Shaft end connecting structure for preventing bearing electric corrosion and motor

Abstract

The application discloses a bearing electric corrosion prevention shaft end connecting structure and a motor. The bearing electric corrosion prevention shaft end connecting structure comprises an end cover, a rotating shaft, a bearing, a first conductive bearing, a conductive shaft, a second conductive bearing and a grounding fixing part. The rotating shaft is fixed on the end cover through the bearing. The conductive shaft is rotatably installed between the end part of the rotating shaft and the grounding fixing part through the first conductive bearing and the second conductive bearing. The diameters of the first conductive bearing and the second conductive bearing are smaller than the diameter of the bearing. The application adopts two conductive small bearings and a conductive shaft to solve the electric corrosion problem of the bearing, and also solves the coaxial problem among the bearing, the conductive bearing and the conductive shaft. The structure is simple, the cost is low, and the bearing is convenient to disassemble, assemble and maintain. The motor has the above advantages of the connecting structure, and has good running stability and long service life.

Description

Technical Field

[0001] This invention belongs to the field of drive motor technology, specifically relating to a shaft end connection structure and motor that prevents bearing electro-corrosion. Background Technology

[0002] Currently, passenger vehicle motor systems use PWM (Pulse Width Modulation) inverter systems to control motor operation. In a PWM inverter system, the common-mode voltage acts on the motor windings, forming a common-mode current path through coupling capacitors in the motor. Shaft current is a component of this common-mode current. Excessive shaft current can cause bearing electro-corrosion. When the bearing voltage between the inner and outer raceways rises to a certain level, exceeding the lubricating oil film threshold voltage, a breakdown discharge will occur. The short-circuit current generated by this discharge produces enormous heat in a short time, causing the metal near the breakdown point to melt. This leads to increasingly poor motor bearing performance, shortening bearing life. Prolonged shaft current can compromise the reliable operation of the motor. Furthermore, as the DC bus voltage increases, the shaft voltage also increases, increasing the probability of bearing electro-corrosion. Common solutions to this problem include using brushes to allow the shaft current to pass through the brushes instead of the bearing. However, brushes are prone to wear and require periodic replacement, which is difficult. Another solution is to use insulated bearings to prevent shaft current generation through discharge between the inner and outer raceways. However, insulated bearings are expensive and not widely adopted. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a shaft end connection structure and motor that is simple in structure, low in cost, and easy to disassemble and maintain to prevent bearing electro-corrosion.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A shaft end connection structure for preventing bearing electro-corrosion includes an end cover, a rotating shaft, a load-bearing bearing, a first conductive bearing, a conductive shaft, a second conductive bearing, and a grounding fixing part. The rotating shaft is fixed to the end cover by the load-bearing bearing. The conductive shaft is rotatably mounted between the end of the rotating shaft and the grounding fixing part by the first conductive bearing and the second conductive bearing. The diameters of the first conductive bearing and the second conductive bearing are both smaller than the diameter of the load-bearing bearing.

[0006] In the aforementioned anti-bearing electro-corrosion shaft end connection structure, preferably, the end of the rotating shaft is provided with a first mounting groove, the grounding fixing part is provided with a second mounting groove, the first conductive bearing is embedded in the first mounting groove, the second conductive bearing is embedded in the second mounting groove, and the two ends of the conductive shaft are respectively embedded in the first conductive bearing and the second conductive bearing.

[0007] In the aforementioned anti-bearing electro-corrosion shaft end connection structure, preferably, a wave spring is provided between the outer ring of the second conductive bearing and the bottom wall of the second mounting groove.

[0008] In the aforementioned anti-bearing electro-corrosion shaft end connection structure, preferably, the outer ring of the first conductive bearing is transition-fitted or interference-fitted with the inner wall of the first mounting groove, the inner ring of the first conductive bearing is clearance-fitted with the conductive shaft, the conductive shaft is interference-fitted with the inner ring of the second conductive bearing, and the outer ring of the second conductive bearing is transition-fitted with the inner wall of the second mounting groove.

[0009] Preferably, in the above-mentioned anti-bearing electro-corrosion shaft end connection structure, the end of the rotating shaft has a first mounting portion extending outward along the axis, and the grounding fixing portion has a second mounting portion extending in the direction of the rotating shaft. The first mounting portion is embedded in the first conductive bearing, the second mounting portion is embedded in the second conductive bearing, and the first conductive bearing and the second conductive bearing are respectively embedded at both ends of the conductive shaft.

[0010] Preferably, in the aforementioned anti-bearing electro-corrosion shaft end connection structure, the conductive shaft is in the form of a hollow sleeve.

[0011] In the aforementioned shaft end connection structure for preventing bearing electro-corrosion, preferably, the first mounting part is interference-fitted or transition-fitted with the inner ring of the first conductive bearing, the outer ring of the first conductive bearing is clearance-fitted with the conductive shaft, the conductive shaft is transition-fitted or clearance-fitted with the outer ring of the second conductive bearing, and the inner ring of the second conductive bearing is interference-fitted with the second mounting part.

[0012] In the aforementioned anti-bearing electro-corrosion shaft end connection structure, preferably, the end of the rotating shaft is provided with a first mounting groove, the grounding fixing part is provided with a second mounting part, the first conductive bearing is embedded in the first mounting groove, the first end of the conductive shaft is embedded in the first conductive bearing, the second conductive bearing is embedded in the second end of the conductive shaft, and the second mounting part is embedded in the second conductive bearing.

[0013] In the aforementioned anti-bearing electro-corrosion shaft end connection structure, preferably, the outer ring of the first conductive bearing is interference-fitted or transition-fitted with the inner sidewall of the first mounting groove, the inner ring of the first conductive bearing is clearance-fitted with the first end of the conductive shaft, the second end of the conductive shaft is interference-fitted with the outer ring of the second conductive bearing, and the inner ring of the second conductive bearing is clearance-fitted with the second mounting part.

[0014] Preferably, in the above-mentioned anti-bearing electro-corrosion shaft end connection structure, the end of the rotating shaft has a first mounting portion extending outward along the axis, the grounding fixing portion is provided with a second mounting groove, the first mounting portion is embedded in the first conductive bearing, the first conductive bearing is embedded in the first end of the conductive shaft, the second end of the conductive shaft is embedded in the second conductive bearing, and the second conductive bearing is embedded in the second mounting groove.

[0015] In the aforementioned anti-bearing electro-corrosion shaft end connection structure, preferably, a wave spring is provided between the outer ring of the second conductive bearing and the bottom wall of the second mounting groove.

[0016] In the aforementioned anti-bearing electro-corrosion shaft end connection structure, preferably, the first mounting part is interference-fitted or transition-fitted with the inner ring of the first conductive bearing, the outer ring of the first conductive bearing is clearance-fitted with the first end of the conductive shaft, the second end of the conductive shaft is interference-fitted with the inner ring of the second conductive bearing, and the outer ring of the second conductive bearing is clearance-fitted with the inner sidewall of the second mounting groove.

[0017] In the aforementioned anti-bearing electro-corrosion shaft end connection structure, preferably, the grounding fixing part is a junction box cover plate, which is fixed to the outside of the end cover and forms a closed conductive bearing chamber with the end cover.

[0018] As a general technical concept, the present invention also provides an electric motor, including the above-mentioned anti-bearing electro-corrosion shaft end connection structure, wherein the end cover includes a front end cover and a rear end cover, the front end of the rotating shaft extends out of the front end cover, the grounding fixing part is fixed to the outside of the front end cover, and the shaft end connection structure is located between the front end of the rotating shaft and the grounding fixing part.

[0019] Another implementation of the aforementioned motor is that the end cover includes a front end cover and a rear end cover, the rear end of the rotating shaft extends out of the rear end cover, the grounding fixing part is fixed to the outside of the rear end cover, and the shaft end connection structure is located between the rear end of the rotating shaft and the grounding fixing part.

[0020] Another implementation of the aforementioned motor is as follows: the end cover includes a front cover and a rear cover; the front end of the rotating shaft extends out of the front cover; the rear end of the rotating shaft extends out of the rear cover; there are two grounding fixing parts, which are respectively installed on the outside of the front cover and the rear cover; and there are two sets of shaft end connection structures, which are respectively installed on the front end and the rear end of the rotating shaft.

[0021] Explanation of relevant terms in this invention:

[0022] DC bus voltage: The voltage supplied by the battery to the electric drive system in the vehicle.

[0023] Load-bearing bearings: bearings that support the motor rotor to bear the radial and axial loads of the motor.

[0024] Conductive small bearing: refers to a bearing with a smaller diameter than the load bearing, used to conduct the shaft current of the rotor to the housing.

[0025] Compared with the prior art, the advantages of the present invention are as follows:

[0026] (1) The shaft end connection structure for preventing bearing electro-corrosion of the present invention adopts a scheme of two conductive small bearings and a conductive shaft for the first time, so as to guide the shaft current on the motor rotor to the ground through the two conductive small bearings and the conductive shaft, thereby avoiding bearing electro-corrosion caused by the shaft current in the bearing.

[0027] This invention utilizes the axial and radial clearance inherent in the bearing itself, allowing it to operate smoothly even with a certain degree of misalignment, thus preventing jamming due to bearing misalignment. It significantly reduces the coaxiality requirements of the load-bearing bearing, the first conductive bearing, the conductive shaft, and the second conductive bearing.

[0028] This invention utilizes the coupling relationship between two conductive small bearings to distribute the rotor speed to the two conductive small bearings. That is, the sum of the speed of the first conductive small bearing and the speed of the second conductive small bearing is equal to the speed of the motor rotor, thereby reducing the speed of the two conductive small bearings and making the bearings last longer.

[0029] When the motor is running, the rotor will have axial and radial movement. This invention uses a non-rigid connection structure with two conductive small bearings to ensure that even if the rotor has axial and radial movement, the two bearings can still run smoothly.

[0030] The shaft end connection structure for preventing bearing electro-corrosion of this invention is simple, low-cost, easy to install and disassemble, and convenient for subsequent maintenance and replacement.

[0031] (2) The motor of the present invention has the above-mentioned advantages of the connection structure because it is equipped with a shaft end connection structure that prevents bearing electro-corrosion. The connection structure can effectively prevent bearing electro-corrosion of the bearing, thereby improving the operating stability and service life of the motor. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the shaft end connection structure for preventing bearing electro-corrosion according to Embodiment 1 of the present invention.

[0033] Figure 2 This is a schematic diagram of the motor structure of Embodiment 1 of the present invention.

[0034] Figure 3 This is a schematic diagram of the shaft end connection structure for preventing bearing electro-corrosion according to Embodiment 2 of the present invention.

[0035] Figure 4 This is a schematic diagram of the motor structure of Embodiment 2 of the present invention.

[0036] Figure 5 This is a schematic diagram of the shaft end connection structure for preventing bearing electro-corrosion in Embodiment 3 of the present invention.

[0037] Figure 6 This is a schematic diagram of the motor structure in Embodiment 3 of the present invention.

[0038] Figure 7 This is a schematic diagram of the shaft end connection structure for preventing bearing electro-corrosion in Embodiment 4 of the present invention.

[0039] Figure 8 This is a schematic diagram of the motor structure in Embodiment 4 of the present invention.

[0040] Legend:

[0041] 1. Housing; 2. Stator; 3. Rotor; 4. Shaft; 41. First mounting slot; 42. First mounting part; 5. Bearing; 6. Front cover; 7. Rear cover; 8. Conductive bearing chamber; 9. First conductive bearing; 10. Conductive shaft; 11. Second conductive bearing; 12. Junction box cover; 121. Second mounting slot; 122. Second mounting part; 13. Wave spring. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0043] Example 1:

[0044] Figure 1 and Figure 2 An embodiment of the anti-bearing electro-corrosion shaft end connection structure of the present invention is shown, including an end cover, a rotating shaft 4, a bearing 5, a first conductive bearing 9, a conductive shaft 10, a second conductive bearing 11, and a grounding fixing part. The rotating shaft 4 is fixed to the end cover by the bearing 5. The conductive shaft 10 is rotatably mounted between the end of the rotating shaft 4 and the grounding fixing part by the first conductive bearing 9 and the second conductive bearing 11. The diameters of the first conductive bearing 9 and the second conductive bearing 11 are both smaller than the diameter of the bearing 5.

[0045] Taking an electric motor as a specific application example, the motor includes a housing 1, a stator 2, a rotor 3, a shaft 4, and end covers. The end covers include a front cover 6 and a rear cover 7, which are fixed to the housing 1. The two ends of the shaft 4 are respectively mounted on the front cover 6 and the rear cover 7 through two bearings 5. The rotor 3 is fixed on the shaft 4. The stator 2 is located on the outer periphery of the rotor 3. The shaft end connection structure that prevents bearing electro-corrosion is installed at the end of the shaft 4.

[0046] During motor operation, the first conductive bearing 9, the second conductive bearing 11, and the two load bearings 5 ​​(i.e., the front load bearing and the rear load bearing) are all on the rotor 3. The housing 1, the front cover 6, the rear cover 7, and the grounding fixing part are connected together as equipotential bodies. The motor housing is grounded. Therefore, the voltages between the first conductive bearing 9, the second conductive bearing 11, the front load bearing, and the rear load bearing, i.e., the bearing voltages, are equal. Because the diameters of the first conductive bearing 9 and the second conductive bearing 11 are smaller than those of the front and rear load bearings, under the same shaft voltage, the smaller conductive bearing (i.e., the first conductive bearing 9 and the second conductive bearing 11) is more prone to discharge. When discharge occurs in the smaller conductive bearing, the front and rear load bearings will not discharge, thus protecting the load bearing 5.

[0047] In this embodiment, the motor employs two small conductive bearings and a conductive shaft 10. This guides the shaft current on the motor rotor to ground via the two small conductive bearings and the conductive shaft 10, preventing electrical corrosion of the load-bearing bearing 5 due to shaft current. Because of the two small conductive bearings, which have axial and radial clearance, the bearings can operate smoothly even with a certain degree of misalignment, avoiding jamming due to misalignment. This reduces the coaxiality requirements of the load-bearing bearing, the first conductive bearing, the conductive shaft, and the second conductive bearing.

[0048] By utilizing the coupling relationship between two conductive small bearings, the rotor speed can be distributed to both bearings. Specifically, the sum of the speeds of the first conductive small bearing 9 and the second conductive small bearing 11 equals the rotor speed, thus reducing the speeds of the two bearings and extending their lifespan. Because the outer ring of the first conductive bearing 9 is fitted to the shaft 4, the rotor speed is the same as the outer ring speed. When the speed of the outer ring of the first conductive bearing 9 is transmitted to the inner ring through the balls, the inner ring speed will be lower than the outer ring speed. The inner ring of the first conductive bearing 9 is assembled with the conductive shaft 10, and both rotate at the same speed. The conductive shaft 10 is assembled with the inner ring of the second conductive bearing 11, and both rotate at the same speed.

[0049] When the motor is running, the rotor will have axial and radial movement. This invention uses a non-rigid connection structure with two conductive small bearings to ensure that even if the rotor has axial and radial movement, the two bearings can still run smoothly.

[0050] In this embodiment, the end of the rotating shaft 4 is provided with a first mounting groove 41, the grounding fixing part is provided with a second mounting groove 121, the first conductive bearing 9 is embedded in the first mounting groove 41, the second conductive bearing 11 is embedded in the second mounting groove 121, and the two ends of the conductive shaft 10 are respectively embedded in the first conductive bearing 9 and the second conductive bearing 11.

[0051] In this embodiment, to prevent the conductive small bearing from shifting during operation, a wave spring 13 is provided between the outer ring of the second conductive bearing 11 and the bottom wall of the second mounting groove 121 to pre-tighten the second conductive bearing 11.

[0052] To facilitate installation and disassembly, in this embodiment, the outer ring of the first conductive bearing 9 is fitted with the inner wall of the first mounting groove 41 in a transition fit. Of course, in other embodiments, an interference fit can also be used. In this embodiment, the inner ring of the first conductive bearing 9 is fitted with the conductive shaft 10 in a clearance fit, the conductive shaft 10 is fitted with the inner ring of the second conductive bearing 11 in an interference fit, and the outer ring of the second conductive bearing 11 is fitted with the inner wall of the second mounting groove 121 in a transition fit.

[0053] In this embodiment, the grounding fixing part is the junction box cover plate 12, which is fixed on the outside of the end cover and forms a closed conductive bearing chamber 8 with the end cover.

[0054] Two small conductive bearings and a conductive shaft 10 are installed in the conductive bearing chamber 8 on the outside of the motor end cover. The space is independent, which facilitates installation, disassembly and subsequent maintenance and replacement.

[0055] In other embodiments, the grounding fixing part can also be a fixing bracket installed inside the motor housing, which is grounded, resulting in high overall space utilization of the motor.

[0056] During installation, the first conductive bearing 9 is first assembled in the rotating shaft 4, then the conductive shaft 10 and the second conductive bearing 11 are assembled together and then assembled together with the junction box cover plate 12, and finally the conductive shaft 10 is assembled together with the inner ring of the first conductive bearing 9.

[0057] The shaft end connection structure for preventing bearing electro-corrosion in this embodiment is simple, low-cost, easy to install and disassemble, and convenient for subsequent maintenance and replacement.

[0058] An electric motor includes the bearing electro-corrosion prevention shaft end connection structure described in this embodiment. The rear end of the rotating shaft 4 extends out of the rear end cover 7, and the junction box cover 12 is fixed to the outside of the rear end cover 7. The shaft end connection structure is located between the rear end of the rotating shaft 4 and the junction box cover 12.

[0059] The motor of the present invention has the advantages of the shaft end connection structure that prevents bearing electro-corrosion, and the shaft end connection structure can effectively prevent bearing electro-corrosion of the bearing 5, thereby improving the operating stability and service life of the motor.

[0060] In other embodiments, the shaft end connection structure for preventing bearing electro-corrosion can also be set at the front end of the rotating shaft 4. Specifically, the front end of the rotating shaft 4 extends out of the front end cover 6, the junction box cover 12 is fixed on the outside of the front end cover 6, and the shaft end connection structure is located between the front end of the rotating shaft 4 and the junction box cover 12.

[0061] In other embodiments, anti-bearing electro-corrosion shaft end connection structures can also be provided at both the front and rear ends of the rotating shaft 4.

[0062] Example 2:

[0063] Figure 3 and Figure 4 An embodiment of the shaft end connection structure for preventing bearing electro-corrosion of the present invention is shown, including an end cover, a rotating shaft 4, a load-bearing bearing 5, a first conductive bearing 9, a conductive shaft 10, a second conductive bearing 11, and a grounding fixing part. The rotating shaft 4 is fixed to the end cover by the load-bearing bearing 5. The conductive shaft 10 is rotatably mounted between the end of the rotating shaft 4 and the grounding fixing part by the first conductive bearing 9 and the second conductive bearing 11. The diameters of the first conductive bearing 9 and the second conductive bearing 11 are both smaller than the diameter of the load-bearing bearing 5.

[0064] Taking an electric motor as a specific application example, the motor includes a housing 1, a stator 2, a rotor 3, a shaft 4, and end covers. The end covers include a front cover 6 and a rear cover 7, which are fixed to the housing 1. The two ends of the shaft 4 are respectively mounted on the front cover 6 and the rear cover 7 through two bearings 5. The rotor 3 is fixed on the shaft 4. The stator 2 is located on the outer periphery of the rotor 3. The shaft end connection structure that prevents bearing electro-corrosion is installed at the end of the shaft 4.

[0065] During motor operation, the first conductive bearing 9, the second conductive bearing 11, and the two load-bearing bearings 5 ​​(i.e., the front load-bearing bearing and the rear load-bearing bearing) are all on the rotor 3. The housing 1, the front cover 6, the rear cover 7, and the grounding fixing part are connected together as equipotential bodies. The motor housing is grounded. Therefore, the voltages between the first conductive bearing 9, the second conductive bearing 11, the front load-bearing bearing, and the rear load-bearing bearing, i.e., the bearing voltages, are equal. Because the diameters of the first conductive bearing 9 and the second conductive bearing 11 are smaller than those of the front and rear load-bearing bearings, under the same shaft voltage, the smaller conductive bearing is more prone to discharge. When discharge occurs in the smaller conductive bearing, the front and rear load-bearing bearings will not discharge, thus protecting the load-bearing bearing 5.

[0066] In this embodiment, the motor employs two small conductive bearings and a conductive shaft 10. This guides the shaft current on the motor rotor to ground via the two small conductive bearings and the conductive shaft 10, preventing electrical corrosion of the load-bearing bearing 5 due to shaft current. Because of the two small conductive bearings, which have axial and radial clearance, the bearings can operate smoothly even with a certain degree of misalignment, avoiding jamming due to misalignment. This reduces the coaxiality requirements of the load-bearing bearing, the first conductive bearing, the conductive shaft, and the second conductive bearing.

[0067] By utilizing the coupling relationship between the two conductive small bearings, the rotor speed can be distributed to the two conductive small bearings. That is, the sum of the speed of the first conductive small bearing 9 and the speed of the second conductive small bearing 11 is equal to the speed of the motor rotor, thereby reducing the speed of the two conductive small bearings and making the bearings last longer.

[0068] When the motor is running, the rotor will have axial and radial movement. This invention uses a non-rigid connection structure with two conductive small bearings to ensure that even if the rotor has axial and radial movement, the two bearings can still run smoothly.

[0069] In this embodiment, the rear end of the rotating shaft 4 has a first mounting portion 42 extending outward along the axis, and the grounding fixing portion has a second mounting portion 122 extending towards the rear end cover 7. The first mounting portion 42 is embedded in the first conductive bearing 9, and the second mounting portion 122 is embedded in the second conductive bearing 11. The first conductive bearing 9 and the second conductive bearing 11 are respectively embedded at both ends of the conductive shaft 10.

[0070] In this embodiment, the conductive shaft 10 is a hollow sleeve, which is beneficial for the lightweight design of the conductive shaft 10 and can also save costs. Of course, in other embodiments, the conductive shaft 10 can also be a non-hollow cylinder with grooves at both ends. The first conductive bearing 9 and the second conductive bearing 11 are respectively embedded in the grooves at both ends of the conductive shaft 10.

[0071] In this embodiment, the first mounting part 42 is interference-fitted with the inner ring of the first conductive bearing 9. Of course, in other embodiments, a transition fit can also be used. In this embodiment, the outer ring of the first conductive bearing 9 is clearance-fitted with the conductive shaft 10, and the conductive shaft 10 is transition-fitted with the outer ring of the second conductive bearing 11. In other embodiments, a clearance fit can also be used. In this embodiment, the inner ring of the second conductive bearing 11 is interference-fitted with the second mounting part 122.

[0072] In this embodiment, the grounding fixing part is the junction box cover plate 12, which is fixed on the outside of the end cover and forms a closed conductive bearing chamber 8 with the end cover.

[0073] Two small conductive bearings and a conductive shaft 10 are installed in the conductive bearing chamber 8 on the outside of the motor end cover. The space is independent, which facilitates installation, disassembly and subsequent maintenance and replacement.

[0074] During installation, the first conductive bearing 9 is first assembled on the first mounting part 42 at the rear end of the rotating shaft 4, then the junction box cover plate 12 is assembled with the second conductive bearing 11 and then assembled with the conductive shaft 10, and finally the conductive shaft 10 is assembled with the outer ring of the first conductive bearing 9.

[0075] The shaft end connection structure for preventing bearing electro-corrosion in this embodiment is simple, low-cost, easy to install and disassemble, and convenient for subsequent maintenance and replacement.

[0076] An electric motor includes the bearing electro-corrosion prevention shaft end connection structure described in this embodiment. The rear end of the rotating shaft 4 extends out of the rear end cover 7, and the junction box cover 12 is fixed to the outside of the rear end cover 7. The shaft end connection structure is located between the rear end of the rotating shaft 4 and the junction box cover 12.

[0077] The motor of the present invention has the advantages of the shaft end connection structure that prevents bearing electro-corrosion, and the connection structure can effectively prevent bearing electro-corrosion of the bearing 5, thereby improving the operating stability and service life of the motor.

[0078] In other embodiments, the shaft end connection structure for preventing bearing electro-corrosion can also be set at the front end of the rotating shaft 4. Specifically, the front end of the rotating shaft 4 extends out of the front end cover 6, the junction box cover 12 is fixed on the outside of the front end cover 6, and the shaft end connection structure is located between the front end of the rotating shaft 4 and the junction box cover 12.

[0079] In other embodiments, anti-bearing electro-corrosion shaft end connection structures can also be provided at both the front and rear ends of the rotating shaft 4.

[0080] Example 3:

[0081] Figure 5 and Figure 6 An embodiment of the anti-bearing electro-corrosion shaft end connection structure of the present invention is shown, including an end cover, a rotating shaft 4, a bearing 5, a first conductive bearing 9, a conductive shaft 10, a second conductive bearing 11, and a grounding fixing part. The rotating shaft 4 is fixed to the end cover by the bearing 5. The conductive shaft 10 is rotatably mounted between the end of the rotating shaft 4 and the grounding fixing part by the first conductive bearing 9 and the second conductive bearing 11. The diameters of the first conductive bearing 9 and the second conductive bearing 11 are both smaller than the diameter of the bearing 5.

[0082] Taking an electric motor as a specific application example, the motor includes a housing 1, a stator 2, a rotor 3, a shaft 4, and end covers. The end covers include a front cover 6 and a rear cover 7, which are fixed to the housing 1. The two ends of the shaft 4 are respectively mounted on the front cover 6 and the rear cover 7 through two bearings 5. The rotor 3 is fixed on the shaft 4. The stator 2 is located on the outer periphery of the rotor 3. The shaft end connection structure that prevents bearing electro-corrosion is installed at the end of the shaft 4.

[0083] During motor operation, the first conductive bearing 9, the second conductive bearing 11, and the two load-bearing bearings 5 ​​(i.e., the front load-bearing bearing and the rear load-bearing bearing) are all on the rotor 3. The housing 1, the front cover 6, the rear cover 7, and the grounding fixing part are connected together as equipotential bodies. The motor housing is grounded. Therefore, the voltages between the first conductive bearing 9, the second conductive bearing 11, the front load-bearing bearing, and the rear load-bearing bearing, i.e., the bearing voltages, are equal. Because the diameters of the first conductive bearing 9 and the second conductive bearing 11 are smaller than those of the front and rear load-bearing bearings, under the same shaft voltage, the smaller conductive bearing is more prone to discharge. When discharge occurs in the smaller conductive bearing, the front and rear load-bearing bearings will not discharge, thus protecting the load-bearing bearing 5.

[0084] In this embodiment, the motor employs two small conductive bearings and a conductive shaft 10. This guides the shaft current on the motor rotor to ground via the two small conductive bearings and the conductive shaft 10, preventing electrical corrosion of the load-bearing bearing 5 due to shaft current. Because of the two small conductive bearings, which have axial and radial clearance, the bearings can operate smoothly even with a certain degree of misalignment, avoiding jamming due to misalignment. This reduces the coaxiality requirements of the load-bearing bearing, the first conductive bearing, the conductive shaft, and the second conductive bearing.

[0085] By utilizing the coupling relationship between the two conductive small bearings, the rotor speed can be distributed to the two conductive small bearings. That is, the sum of the speed of the first conductive small bearing 9 and the speed of the second conductive small bearing 11 is equal to the speed of the motor rotor, thereby reducing the speed of the two conductive small bearings and making the bearings last longer.

[0086] When the motor is running, the rotor will have axial and radial movement. This invention uses a non-rigid connection structure with two conductive small bearings to ensure that even if the rotor has axial and radial movement, the two bearings can still run smoothly.

[0087] In this embodiment, the end of the rotating shaft 4 is provided with a first mounting groove 41, the grounding fixing part is provided with a second mounting part 122, the first conductive bearing 9 is embedded in the first mounting groove 41, the first end of the conductive shaft 10 is embedded in the first conductive bearing 9, the second conductive bearing 11 is embedded in the second end of the conductive shaft 10, and the second mounting part 122 is embedded in the second conductive bearing 11.

[0088] In this embodiment, the outer ring of the first conductive bearing 9 is interference-fitted with the inner wall of the first mounting groove 41. In other embodiments, a transition fit can also be used. In this embodiment, the inner ring of the first conductive bearing 9 is clearance-fitted with the first end of the conductive shaft 10, the second end of the conductive shaft 10 is interference-fitted with the outer ring of the second conductive bearing 11, and the inner ring of the second conductive bearing 11 is clearance-fitted with the second mounting part 122.

[0089] In this embodiment, the grounding fixing part is the junction box cover plate 12, which is fixed on the outside of the end cover and forms a closed conductive bearing chamber 8 with the end cover.

[0090] Two small conductive bearings and a conductive shaft 10 are installed in the conductive bearing chamber 8 on the outside of the motor end cover. The space is independent, which facilitates installation, disassembly and subsequent maintenance and replacement.

[0091] During installation, the first conductive bearing 9 is first assembled into the first mounting groove 41 at the rear end of the rotating shaft 10, the conductive shaft 10 is assembled with the outer ring of the second conductive bearing 11, the junction box cover 12 is assembled with the second conductive bearing 11 and the conductive shaft 10, and finally the inner ring of the first conductive bearing 9 is installed.

[0092] The shaft end connection structure for preventing bearing electro-corrosion in this embodiment is simple, low-cost, easy to install and disassemble, and convenient for subsequent maintenance and replacement.

[0093] An electric motor includes the bearing electro-corrosion prevention shaft end connection structure described in this embodiment. The rear end of the rotating shaft 4 extends out of the rear end cover 7, and the junction box cover 12 is fixed to the outside of the rear end cover 7. The shaft end connection structure is located between the rear end of the rotating shaft 4 and the junction box cover 12.

[0094] The motor of the present invention has the advantages of the shaft end connection structure that prevents bearing electro-corrosion, and the shaft end connection structure can effectively prevent bearing electro-corrosion of the bearing 5, thereby improving the operating stability and service life of the motor.

[0095] In other embodiments, the shaft end connection structure for preventing bearing electro-corrosion can also be set at the front end of the rotating shaft 4. Specifically, the front end of the rotating shaft 4 extends out of the front end cover 6, the junction box cover 12 is fixed on the outside of the front end cover 6, and the shaft end connection structure is located between the front end of the rotating shaft 4 and the junction box cover 12.

[0096] In other embodiments, anti-bearing electro-corrosion shaft end connection structures can also be provided at both the front and rear ends of the rotating shaft 4.

[0097] Example 4:

[0098] Figure 7 and Figure 8 An embodiment of the shaft end connection structure for preventing bearing electro-corrosion of the present invention is shown, including an end cover, a rotating shaft 4, a load-bearing bearing 5, a first conductive bearing 9, a conductive shaft 10, a second conductive bearing 11, and a grounding fixing part. The rotating shaft 4 is fixed to the end cover by the load-bearing bearing 5. The conductive shaft 10 is rotatably mounted between the end of the rotating shaft 4 and the grounding fixing part by the first conductive bearing 9 and the second conductive bearing 11. The diameters of the first conductive bearing 9 and the second conductive bearing 11 are both smaller than the diameter of the load-bearing bearing 5.

[0099] Taking an electric motor as a specific application example, the motor includes a housing 1, a stator 2, a rotor 3, a shaft 4, and end covers. The end covers include a front cover 6 and a rear cover 7, which are fixed to the housing 1. The two ends of the shaft 4 are respectively mounted on the front cover 6 and the rear cover 7 through two bearings 5. The rotor 3 is fixed on the shaft 4. The stator 2 is located on the outer periphery of the rotor 3. The shaft end connection structure that prevents bearing electro-corrosion is installed at the end of the shaft 4.

[0100] During motor operation, the first conductive bearing 9, the second conductive bearing 11, and the two load-bearing bearings 5 ​​(i.e., the front load-bearing bearing and the rear load-bearing bearing) are all on the rotor 3. The housing 1, the front cover 6, the rear cover 7, and the grounding fixing part are connected together as equipotential bodies. The motor housing is grounded. Therefore, the voltages between the first conductive bearing 9, the second conductive bearing 11, the front load-bearing bearing, and the rear load-bearing bearing, i.e., the bearing voltages, are equal. Because the diameters of the first conductive bearing 9 and the second conductive bearing 11 are smaller than those of the front and rear load-bearing bearings, under the same shaft voltage, the smaller conductive bearing is more prone to discharge. When discharge occurs in the smaller conductive bearing, the front and rear load-bearing bearings will not discharge, thus protecting the load-bearing bearing 5.

[0101] In this embodiment, the motor employs two small conductive bearings and a conductive shaft 10. This guides the shaft current on the motor rotor to ground via the two small conductive bearings and the conductive shaft 10, preventing electrical corrosion of the load-bearing bearing 5 due to shaft current. Because of the two small conductive bearings, which have axial and radial clearance, the bearings can operate smoothly even with a certain degree of misalignment, avoiding jamming due to misalignment. This reduces the coaxiality requirements of the load-bearing bearing, the first conductive bearing, the conductive shaft, and the second conductive bearing.

[0102] By utilizing the coupling relationship between the two conductive small bearings, the rotor speed can be distributed to the two conductive small bearings. That is, the sum of the speed of the first conductive small bearing 9 and the speed of the second conductive small bearing 11 is equal to the speed of the motor rotor, thereby reducing the speed of the two conductive small bearings and making the bearings last longer.

[0103] When the motor is running, the rotor will have axial and radial movement. This invention uses a non-rigid connection structure with two conductive small bearings to ensure that even if the rotor has axial and radial movement, the two bearings can still run smoothly.

[0104] In this embodiment, the rear end of the rotating shaft 4 has a first mounting part 42 extending outward along the axis, and the grounding fixing part is provided with a second mounting groove 121. The first mounting part 42 is embedded in the first conductive bearing 9, the first conductive bearing 9 is embedded in the first end of the conductive shaft 10, the second end of the conductive shaft 10 is embedded in the second conductive bearing 11, and the second conductive bearing 11 is embedded in the second mounting groove 121.

[0105] In this embodiment, to prevent the conductive small bearing from shifting during operation, a wave spring 13 is installed between the outer ring of the second conductive bearing 11 and the bottom wall of the second mounting groove 121 to pre-tighten the second conductive bearing 11.

[0106] To facilitate installation and disassembly, in this embodiment, the first mounting part 42 is interference-fitted with the inner ring of the first conductive bearing 9. In other embodiments, a transition fit can also be used. In this embodiment, the outer ring of the first conductive bearing 9 is clearance-fitted with the first end of the conductive shaft 10, the second end of the conductive shaft 10 is interference-fitted with the inner ring of the second conductive bearing 11, and the outer ring of the second conductive bearing 11 is clearance-fitted with the inner sidewall of the second mounting groove 121.

[0107] In this embodiment, the grounding fixing part is the junction box cover plate 12, which is fixed on the outside of the end cover and forms a closed conductive bearing chamber 8 with the end cover.

[0108] Two small conductive bearings and a conductive shaft 10 are installed in the conductive bearing chamber 8 on the outside of the motor end cover. The space is independent, which facilitates installation, disassembly and subsequent maintenance and replacement.

[0109] During installation, the first conductive bearing 9 is first assembled on the first mounting part 42 at the rear end of the rotating shaft 4, the conductive shaft 10 is assembled with the inner ring of the second conductive bearing 11, and then the junction box cover 12, the wave spring 13 and the conductive small bearing 2 are assembled together.

[0110] The shaft end connection structure for preventing bearing electro-corrosion in this embodiment is simple, low-cost, easy to install and disassemble, and convenient for subsequent maintenance and replacement.

[0111] An electric motor includes the bearing electro-corrosion prevention shaft end connection structure described in this embodiment. The rear end of the rotating shaft 4 extends out of the rear end cover 7, and the junction box cover 12 is fixed to the outside of the rear end cover 7. The shaft end connection structure is located between the rear end of the rotating shaft 4 and the junction box cover 12.

[0112] The motor of the present invention has the advantages of the shaft end connection structure that prevents bearing electro-corrosion, and the shaft end connection structure can effectively prevent bearing electro-corrosion of the bearing 5, thereby improving the operating stability and service life of the motor.

[0113] In other embodiments, the shaft end connection structure for preventing bearing electro-corrosion can also be set at the front end of the rotating shaft 4. Specifically, the front end of the rotating shaft 4 extends out of the front end cover 6, the junction box cover 12 is fixed on the outside of the front end cover 6, and the shaft end connection structure is located between the front end of the rotating shaft 4 and the junction box cover 12.

[0114] In other embodiments, anti-bearing electro-corrosion shaft end connection structures can also be provided at both the front and rear ends of the rotating shaft 4.

[0115] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. The technical features involved in the various embodiments of the present invention described above can be combined with each other as long as they do not conflict with each other. All technical solutions within the scope of the present invention's concept are within the protection scope of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should be considered within the protection scope of the present invention.

Claims

1. A shaft end connection structure for preventing bearing electro-corrosion, characterized in that: The device includes an end cap, a rotating shaft (4), a load-bearing bearing (5), a first conductive bearing (9), a conductive shaft (10), a second conductive bearing (11), and a grounding fixing part. The rotating shaft (4) is fixed to the end cap by the load-bearing bearing (5). The conductive shaft (10) is rotatably mounted between the end of the rotating shaft (4) and the grounding fixing part by the first conductive bearing (9) and the second conductive bearing (11). The diameters of the first conductive bearing (9) and the second conductive bearing (11) are both smaller than the diameter of the load-bearing bearing (5).

2. The shaft end connection structure for preventing bearing electro-corrosion according to claim 1, characterized in that: The end of the rotating shaft (4) is provided with a first mounting groove (41), and the grounding fixing part is provided with a second mounting groove (121). The first conductive bearing (9) is embedded in the first mounting groove (41), and the second conductive bearing (11) is embedded in the second mounting groove (121). The two ends of the conductive shaft (10) are respectively embedded in the first conductive bearing (9) and the second conductive bearing (11).

3. The shaft end connection structure for preventing bearing electro-corrosion according to claim 2, characterized in that: A wave spring (13) is provided between the outer ring of the second conductive bearing (11) and the bottom wall of the second mounting groove (121); And / or, the outer ring of the first conductive bearing (9) is transition-fitted or interference-fitted with the inner wall of the first mounting groove (41), the inner ring of the first conductive bearing (9) is clearance-fitted with the conductive shaft (10), the conductive shaft (10) is interference-fitted with the inner ring of the second conductive bearing (11), and the outer ring of the second conductive bearing (11) is transition-fitted with the inner wall of the second mounting groove (121).

4. The shaft end connection structure for preventing bearing electro-corrosion according to claim 1, characterized in that: The end of the rotating shaft (4) has a first mounting portion (42) extending outward along the axis, and the grounding fixing portion has a second mounting portion (122) extending in the direction of the rotating shaft (4). The first mounting portion (42) is embedded in the first conductive bearing (9), and the second mounting portion (122) is embedded in the second conductive bearing (11). The first conductive bearing (9) and the second conductive bearing (11) are respectively embedded at both ends of the conductive shaft (10).

5. The shaft end connection structure for preventing bearing electro-corrosion according to claim 4, characterized in that: The conductive shaft (10) is in the shape of a hollow sleeve; And / or, the first mounting part (42) is interference-fitted or transition-fitted with the inner ring of the first conductive bearing (9), the outer ring of the first conductive bearing (9) is clearance-fitted with the conductive shaft (10), the conductive shaft (10) is transition-fitted or clearance-fitted with the outer ring of the second conductive bearing (11), and the inner ring of the second conductive bearing (11) is interference-fitted with the second mounting part (122).

6. The shaft end connection structure for preventing bearing electro-corrosion according to claim 1, characterized in that: The end of the rotating shaft (4) is provided with a first mounting groove (41), and the grounding fixing part is provided with a second mounting part (122). The first conductive bearing (9) is embedded in the first mounting groove (41), the first end of the conductive shaft (10) is embedded in the first conductive bearing (9), the second conductive bearing (11) is embedded in the second end of the conductive shaft (10), and the second mounting part (122) is embedded in the second conductive bearing (11).

7. The shaft end connection structure for preventing bearing electro-corrosion according to claim 6, characterized in that: The outer ring of the first conductive bearing (9) is press-fitted or transition-fitted with the inner wall of the first mounting groove (41), the inner ring of the first conductive bearing (9) is clearance-fitted with the first end of the conductive shaft (10), the second end of the conductive shaft (10) is press-fitted with the outer ring of the second conductive bearing (11), and the inner ring of the second conductive bearing (11) is clearance-fitted with the second mounting part (122).

8. The shaft end connection structure for preventing bearing electro-corrosion according to claim 1, characterized in that: The end of the rotating shaft (4) has a first mounting part (42) extending outward along the axis, and the grounding fixing part is provided with a second mounting groove (121). The first mounting part (42) is embedded in the first conductive bearing (9), the first conductive bearing (9) is embedded in the first end of the conductive shaft (10), the second end of the conductive shaft (10) is embedded in the second conductive bearing (11), and the second conductive bearing (11) is embedded in the second mounting groove (121).

9. The shaft end connection structure for preventing bearing electro-corrosion according to claim 8, characterized in that: A wave spring (13) is provided between the outer ring of the second conductive bearing (11) and the bottom wall of the second mounting groove (121); And / or, the first mounting part (42) is interference-fitted or transition-fitted with the inner ring of the first conductive bearing (9), the outer ring of the first conductive bearing (9) is clearance-fitted with the first end of the conductive shaft (10), the second end of the conductive shaft (10) is interference-fitted with the inner ring of the second conductive bearing (11), and the outer ring of the second conductive bearing (11) is clearance-fitted with the inner wall of the second mounting groove (121).

10. The shaft end connection structure for preventing bearing electro-corrosion according to any one of claims 1 to 9, characterized in that: The grounding fixing part is a junction box cover (12), which is fixed to the outside of the end cover and forms a closed conductive bearing chamber (8) with the end cover.

11. An electric motor, characterized in that, The shaft end connection structure for preventing bearing electro-corrosion as described in any one of claims 1 to 10 includes a front end cover (6) and a rear end cover (7), the front end of the rotating shaft (4) extends out of the front end cover (6), the grounding fixing part is fixed to the outside of the front end cover (6), and the shaft end connection structure is located between the front end of the rotating shaft (4) and the grounding fixing part; And / or, the end cap includes a front end cap (6) and a rear end cap (7), the rear end of the rotating shaft (4) extends out of the rear end cap (7), the grounding fixing part is fixed to the outside of the rear end cap (7), and the shaft end connection structure is located between the rear end of the rotating shaft (4) and the grounding fixing part.

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