A coaxial electric drive axle lubricating oil sealing structure

Abstract

The application relates to the technical field of automobile transmission systems, and particularly discloses a coaxial electric drive axle lubricating oil sealing structure. In order to solve the problem that the sealing lip of an oil seal continuously rubs against the surface of a rotating shaft, leading to a decrease in sealing performance, the coaxial electric drive axle lubricating oil sealing structure comprises an elastic sealing ring, two rotating rings, a ring groove and an air inlet, the elastic sealing ring is sleeved and fixed on a transmission shaft, the two rotating rings are tightly connected to the two side walls of the elastic sealing ring and are coaxially arranged with the elastic sealing ring, a gas collection chamber is formed between the two rotating rings and the elastic sealing ring, an air inlet that is in communication with the gas collection chamber is arranged on the inner wall of a bridge pipe, the ring groove is arranged on the inner wall of the bridge pipe and is used for accommodating the two rotating rings, the air inlet is arranged on the inner wall of the ring groove and is used for introducing gas into the gas collection chamber, and a non-contact gap is formed between the outer peripheral wall of the rotating ring and the groove wall of the ring groove. The sealing effect between the bridge pipe and the transmission shaft is improved, and the loss of lubricating oil is reduced.

Description

Technical Field

[0001] This utility model relates to the field of automotive transmission system technology, and in particular to a lubricating oil sealing structure for a coaxial electric drive axle. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the demand for integrated, efficient, and lightweight drive systems is becoming increasingly prominent. Traditional centralized drive architectures, due to their long transmission chains, high energy losses, and limited layout space, are gradually failing to meet the higher requirements of new energy vehicles for power performance, range, and chassis space utilization. Electric drive axles, as a new type of drive solution that highly integrates core components such as drive motors, reducers, and axles, can effectively shorten the power transmission path, reduce energy losses, and save chassis layout space. They have become a key technological direction for improving the overall performance of new energy vehicles and show broad application prospects in passenger cars, commercial vehicles, and other fields.

[0003] In current electric drive axle products on the market, when adding lubricating oil to the gears on the differential, the lubricating oil can easily flow into the gap between the axle housing and the drive shaft due to the large internal space of the axle housing, resulting in a large waste of lubricating oil. The conventional method is to install a rotary seal between the drive shaft and the axle housing to prevent lubricating oil from flowing into the gap between the drive shaft and the axle housing.

[0004] However, during the rotation of the drive shaft, the sealing lip of the oil seal continuously rubs against the surface of the rotating shaft. The heat generated by the friction will accelerate the aging of the oil seal, and long-term friction will lead to a decrease in sealing performance, causing lubricating oil to flow into the gap between the drive shaft and the axle housing, resulting in lubricating oil waste. Utility Model Content

[0005] To improve the sealing effect between the bridge tube and the drive shaft, this application provides a coaxial electric drive axle lubricating oil sealing structure.

[0006] The coaxial electric drive axle lubricating oil sealing structure provided in this application adopts the following technical solution:

[0007] A coaxial electric drive axle lubricating oil sealing structure, including

[0008] The system includes a gearbox, a differential, a driveshaft, and an axle tube, wherein the axle tube is sleeved outside the driveshaft, one end of the axle tube is connected to the gearbox, one end of the driveshaft is inserted into the gearbox and connected to the differential via a spline, and also includes;

[0009] The main sealing structure includes:

[0010] An elastic sealing ring is fitted and fixed onto the drive shaft;

[0011] Two rotating rings are tightly connected to the two side walls of the elastic sealing ring and are coaxially arranged with the elastic sealing ring. A gas collecting chamber is formed between the two rotating rings and the elastic sealing ring. An air inlet communicating with the gas collecting chamber is opened on the inner wall of the bridge tube.

[0012] A ring groove is formed on the inner wall of the bridge tube to accommodate the two rotating rings;

[0013] An air inlet is provided on the inner wall of the annular groove for introducing gas into the gas collecting chamber, wherein a non-contact gap is formed between the outer peripheral wall of the rotating ring and the groove wall of the annular groove.

[0014] Furthermore, both sides of the elastic sealing ring protrude to form limiting posts, which are used to insert into the inner ring of the rotating ring; several arc-shaped positioning blocks are distributed circumferentially on the circumferential wall of the limiting post, and positioning slots that engage with the arc-shaped positioning blocks are opened on the inner ring wall of the rotating ring.

[0015] Furthermore, it also includes an auxiliary sealing structure, which includes a rotating shaft lip seal ring disposed on the side of the annular groove away from the gearbox.

[0016] Furthermore, the lip of the rotary shaft lip seal is positioned facing the gearbox direction.

[0017] Furthermore, it also includes an air supply system connected to the air inlet, the air supply system being equipped with a pressure regulating device for controlling the gas pressure in the air collecting chamber.

[0018] Furthermore, the pressure regulating device includes a pressure sensor and a pressure regulating valve, configured to maintain the gas pressure in the gas collection chamber higher than the oil pressure inside the gearbox.

[0019] Furthermore, an oil return hole is provided at the bottom of the annular groove, and the oil return hole is connected to the inside of the gearbox through an oil return pipeline.

[0020] Furthermore, the friction surface of the rotating ring is coated with a wear-resistant coating.

[0021] In summary, this application includes at least one of the following beneficial technical effects:

[0022] 1. In the main sealing structure, the elastic sealing ring is fixed to the drive shaft and rotates synchronously with it. The two rotating rings are tightly connected to both sides of the sealing ring and form a gas collecting chamber. The annular groove on the inner wall of the bridge tube accommodates the rotating ring and the air inlet introduces gas into the gas collecting chamber. At the same time, the outer peripheral wall of the rotating ring and the groove wall of the annular groove form a non-contact gap.

[0023] During operation, the gas introduced through the air inlet forms a stable air pressure in the gas collection chamber. This air pressure can prevent the lubricating oil in the gearbox from leaking outward along the gap between the drive shaft and the axle tube, reducing the waste of lubricating oil. The non-contact gap can prevent friction between the rotating ring and the inner wall of the axle tube when the rotating ring rotates, which reduces component wear and avoids aging of sealing components due to frictional heat. It is suitable for the high-speed rotation of the electric drive axle drive shaft and effectively extends the service life of the sealing structure. At the same time, the gas barrier design is more adaptable to oil pressure fluctuations in the gearbox than traditional lip seals, improving the stability of the seal.

[0024] 2. The limiting posts on both sides of the elastic sealing ring are inserted into the inner ring of the rotating ring, which can initially achieve coaxial positioning of the rotating ring and the sealing ring, preventing radial displacement of the rotating ring during assembly or operation. The arc-shaped positioning block on the circumferential wall of the limiting post engages with the positioning groove on the inner ring wall of the rotating ring, which can further limit the relative rotation between the rotating ring and the sealing ring. This dual positioning structure ensures that the rotating ring and the sealing ring always maintain a stable relative position when rotating synchronously with the drive shaft, avoiding changes in the sealing boundary of the gas collecting chamber due to their relative rotation, preventing gas leakage from the connection between the rotating ring and the sealing ring, thereby maintaining the pressure stability in the gas collecting chamber, ensuring the sealing effect of the gas barrier, reducing frictional loss between the rotating ring and the sealing ring, and improving the overall reliability of the main sealing structure.

[0025] 3. A rotary shaft lip seal is installed on the side of the annular groove away from the gearbox. This seal serves as an auxiliary sealing component and can provide secondary protection against minor lubricant leakage when the main sealing structure experiences a small amount of lubricant leakage due to abnormal conditions (such as a brief shortage of air source pressure or a slight change in the sealing gap). Through the synergistic effect of the main seal and the auxiliary seal, a double sealing guarantee is formed, reducing the risk of a large amount of lubricant leakage due to the failure of a single sealing structure. Especially during the long-term operation of the electric drive axle, even if the performance of the main seal slowly declines, the auxiliary seal can still maintain a basic sealing function, preventing lubricant leakage from contaminating external components or intruding into the motor, thus ensuring the overall operational safety of the electric drive axle.

[0026] 4. The oil return hole at the bottom of the ring groove is connected to the inside of the gearbox through the oil return line. When a small amount of lubricating oil seeps into the ring groove due to special operating conditions (such as instantaneous pressure shock), the lubricating oil will collect at the oil return hole at the bottom of the ring groove under the action of gravity, and then flow back into the differential through the oil return line. This design realizes the recycling of seeping lubricating oil, avoids the accumulation of lubricating oil in the ring groove, which will cause the sealing gap to be blocked by oil stains and affect the gas flow in the air collection chamber. It also reduces the waste of lubricating oil and lowers the maintenance cost of the electric drive axle. In addition, the lubricating oil flowing back to the differential can continue to participate in the lubrication cycle, avoiding its retention in the axle tube, which will cause component corrosion or affect the performance of other sealing components. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a cross-sectional structural diagram of the electric drive bridge in an embodiment of this application;

[0029] Figure 2 for Figure 1 Enlarged structural diagram at point A;

[0030] Figure 3 This is an enlarged structural schematic diagram of the main sealing structure in an embodiment of this application;

[0031] Figure 4 This is an enlarged structural schematic diagram of the sidewall of the elastic sealing ring, as shown in an embodiment of this application.

[0032] Explanation of reference numerals in the attached drawings: 1. Gearbox; 2. Differential; 3. Drive shaft; 4. Axle tube; 5. Main sealing structure; 51. Elastic sealing ring; 511. Limiting post; 512. Arc-shaped positioning block; 52. Rotating ring; 521. Positioning groove; 53. Annular groove; 54. Air inlet; 55. Air collection chamber; 56. Oil return hole; 6. Auxiliary sealing structure; 61. Rotating shaft lip seal. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. Therefore, the detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to represent selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0034] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0035] This application discloses a lubricating oil sealing structure for a coaxial electric drive axle, referring to... Figure 1 and Figure 2It includes a gearbox 1, a differential 2, a drive shaft 3, and an axle tube 4. The drive shaft 3 is rotatably mounted inside the axle tube 4, with one end connected to the differential 2 via a spline and the other end connected to the wheel hub. The differential 2 is located inside the gearbox 1. One end of the axle tube 4 is connected to the gearbox 1. The gearbox 1 is filled with lubricating oil for lubricating the differential 2 and other transmission components.

[0036] Reference Figures 2 to 4 The bridge tube 4 is equipped with a sealing structure, which includes a main sealing structure 5. The main sealing structure 5 includes an elastic sealing ring 51, a rotating ring 52, an annular groove 53, and an air inlet 54. The elastic sealing ring 51 is made of fluororubber and is fixedly fitted onto the section of the drive shaft 3 near the gearbox 1 by an interference fit. Both sides of the elastic sealing ring 51 protrude to form limit posts 511, and four arc-shaped positioning blocks 512 are distributed circumferentially on the circumferential wall of the limit posts 511. The rotating ring 52 is made of high-strength aluminum alloy, and its inner ring wall has positioning grooves 521 corresponding to the arc-shaped positioning blocks 512.

[0037] The limiting posts 511 on both sides of the elastic sealing ring 51 are inserted into the inner ring of the rotating ring 52, which can initially achieve coaxial positioning of the rotating ring 52 and the sealing ring, preventing radial displacement of the rotating ring 52 during assembly or operation. The arc-shaped positioning block 512 on the circumferential wall of the limiting post 511 engages with the positioning groove 521 on the inner ring wall of the rotating ring 52, which can further limit the relative rotation between the rotating ring 52 and the sealing ring. This dual positioning structure ensures that the rotating ring 52 always maintains a stable relative position with the sealing ring when it rotates synchronously with the drive shaft 3, avoiding changes in the sealing boundary of the gas collecting chamber 55 due to their relative rotation, preventing gas leakage from the connection between the rotating ring 52 and the sealing ring, thereby maintaining the pressure stability in the gas collecting chamber 55, ensuring the sealing effect of the gas barrier, and reducing frictional loss between the rotating ring 52 and the sealing ring, thus improving the overall reliability of the main sealing structure 5.

[0038] Reference Figure 2 The diameter of the rotating ring 52 is larger than that of the elastic sealing ring 51, and a gas collecting chamber 55 is formed between the two rotating rings 52 and the elastic sealing ring 51. An annular groove 53 is machined on the inner wall of the bridge tube 4 to accommodate the rotating rings 52. A non-contact gap exists between the outer peripheral wall of the rotating ring 52 and the groove wall of the annular groove 53. The friction surface of the rotating ring 52 is covered with a wear-resistant coating. An air inlet 54 is provided on the wall of the annular groove 53 for introducing compressed air or inert gas into the gas collecting chamber 55.

[0039] During operation, the gas introduced through the air inlet 54 forms a stable air pressure in the gas collection chamber 55. This air pressure can prevent the lubricating oil in the gearbox 1 from leaking outward along the gap between the drive shaft 3 and the axle tube 4. The non-contact gap can prevent the rotating ring 52 from rubbing against the inner wall of the axle tube 4 when it rotates. This reduces component wear and avoids aging of sealing components due to frictional heat. It is suitable for the high-speed rotation of the electric drive axle drive shaft 3 and effectively extends the service life of the sealing structure. At the same time, the gas barrier design is more adaptable to oil pressure fluctuations in the gearbox 1 than the traditional lip seal, improving the stability of the seal.

[0040] During the operation of the electric drive axle, the rotating ring 52 rotates at high speed with the drive shaft 3. Its surface may generate slight friction with the surrounding components of the ring groove 53. The wear-resistant coating can significantly improve the hardness and wear resistance of the rotating ring 52 surface, reduce surface wear during the friction process, and prevent the rotating ring 52 from thinning or scratching due to long-term friction. This prevents changes in the sealing boundary of the gas collecting chamber 55, maintains the tight connection between the rotating ring 52 and the sealing ring, and ensures the sealing performance of the gas collecting chamber 55. At the same time, the wear-resistant coating can also improve the oil and corrosion resistance of the rotating ring 52, extend the service life of the rotating ring 52, and reduce the frequency of maintenance and replacement of the sealing structure.

[0041] Reference Figure 2 The bottom of the annular groove 53 is provided with an oil return hole 56, which is connected to the inside of the gearbox 1 through an oil return pipeline. When a small amount of lubricating oil seeps into the annular groove 53 due to special operating conditions (such as instantaneous pressure shock), the lubricating oil will collect at the oil return hole 56 at the bottom of the annular groove 53 under the action of gravity, and then flow back into the gearbox 1 through the oil return pipeline. This realizes the recycling of seeping lubricating oil, avoids the accumulation of lubricating oil in the annular groove 53, which would cause the sealing gap to be blocked by oil sludge and affect the gas flow in the air collection chamber 55. It also reduces the waste of lubricating oil and lowers the maintenance cost of the electric drive axle. In addition, the lubricating oil flowing back to the differential 2 can continue to participate in the lubrication cycle, preventing it from remaining in the axle tube 4 and causing corrosion of components or affecting the performance of other sealing components.

[0042] The air inlet 54 is connected to an air supply system (not shown in the figure). The air supply system includes a pressure sensor and a pressure regulating valve, which can maintain the gas pressure in the air collection chamber 55 higher than the oil pressure inside the gearbox 1.

[0043] Reference Figure 2The sealing structure includes an auxiliary sealing structure 6, which includes a rotating shaft lip seal 61. The rotating shaft lip seal 61 is installed on the inner wall of the bridge tube 4. The outer ring of the rotating shaft lip seal 61 is interference-fitted and fixed to the inner wall of the bridge tube 4, while the inner ring of the rotating shaft lip seal 61 is tightly fitted to the outer wall of the rotating drive shaft 3 to form a sealing surface. The rotating shaft lip seal 61 is located on the side of the annular groove 53 away from the gearbox 1, and the lip of the rotating shaft lip seal 61 is set towards the gearbox 1.

[0044] The rotary shaft lip seal 61 can provide secondary protection against minor lubricant leakage when the main sealing structure 5 experiences a small amount of lubricant leakage due to abnormal conditions (such as a brief shortage of air source pressure or a slight change in the sealing gap). The lip of the rotary shaft lip seal 61 is positioned facing the gearbox 1, so that the lip directly faces the lubricant that may leak from the main sealing side (closer to the gearbox 1). When a small amount of lubricant breaks through the main seal and enters the annular groove 53 away from the gearbox 1, the lip can directly contact the lubricant and, through its own elasticity, tightly adhere to the drive shaft 3, forming an effective sealing surface and preventing the lubricant from continuing to diffuse to the outside of the bridge tube 4.

[0045] Through the synergistic effect of the main sealing structure 5 and the auxiliary sealing structure 6, a double sealing guarantee is formed, reducing the risk of a large amount of lubricating oil leakage due to the failure of a single sealing structure. Especially during the long-term operation of the electric drive axle, even if the performance of the main sealing structure 5 slowly declines, the auxiliary sealing structure 6 can still maintain the basic sealing function, preventing lubricating oil leakage from contaminating external components or intruding into the motor, and ensuring the overall safety of the electric drive axle operation.

[0046] The implementation principle of the coaxial electric drive axle lubricating oil sealing structure in this application embodiment is as follows: The gas supply system continuously provides gas at a stable pressure to the gas collection chamber 55. When the gas passes through the non-contact gap, it forms a directional airflow barrier, effectively preventing the lubricating oil in the gearbox 1 from leaking outward. The rotating shaft lip seal ring 61 serves as a second line of defense, providing redundant protection. The oil return hole 56 can guide any trace amounts of lubricating oil that may have seeped in back to the gearbox 1. The pressure regulating system monitors and adjusts the air pressure in real time to ensure optimal sealing performance.

[0047] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A coaxial electric drive axle lubricating oil sealing structure, comprising a gearbox (1), a differential (2), a drive shaft (3), and an axle tube (4), wherein the axle tube (4) is sleeved outside the drive shaft (3), one end of the axle tube (4) is connected to the gearbox (1), and one end of the drive shaft (3) is inserted into the gearbox (1) and connected to the differential (2) via a spline, characterized in that, Also includes: The main sealing structure (5) includes: An elastic sealing ring (51) is fitted and fixed on the drive shaft (3); Two rotating rings (52) are tightly connected to the two side walls of the elastic sealing ring (51) and are coaxially arranged with the elastic sealing ring (51). A gas collecting chamber (55) is formed between the two rotating rings (52) and the elastic sealing ring (51). An air inlet (54) communicating with the gas collecting chamber (55) is opened on the inner wall of the bridge pipe (4). A ring groove (53) is formed on the inner wall of the bridge tube (4) to accommodate the two rotating rings (52). An air inlet (54) is provided on the inner wall of the annular groove (53) for introducing gas into the gas collection chamber (55), wherein a non-contact gap is formed between the outer peripheral wall of the rotating ring (52) and the groove wall of the annular groove (53).

2. The coaxial electric drive axle lubricating oil sealing structure according to claim 1, characterized in that, Both sides of the elastic sealing ring (51) protrude to form a limiting post (511), which is used to insert into the inner ring of the rotating ring (52); a number of arc-shaped positioning blocks (512) are distributed circumferentially on the circumferential wall of the limiting post (511), and a positioning groove (521) is opened on the inner ring wall of the rotating ring (52) to engage with the arc-shaped positioning block (512).

3. The coaxial electric drive axle lubricating oil sealing structure according to claim 2, characterized in that, It also includes an auxiliary sealing structure (6), which includes a rotating shaft lip seal (61) disposed on the side of the annular groove (53) away from the gearbox (1).

4. The coaxial electric drive axle lubricating oil sealing structure according to claim 3, characterized in that, The lip of the rotating shaft lip seal (61) is positioned facing the gearbox (1).

5. The coaxial electric drive axle lubricating oil sealing structure according to claim 1, characterized in that, It also includes a gas supply system connected to the air inlet (54), and the gas supply system is equipped with a pressure regulating device for controlling the gas pressure in the gas collecting chamber (55).

6. The coaxial electric drive axle lubricating oil sealing structure according to claim 5, characterized in that, The pressure regulating device includes a pressure sensor and a pressure regulating valve, configured to maintain the gas pressure in the gas collection chamber (55) higher than the oil pressure inside the gearbox (1).

7. The coaxial electric drive axle lubricating oil sealing structure according to claim 6, characterized in that, The bottom of the annular groove (53) is provided with an oil return hole (56), which is connected to the inside of the gearbox (1) through an oil return pipeline.

8. The coaxial electric drive axle lubricating oil sealing structure according to claim 1, characterized in that, The friction surface of the rotating ring (52) is covered with a wear-resistant coating.

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