Exhaust structure of motor gear box for vehicle
By incorporating a combination of an exhaust valve, labyrinth, return plate, and baffle plate within the motor gearbox, the problem of gas failing to escape after the lubricating oil heats up is solved. This achieves effective oil return and dry gas discharge, preventing gearbox oil leakage and improving the reliability of the motor.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TAIZHOU JINYU ELECTROMECHANICAL
- Filing Date
- 2025-07-07
- Publication Date
- 2026-06-26
AI Technical Summary
In the prior art, the gas generated by the lubricating oil in the motor gearbox after heating cannot be effectively discharged, resulting in oil leakage from the gearbox. Furthermore, the lubricating oil is prone to leaking from the exhaust valve, affecting its use.
An exhaust structure for an automotive motor gearbox is designed, including an exhaust valve, a labyrinth, a return plate, and a baffle plate. By forming interconnected chambers and a return groove, oil flows back into the gearbox, and gas is discharged through the labyrinth. An S-shaped curved air passage is formed in the labyrinth to enhance the condensation effect. A sealing gasket separates the labyrinth chambers to further condense the oil and gas. The return plate blocks splashing oil and reduces oil leakage.
It effectively prevents oil leakage from the exhaust valve, enhances the oil-gas condensation effect, ensures lubricating oil return, avoids gearbox oil leakage, and improves operational stability.
Smart Images
Figure CN224414311U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an exhaust structure for a vehicle motor gearbox, belonging to the field of motor technology. Background Technology
[0002] An electric vehicle's motor includes a drive mechanism and a gearbox. The drive mechanism drives the gears inside the gearbox to rotate, and the gears in the gearbox drive the wheel hub to rotate. The gearbox typically contains lubricating oil to lubricate the gears. As the motor runs, the high-speed rotation of the gears generates heat, causing the gearbox to heat up. However, the gas generated by the heated lubricating oil cannot escape, leading to oil leakage and affecting operation. Existing technology addresses this problem by incorporating an exhaust valve and an exhaust labyrinth. However, if too much lubricating oil enters the exhaust labyrinth inlet, the oil will leak from the exhaust valve, reducing the oil level in the gearbox and affecting its performance. Utility Model Content
[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing an exhaust structure for a vehicle motor gearbox that prevents oil leakage from the gearbox and exhaust valve.
[0004] To achieve this objective, the technical solution adopted by this utility model is:
[0005] An exhaust structure for an automotive motor gearbox includes an exhaust valve, a labyrinth, a return plate, and several baffles located within the gearbox. The return plate is situated on the side of several gears within the gearbox, forming a return groove between the return plate and the inner wall of the gearbox. The baffles create several interconnected chambers within the gearbox, located between the labyrinth and the return groove. The chambers communicate with both the return groove and the labyrinth. The exhaust valve communicates with the labyrinth. The return groove has return ports at both ends that communicate with the interior of the gearbox. Oil entering the chambers can flow through the return groove and return to the gearbox. When the gas pressure inside the gearbox increases, the gas is discharged through the labyrinth and from the exhaust valve.
[0006] As a further optimization of the above technical solution: the gearbox is also provided with a sealing gasket, and the labyrinth includes a first labyrinth cavity and a second labyrinth cavity that are interconnected. The sealing gasket divides the first labyrinth cavity into an upper chamber and a lower chamber that are interconnected. The upper chamber and the second labyrinth cavity are connected through a second through hole. The second labyrinth cavity is connected to the exhaust valve. The lower chamber is connected to the first chamber through the first through hole. Oil and gas first enter the lower chamber of the first labyrinth cavity. After the oil and gas condense in the lower chamber, the gas passes through the upper chamber and the second labyrinth cavity and is discharged through the exhaust valve. The oil that has condensed in the lower chamber flows back through the return groove.
[0007] As a further optimization of the above technical solution: the maze includes a first baffle, a second baffle, and a third baffle. An exhaust slit is formed between the first baffle and the inner wall of the gearbox. The second baffle and the third baffle divide the exhaust slit into a first maze cavity and a second maze cavity. A first through hole is formed on the second baffle, connecting the cavity and the first maze cavity. The first through hole serves as the entrance to the maze. A second through hole is formed on the third baffle, connecting the first maze cavity and the second maze cavity. The second through hole is located above or below the first through hole. The second through hole and the first through hole form an S-shaped curved air passage within the maze.
[0008] As a further optimization of the above technical solution: the baffle plate includes a third baffle plate and a fourth baffle plate and a fifth baffle plate located on both sides of the third baffle plate. A second chamber is formed between the end of the third baffle plate and the return plate, and between the fourth baffle plate. A third chamber is formed between the third baffle plate, the fifth baffle plate, and the inner wall of the gearbox. A second connecting port is formed on the fourth baffle plate, connecting the second chamber and the return groove. A third connecting port is formed on the fifth baffle plate, connecting the third chamber and the return groove. A first through hole connects the second chamber and the first labyrinth cavity, and the first through hole is inverted L-shaped. A return hole is also formed on the second baffle plate, connecting the first labyrinth cavity and the third chamber. A third return port is provided at one end of the return groove, connecting the second chamber and the inside of the gearbox. An inlet baffle is provided on one side of the third return port. A fourth return port is provided at the other end of the return groove, and an outlet baffle is provided inside the fourth return port.
[0009] As a further optimization of the above technical solution: the oil enters the second chamber through the third return port, and the oil in the second chamber can flow into the return groove through the second connecting port; part of the oil in the second chamber moves to the lower chamber of the first labyrinth cavity through the inverted L-shaped first through hole, and condenses in the lower chamber; the condensed oil enters the third chamber through the return hole, and flows into the return groove through the third connecting port; the oil in the return groove is connected to the oil in the gearbox through the fourth return port.
[0010] As a further optimization of the above technical solution: the gearbox includes a housing and a cover, the gear inside the gearbox includes a driving tooth and several driven teeth, and part of the return plate is bent around the driven teeth or the driving teeth.
[0011] As a further optimization of the above technical solution: the driven tooth includes a first driven tooth and a second driven tooth, the first driven tooth is located between the driving tooth and the second driven tooth, and the first driven tooth meshes with both the driving tooth and the second driven tooth, one end of the return plate is bent around the first driven tooth and located in the triangular gap between the first driven tooth and the driving tooth, and the other end of the return plate extends to the side of the second driven tooth.
[0012] As a further optimization of the above technical solution: the baffle plate includes a first baffle plate and a second baffle plate, the end of the return plate is bent towards the first baffle plate, the gap between the end of the return plate and the first baffle plate is the first return port of the return channel, the gap between the other end of the return plate and the inner wall of the gearbox is the second return port of the return channel, a first chamber communicating with the labyrinth is formed between the first baffle plate and the second baffle plate, and the gap between the first baffle plate and the second baffle plate is the first communication port between the first chamber and the return channel.
[0013] Compared with existing technologies, this invention reduces the amount of oil splashed into the labyrinth during gear rotation by setting up a baffle plate, and also reduces the amount of oil reaching the labyrinth inlet, effectively preventing oil leakage from the exhaust valve. The oil in the chamber flows through the return groove and returns to the gearbox, achieving the effect of oil recirculation. An S-shaped curved air passage is formed in the labyrinth, extending the exhaust path of oil and gas in the labyrinth, which helps the oil and gas to condense and allows the oil to return. The gas is discharged from the exhaust valve, preventing the exhaust valve from leaking oil due to gas carrying oil, and at the same time, the gas discharge can prevent oil leakage from the gearbox. The sealing gasket divides the first labyrinth cavity into an interconnected upper chamber and a lower chamber, further increasing the condensation effect of oil and gas in the labyrinth, ensuring that the oil and gas condense in the lower chamber. The condensed oil enters the third chamber through the return hole and flows into the return groove through the third connecting port. The gas flows back through the upper chamber and the second labyrinth chamber, and is discharged through the exhaust valve. Meanwhile, the remaining oil in the lower chamber acts as an oil-liquid separator for subsequent oil-gas intake, enhancing the condensation effect of small droplets in the oil-gas mixture and making the gas discharged from the exhaust valve drier. A return plate divides the space at the bottom of the gearbox where lubricating oil is stored into two parts: the gearbox body and the return channel. The return plate blocks splashed oil, reducing its impact on the oil in the return channel and the labyrinth, ensuring the oil in the return channel is more stable than in the gearbox and preventing the oil in the return channel from impacting the labyrinth backwards. Due to environmental factors, automotive motors operate on inclines and declines. When the height of the first labyrinth chamber increases, the pressure of the oil increases after entering the first labyrinth chamber, increasing the downward flow velocity of the oil in the first labyrinth chamber and accelerating its return to the return channel. Attached Figure Description
[0014] Figure 1This is a cross-sectional structural diagram of Embodiment 1 of this utility model.
[0015] Figure 2 This is a schematic diagram of the structure after the hidden box cover is concealed in Embodiment 1 of this utility model.
[0016] Figure 3 This is a schematic diagram of the box cover in Embodiment 1 of this utility model.
[0017] Figure 4 This is a cross-sectional structural diagram of Embodiment 2 of this utility model.
[0018] Figure 5 This is a schematic diagram of the structure after concealing the box cover and sealing gasket in Embodiment 2 of this utility model.
[0019] Figure 6 This is a schematic diagram of the structure of the hidden box cover in Embodiment 2 of this utility model.
[0020] Figure 7 This is a schematic diagram of the box cover in Embodiment 2 of this utility model. Detailed Implementation
[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0022] Example 1:
[0023] like Figure 1-3 As shown, an exhaust structure for an automotive motor gearbox includes an exhaust valve 1, a labyrinth 3, a return plate 2, and several baffles located within the gearbox 7. The return plate 2 is positioned on the side of several gears within the gearbox 7, forming a return groove 21 between the return plate 2 and the inner wall of the gearbox 7. The baffles create several interconnected chambers within the gearbox 7, located between the labyrinth 3 and the return groove 21. The chambers communicate with both the return groove 21 and the labyrinth 3, and the exhaust valve 1 communicates with the labyrinth 3. The return groove 21 has return ports at both ends that communicate with the interior of the gearbox 7. Oil entering the chambers flows through the return groove 21 and returns to the gearbox 7. After the pressure inside the gearbox 7 increases, the gas is discharged through the labyrinth 3 from the exhaust valve 1, preventing oil leakage from the gearbox 7. The baffles reduce the amount of oil splashed into the labyrinth 3 during gear rotation and also reduce the amount of oil reaching the labyrinth inlet. The oil within the chambers flows through the return groove 21 and returns to the gearbox 7.
[0024] In the above technical solution: the maze 3 includes a first baffle 31, a second baffle 32, and a third baffle 33. An exhaust slit is formed between the first baffle 31 and the inner wall of the gearbox 7. The second baffle 32 and the third baffle 33 divide the exhaust slit into a first maze cavity 36 and a second maze cavity 37. The second baffle 32 has a first through hole 34 connecting the cavity and the first maze cavity 36, serving as the entrance to the maze 3. The third baffle 33 has a second through hole 35 connecting the first maze cavity 36 and the second maze cavity 37, and the exhaust valve 1 is connected to the second maze cavity 37. The second through hole 35 is located above or below the first through hole 34, meaning the second through hole 35 and the first through hole 34 are staggered vertically, forming an S-shaped curved air passage within the maze 3.
[0025] The first baffle 4 is formed by bending and extending the end of the first baffle 31.
[0026] In the above technical solution: the gearbox 7 includes a housing 71 and a cover 72. In this embodiment, the first through hole 34 is located on the cover 72, and the second through hole 35 is located on the housing 71. The gears inside the gearbox 7 include driving teeth 73 and several driven teeth. Part of the return plate 2 is bent around the driven teeth or driving teeth 73 to block the splashed oil and reduce the impact of splashed oil on the labyrinth 3.
[0027] In this embodiment, the driven teeth include a first driven tooth 74 and a second driven tooth 75. The first driven tooth 74 is located between the driving tooth 73 and the second driven tooth 75, and the first driven tooth 74 meshes with both the driving tooth 73 and the second driven tooth 75. In this embodiment, one end of the return plate 2 is curved around the first driven tooth 74 and located in the triangular gap between the first driven tooth 74 and the driving tooth 73, thereby blocking the splashed oil and reducing the impact of the splashed oil on the labyrinth 3. The other end of the return plate 2 extends to the side of the second driven tooth 75, reducing the impact of the turbulent flow of oil stirred by the second driven tooth 75 on the oil in the return tank 21, and ensuring that the oil in the return tank 21 is relatively calm.
[0028] In the above technical solution: the baffle includes a first baffle 4 and a second baffle 5. The end of the return plate 2 is bent towards the first baffle 4, and the gap between the end of the return plate 2 and the first baffle 4 is the first return port 22 of the return channel 21. The gap between the other end of the return plate 2 and the inner wall of the gearbox 7 is the second return port 23 of the return channel 21. A first chamber 41 communicating with the labyrinth 3 is formed between the first baffle 4 and the second baffle 5, and the gap between the first baffle 4 and the second baffle 5 is the first communication port 42 between the first chamber 41 and the return channel 21. The angle between the straight line containing the first return port 22 and the straight line containing the first connecting port 42 is ≥90°. The smaller opening of the first connecting port 42 reduces the amount of oil entering the first chamber 41. The first baffle plate 4 prevents the oil in the first chamber 41 from becoming turbulent due to gear agitation, ensuring the calmness and stability of the oil in the first chamber 41. This allows the oil in the first chamber 41 to return to the bottom of the gearbox 7 along the return channel 21, greatly reducing the amount of oil entering the labyrinth 3. The smaller openings of the first return port 22 and the second return port 23 reduce the impact of turbulent oil flow after gear agitation on the oil in the return channel 21, ensuring the oil in the return channel 21 remains relatively calm and reducing the impact of backflow and splashing of oil in the return channel 21 on the entrance of the labyrinth 3.
[0029] Figure 1 This describes the state of the motor when the vehicle using this embodiment is traveling on a level road. Figure 1 When the drive gear 73 rotates clockwise, the vehicle is in a downhill position. Figure 1 When the vehicle rotates counterclockwise along the drive gear 73, it is in an uphill state. Regardless of whether it is in an uphill state or a flat road state (the slope of the uphill or downhill will usually not exceed 30°), the labyrinth 3 is always above the oil surface. The return plate 2 and several baffles can reduce the impact of oil splashing on the inlet of the labyrinth 3 and avoid the oil leakage of the exhaust valve 1. When it is in a downhill state (30° counterclockwise), the oil may partially overflow the second return port 23, but due to the pressure, the oil will not flow back to the first return port 22 and will not affect the labyrinth inlet.
[0030] Example 2:
[0031] This embodiment is largely similar to the previous embodiment in terms of technical solution. The differences will be described in detail below, while the contents that are the same in both will not be repeated here.
[0032] In this embodiment, as Figure 4-7As shown, the gearbox 7 is also equipped with a sealing gasket 6, which divides the first labyrinth cavity 36 into an interconnected upper chamber and a lower chamber. The upper chamber is connected to the second labyrinth cavity 37 through a second through hole 35, and the lower chamber is connected to the other chambers through a first through hole 34. Oil and gas first enter the lower chamber of the first labyrinth cavity 36. After condensation in the lower chamber, the gas passes through the upper chamber and the second labyrinth cavity 37 and is discharged through the exhaust valve 1. The condensed oil in the lower chamber flows back through the return groove 21; simultaneously, the remaining oil in the lower chamber acts as a gas-liquid separator for subsequent oil and gas entry.
[0033] In the above technical solution: the return plate 2 is arranged around the active tooth 73 to prevent the oil in the return groove 21 from forming turbulence due to the agitation of the active tooth 73, thus avoiding impact on the oil flowing out of the return groove 21. The baffle includes a third baffle 8 and a fourth baffle 9 and a fifth baffle 10 located on both sides of the third baffle 8. A second chamber 81 is formed between the end of the third baffle 8 and the return plate 2, and between the fourth baffle 9. A third chamber 82 is formed between the third baffle 8, the fifth baffle 10, and the inner wall of the gearbox 7. The fourth baffle 9 has a second connecting port 91 connecting the second chamber 81 and the return groove 21, and the fifth baffle 10 has a third connecting port 101 connecting the third chamber 82 and the return groove 21. The first through hole 34 connects the second chamber 81 and the first labyrinth cavity 36, and the first through hole 34 is inverted L-shaped. The second baffle 32 is also provided with a reflux hole 38 connecting the first labyrinth cavity 36 and the third chamber 82. One end of the reflux trough 21 is provided with a third reflux port 24 connecting the second chamber 81 and the inside of the gearbox 7, and an inlet baffle 25 is provided on one side of the third reflux port 24. The inlet baffle 25 reduces the amount of oil splashed onto the third reflux port 24, thereby reducing the amount of oil entering the second chamber 81 and the labyrinth 3. The other end of the reflux trough 21 is provided with a fourth reflux port 26, and an outlet baffle 27 is provided inside the fourth reflux port 26. The outlet baffle 27 separates the fourth reflux port 26, reducing the turbulent flow of oil after gear agitation from entering the reflux trough 21 from the fourth reflux port 26 and affecting the reflux trough 21 without affecting the oil reflux, thus ensuring the calmness of the oil in the reflux trough 21.
[0034] The oil enters the second chamber 81 through the third return port 24. The oil in the second chamber 81 can flow to the return groove 21 through the second connecting port 91. Part of the oil in the second chamber 81 moves to the lower chamber of the first labyrinth cavity 36 through the inverted L-shaped first through hole 34 and condenses in the lower chamber. The condensed oil enters the third chamber 82 through the return hole 38 and flows to the return groove 21 through the third connecting port 101. The oil in the return groove 21 communicates with the oil in the gearbox 7 through the fourth return port 26. The gas passes through the upper chamber and the second labyrinth cavity 37 and is discharged through the exhaust valve 1.
[0035] According to the liquid pressure formula "P = ρgh" (where "ρ" is the liquid density, "g" is the acceleration due to gravity, and "h" is the liquid depth), the pressure is directly proportional to the liquid height (i.e., depth "h"). Vehicle motors are affected by the operating environment, including uphill and downhill sections. When the height of the first labyrinth cavity 36 increases, the pressure of the oil entering the first labyrinth cavity 36 increases. Although the size of the return hole 38 is fixed, the increased pressure of the oil in the first labyrinth cavity 36 leads to an increased downward flow velocity of the oil, accelerating its return to the return channel 21.
[0036] Figure 4 To illustrate the state of the motor when the vehicle using this embodiment is traveling on a level road, when... Figure 4 When the gearbox 7 rotates 30° clockwise along the drive gear 73 (as the vehicle descends a slope), although the inlet position of the third return port 24 decreases, the oil flow rate into the first labyrinth cavity 36 increases, and then the height of the first labyrinth cavity 36 also increases, increasing the oil pressure within the first labyrinth cavity 36 and further increasing the return oil flow rate. Figure 4 When the gearbox 7 rotates counterclockwise by 30° along the drive gear 73 (when the vehicle is going uphill), the inlet position of the third return port 2 is raised, and the flow rate of oil entering the first labyrinth cavity 36 will decrease. This prevents oil leakage from the exhaust valve 1 regardless of whether the vehicle is going uphill or downhill.
[0037] This invention reduces the amount of oil splashed into the labyrinth 3 during gear rotation by setting a baffle plate, and also reduces the amount of oil reaching the labyrinth entrance, effectively preventing oil leakage from the exhaust valve 1. The oil in the chamber flows through the return groove 21 and returns to the gearbox 7, achieving the effect of oil return. An S-shaped curved air passage is formed in the labyrinth 3, which prolongs the exhaust path of oil and gas in the labyrinth 3, helps the oil and gas to condense and return the oil. The gas is discharged from the exhaust valve 1, preventing the exhaust valve 1 from leaking oil due to the gas carrying oil. At the same time, the gas discharge can prevent the gearbox 7 from leaking oil. The sealing gasket 6 divides the first labyrinth cavity 36 into an interconnected upper chamber and a lower chamber, further increasing the condensation effect of oil and gas in the labyrinth 3, ensuring that the oil and gas condense in the lower chamber. The condensed oil enters the third chamber 82 through the return hole 38 and flows to the return groove 21 through the third connecting port 101 for return. The gas flows through the upper chamber and the second labyrinth chamber 37 and is discharged through the exhaust valve 1. At the same time, the oil remaining in the lower chamber acts as an oil-liquid separator for the subsequent oil and gas, enhancing the condensation effect of small droplets in the oil and gas, and making the gas discharged from the exhaust valve drier. By setting a return plate, the space at the bottom of the gearbox where the lubricating oil is stored is divided into two parts: the box body and the return channel. The return plate 2 blocks the splashed oil, reducing the impact of splashed oil on the oil in the return channel 21 and the labyrinth 3, ensuring that the oil in the return channel 2 is more stable than that in the gearbox, and preventing the oil in the return channel 2 from impacting the labyrinth in reverse. The vehicle motor is affected by the operating environment, with uphill and downhill slopes. When the height of the first labyrinth chamber 36 increases, the pressure of the oil increases after entering the first labyrinth chamber 36, and the downward flow velocity of the oil in the first labyrinth chamber 36 increases, accelerating the return of the oil to the return channel 21.
[0038] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should fall within the protection scope of this utility model.
Claims
1. An exhaust structure for a vehicle motor gearbox, characterized in that... The gearbox (7) includes an exhaust valve (1), a labyrinth (3), a return plate (2), and several baffles. The return plate (2) is located on the side of several gears in the gearbox (7). The return plate (2) forms a return groove (21) between itself and the inner wall of the gearbox (7). The baffles form several interconnected chambers in the gearbox (7). The chambers are located between the labyrinth (3) and the return groove (21). The chambers are connected to the return groove (21) and also to the labyrinth (3). The exhaust valve (1) is connected to the labyrinth (3). The two ends of the return groove (21) are provided with return ports that are connected to the inside of the gearbox (7). The oil entering the chamber can flow through the return groove (21) and return to the gearbox (7). After the gas pressure in the gearbox (7) increases, the gas is discharged from the exhaust valve (1) through the labyrinth (3).
2. The exhaust structure of a vehicle motor gearbox according to claim 1, characterized in that... The gearbox (7) is also provided with a sealing gasket (6). The labyrinth (3) includes a first labyrinth cavity (36) and a second labyrinth cavity (37) that are interconnected. The sealing gasket (6) divides the first labyrinth cavity (36) into an upper chamber and a lower chamber that are interconnected. The upper chamber and the second labyrinth cavity (37) are connected through a second through hole (35). The second labyrinth cavity (37) is connected to the exhaust valve (1). The lower chamber is connected to the chamber through a first through hole (34). The oil and gas first enter the lower chamber of the first labyrinth cavity (36). After the oil and gas condense in the lower chamber, the gas passes through the upper chamber and the second labyrinth cavity (37) and is discharged through the exhaust valve (1). The oil that has condensed in the lower chamber flows back through the return groove (21).
3. The exhaust structure of a vehicle motor gearbox according to claim 2, characterized in that... The maze (3) includes a first baffle (31), a second baffle (32) and a third baffle (33). An exhaust slit is formed between the first baffle (31) and the inner wall of the gearbox (7). The second baffle (32) and the third baffle (33) divide the exhaust slit into the first maze cavity (36) and the second maze cavity (37). The second baffle (32) has a first through hole (34) connecting the cavity and the first maze cavity (36). The first through hole (34) serves as the entrance to the maze (3). The third baffle (33) has a second through hole (35) connecting the first maze cavity (36) and the second maze cavity (37). The second through hole (35) is located above or below the first through hole (34). The second through hole (35) and the first through hole (34) form an S-shaped curved air passage in the maze (3).
4. The exhaust structure of a vehicle motor gearbox according to claim 3, characterized in that... The baffle plate includes a third baffle plate (8) and a fourth baffle plate (9) and a fifth baffle plate (10) located on both sides of the third baffle plate (8). A second chamber (81) is formed between the end of the third baffle plate (8) and the return plate (2) and between the fourth baffle plate (9). A third chamber (82) is formed between the third baffle plate (8), the fifth baffle plate (10), and the inner wall of the gearbox (7). A second connecting port (91) is formed on the fourth baffle plate (9) connecting the second chamber (81) and the return groove (21). A third connecting port (91) is formed on the fifth baffle plate (10) connecting the third chamber (82) and the return groove (21). The through-hole (101) connects the second chamber (81) and the first labyrinth cavity (36), and the first through-hole (34) is inverted L-shaped. The second baffle (32) is also provided with a return hole (38) connecting the first labyrinth cavity (36) and the third chamber (82). One end of the return groove (21) is provided with a third return port (24) connecting the second chamber (81) and the inside of the gearbox (7). One side of the third return port (24) is provided with an inlet baffle (25). The other end of the return groove (21) is provided with a fourth return port (26). The fourth return port (26) is provided with an outlet baffle (27). The oil enters the second chamber (81) through the third return port (24), and the oil in the second chamber (81) can flow to the return groove (21) through the second connecting port (91); part of the oil in the second chamber (81) moves to the lower chamber of the first labyrinth cavity (36) through the inverted L-shaped first through hole (34), and condenses in the lower chamber. The condensed oil enters the third chamber (82) through the return hole (38) and flows to the return groove (21) through the third connecting port (101); the oil in the return groove (21) communicates with the oil in the gearbox (7) through the fourth return port (26).
5. The exhaust structure of a vehicle motor gearbox according to claim 1, characterized in that... The gearbox (7) includes a housing (71) and a cover (72). The gear inside the gearbox (7) includes a driving tooth (73) and a number of driven teeth. Part of the return plate (2) is bent around the driven tooth or the driving tooth (73).
6. The exhaust structure of a vehicle motor gearbox according to claim 5, characterized in that... The driven tooth includes a first driven tooth (74) and a second driven tooth (75). The first driven tooth (74) is located between the driving tooth (73) and the second driven tooth (75), and the first driven tooth (74) meshes with both the driving tooth (73) and the second driven tooth (75). One end of the return plate (2) is bent around the first driven tooth (74) and located in the triangular gap between the first driven tooth (74) and the driving tooth (73). The other end of the return plate (2) extends to the side of the second driven tooth (75).
7. The exhaust structure of a vehicle motor gearbox according to claim 1, characterized in that... The baffle plate includes a first baffle plate (4) and a second baffle plate (5). The end of the return plate (2) is bent towards the first baffle plate (4). The gap between the end of the return plate (2) and the first baffle plate (4) is the first return port (22) of the return groove (21). The gap between the other end of the return plate (2) and the inner wall of the gearbox (7) is the second return port (23) of the return groove (21). A first chamber (41) communicating with the labyrinth (3) is formed between the first baffle plate (4) and the second baffle plate (5). The gap between the first baffle plate (4) and the second baffle plate (5) is the first communication port (42) between the first chamber (41) and the return groove (21).