A shaft end structure and motor for preventing bearing electrical corrosion

Abstract

The present invention belongs to the technical field of drive motors, and specifically relates to a shaft end structure and a motor that are resistant to bearing electrical corrosion; a shaft end structure that is resistant to bearing electrical corrosion, comprising a shaft end shell installed on an external working piece and a PCB board installed inside the shaft end shell, the PCB board being provided with a contact seat, the contact seat being provided with a shaft end drive assembly, the shaft end drive assembly comprising an output shaft and a connecting bearing, and also comprising a terminal group, the terminal group comprising an external terminal and a grounding terminal; a motor comprising the aforementioned shaft end structure, and also comprising a motor bracket and an external working piece, the shaft end shell being installed on the motor bracket, and the external working piece being installed on the output shaft; the present invention provides a shaft end structure and a motor that are resistant to bearing electrical corrosion, so as to solve the problems of operating difficulties, high costs and high potential risks in the bearing electrical corrosion protection schemes in the prior art.

Description

Technical Field

[0001] The present invention belongs to the technical field of drive motors, and in particular relates to a shaft end structure and a motor capable of preventing electrical corrosion of bearings. Background Art

[0002] When a PWM inverter drives a motor, the high-frequency switching of the power components generates a high-frequency common-mode voltage, which in turn forms a common-mode current path through the motor's coupling capacitors. The shaft current is part of this common-mode current. When the bearing voltage between the inner and outer raceways exceeds the oil film threshold voltage, it breaks down the bearing oil film, causing electrical corrosion and damaging the bearing, shortening its lifespan and, consequently, the fan's. To prevent bearing electrical corrosion, it is crucial to design the shaft-end connection structure to prevent the shaft current from looping.

[0003] The commonly used solutions to this problem currently include using brushes to allow the shaft current to pass through the brushes instead of through the bearings. However, in this solution, the brushes are prone to wear and need to be replaced regularly, which is difficult to replace. Another solution is to use insulating bearings to prevent discharge between the inner and outer rings of the bearings to generate shaft current, but insulating bearings are expensive and not suitable for promotion. There is also a method of adding components inside the motor to divert the shaft current on the rotor to the ground, so as to protect the bearings when the PWM inverter (or similar energy supply equipment) drives the motor to work normally. However, this solution may cause the common-mode voltage to be too large when the PWM inverter (or similar energy supply equipment) itself fails, which may lead to the occurrence of electrical corrosion. In this case, the shaft current generated by the high-frequency common-mode voltage is extremely large, which will instantly damage the bearings or even directly damage the motor, posing a high potential risk. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a shaft end structure and a motor that prevents bearing electrical corrosion, so as to solve the problems of the prior art bearing electrical corrosion protection schemes such as difficult operation, high cost and high potential risks.

[0005] One solution of the present invention provides a shaft end structure for preventing bearing electrical corrosion, comprising a shaft end housing mounted on an external working piece and a PCB board mounted inside the shaft end housing, wherein the PCB board is provided with a contact seat, and a shaft end drive assembly is mounted on the contact seat, wherein the shaft end drive assembly includes an output shaft and a connecting bearing;

[0006] It also includes a terminal group, the terminal group includes an external terminal and a grounding terminal, the external terminal is used to connect to an external power supply device, and the grounding terminal is used for grounding;

[0007] The contact seat is used to cooperate with the external terminal to connect to the negative pole of the external energy supply device, thereby forming a circuit and releasing the circuit voltage and current;

[0008] The shaft end drive assembly is used to cooperate with the external terminal through the PCB board to connect to the positive pole of the external energy supply device and form a loop in the shaft end housing to drive the output shaft to rotate.

[0009] It should be noted that when the PWM inverter drives the motor, the high-frequency switching of the power element will generate a high-frequency common-mode voltage, thereby generating parasitic capacitance. In the present invention, when the high-frequency common-mode voltage is generated, the parasitic capacitance is specifically generated in the shaft-end drive assembly. However, the core idea of ​​the present invention is to isolate the parasitic capacitance from the connecting bearing in the shaft-end drive assembly to protect the connecting bearing from the influence of electrical corrosion. The specific structure of the shaft-end drive assembly has been fully described below and will not be repeated here. The contact seat cooperates with the external terminal in this solution, specifically by setting the terminal connected to the negative pole of the external energy supply device in the external terminal on the contact seat to achieve the effect of forming a new circuit and releasing voltage and current.

[0010] Specifically, the specific design idea of ​​the present invention is to transform the original series circuit in which the current direction is the positive pole of the external energy supply device, the shaft end drive component, the grounding terminal to the ground through the shaft end drive component and the PCB board, into a circuit in which the current direction is the positive pole of the external energy supply device, the positive pole of the PCB board, the shaft end drive component, the negative pole of the PCB board, the contact seat, and the negative pole of the external energy supply device as circuit one, and the current direction is the positive pole of the external energy supply device, the positive pole of the PCB board, the shaft end drive component, the negative pole of the PCB board, the contact seat, and the negative pole of the external energy supply device as circuit two. The new circuit in which circuit one and circuit two are connected in parallel can isolate the parasitic capacitance generated by the high-frequency common-mode voltage from the shaft end drive component through circuit one and release the voltage and current to the negative pole of the external energy supply device, thereby reducing the current in circuit two where the connected bearing is located, thereby protecting the connected bearing from the influence of electrical corrosion.

[0011] It should be noted that the external working part can be a working part of the same type as the output shaft, such as a fan blade, and the installation of the external working part and the output shaft is completed by providing a mounting hole or mounting groove on the external working part for installing the output shaft.

[0012] It should be noted that the external energy supply equipment can specifically be a power grid, frequency converter, inverter and other similar energy supply equipment with alternating voltage. The present invention can be applied to any energy supply equipment with alternating voltage to prevent the connecting bearings or specific components in the working equipment connected thereto from experiencing electrical corrosion, which may affect the normal operation and service life of the working equipment.

[0013] In this solution, by arranging a PCB board inside the shaft end housing and additionally arranging a contact seat for connecting the shaft end drive assembly on the PCB board, it is possible to cooperate with the terminal group and the external energy supply device to form a new parallel circuit in the shaft end drive assembly. Then, through this parallel circuit, the connection circuit between the output shaft and the connecting bearing in the shaft end drive assembly and the external energy supply device is changed, so that the connecting bearing in the shaft end drive assembly and the output shaft are not directly connected in series with the external energy supply device, so as to release the voltage back to the negative pole and greatly reduce the shaft current of both the connecting bearing and the output shaft, thereby achieving a protective effect on the circuit where the output shaft and the connecting bearing are located;

[0014] Compared with existing bearing electrical corrosion protection solutions, the main advantages of the present invention are:

[0015] 1. When the present invention is used, it only needs to be installed in the corresponding position. After it is put into use, no additional operations such as replacing parts are required, nor is it necessary to regularly replace internal wear parts. Moreover, no additional wear parts will be worn out during use, resulting in additional costs for wear parts. The present invention has the advantages of simple operation and no additional parts costs during use.

[0016] 2. The present invention has a simple structure. By adding a PCB board to the shaft end housing, adding a contact seat to the PCB board, and adding external wiring terminals to the PCB board and the contact seat, the output shaft and bearing in the shaft end structure are avoided from being connected in series with the external energy supply device. The voltage and current are released through the external wiring terminals to greatly reduce the shaft current in the circuit where the output shaft and the connected bearing are located, thereby realizing protection of the connected bearing. Based on the simple structure and low cost, the present invention avoids the high cost of using insulating bearings on the one hand, and solves the high potential risk of damage to the bearings and even the motor due to failure of the external energy supply device on the other hand.

[0017] In one embodiment, the external connection terminal is provided on the PCB board, and the ground connection terminal is provided on the shaft end housing.

[0018] In one embodiment, the external connection terminal includes a positive terminal and a negative terminal, the positive terminal is used to connect to the positive electrode of the external power supply, and the negative terminal is used to connect to the negative electrode of the external power supply and a ground connection terminal.

[0019] It should be noted that the positive terminal is specifically provided on the PCB board, and the negative terminal is specifically provided on the contact seat. The positive terminal and the negative terminal are respectively connected to the positive and negative electrodes of the external energy supply device through wires, and the negative terminal is also connected to the ground terminal.

[0020] Specifically, in the actual working process of the present invention, two circuits are included. The first is circuit one in which the current direction is the positive pole of the external energy supply device, the positive terminal on the PCB board, the shaft end drive assembly, the negative terminal on the contact seat, and the negative pole of the external energy supply device. The second is circuit two in which the current direction is the positive pole of the external energy supply device, the positive terminal on the PCB board, the shaft end drive assembly, the negative terminal on the contact seat, the grounding terminal, and the ground. The negative terminal is connected to the negative pole of the external energy supply device from the contact seat through a wire, and the positive terminal is connected to the positive pole of the external energy supply device from the PCB board through a wire.

[0021] In this solution, by setting the positive terminal on the PCB board and the negative terminal on the contact seat on the PCB board, a circuit connected to the negative pole of the external energy supply device can be connected in parallel in the circuit formed by the PCB board, the contact seat and the shaft end drive assembly, so as to release part of the high-frequency common-mode voltage caused by the external energy supply device and share the shaft current in the circuit originally formed by the PCB board, the contact seat and the shaft end drive assembly, thereby protecting the connected bearing from the influence of electrical corrosion.

[0022] In one embodiment, the shaft end drive assembly further comprises a copper tube, the inner wall of the copper tube is provided with a groove for mounting the connecting bearing, the connecting bearing is mounted inside the copper tube, and the output shaft is mounted in the connecting bearing.

[0023] In one embodiment, there are at least two connecting bearings.

[0024] It should be noted that the groove in the inner wall of the copper tube is adapted to connect the bearing, which can specifically be a ball bearing. There are at least two connecting bearings and they are respectively located at the two ends of the copper tube. The connection between the output shaft and the ball bearing can be achieved through clearance fit.

[0025] In this solution, providing at least two connecting bearings can enhance the stability of the output shaft in rotating in the copper tube.

[0026] In one solution, an iron core is installed outside the copper tube, an insulating rack is installed on the iron core, a coil is provided on the insulating rack, and the coil is tightly wound around the iron core through the insulating rack.

[0027] In one solution, a magnetic sleeve is installed on the outside of the iron core, and the magnetic sleeve is in contact with the inner wall of the shaft end housing.

[0028] It should be noted that the magnetic sleeve itself continuously generates a permanent magnetic field. When the external power supply device is working, current passes through the coil and generates a magnetic field around the coil. The magnetic field of the magnetic sleeve interacts with the magnetic field of the coil. The external power supply device continuously provides DC current to the coil, thereby generating a coil magnetic field to drive the fan blades to rotate continuously.

[0029] In this solution, by arranging the coordination between the iron core, the coil and the magnetic sleeve, it is possible to cooperate with an external energy supply device, and drive the output shaft to rotate at high speed through the direct current provided by the external energy supply device.

[0030] One solution of the present invention provides a motor, comprising the aforementioned shaft end structure for preventing bearing electrical corrosion, and also comprising a motor bracket and an external working piece, wherein the shaft end housing is mounted on the motor bracket, and the external working piece is mounted on the output shaft.

[0031] In one embodiment, the external working member has a connecting groove for connecting to the output shaft.

[0032] In one embodiment, a fastener is provided in the connecting groove, and the fastener is interference-connected with the output shaft.

[0033] It should be noted that the external working part can be a working part of the same type as the output shaft, such as a fan blade, and the installation of the external working part and the output shaft is completed by providing a mounting hole or mounting groove on the external working part for installing the output shaft.

[0034] In this solution, the motor provided by the present invention has the advantages of the aforementioned shaft end structure that prevents bearing electrical corrosion because it is installed with the aforementioned shaft end structure that prevents bearing electrical corrosion; in addition, the motor provided by the present invention can be connected to a variety of different external working parts, and through the interference connection between the fastener installed in the connecting groove and the output shaft, the output shaft is tightly connected to the external working part, thereby enhancing the connection strength of the external working part. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0036] Figure 1 This is a schematic diagram of the overall structure of a shaft end structure and a motor for preventing electrical corrosion of bearings according to one embodiment of the present invention;

[0037] Figure 2 for Figure 1 A schematic diagram of the overall structure from another perspective;

[0038] Figure 3 for Figure 1 One of the vertical sections;

[0039] Figure 4 for Figure 1One of the horizontal sections;

[0040] Figure 5 Schematic diagram of the circuit principle of Example 1.

[0041] Among them, 1. shaft end housing; 2. shaft end drive assembly; 21. output shaft; 22. connecting bearing; 23. copper tube; 231. groove; 24. iron core; 25. magnetic sleeve; 3. motor bracket; 4. external working part; 41. connecting groove; 42. fastener. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0044] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0045] It should be noted in advance that the present invention does not specifically limit the specific structure of the PCB board, contact seat and terminal group used in the present invention. Among them, the contact seat is limited only to having a structure capable of installing the shaft end drive component 2 and having external terminal blocks. The PCB board is limited only to having external terminal blocks. The terminal group is limited only to being respectively arranged on the contact seat, the PCB board and the shaft end housing 1. Therefore, the above-mentioned specific structure is not reflected in the accompanying drawings.

[0046] Please refer to Figure 1-5 One embodiment of the present invention provides a shaft end structure for preventing bearing electrical corrosion, comprising a shaft end housing mounted on an external working member 4 and a PCB board mounted inside the shaft end housing, wherein the PCB board is provided with a contact seat, and a shaft end drive assembly 2 is mounted on the contact seat, wherein the shaft end drive assembly 2 includes an output shaft 21 and a connecting bearing 22;

[0047] It also includes a terminal group, the terminal group includes an external terminal and a grounding terminal, the external terminal is used to connect to an external power supply device, and the grounding terminal is used for grounding;

[0048] The contact seat is used to cooperate with the external terminal to connect to the negative pole of the external energy supply device, thereby forming a circuit and releasing the circuit voltage and current;

[0049] The shaft end drive assembly 2 is used to cooperate with the external terminal through the PCB board to connect to the positive pole of the external energy supply device and form a loop in the shaft end housing 1, thereby driving the output shaft 21 to rotate.

[0050] It should be noted that when the PWM inverter drives the motor, the high-frequency switching of the power element will generate a high-frequency common-mode voltage, thereby generating parasitic capacitance. In the present invention, when the high-frequency common-mode voltage is generated, the parasitic capacitance is specifically generated in the shaft-end drive assembly 2. However, the core idea of ​​the present invention is to isolate the parasitic capacitance from the connecting bearing 22 in the shaft-end drive assembly 2 to protect the connecting bearing 22 from the influence of electrical corrosion. The specific structure of the shaft-end drive assembly 2 has been fully described below and will not be repeated here. The contact seat cooperates with the external terminal in this solution, specifically by setting the terminal connected to the negative pole of the external energy supply device in the external terminal on the contact seat to achieve the effect of forming a new circuit and releasing voltage and current.

[0051] Specifically, the specific design idea of ​​the present invention is to transform a series circuit whose current direction is the positive pole of the external energy supply device, the shaft end drive component 2, the grounding terminal to the ground through the shaft end drive component 2 and the PCB board, into a circuit whose current direction is the positive pole of the external energy supply device, the positive pole of the PCB board, the shaft end drive component 2, the contact seat, the negative pole of the PCB board, and the negative pole of the external energy supply device as circuit one, and a circuit whose current direction is the positive pole of the external energy supply device, the positive pole of the PCB board, the shaft end drive component 2, the negative pole of the PCB board, and the grounding terminal to the ground as circuit two, a new circuit in which circuit one and circuit two are connected in parallel. The new circuit can isolate the parasitic capacitance generated by the high-frequency common-mode voltage from the shaft end drive component 2 through circuit one and release the voltage and current to the negative pole of the external energy supply device, thereby greatly reducing the current in circuit two where the connecting bearing 22 is located, thereby protecting the connecting bearing 22 from the influence of electrical corrosion.

[0052] It should be additionally explained that the external working part 4 can be a working part of the same type as the output shaft 21, such as a fan blade, and the installation of the external working part 4 and the output shaft 21 is completed by providing an installation hole or installation groove on the external working part 4 for installing the output shaft 21.

[0053] It should be noted that the external energy supply equipment can specifically be a power grid, a frequency converter, an inverter, or other similar energy supply equipment with alternating voltage. The present invention can be applied to any energy supply equipment with alternating voltage to prevent the connecting bearings 22 or specific components in the working equipment connected thereto from experiencing electrical corrosion, thereby affecting the normal operation and service life of the working equipment.

[0054] In this embodiment, by arranging a PCB board inside the shaft end housing 1 and additionally arranging a contact seat for connecting the shaft end drive assembly 2 on the PCB board, it is possible to cooperate with the terminal group and the external energy supply device to form a new parallel circuit in the shaft end drive assembly 2. Then, through the parallel circuit, the connection circuit between the output shaft 21 and the connecting bearing 22 in the shaft end drive assembly 2 and the external energy supply device is changed, so that the connecting bearing 22 and the output shaft 21 in the shaft end drive assembly 2 are not directly connected in series with the external energy supply device, so as to release the voltage back to the negative pole and greatly reduce the shaft current of the connecting bearing 22 and the output shaft 21, thereby achieving a protective effect on the circuit where the output shaft 21 and the connecting bearing 22 are located;

[0055] Compared with existing bearing electrical corrosion protection solutions, the main advantages of the present invention are:

[0056] 1. When the present invention is used, it only needs to be installed in the corresponding position. After it is put into use, no additional operations such as replacing parts are required, nor is it necessary to regularly replace internal wear parts. Moreover, no additional wear parts will be worn out during use, resulting in additional costs for wear parts. The present invention has the advantages of simple operation and no additional parts costs during use.

[0057] 2. The present invention has a simple structure. By adding a PCB board to the shaft end housing 1, adding a contact seat to the PCB board, and adding external wiring terminals to the PCB board and the contact seat, the output shaft 21 and the bearing in the shaft end structure are connected in series with the external energy supply device. The voltage and current are released through the external wiring terminals to greatly reduce the shaft current in the circuit where the output shaft 21 and the connecting bearing 22 are located, thereby achieving protection for the connecting bearing 22. Based on the simple structure and low cost, the present invention avoids the high cost of using insulating bearings on the one hand, and solves the high potential risk of damage to the bearings and even the motor due to a failure of the external energy supply device on the other hand.

[0058] In one embodiment, the external terminal is provided on the PCB board, and the ground terminal is provided on the shaft end housing 1 .

[0059] In one embodiment, the external connection terminal includes a positive terminal and a negative terminal, the positive terminal is used to connect to the positive electrode of the external power supply, and the negative terminal is used to connect to the negative electrode of the external power supply and a ground connection terminal.

[0060] It should be noted that the positive terminal is specifically provided on the PCB board, and the negative terminal is specifically provided on the contact seat. The positive terminal and the negative terminal are respectively connected to the positive and negative electrodes of the external energy supply device through wires, and the negative terminal is also connected to the ground terminal.

[0061] Specifically, in the actual working process of the present invention, two circuits are included. The first is circuit one in which the current direction is the positive pole of the external energy supply device, the shaft end drive component 2, the PCB board, the contact seat, and the negative pole of the external energy supply device. The second is circuit two in which the current direction is the positive pole of the external energy supply device, the shaft end drive component 2, the grounding terminal to the ground, wherein the negative terminal is connected to the negative pole of the external energy supply device from the contact seat through a wire, and the positive terminal is connected to the positive pole of the external energy supply device from the PCB board through a wire.

[0062] In this embodiment, by setting the positive terminal on the PCB board and the negative terminal on the contact seat on the PCB board, a circuit connected to the negative pole of the external energy supply device can be connected in parallel in the circuit formed by the PCB board, the contact seat and the shaft end drive assembly 2, so as to release part of the high-frequency common mode voltage caused by the external energy supply device and share the shaft current in the circuit originally formed by the PCB board, the contact seat and the shaft end drive assembly 2, thereby protecting the connecting bearing 22 from the influence of electrical corrosion.

[0063] In one embodiment, the shaft end drive assembly 2 further includes a copper tube 23 , the inner wall of which is provided with a groove 231 for mounting the connecting bearing 22 . The connecting bearing 22 is mounted inside the copper tube 23 , and the output shaft 21 is mounted in the connecting bearing 22 .

[0064] In one embodiment, at least two connecting bearings 22 are provided.

[0065] It should be noted that the groove 231 in the inner wall of the copper tube 23 is adapted to the connecting bearing 22. The connecting bearing 22 can specifically be a ball bearing. There are at least two connecting bearings 22 and they are respectively located at the two ends of the copper tube 23. The connection between the output shaft 21 and the ball bearing can be achieved through clearance fit.

[0066] In this embodiment, providing at least two connecting bearings 22 can enhance the stability of the output shaft 21 rotating in the copper tube 23 .

[0067] In one embodiment, an iron core 24 is installed on the outside of the copper tube 23, an insulating stack (not shown) is installed on the iron core 24, a coil (not shown) is provided on the insulating stack (not shown), and the coil (not shown) is tightly wound on the iron core 24 through the insulating stack (not shown).

[0068] In one embodiment, a magnetic sleeve 25 is installed outside the iron core 24 , and the magnetic sleeve 25 is in contact with the inner wall of the shaft end housing 1 .

[0069] It should be noted that the magnetic sleeve 25 itself continuously generates a permanent magnetic field. When the external power supply device is working, current passes through the coil (not shown) and generates a coil magnetic field around the coil (not shown). The magnetic field of the magnetic sleeve 25 interacts with the coil magnetic field, and the external power supply device continuously provides direct current to drive the fan blades to rotate continuously; in this process, the copper tube 23 contacts the negative pole of the PCB board to form a loop, which can isolate the voltage from flowing through the connecting bearing 22.

[0070] In this embodiment, by arranging the cooperation between the iron core 24, the coil (not shown) and the magnetic sleeve 25, it is possible to cooperate with an external power supply device and drive the output shaft 21 to rotate at high speed through the direct current provided by the external power supply device.

[0071] One of the schemes of the present invention provides a motor, including the aforementioned shaft end structure for preventing bearing electrical corrosion, and also including a motor bracket 3 and an external working piece 4, the shaft end housing 1 is installed on the motor bracket 3, and the external working piece 4 is installed on the output shaft 21.

[0072] In one embodiment, a connecting groove 41 for connecting to the output shaft 21 is formed on the external working member 4 .

[0073] In one embodiment, a fastener 42 is provided in the connection groove 41 , and the fastener 42 is interference-connected with the output shaft 21 .

[0074] It should be noted that the external working part 4 can be a working part of the same type as the output shaft 21, such as a fan blade, and the installation of the external working part 4 and the output shaft 21 is completed by providing an installation hole or installation groove on the external working part 4 for installing the output shaft 21.

[0075] In this embodiment, the motor provided by the present invention has the advantages of the aforementioned shaft end structure that prevents bearing electrical corrosion because it is installed with the aforementioned shaft end structure that prevents bearing electrical corrosion; in addition, the motor provided by the present invention can be connected to a variety of different external working parts 4, and through the interference connection between the fastener 42 installed in the connecting groove 41 and the output shaft 21, the output shaft 21 is tightly connected to the external working part 4, thereby enhancing the connection strength of the external working part 4.

[0076] The specific structure and working principle of one preferred embodiment of the present invention are described below:

[0077] Example 1

[0078] The motor includes a shaft end housing 1 and a motor bracket 3. The shaft end housing 1 is mounted on the motor bracket 3. A PCB board is mounted inside the shaft end housing 1. A contact seat is provided on the PCB board. A ground terminal is provided on the shaft end housing 1. A positive terminal is provided on the PCB board. A negative terminal is provided on the contact seat. A shaft end drive assembly 2 is also mounted on the contact seat.

[0079] The PCB board and the contact seat in the shaft end housing 1 are connected to the positive and negative electrodes of the external energy supply device through the positive and negative terminals respectively;

[0080] The shaft end drive assembly 2 includes a magnetic sleeve 25, an iron core 24, a coil (not shown), and a copper tube 23. The iron core 24 is mounted around the outside of the copper tube 23. An insulating stack (not shown) is provided on the iron core 24. The coil (not shown) is tightly wound around the iron core 24 through the insulating stack (not shown). The outer ring of the iron core 24 is provided with a magnetic sleeve 25.

[0081] The copper tube 23 is provided with a groove 231 for mounting the connecting bearing 22. The connecting bearing 22 is mounted in the groove 231. The output shaft 21 is mounted in the connecting bearing 22. The output end of the output shaft 21 is connected to the external working part 4 through a connecting groove 41 and a fastener 42 on the external working part. The connecting bearing 22 is specifically a ball bearing, and the external working part 4 is specifically a fan blade.

[0082] Please refer to Figure 5 It should be noted that the equivalent resistance of the middle tube is the resistance of the equivalent copper tube 23, and the variable equivalent resistance of the oil film is the resistance of the grease connected to the bearing itself. In actual use, the external energy supply device supplies power to the motor. When the motor is working, two circuits are formed inside the motor. The current direction of circuit one is: the positive pole of the external energy supply device, the positive terminal on the PCB board, the coil (not shown), the iron core 24, the copper tube 23, the negative terminal on the contact seat, and the negative pole of the external energy supply device. The current direction of circuit two is: the positive pole of the external energy supply device, the positive terminal on the PCB board, the coil (not shown), the iron core 24, the copper tube 23, the negative terminal on the contact seat, the grounding terminal on the shaft end housing 1, and the ground;

[0083] When the current in the aforementioned loop passes through the coil (not shown), a magnetic field will be generated around the coil (not shown). Since the magnetic sleeve 25 itself continuously generates the magnetic sleeve 25 magnetic field, the magnetic sleeve 25 magnetic field interacts with the coil magnetic field, and the external energy supply device continuously provides direct current to drive the fan blades to rotate continuously; in this process, the copper tube 23 contacts the negative pole of the PCB board to form a loop, which can isolate the current from flowing through the connecting bearing 22.

[0084] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A shaft end structure for preventing bearing electrical corrosion, characterized in that: It includes a shaft end housing mounted on an external working piece and a PCB board mounted inside the shaft end housing, wherein the PCB board is provided with a contact seat, and a shaft end drive assembly is mounted on the contact seat, wherein the shaft end drive assembly includes an output shaft and a connecting bearing; It also includes a terminal group, the terminal group includes an external terminal and a grounding terminal, the external terminal is used to connect to an external power supply device, and the grounding terminal is used for grounding; The shaft end drive assembly includes a copper tube, an iron core and a magnetic sleeve. The inner wall of the copper tube is provided with a groove for installing a connecting bearing. There are at least two connecting bearings and they are positioned at both ends of the copper tube through the groove. The output shaft is installed in the connecting bearings. An iron core is installed outside the copper tube, an insulating stack is installed on the iron core, a coil is arranged on the insulating stack, and the coil is tightly wound on the iron core through the insulating stack; A magnetic sleeve is installed on the outside of the iron core, and the magnetic sleeve is attached to the inner wall of the shaft end housing and interacts with the induced magnetic field generated by the coil; The contact seat is used to cooperate with the external terminal block to form two parallel circuits: the positive pole of the external energy supply device is connected to the negative pole of the external energy supply device and the ground terminal through the positive pole of the PCB board and the shaft end drive assembly, so as to release part of the high-frequency common mode voltage caused by the external energy supply device, share the shaft current in the circuit originally formed by the PCB board, the contact seat and the shaft end drive assembly, and isolate the electrical corrosion path of the connected bearing; The shaft end drive assembly is used to cooperate with the external terminal block through the PCB board to connect to the positive electrode of the external energy supply device and form a circuit in the shaft end housing to drive the output shaft to rotate; When the PWM inverter drives the motor, the high-frequency switching of the power components will generate high-frequency common-mode voltage, which in turn generates parasitic capacitance. When the high-frequency common-mode voltage is generated, parasitic capacitance is generated in the shaft-end drive assembly. By isolating the parasitic capacitance from the connecting bearing in the shaft-end drive assembly, the connecting bearing is protected from the influence of electrical corrosion; the contact seat and the external terminal are matched, and the terminal connected to the negative pole of the external power supply device is set on the contact seat to form a new circuit and release voltage and current.

2. The shaft end structure for preventing bearing electrical corrosion according to claim 1, characterized in that: The external connection terminal is arranged on the PCB board, and the ground connection terminal is arranged on the shaft end housing.

3. The shaft end structure for preventing bearing electrical corrosion according to claim 2, characterized in that: The external connection terminal includes a positive terminal and a negative terminal. The positive terminal is used to connect to the positive electrode of an external power source, and the negative terminal is used to connect to the negative electrode of the external power source and a ground connection terminal.

4. A motor, characterized in that: It comprises the shaft end structure for preventing bearing electrical corrosion as described in any one of claims 1 to 3, and also comprises a motor bracket and an external working piece, wherein the shaft end housing is mounted on the motor bracket and the external working piece is mounted on the output shaft.

5. A motor according to claim 4, characterized in that: The external working piece is provided with a connecting groove for connecting with the output shaft.

6. A motor according to claim 5, characterized in that: A fastener is provided in the connecting groove, and the fastener is interference-connected with the output shaft.

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