A structure for reducing shaft electro corrosion

Abstract

The application relates to the technical field of motors, in particular to a structure for reducing shaft electric corrosion, which comprises a conductive wear-resistant ring, the conductive wear-resistant ring is sleeved and fixed to the outer wall of a rotating shaft; an elastic friction piece is attached to the side of the conductive wear-resistant ring away from the rotating shaft, a plurality of wave crests are arranged on the side of the elastic friction piece away from the conductive wear-resistant ring, and the wave crests abut against the inner wall of a motor shell. The application has the possible effect of reducing shaft electric corrosion.

Description

Technical Field

[0001] This application relates to the technical field of electric motors, and in particular to a structure for reducing axial electrical corrosion. Background Technology

[0002] Permanent magnet synchronous motors, as one of the core components of new energy vehicles, account for over 70% of the market and play a crucial role in improving vehicle performance and energy efficiency. However, with the widespread adoption of frequency conversion technology, shaft current issues caused by high-frequency common-mode voltage have become a key factor affecting motor reliability and lifespan. This problem not only exacerbates bearing electrochemical corrosion but also triggers a series of issues such as noise, vibration, and harshness (NVH), severely impacting user experience and equipment performance.

[0003] To address the problem of bearing electro-corrosion caused by shaft current, various solutions have been proposed in the industry. Common methods include using insulated bearings to isolate shaft current, employing annular carbon brushes for radial current conduction, and using elastic conductive sheets to press against the bearing inner ring to create a current conduction path. Specifically, insulated bearings achieve shaft current isolation through ceramic coatings or other non-conductive materials; annular carbon brushes provide a current conduction path through radial contact with the shaft; and rolling bearing current conduction solutions utilize elastic conductive sheets to press against the bearing inner ring to achieve current diversion.

[0004] However, all of the above solutions have their own drawbacks. Although insulated bearings can effectively isolate shaft current, their high cost limits the possibility of large-scale application. Annular carbon brushes are prone to poor contact or failure in high-temperature and oily environments. Rolling bearing current guiding solutions may lead to localized electrical load concentration due to uneven force applied by the elastic conductive sheet, which may further aggravate bearing wear. Utility Model Content

[0005] To reduce the possibility of axial electrical corrosion, this application provides a structure that reduces axial electrical corrosion.

[0006] This application provides a structure for reducing axial electrical corrosion, employing the following technical solution:

[0007] A structure for reducing axial electrical corrosion includes:

[0008] A conductive wear-resistant ring is fitted and fixed to the outer wall of the rotating shaft;

[0009] The elastic friction element is in contact with the side of the conductive wear-resistant ring away from the rotating shaft. The side of the elastic friction element away from the conductive wear-resistant ring has multiple peaks, which abut against the inner wall of the motor housing.

[0010] By adopting the above technical solution, the elastic friction plate provides axial pressure to ensure reliable contact between the conductive wear-resistant ring and the friction plate, thereby providing a reliable axial current conduction path. The structure is simple, easy to install and replace, has good dynamic conductivity, and the dynamic contact is a surface contact, ensuring a small dynamic contact resistance.

[0011] Optionally, a ventilation groove is provided on the side of the conductive wear-resistant ring near the elastic friction element, and the ventilation groove is distributed circumferentially along the guide wear-resistant ring.

[0012] By adopting the above technical solutions, the heat generated during the friction process can be dissipated in a timely manner, reducing the possibility of excessively high local temperatures leading to a decline in material performance. This reduces wear caused by thermal effects, such as adhesive wear and thermal fatigue wear, thereby improving service life.

[0013] Optionally, the ventilation groove extends through the inner and outer ring walls of the conductive wear-resistant ring.

[0014] By adopting the above technical solution, the inner wall and outer wall of the conductive wear-resistant ring are connected, further improving the heat dissipation efficiency.

[0015] Optionally, the elastic friction element includes an annular friction plate and a wave-shaped elastic element. One side of the annular friction plate is connected to the wave-shaped elastic element, which is annular with a wave crest. The side of the annular friction plate away from the wave-shaped elastic element is attached to a conductive wear-resistant sheet, and the side of the wave-shaped elastic element away from the annular friction plate abuts against the inner wall of the motor housing.

[0016] By adopting the above technical solution, under the elastic force of the waveform elastic element, the annular friction plate and the conductive wear-resistant ring are tightly bonded, thereby improving the surface contact stability and enabling the shaft current to be stably discharged.

[0017] Optionally, the inner ring diameter of the conductive wear-resistant ring is larger than the inner ring diameter of the annular friction plate.

[0018] By adopting the above technical solution, the hot air on the outer wall of the shaft can flow out through the inner wall of the annular friction plate and the ventilation groove, thereby further improving the heat dissipation efficiency.

[0019] Optionally, the wave-shaped elastic element is made of beryllium copper.

[0020] By adopting the above technical solutions, beryllium copper has high strength, high hardness, and good elastic limit, fatigue limit, and wear resistance, while also possessing good corrosion resistance, thermal conductivity, and electrical conductivity.

[0021] Optionally, the conductive wear-resistant ring is made of graphite material.

[0022] By adopting the above technical solution, graphite has good self-lubricating properties. In its crystal structure, carbon atoms are arranged in layers, and the bonding force between layers is weak, making it easy for relative sliding to occur. During the friction process, a lubricating film can be formed on the friction surface, thereby reducing the coefficient of friction and reducing wear. Secondly, it is inexpensive. Compared with conductive fibers, commonly used metals and conductive materials such as graphite are cheaper and have simpler manufacturing processes.

[0023] Optionally, the side of the elastic friction element closest to the conductive wear-resistant ring is plated with a wear-resistant metal coating.

[0024] By adopting the above technical solutions, the wear of the conductive wear-resistant ring can be slowed down, and its service life can be improved.

[0025] In summary, this application includes at least one of the following beneficial technical effects:

[0026] 1. The elastic friction pad provides axial pressure to ensure reliable contact between the conductive wear-resistant ring and the friction pad, thereby providing a reliable axial current conduction path. It has a simple structure, is easy to install and replace, has good dynamic conductivity, and the dynamic contact is a surface contact, ensuring a small dynamic contact resistance.

[0027] 2. Dissipate the heat generated during friction in a timely manner to reduce the possibility of excessive local temperature leading to a decline in material performance, thereby reducing wear caused by thermal effects, such as adhesive wear and thermal fatigue wear, and improving service life;

[0028] 3. Graphite has good self-lubricating properties. In its crystal structure, carbon atoms are arranged in layers, and the bonding force between the layers is weak, making it easy for relative sliding to occur. During the friction process, a lubricating film can be formed on the friction surface, thereby reducing the coefficient of friction and reducing wear. Secondly, it is inexpensive. Compared with conductive fibers, commonly used metals, conductive materials such as graphite are cheaper and have simpler manufacturing processes. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure in an embodiment of this application.

[0030] Figure 2 yes Figure 1 Enlarged view of point A in the middle.

[0031] Figure 3 This is a schematic diagram of the conductive wear-resistant ring and elastic friction element in Embodiment 1 of this application.

[0032] Figure 4 This is a schematic diagram of the conductive wear-resistant ring and elastic friction element in Embodiment 2 of this application.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1. Conductive wear-resistant ring; 11. Ventilation slot; 2. Shaft; 3. Motor housing; 4. Annular friction plate; 5. Waveform elastic element. Detailed Implementation

[0035] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0036] This application discloses a structure for reducing axial electrical corrosion.

[0037] Example 1

[0038] Reference Figure 1 and Figure 2 A structure for reducing axial electrical corrosion includes a conductive wear-resistant ring 1 and an elastic friction element. The conductive wear-resistant ring 1 is fitted and fixed to the outer wall of the rotating shaft 2. One side of the conductive wear-resistant ring 1 is fixedly connected to the rotating shaft 2. The elastic friction element is in contact with the side of the conductive wear-resistant ring 1 away from the rotating shaft 2. The side of the elastic friction element away from the conductive wear-resistant ring 1 is provided with multiple peaks, which abut against the inner wall of the motor housing 3.

[0039] Connecting the conductive wear-resistant ring 1 directly to the rotating shaft 2 can stabilize the conduction of shaft current and reduce the electro-corrosion caused by current passing through the bearing. The wave crest design of the elastic friction component ensures that it maintains close contact with the inner wall of the motor housing 3, ensuring good conductivity even at high speeds. Due to the uniform distribution of the wave crests and reasonable pressure dispersion, the possibility of local overheating and poor contact is reduced, thereby improving the reliability and service life of the overall structure.

[0040] Specifically, the conductive wear-resistant ring 1 is made of graphite material, which has excellent self-lubricating and conductive properties. It can form a transfer film to reduce the coefficient of friction while ensuring stable current conduction.

[0041] Reference Figure 2 and Figure 3 The conductive wear-resistant ring 1 has a ventilation groove 11 on the side near the elastic friction element. The ventilation groove 11 is evenly distributed along the circumference of the guide wear-resistant ring and penetrates the inner and outer ring walls of the conductive wear-resistant ring 1. The design of the ventilation groove 11 uses centrifugal force to drive airflow to cool the friction surface, reducing the possibility of heat accumulation affecting the material properties. At the same time, it reduces the possibility that long-term grinding will cause the friction surface of the conductive wear-resistant ring 1 and the elastic friction element to become a mirror surface, so that the exhaust air forms a vacuum bond, thereby driving the elastic friction element to rotate together.

[0042] The elastic friction element includes an annular friction plate 4 and a wave-shaped elastic element 5. One side of the annular friction plate 4 is fixedly connected to the wave-shaped elastic element 5. The annular friction plate 4 and the wave-shaped elastic element 5 are welded together by welding technology such as ultrasonic welding or laser welding. The wave-shaped elastic element 5 is annular with the crest located on the wave-shaped elastic element 5. The side of the annular friction plate 4 away from the wave-shaped elastic element 5 is attached to the conductive wear-resistant ring 1, while the side of the wave-shaped elastic element 5 away from the annular friction plate 4 abuts against the inner wall of the motor housing 3. The outer wall of the wave-shaped elastic element 5 is attached to the inner wall of the motor housing 3 to limit the movement of the wave-shaped elastic element 5, so that the axis of the wave-shaped elastic element 5 is collinear with the axis of the rotating shaft 2. In this example, the wave-shaped elastic element 5 is a wave spring.

[0043] The wave-shaped elastic element 5 is made of beryllium copper, which has high hardness, wear resistance and good conductivity, ensuring double-sided contact with the conductive wear-resistant ring 1 and the inner wall of the motor housing 3. The annular friction plate 4 can also be made of silver-plated copper to further improve conductivity. Meanwhile, since the conductive wear-resistant ring 1 is made of graphite, the graphite can be embedded in the tiny pores and defects on the surface of the copper alloy, making the friction surface smoother, reducing the interaction of microscopic protrusions and depressions between the friction pairs, and further reducing friction loss.

[0044] The wave elastic element 5 has at least three peaks, which can evenly distribute pressure under compression, avoiding local overheating and poor contact.

[0045] The inner ring diameter of the conductive wear-resistant ring 1 is larger than that of the inner ring diameter of the annular friction plate 4. This design creates a certain gap between the inner wall of the conductive wear-resistant ring 1, the inner wall of the annular friction plate 4, and the outer wall of the rotating shaft 2, which facilitates gas flow, reduces the possibility of interference caused by thermal expansion, and improves heat dissipation.

[0046] In addition, the annular friction plate 4 is plated with a wear-resistant metal coating, such as a nickel-chromium alloy coating, on the side near the conductive wear-resistant ring 1, which can provide additional protection during friction and extend service life.

[0047] The implementation principle of this embodiment 1 is as follows: When the motor is running, the shaft current generated by the common mode voltage is led out through two paths. One is the current path formed by the breakdown of the bearing oil film, and the other is the current guiding path formed by the conductive wear-resistant ring 1 and the elastic friction element. Since the dynamic surface contact resistance between the elastic friction element and the conductive wear-resistant ring 1 is low, and the airflow of the ventilation slot 11 can effectively carry away the heat generated by friction, the risk of bearing electro-corrosion can be significantly reduced. Compared with the traditional solution, this embodiment has a simple structure, low installation and maintenance costs, and high reliability, and is particularly suitable for permanent magnet synchronous motors in the electric drive system of new energy vehicles.

[0048] Example 2

[0049] Reference Figure 4The difference from Embodiment 1 is that for individual motors with low shaft voltage, the conductive wear-resistant ring 1 can be replaced with a simpler ring structure without ventilation grooves; the elastic friction element can be directly replaced with a wave spring ring structure.

[0050] The implementation principle of this embodiment 2 is: to meet the usage requirements, the simplified structure is easier to process and has a lower cost.

[0051] The above are all preferred embodiments of this application. These embodiments are only explanations of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A structure for reducing axial electrical corrosion, characterized in that, include: A conductive wear-resistant ring (1) is fitted and fixed to the outer wall of the rotating shaft (2); The elastic friction element is attached to the side of the conductive wear-resistant ring (1) away from the rotating shaft (2). The side of the elastic friction element away from the conductive wear-resistant ring (1) has multiple peaks, which abut against the inner wall of the motor housing (3).

2. The structure for reducing axial electrical corrosion according to claim 1, characterized in that, The conductive wear-resistant ring (1) has a ventilation groove (11) on the side near the elastic friction element, and the ventilation groove (11) is distributed along the circumference of the guide wear-resistant ring.

3. The structure for reducing axial electrical corrosion according to claim 2, characterized in that, The ventilation groove (11) runs through the inner and outer ring walls of the conductive wear-resistant ring (1).

4. The structure for reducing axial electrical corrosion according to claim 1, characterized in that, The elastic friction element includes an annular friction plate (4) and a wave-shaped elastic element (5). One side of the annular friction plate (4) is connected to the wave-shaped elastic element (5). The wave-shaped elastic element (5) is annular with a wave crest. The side of the annular friction plate (4) away from the wave-shaped elastic element (5) is attached to a conductive wear-resistant sheet. The side of the wave-shaped elastic element (5) away from the annular friction plate (4) abuts against the inner wall of the motor housing (3).

5. The structure for reducing axial electrical corrosion according to claim 4, characterized in that, The inner ring diameter of the conductive wear-resistant ring (1) is larger than that of the inner ring diameter of the annular friction plate (4).

6. The structure for reducing axial electrical corrosion according to claim 4, characterized in that, The wave-shaped elastic element (5) is made of beryllium copper.

7. The structure for reducing axial electrical corrosion according to claim 1, characterized in that, The conductive wear-resistant ring (1) is made of graphite material.

8. The structure for reducing axial electrical corrosion according to claim 1, characterized in that, The side of the elastic friction element near the conductive wear-resistant ring (1) is coated with a wear-resistant metal coating.

Images