface of the brush (11), and a wire (14) is connected between the conductive frame (13) and the connector (19).

2. The variable frequency motor shaft current protection insulation device according to claim 1, characterized in that: The connecting plate (6) is used to contact the fixing plate (4), and the mounting plate (5) is provided with bolt holes (9) for screws to pass through to fix the mounting plate (5) and the fixing plate (4) to each other.

3. The variable frequency motor shaft current protection insulation device according to claim 1, characterized in that: A guide rod (8) for guiding the position of the mounting plate (5) is fixedly mounted on a side surface of the fixing plate (4) facing the connecting plate (6); a guide hole (7) corresponding to the guide rod (8) is penetrated through the mounting plate (5); and the guide rod (8) is slidably connected to the guide hole (7).

4. The variable frequency motor shaft current protection insulation device according to claim 1, characterized in that: An opening (18) is provided on the side of the sliding bin (10); a conductive rod (16) for plugging into the fixed disk (4) is fixedly passed through the mounting plate (5); a spring leaf (17) is fixedly connected to one end of the conductive rod (16) located on the side of the sliding bin (10); the spring leaf (17) and the brush (11) are in contact with each other.

5. The variable frequency motor shaft current protection insulation device according to claim 4, characterized in that: One end of the spring sheet (17) is fixed to the conductive rod (16), and the other end is wrapped around the conductive rod (16) in a curled shape and adheres to the side wall of the brush (11).

6. The variable frequency motor shaft current protection insulation device according to claim 1, characterized in that: A compression spring (12) is connected between the brush (11) and the inner top wall of the sliding bin (10), and two ends of the compression spring (12) are respectively fixedly connected to the inner top wall of the sliding bin (10) and the top end of the brush (11) through two spring seats.

7. The variable frequency motor shaft current protection insulation device according to claim 1, characterized in that: The sliding bin (10) is a rectangular structure with an open lower end.

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