A waterproof breather plug, a gearbox and a vehicle

Abstract

Embodiments of the present application relate to a waterproof breather plug, a gearbox and a vehicle. The waterproof breather plug includes a main body, a stepped hole provided in the main body. The stepped hole includes a first through hole, a second through hole and a third through hole with sequentially increasing inner diameters, a first channel provided on the main body, a guide post slidably connected to the second through hole, a fixing ring fixed in the third through hole, a spring with both ends respectively abutted against the guide post and the fixing ring, a one-way ventilation membrane provided in the third through hole, a protective cover fixed on the second end of the main body, a second channel provided in the guide post, and a drainage channel. The gearbox includes the above waterproof breather plug, and the vehicle includes the above gearbox. The waterproof breather plug, the gearbox and the vehicle disclosed in the embodiments of the present application ensure the stability of the opening pressure through mechanical structure components, and at the same time can prevent lubricating oil from entering the inner cavity of the breather plug to contaminate the one-way ventilation membrane. The one-way ventilation membrane can also prevent external dust and water vapor from entering the breather plug.

Description

Technical Field

[0001] This application relates to the technical field of sealed exhaust, and particularly to a waterproof breather plug, a gearbox and a vehicle. Background Art

[0002] In an automotive gearbox, a ventilation system is essential, and the ventilation system has functions such as connecting the internal and external air and balancing pressure. Currently, the breather plugs used in the ventilation system have defects such as being prone to water ingress and blockage after the ventilation membrane is contaminated with oil. Summary of the Invention

[0003] Embodiments of this application provide a waterproof breather plug, a gearbox and a vehicle, which ensure the stability of the opening pressure through mechanical structure components, and at the same time can prevent lubricating oil from entering the inner cavity of the breather plug to contaminate the one-way ventilation membrane, and the one-way ventilation membrane can also prevent external dust and water vapor from entering the breather plug.

[0004] The above object of the embodiments of this application is achieved through the following technical solutions:

[0005] In a first aspect, embodiments of this application provide a waterproof breather plug, including:

[0006] A main body, in which a stepped hole is provided. The stepped hole includes a first through hole, a second through hole and a third through hole with gradually increasing inner diameters. The first through hole communicates with the first end of the main body, and the third through hole communicates with the second end of the main body;

[0007] A first channel, provided on the side wall of the main body, and the first channel communicates with the external atmosphere;

[0008] A guide post, slidably connected to the second through hole;

[0009] A fixing ring, fixed in the third through hole;

[0010] A spring, with both ends of the spring respectively abutting against the guide post and the fixing ring;

[0011] A one-way ventilation membrane, provided in the third through hole;

[0012] A protective cover, fixed on the second end of the main body, used to form a channel at the second end of the main body, and the channel is used to connect the third through hole and the first channel;

[0013] A second channel, provided in the guide post, and the second channel is used to connect the second through hole and the third through hole; and

[0014] At least one drainage channel, provided on the main body, used to connect the space on the exhaust side of the one-way ventilation membrane and the first channel.

[0015] In a possible implementation manner of the first aspect, a sealing member is provided between the bottom surface of the second through hole and the end of the guide post close to the first through hole.

[0016] In a possible implementation of the first aspect, an annular contact surface is provided on the body, and the outer diameter of the annular contact surface is greater than the outer diameter of the first end of the body.

[0017] In a possible implementation of the first aspect, connecting threads are provided on the first end of the body.

[0018] In a possible implementation of the first aspect, a sealing ring is provided on the first end of the body, and the sealing ring is located between the annular contact surface and the connecting threads.

[0019] In a possible implementation of the first aspect, in the axial direction of the third through hole, there are at least two drainage channels with different distances from the bottom surface of the third through hole.

[0020] In a possible implementation of the first aspect, it further includes a pressure ring arranged in the third through hole, and the pressure ring is used to press the one-way ventilation membrane against the fixed ring.

[0021] In a possible implementation of the first aspect, at least one drainage hole is provided on the pressure ring, and at least one drainage hole communicates with a matching drainage channel.

[0022] In a possible implementation of the first aspect, the number of drainage holes is multiple, and in the axial direction of the pressure ring, there are at least two drainage holes with different distances from the same end surface of the pressure ring.

[0023] In a possible implementation of the first aspect, there are multiple communication points between the second channel and the second through hole.

[0024] In a possible implementation of the first aspect, the communication points between the multiple second channels and the second through hole are evenly arranged around the axis of the guide post.

[0025] In a possible implementation of the first aspect, the guide post includes a first part and a second part provided on the first part;

[0026] The outer diameter of the first part is greater than the outer diameter of the second part;

[0027] The first end of the second channel communicates with the side wall of the second part.

[0028] In a second aspect, an embodiment of the present application provides a gearbox, including the waterproof ventilation plug as described in the first aspect and any possible implementation of the first aspect.

[0029] In a third aspect, an embodiment of the present application provides a vehicle, including the gearbox as described in the second aspect.

[0030] In summary, the waterproof vent plug, transmission, and vehicle provided by the embodiments of the present application use a mechanical sealing method, which can automatically open when the pressure increases and automatically close when the pressure returns to normal. It can prevent oil from entering and causing the one-way ventilation membrane to fail, and can also drain the accumulated water inside through the drainage channel after water ingress to ensure the normal operation of the exhaust work. Brief Description of the Drawings

[0031] Figure 1 FIG. is a schematic structural diagram of a waterproof vent plug provided by an embodiment of the present application.

[0032] Figure 2 is based on Figure 1 the three-dimensional exploded view given.

[0033] Figure 3 is based on Figure 1 a schematic diagram of a waterproof vent plug in an open state given, and the arrow in the figure indicates the air flow direction.

[0034] Figure 4 FIG. is a schematic internal structure diagram of a main body provided by an embodiment of the present application.

[0035] Figure 5 FIG. is a schematic three-dimensional structure diagram of a main body provided by an embodiment of the present application.

[0036] Figure 6 FIG. is a schematic three-dimensional structure diagram of a guide post provided by an embodiment of the present application.

[0037] Figure 7 FIG. is a schematic three-dimensional structure diagram of a pressure ring provided by an embodiment of the present application.

[0038] Figure 8 FIG. is a schematic diagram of the distribution of drainage holes on a pressure ring provided by an embodiment of the present application.

[0039] In the figure, 1, main body; 2, guide post; 3, fixed ring; 4, spring; 5, one-way ventilation membrane; 6, pressure ring; 7, protective cover; 8, drainage channel; 9, seal; 11, stepped hole; 12, first channel; 14, annular contact surface; 15, connecting thread; 16, sealing ring; 21, first part; 22, second part; 23, second channel; 61, drainage hole; 71, channel; 111, first through hole; 112, second through hole; 113, third through hole. Detailed Description of the Embodiments

[0040] The following further elaborates on the technical solutions in the present application with reference to the accompanying drawings.

[0041] To better understand the technical solutions in the present application, the prior art will first be briefly introduced.

[0042] During the operation of the automobile transmission (reducer), the reducer heats up, the internal gas expands, and the internal air pressure surges. If the increased pressure cannot be released in time, it will cause the lubricating oil to leak from the seal or sealing surface, which is not conducive to the heat dissipation of the transmission (reducer).

[0043] Therefore, transmissions (reducers) are equipped with ventilation systems that connect to the atmosphere to balance the internal air pressure of the reducer, ensuring that each seal or sealing surface operates under a reasonable pressure differential to prevent transmission (reducer) lubricant leakage. At the same time, external dust or moisture cannot enter the transmission (reducer) to prevent the lubricant from deteriorating and causing premature failure of internal components.

[0044] The mainstream vent plugs on the market are divided into normal-pass vent plugs, one-way structure vent plugs, and one-way membrane vent plugs. The following introduces these three types of vent plugs respectively.

[0045] The conventional vent plug is usually connected to the atmosphere with a straight-through pipe and a dust cap is installed on the head. This structure has a low dust and water resistance level. Dust and water vapor can enter the reducer and cause the lubricating oil to deteriorate. The vehicle cannot pass the water test.

[0046] The one-way structure vent plug will exhaust air to the outside when the internal air pressure is greater than the opening pressure of the vent plug. If the vehicle is wading through water while exhausting, water will enter the open vent channel and the vehicle will fail the water wading test.

[0047] The one-way membrane vent plug can effectively prevent external dust and water from entering the gearbox, but when the vent membrane is stained with oil, the vent pores will be blocked and ventilation will be impossible.

[0048] See also Figure 1 and Figure 2 , is a waterproof vent plug disclosed in an embodiment of the present application, which is mainly composed of a main body 1, a guide column 2, a fixing ring 3, a spring 4, a one-way vent membrane 5 and a protective cover 7. Specifically, a stepped hole 11 is provided in the main body 1, and the function of the stepped hole 11 is to place the mechanical switch structure and the one-way vent membrane 5, etc.

[0049] See also Figure 4 The stepped hole 11 consists of a first through hole 111, a second through hole 112 and a third through hole 113. The three through holes are connected end to end, and the inner diameters increase sequentially, that is, the inner diameter of the first through hole 111 is smaller than the inner diameter of the second through hole 112, and the inner diameter of the second through hole 112 is smaller than the inner diameter of the third through hole 113.

[0050] The first through-hole 111 communicates with the first end of the main body 1, and the third through-hole 113 communicates with the second end of the main body 1. The first end of the main body 1 is used to connect to the device that needs air pressure adjustment. When exhausting is required, the excess gas inside the device sequentially passes through the first through-hole 111, the second through-hole 112, and the third through-hole 113.

[0051] Please refer to Figure 1 , the guide post 2 is located in the second through-hole 112 and is slidably connected to the second through-hole 112. Its function is to cooperate with the fixing ring 3 to control the on-off of the first through-hole 111 and the second through-hole 112. The fixing ring 3 is fixed in the third through-hole 113.

[0052] The guide post 2 has two positions, one is the closed position and the other is the open position. When the guide post 2 is in the closed position, the first through-hole 111 and the second through-hole 112 are in a disconnected state. When the guide post 2 is in the open position, the first through-hole 111 and the second through-hole 112 are in a connected state.

[0053] The power for the guide post 2 to move from the open position to the closed position is provided by the spring 4. The two ends of the spring 4 respectively abut against the guide post 2 and the fixing ring 3. Its function is to push one end of the guide post 2 to abut against the bottom surface of the second through-hole 112. Under the thrust of the spring 4, one end of the guide post 2 will abut against the bottom surface of the second through-hole 112.

[0054] The power for the guide post 2 to move from the closed position to the open position is provided by the air pressure inside the device. Because during use, the first through-hole 111 communicates with the space inside the device. That is to say, the air pressure in the first through-hole 111 is the same as the air pressure in the space inside the device. When the air pressure in the space inside the device changes, the air pressure in the first through-hole 111 will also change accordingly. However, since the guide post 2 blocks the connection between the first through-hole 111 and the second through-hole 112 at this time, the air pressure in the second through-hole 112 will not change.

[0055] Please refer to Figure 3 , when the air pressure inside the device increases, the air pressure in the first through-hole 111 will increase accordingly. At this time, the pressure acting on the guide post 2 will also increase. When the pressure increases to exceed the force exerted by the spring 4 on the guide post 2, the guide post 2 will move in the direction away from the first through-hole 111. At this time, a gap appears between the guide post 2 and the bottom surface of the second through-hole 112, and the first through-hole 111 and the second through-hole 112 are connected.

[0056] After the first through-hole 111 and the second through-hole 112 are connected, the excess gas inside the device will pass through the first through-hole 111 and flow into the second through-hole 112.

[0057] The one-way ventilation membrane 5 is placed inside the third through-hole 113, and its function is to restrict the flow direction of the gas inside the third through-hole 113. The one-way ventilation membrane 5 has the property of one-way gas passage, that is, gas can only flow from one side of the one-way ventilation membrane 5 to the other side and cannot flow in the reverse direction. This enables the gas inside the second through-hole 112 to flow through the one-way ventilation membrane 5 and into the third through-hole 113, but the gas inside the third through-hole 113 cannot flow into the second through-hole 112. At the same time, the one-way ventilation membrane 5 can also intercept dust, water vapor, etc.

[0058] The first channel 12 is located on the side wall of the main body 1 and is in communication with the external atmosphere, and its function is to discharge the excess gas inside the main body 1.

[0059] Please refer to Figure 1 , the protective cover 7 is fixed on the second end of the main body 1, and moreover, the protective cover 7 can also form a channel 71 at the second end of the main body 1. The channel 71 is used to connect the third through-hole 113 and the first channel 12. Since the third through-hole 113 is located inside the main body and the first channel 12 is located outside the main body 1 and they cannot be directly connected, after adding the channel 71, the gas flowing out of the third through-hole 113 can first flow into the channel 71 and then flow into the atmosphere through the first channel 12.

[0060] According to the records in the above content, the excess gas inside the device will sequentially pass through the first through-hole 111, the second through-hole 112, and the third through-hole 113, and then pass through the channel 71 and the first channel 12, and finally be discharged from the waterproof ventilation plug disclosed in the embodiment of the present application.

[0061] In some possible implementation manners, the protective cover 7 is connected to the main body 1 by riveting.

[0062] In some other possible implementation manners, the protective cover 7 is connected to the main body 1 by interference press-fitting.

[0063] It should be understood that the protective cover 7 can wrap the second end of the main body 1. Considering from the perspective of exhaust, the main body 1 no longer has the axial exhaust function. However, since the protective cover 7 connects the third through-hole 113 and the first channel 12, the main body 1 has the radial exhaust function. Combining a specific scenario, if there is a wading situation, the water will contact the outer surface of the protective cover 7 but will not enter the protective cover 7. Only during immersion or long-term immersion, the water will flow into the protective cover 7 along the first channel 12.

[0064] When there is no protective cover 7, that is, when the main body has the axial exhaust function, if there is a wading situation, then the water will directly enter the main body 1 from the exhaust port.

[0065] The second channel 23 is provided in the guide post 2 and functions to connect the second through hole 112 and the third through hole 113.

[0066] It should be understood that when the guide post 2 is located in the second channel 23, a part of the second channel 23 will be blocked, resulting in the gas in the second through hole 112 being unable to enter the third through hole 113 during the exhaust process. Therefore, the second channel 23 is required to connect the second through hole 112 and the third through hole 113.

[0067] The main function of the drainage channel 8 is to drain the water entering the main body 1. Combining a specific usage scenario, when water enters the main body 1, the water will flow through the first channel 12 and the channel 71 into the space on the exhaust side of the one-way ventilation membrane 5. However, due to the interception of the one-way ventilation membrane 5, this water will accumulate in the space on the exhaust side of the one-way ventilation membrane 5.

[0068] The drainage channel 8 is provided on the main body 1 and can connect the space on the exhaust side of the one-way ventilation membrane 5 with the first channel 12. In this way, the water accumulated on the exhaust side of the one-way ventilation membrane 5 can flow into the first channel 12 through the drainage channel 8 and then flow out through the first channel 12.

[0069] It should also be understood that the first channel 12 is connected to the external atmosphere, so it can be used both as an exhaust channel and as a drainage channel.

[0070] Overall, the waterproof ventilation plug provided in the embodiment of the present application uses a mechanical sealing method. When the air pressure inside the device increases, it will push the guide post 2 to move. At this time, the waterproof ventilation plug changes from a closed state to an open state. After the excess gas is discharged, the waterproof ventilation plug automatically changes from the open state to the closed state.

[0071] Since the daily state of the waterproof ventilation plug is the closed state, the oil inside the machine will not enter the main body 1 and cause the one-way ventilation membrane 5 to be contaminated by the oil.

[0072] When external water enters the main body 1, this water will accumulate on the exhaust side of the one-way ventilation membrane 5. Due to the blockage of the one-way ventilation membrane 5, the water entering the main body 1 will not enter the machine connected to the waterproof ventilation plug. The water on the exhaust side of the one-way ventilation membrane 5 will flow into the first channel 12 through the drainage channel 8 and then flow out through the first channel 12.

[0073] Please refer to Figure 1 , as a specific implementation manner of the waterproof ventilation plug provided in the application, a sealing member 9 is provided between the bottom surface of the second through hole 112 and the end of the guide post 2 close to the first through hole 111. The function of the sealing member 9 is to improve the sealing performance of the guide post 2.

[0074] It should be understood that both the main body 1 and the guide post 2 are made of rigid materials. Therefore, the fit between the two may not be tight, presenting a potential leakage risk. After adding the seal 9, the seal 9 is located between the bottom surface of the second through hole 112 and the guide post 2. When the guide post 2 contacts the seal 9, the seal 9 deforms, capable of providing better sealing performance.

[0075] In some possible implementation manners, the seal 9 is an O-ring.

[0076] In some other possible implementation manners, the seal 9 is a gasket.

[0077] Please refer to Figure 4 and Figure 5 , as a specific implementation manner of the waterproof breather plug provided in the application, an annular contact surface 14 is provided on the main body 1, and the outer diameter of the annular contact surface 14 is greater than the outer diameter of the first end of the main body 1. The function of increasing the annular contact surface 14 is to improve the sealing performance at the connection between the main body 1 and the device. When the annular contact surface 14 contacts the surface at the connection with the device, slight deformation can occur at the contacting part, making it not easy to leak here.

[0078] There are the following several connection methods between the main body 1 and the device.

[0079] First, a connection thread 15 is provided on the first end of the main body 1, and the main body 1 and the device are connected by a threaded connection method.

[0080] Second, there is no thread on the first end of the main body 1, but there is a bolt on the main body 1. One end of the bolt passes through the hole on the main body 1 and is screwed into the threaded hole on the device to fix the main body 1 on the device.

[0081] For the above two methods, an O-ring 16 can be added on the first end of the main body 1. The O-ring 16 is located between the annular contact surface 14 and the connection thread 15. Its function is to improve the sealing performance at the connection, prevent leakage, and at the same time, it can also prevent the lubricating oil inside the gearbox from leaking through the joint surface of this part, and also prevent external water vapor or dust from entering the inside of the transmission (reducer).

[0082] Please refer to Figure 6 , as a specific implementation manner of the waterproof breather plug provided in the application, the guide post 2 is composed of a first part 21 and a second part 22. The first part 21 and the second part 22 are integrally formed, and moreover, the outer diameter of the first part 21 is greater than the outer diameter of the second part 22.

[0083] The first part 21 of the guide post 2 is slidably connected to the second through hole 112, and there is a gap between the second part 22 and the inner wall of the second through hole 112. The function of this gap is to enable the air flowing in from the first through hole 111 to quickly flow into the second channel 23.

[0084] The first end of the second channel 23 communicates with the side wall of the second part 22. Since there is a gap between the second part 22 and the inner wall of the second through hole 112, the air flowing in from the first through hole 111 can quickly flow into the second channel 23. This structure can improve the exhaust speed without changing the volume of the guide post 2.

[0085] Please refer to Figure 1 , as a specific implementation of the waterproof vent plug provided in the application, the number of the drainage channels 8 can be one or multiple. When the number of the drainage channels 8 is appropriately increased, the accumulated water on the exhaust side of the one-way ventilation membrane 5 can be quickly discharged.

[0086] When the number of the drainage channels 8 is multiple, in the axial direction of the third through hole 113, at least two drainage channels 8 have different distances from the bottom surface of the third through hole 113. In this way, the accumulated water on the exhaust side of the one-way ventilation membrane 5 can be drained as much as possible.

[0087] It should be understood that the drainage channel 8 can only allow the water above the lowest point of the drainage channel 8 to flow out, and the water below the lowest point of the water channel 8 cannot flow out through the water channel 8. When the heights of the drainage channels 8 are the same, there is a possibility that the accumulated water on the exhaust side of the one-way ventilation membrane 5 cannot be discharged. When the distance between one drainage channel 8 and the one-way ventilation membrane 5 is very small, the possibility of accumulated water on the exhaust side of the one-way ventilation membrane 5 can be avoided.

[0088] Please refer to Figure 1 , as a specific implementation of the waterproof vent plug provided in the application, the pressure ring 6 in the third through hole 113 serves to press the one-way ventilation membrane 5 against the fixing ring 3, which can prevent the one-way ventilation membrane 5 from shifting due to influences such as air flow and vibration.

[0089] Of course, the one-way ventilation membrane 5 can also be fixed in the third through hole 113 by means of interference fit, etc. However, during long-term use, the connection may also become loose.

[0090] After adding the pressure ring 6, the pressure ring 6 can directly press the one-way ventilation membrane 5 against the fixing ring 3.

[0091] In some possible implementation manners, the mating relationship between the pressure ring 6 and the inner wall of the third through hole 113 is interference fit. Since the pressure ring 6 has a certain thickness and can withstand a certain amount of slight deformation, a relatively large interference amount can be used to ensure the connection strength with the third through hole 113.

[0092] Please refer to Figure 7, Further, drain holes 61 are added to the pressure ring 6. The number of drain holes 61 can be one or multiple. The drain holes 61 communicate with the matching drain channels 8, and the function is to enable the water inside the pressure ring 6 to be discharged through the drain holes 61 and the drain channels 8.

[0093] It should be understood that the pressure ring 6 has a certain thickness, so a water accumulation area will be formed on the exhaust side of the one-way ventilation membrane 5. The water accumulation area will cause the water on the exhaust side of the one-way ventilation membrane 5 to not be completely discharged. To avoid this situation, drain holes 61 are added to the pressure ring 6 and the drain holes 61 are aligned with the surrounding drain channels 8 when installing the pressure ring 6, so that the water in the water accumulation area can flow out through the drain holes 61 and the drain channels 8.

[0094] Please refer to Figure 8 , the number of drain holes 61 is multiple. To achieve a better drainage effect, in the axial direction of the pressure ring 6, at least two drain holes 61 have different distances from the same end face of the pressure ring 6, that is, based on one end face of the pressure ring 6, there are multiple drainage heights.

[0095] Similar to the description of the drain channel 8 in the previous text, after such adjustment, at least one drain hole 61 can be made as close as possible to the one-way ventilation membrane 5, so that the water on the exhaust side of the one-way ventilation membrane 5 can flow out as much as possible.

[0096] Please refer to Figure 1 and Figure 6 , as a specific implementation manner of the waterproof vent plug provided in the application, there are multiple communication points between the second channel 23 and the second through hole 112. The purpose of this is to enable the gas flowing into the second through hole 112 from the first through hole 111 to be discharged quickly.

[0097] Further, the communication points between the multiple second channels 23 and the second through hole 112 are arranged uniformly around the axis of the guide post 2.

[0098] It should be understood that when the guide post 2 is separated from the bottom surface of the second through hole 112 or the seal 9, the gas in the first through hole 111 will flow evenly around the guide post 2 and then enter the second through hole 112. When the communication points between the second channel 23 and the second through hole 112 are arranged uniformly around the axis of the guide post 2, the gas flowing into the second through hole 112 can quickly flow into the second channel 23 from the nearest communication point between the second channel 23 and the second through hole 112.

[0099] The embodiment of the present application also discloses a gearbox, including the waterproof vent plug described above.

[0100] The embodiment of the present application also discloses a vehicle, including the gearbox described above.

[0101] The embodiments of this specific implementation manner are all preferred embodiments of this application, and do not limit the protection scope of this application. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A waterproof vent plug, characterized in that, Comprising: A main body (1) with a stepped hole (11) provided therein. The stepped hole (11) includes a first through hole (111), a second through hole (112), and a third through hole (113) with sequentially increasing inner diameters. The first through hole (111) communicates with the first end of the main body (1), and the third through hole (113) communicates with the second end of the main body (1); A first channel (12) provided on the side wall of the main body (1), and the first channel (12) communicates with the external atmosphere; A guide post (2) slidably connected to the second through hole (112). The guide post (2) has two positions, one is a closed position and the other is an open position. When the guide post (2) is in the closed position, the first through hole (111) and the second through hole (112) are in a disconnected state. When the guide post (2) is in the open position, the first through hole (111) and the second through hole (112) are in a connected state; A fixing ring (3) fixed in the third through hole (113); A spring (4) with both ends respectively abutting against the guide post (2) and the fixing ring (3); A one-way ventilation membrane (5) provided in the third through hole (113); A protective cover (7) fixed to the second end of the main body (1) for forming a channel (71) at the second end of the main body (1), and the channel (71) is used to connect the third through hole (113) and the first channel (12); A second channel (23) provided in the guide post (2), and the second channel (23) is used to connect the second through hole (112) and the third through hole (113); and At least one drainage channel (8) provided on the main body (1) for connecting the space on the exhaust side of the one-way ventilation membrane (5) and the first channel (12).

2. The waterproof vent plug according to claim 1, characterized in that, A seal (9) is provided between the bottom surface of the second through hole (112) and the end of the guide post (2) close to the first through hole (111).

3. A waterproof ventilation plug according to claim 1, characterized in that, The main body (1) is provided with an annular contact surface (14), and the outer diameter of the annular contact surface (14) is greater than the outer diameter of the first end of the main body (1).

4. The waterproof vent plug according to claim 3, characterized in that, The first end of the main body (1) is provided with a connecting thread (15).

5. The waterproof vent plug according to claim 4, characterized in that, A sealing ring (16) is provided on the first end of the main body (1), and the sealing ring (16) is located between the annular contact surface (14) and the connecting thread (15).

6. The waterproof vent plug according to claim 1, wherein, In the axial direction of the third through hole (113), at least two drainage channels (8) have different distances from the bottom surface of the third through hole (113).

7. The waterproof vent plug according to claim 1, characterized in that, It further includes a pressure ring (6) provided in the third through hole (113). The pressure ring (6) is used to press the one-way ventilation membrane (5) against the fixing ring (3). The pressure ring (6) is provided with at least one drainage hole (61), and the drainage hole (61) communicates with the matching drainage channel (8). The number of the drainage holes (61) is multiple. In the axial direction of the pressure ring (6), at least two drainage holes (61) have different distances from the same end face of the pressure ring (6). The communication points between the second channel (23) and the second through hole (112) are multiple, and the multiple communication points between the second channel (23) and the second through hole (112) are evenly arranged around the axis of the guide post (2).

8. A waterproof vent plug according to any one of claims 1 to 7, characterized in that, The guide pin (2) includes a first part (21) and a second part (22) provided on the first part (21); The outer diameter of the first part (21) is larger than the outer diameter of the second part (22); The first end of the second channel (23) communicates with the side wall of the second part (22).

9. A transmission, characterized in that, It includes the waterproof breather plug according to any one of claims 1 to 8.

10. A vehicle, characterized in that, It includes the waterproof breather plug according to any one of claims 1 to 8 or the gearbox according to claim 9.

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