Air filter regulator for gearboxes

Abstract

This utility model discloses an air filter regulator for a gearbox, including a valve body with a valve seat inside. The valve seat has a vent hole, and a piston rod is installed with a gap in the vent hole. One end of the piston rod is connected to a valve core, which is connected to a snap-fit ​​valve via an elastic element. A composite filter screen is installed on the snap-fit ​​valve, located at the air inlet of the valve body, to filter the air entering the valve body. A threaded cap is connected to the end of the composite filter screen away from the snap-fit ​​valve and is installed on the valve body. The composite filter screen is a nano-porous metal mesh with an oleophobic glass fiber mesh nested within it. A piston is connected to the other end of the piston rod and is installed in the valve body. This air filter regulator, by incorporating a composite filter screen within the valve body, filters the air entering the valve body, ensuring efficient interception of micron-sized particles and oil mist.

Description

Technical Field

[0001] This utility model belongs to the technical field of auxiliary components for transmissions, specifically to an air filter regulator for transmissions. Background Technology

[0002] Traditional mechanical gearboxes use pneumatic shifting. Air filtered by an air filter passes through different chambers, driving cylinders to move left and right to switch between high and low gears. Existing air filters consist of a housing with a foam filter cartridge installed inside, secured by a cover. The foam filter cartridge filters the dry air entering the gearbox. Initially, this type of air filter effectively filters the air entering the gearbox. However, over time, impurities from the filtered air accumulate on the foam filter cartridge, reducing its filtration efficiency. This allows some airborne particles to enter the cylinders, causing them to stick over time. Consequently, the air filter needs to be replaced after a period of use. Utility Model Content

[0003] To address the problem that existing air filters have poor air filtration efficiency after a period of use, this invention provides an air filter regulator for gearboxes.

[0004] To achieve the above objectives, this utility model provides the following technical solution: This utility model proposes an air filter regulator for a gearbox, including a valve body, a valve seat provided in the valve body, a vent hole provided on the valve seat, a piston rod installed in the vent hole with a gap, a valve core connected to one end of the piston rod, a snap-fit ​​valve connected to the valve core through an elastic element, a composite filter screen installed on the snap-fit ​​valve, and the composite filter screen being located at the air inlet of the valve body to filter the air entering the valve body; A threaded top cover is connected to one end of the composite filter screen away from the snap-fit ​​valve, and the threaded top cover is installed on the valve body; The composite filter screen includes a nano-porous metal mesh, and an oleophobic glass fiber mesh is nested inside the nano-porous metal mesh. The other end of the piston rod is connected to a piston, which is installed in the valve body at a position below the air outlet.

[0005] Preferably, the elastic element is a first spring.

[0006] Preferably, the diameter of the composite filter screen gradually increases from the snap-fit ​​valve to the threaded top cover.

[0007] Preferably, a first porous filter screen is fixed inside the air inlet by a first retaining spring.

[0008] Preferably, a third porous filter is fixed inside the air outlet by a second retaining spring.

[0009] Preferably, a pressure regulating component is provided on the piston at a position away from the piston rod. The pressure regulating component is installed inside a threaded bottom cover, which is installed on the valve body. An adjusting element is installed in the threaded bottom cover, and one end of the adjusting element abuts against the pressure regulating component at a position away from the piston. An overflow hole is inclinedly provided on the threaded bottom cover.

[0010] Preferably, the pressure regulating assembly includes a second spring and a pressure regulating support plate, one end of the second spring abuts against the piston, the other end of the second spring abuts against the pressure regulating support plate, and a position on the pressure regulating support plate away from the second spring abuts against the regulating member.

[0011] Preferably, the adjusting component includes a pressure adjusting screw and a bottom cover locking screw. The threaded bottom cover has a threaded hole, and the pressure adjusting screw and the bottom cover locking screw are installed in the threaded hole. One end of the pressure adjusting screw has a connecting groove, and the inner end of the bottom cover locking screw is installed in the connecting groove. One end of the pressure adjusting screw abuts against the pressure adjusting support plate.

[0012] Preferably, a second porous filter screen is connected to the threaded bottom cover at the position inside the threaded hole via a third snap ring.

[0013] Preferably, a one-way membrane is provided between the second porous filter screen and the threaded hole.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects: This utility model proposes an air filter regulator for a gearbox. This air filter regulator sets up a composite filter screen in the valve body. The composite filter screen uses a nano-perforated metal mesh and an oleophobic glass fiber mesh to perform dual filtration of the air entering the valve body, ensuring the interception efficiency of micron-sized particles and oil mist.

[0015] Furthermore, the diameter of the composite filter in this air filter regulator gradually increases from the snap-on valve to the threaded top cover, reducing the uneven force caused by the composite filter shaking under strong airflow, thus preventing internal jamming.

[0016] Furthermore, a first porous filter screen is installed in the air inlet of this air filter regulator. The first porous filter screen initially filters the air entering the valve body, reducing the filtration load of the composite filter screen, extending the life of the composite filter screen, and reducing the replacement frequency of the composite filter screen.

[0017] Furthermore, this air filter regulator is equipped with a third porous filter in the air outlet. This third porous filter further filters the air filtered by the composite filter, thereby improving the cleanliness of the air. At the same time, it also prevents impurities in the air path from being drawn back into the air filter regulator.

[0018] Furthermore, this air filter regulator has a second porous filter screen installed inside the threaded bottom cover above the overflow hole, and a one-way diaphragm installed between the second porous filter screen and the threaded hole. This allows excess gas in the outlet chamber to be discharged, preventing impurities outside the valve body from entering the outlet chamber, thus ensuring the effectiveness and safety of the air filter regulator in filtering air. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of an air filter regulator for a gearbox proposed in this utility model. Figure 2 This is a three-dimensional structural diagram of an air filter regulator for a gearbox proposed in this utility model from another perspective. Figure 3 This is a front cross-sectional view of an air filter regulator for a gearbox proposed in this utility model; Figure 4 This is a side cross-sectional view of an air filter regulator for a gearbox proposed in this utility model; Figure 5 for Figure 3 Enlarged view of point A in the middle; Figure 6 for Figure 3 Enlarged view of point B in the middle; Figure 7 for Figure 3 Enlarged view of point C in the middle; Figure 8 for Figure 3 Enlarged view of point D in the middle; Figure 9 for Figure 3 Cross-sectional view at EE; Figure 10 for Figure 3 Cross-sectional view at the FF point; In the attached diagram: 1. First porous filter screen; 2. First snap ring; 3. Air inlet; 4. Snap-on valve; 5. First fastening screw; 6. Threaded bottom cover; 7. Second porous filter screen; 8. Composite filter screen; 9. Valve body; 10. Second snap ring; 11. Air outlet; 12. Third porous filter screen; 13. Second fastening screw; 14. Pressure regulating support plate; 15. One-way diaphragm; 16. Threaded top cover; 17. First sealing ring; 18. First spring; 19. Valve core; 20. Valve seat; 21. Piston; 22. Third snap ring; 23. Pressure regulating screw; 24. Top cover locking screw; 25. Second sealing ring; 26. Piston rod; 27. Third sealing ring; 28. Second spring; 29. ​​Overflow hole; 30. Bottom cover locking screw. Detailed Implementation

[0020] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this invention. Therefore, the drawings and description are considered exemplary in nature and not restrictive.

[0021] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0026] This utility model proposes an air filter regulator for a gearbox, such as... Figures 1-10As shown, the device includes a valve body 9, within which a valve seat 20 is provided. The valve seat 20 divides the interior of the valve body 9 into an inlet chamber and an outlet chamber. The inlet chamber is located above the outlet chamber. An air inlet 3 is horizontally positioned on the inlet chamber, and one end of an air inlet pipe is connected to the air inlet 3. An air outlet 11 is inclined upward on the outlet chamber, and the air outlet 11 is connected to a transmission via a pipeline. A vent hole is provided on the valve seat 20, and a piston rod 26 is installed in the vent hole. A certain gap is reserved between the inner wall of the vent hole and the outer wall of the piston rod 26 for the flow of filtered air. One end of the piston rod 26 extends into the inlet chamber, and the other end of the piston rod 26 extends into the inlet chamber. A valve core 19 is connected to the end of the piston rod 26 located in the inlet chamber. The valve core 19 is a triangular flange prism. A concave pedestal that mates with the valve core 19 is provided inside the valve seat 20. A snap-fit ​​valve is connected to the top end of the valve core 19 via an elastic element. Door 4 has a first spring 18 as its elastic element. The first spring 18 is installed on the top boss of the valve core 19 to ensure the stability of the valve core 19's vertical movement, thus guaranteeing verticality and reducing the valve core 19's shaking caused by airflow disturbance. The upper end face of the snap-fit ​​valve 4 is provided with a slot, and a composite filter screen 8 is installed in the slot. The composite filter screen 8 is installed inside the valve body 9 at the position of the air inlet 3 to filter the air entering the valve body 9 through the air inlet 3. A threaded top cover 16 is connected to the end of the composite filter screen 8 away from the snap-fit ​​valve 4. The threaded top cover 16 is installed on the valve body 9. The composite filter screen 8 includes a nano-sand porous metal mesh, and an oleophobic glass fiber mesh is nested inside the nano-sand porous metal mesh. The other end of the piston rod 26 is connected to a piston 21. A through hole is provided at the center position of the piston rod 26 and the piston 21. The piston 21 is installed inside the valve body 9 below the air outlet 11. In this air filter regulator, air enters the valve body 9 through the air inlet 3. The combination of oleophobic glass fiber mesh and nano-porous metal mesh ensures the interception efficiency of micron-sized particles and oil mist, while suppressing the efficiency reduction caused by icing in extreme low-temperature environments. Compared with the original filter structure, the filtration efficiency is improved and a good environment is ensured inside the valve body 9. The filtered air enters the intake chamber through the snap-on valve 4 and the through hole on the valve seat 20, and is delivered to the gear shifting mechanism of the transmission through the air outlet 11 on the intake chamber.

[0027] like Figure 3 As shown, an annular groove is provided on the outer wall of piston 21, and a third sealing ring 27 is installed in the annular groove. The outer wall of the third sealing ring 27 fits against the inner wall of valve body 9 to seal the gap between the outer wall of piston 21 and the inner wall of valve body 9.

[0028] like Figure 3As shown, a second sealing ring 25 is provided between the inner wall of the threaded top cover 16 and the upper end of the composite filter screen 8. The second sealing ring 25 is used to seal the gap between the inner wall of the threaded top cover 16 and the upper end of the composite filter screen 8. A first sealing ring 17 is provided between the threaded top cover 16 and the valve body 9. A connecting hole is provided on the top end face of the threaded top cover 16. The inner end of the connecting hole communicates with the interior of the valve body 9. A top cover locking screw 24 is screwed into the connecting hole.

[0029] like Figure 3 As shown, a pressure regulating hole is provided on the valve body 9 at the position of the air outlet chamber, and a first fastening screw 5 is screwed into the pressure regulating hole.

[0030] like Figure 3 As shown, the diameter of the composite filter 8 gradually increases from the snap-fit ​​valve 4 to the threaded top cover 16, reducing the uneven force caused by the swaying of the composite filter 8 under strong airflow. This avoids the force changes of the elastic element and the uneven wear of the valve core 19 caused by the loosening of the snap-fit ​​valve 4, which could lead to internal jamming. Multiple limiting platforms are set near the valve seat 20 in the air intake chamber. The multiple limiting platforms are circumferentially and evenly spaced around the inner wall of the valve body 9. The bottom end face of the limiting platform is attached to the upper end face of the snap-fit ​​valve 4, and the inner end face of the limiting platform is attached to the outer wall of the composite filter 8. The snap-fit ​​valve 4 is fixed by the limiting platform. When it is necessary to disassemble the snap-fit ​​valve 4, the connection between the snap-fit ​​valve 4 and the limiting platform is disengaged by rotating the snap-fit ​​valve 4, which facilitates the disassembly of the snap-fit ​​valve 4 and the cleaning of the internal space of the valve body 9. The limiting platform also ensures the verticality of the elastic element.

[0031] like Figure 3 and Figure 5 As shown, a first porous filter 1 is fixed inside the air inlet 3 by a first retaining spring 2. Specifically, the side of the first porous filter 1 away from the air intake chamber is locked by the air input pipe, and the first retaining spring 2 is provided on the side of the first porous filter 1 near the air intake chamber. A first annular groove is provided inside the air inlet 3, and the first retaining spring 2 is locked in the first annular groove. The first porous filter 1 is a diaphragm filter. The first porous filter 1 initially filters the air inside the input valve body 9, reducing the all-round dust prevention burden of the composite filter 8, reducing the replacement frequency of the composite filter 8, and saving costs. Furthermore, since the first porous filter 1 is located at the interface end of the air input pipe, it is easy to clean. like Figure 3 and Figure 6As shown, a third porous filter 12 is fixed inside the air outlet 11 by a second retaining spring 10. Specifically, a retaining plate is provided inside the air outlet 11, and the third porous filter 12 is installed on the outer wall of the retaining plate inside the air outlet 11. A second retaining spring 10 is provided on the outer wall of the third porous filter 12 inside the air outlet 11 to fix the third porous filter 12 inside the air outlet 11. The third porous filter 12 is an oleophobic and hydrophobic filter. The air filtered by the composite filter 8 is further filtered by the third porous filter 12, which further improves the cleanliness of the air entering the gearbox. At the same time, it also prevents oil mist or other impurities inside the gearbox from flowing back into the valve body 9. A cleaning hole is provided on the valve body 9 at the position of the third porous filter 12. A second fastening screw 13 is screwed into the cleaning hole. When cleaning is required, the third porous filter 12 can be cleaned regularly by removing the second fastening screw 13, reducing the replacement frequency.

[0032] like Figure 3 and Figure 4 As shown, a pneumatic pressure regulating component is provided on the piston 21 at a position away from the piston rod 26. The pneumatic pressure regulating component is installed inside the threaded bottom cover 6, which is installed on the valve body 9. An adjusting component is installed in the threaded bottom cover 6, and one end of the adjusting component abuts against the pneumatic pressure regulating component at a position away from the piston 21. An overflow hole 29 is inclined downward on the threaded bottom cover 6. That is, the height of the port inside the threaded bottom cover 6 is higher than the port outside the threaded bottom cover 6. The inclined downward overflow hole 29 can effectively prevent water from entering the interior of the valve body 9, reducing the possibility of rust, jamming, breakage and failure of the internal parts of the valve body 9 due to water entering.

[0033] like Figure 3 and Figure 4 As shown, the air pressure regulating assembly includes a second spring 28 and a pressure regulating support plate 14. One end of the second spring 28 abuts against the piston 21, and the other end of the second spring 28 abuts against the pressure regulating support plate 14. The pressure regulating support plate 14 abuts against the regulating member at a position away from the second spring 28.

[0034] like Figure 3 , Figure 4 and Figure 7As shown, the adjusting components include a pressure adjusting screw 23 and a bottom cover locking screw 30. The threaded bottom cover 6 has a threaded hole, and the pressure adjusting screw 23 and the bottom cover locking screw 30 are installed in the threaded hole. The pressure adjusting screw 23 is used to adjust the air pressure at the output port of the air filter, and the bottom cover locking screw 30 is used to prevent the pressure adjusting screw 23 from loosening and falling out due to continuous pressure. The pressure adjusting screw 23 and the bottom cover locking screw 30 are joined by a tenon and mortise joint, with a reserved space in the middle. Compared with the traditional one-piece pressure adjusting screw, this method can effectively prevent the screw from coming out under force, improve the service life of the structure, ensure air pressure stability, and reduce air pressure fluctuations.

[0035] like Figure 3 , Figure 4 and Figure 7 As shown, a second porous filter 7 is connected to the inner port of the threaded hole on the threaded bottom cover 6 via a third snap ring 22. The second porous filter 7 isolates the debris entering the inner cavity of the threaded bottom cover 6 from the overflow hole 29 within the threaded bottom cover 6 at the lower end of the second porous filter 7, ensuring the cleanliness of the entire air outlet chamber, reducing the corrosion of internal components by oil sludge and other impurities, and extending the service life of the air filter regulator.

[0036] like Figure 3 , Figure 4 and Figure 7 As shown, a one-way diaphragm 15 is provided between the second porous filter 7 and the threaded hole. When excess gas in the outlet chamber needs to be discharged, the gas passes through the second porous filter 7, blowing open the one-way diaphragm 15 and discharging from the overflow hole 29. Air or impurities entering the outlet chamber through the overflow hole 29 cannot pass through the second porous filter 7 due to the action of the one-way diaphragm 15, preventing external impurities from entering the outlet chamber and contaminating the air filtered by the composite filter 8. Simultaneously, the one-way diaphragm 15 and the pressure adjusting screw 23 are interference-fitted, preventing the pressure adjusting screw 23 from being dislodged under force and sharing some of the force on the bottom cover locking screw 30.

[0037] When using this air filter regulator, adjust the pressure adjusting screw 23 according to the user's gas pressure requirements to make the air pressure at the air outlet 11 reach the required value, and tighten the bottom cover locking screw 30; when the gearbox switches between high and low gears, the integrated valve intake air passage is connected, and the air source of the whole vehicle air cylinder reaches the air inlet 3 of the gearbox air filter regulator through the connecting air passage; the air first passes through the first porous filter 1, then through the composite filter 8, and enters the valve seat 20 through the pre-reserved small hole at the top of the snap-on valve 4. At this time, the valve core 19 is kept in a balanced state under the force of the piston rod 26 and the first spring 18, and the passage between the valve seat 20 and the valve core 19 is in the open state; the air passing through the valve seat 20 quickly fills the top of the piston 21, then passes through the third porous filter 12, and enters the integrated valve intake pipe connected to the gearbox through the air outlet 11; When the air pressure at the air outlet 11 reaches the set value, the air gathered at the top of the piston 21 pushes the piston 21, which in turn compresses the second spring 28 and moves downward. At the same time, the valve core 19 moves downward under the action of the first spring 18 and gravity. The bottom of the valve core 19 is in contact with the upper surface of the valve seat 20, and the airflow channel is closed, so the air inlet 3 no longer receives air. When the air pressure at the air outlet 11 is greater than the set value, since the channel between the valve core 19 and the valve seat 20 is closed, the air pressure acts on the piston 21, and the piston 21 continues to compress the second spring 28 and moves downward. The piston rod 26 separates from the valve core 19, and the excess gas enters the cavity where the threaded bottom cover 6 is located through the through hole on the piston rod 26 and the piston 21, passes through the second porous filter screen 7, and is then discharged to the outside of the valve body 9 through the overflow hole 29. The piston 21 moves upward due to the decrease in pressure, and the piston rod 26 moves upward and is in contact with the bottom surface of the valve core 19, closing the air passage where the overflow hole 29 is located again.

[0038] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. It will be apparent to those skilled in the art that this utility model is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and thus all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this utility model. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0039] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of this utility model and should not be used to limit the scope of protection of this utility model. Any modifications made to the technical solutions based on the technical concept proposed by this utility model shall fall within the scope of protection of the claims of this utility model.

Claims

1. An air filter regulator for a gearbox, characterized in that, Includes a valve body (9), a valve seat (20) is provided inside the valve body (9), a vent hole is provided on the valve seat (20), a piston rod (26) is installed in the vent hole with a gap, a valve core (19) is connected to one end of the piston rod (26), a snap-fit ​​valve (4) is connected to the valve core (19) through an elastic element, a composite filter screen (8) is installed on the snap-fit ​​valve (4), and the composite filter screen (8) is located at the air inlet (3) inside the valve body (9) to filter the air entering the valve body (9); The composite filter screen (8) is connected to a threaded top cover (16) at one end away from the snap-on valve (4), and the threaded top cover (16) is installed on the valve body (9). The composite filter (8) is a nano-porous metal mesh, and an oleophobic glass fiber mesh is nested inside the nano-porous metal mesh; The other end of the piston rod (26) is connected to a piston (21), which is installed inside the valve body (9) below the air outlet (11).

2. The air filter regulator for a gearbox according to claim 1, characterized in that, The elastic element is the first spring (18).

3. The air filter regulator for a gearbox according to claim 1, characterized in that, The diameter of the composite filter (8) gradually increases from the snap-fit ​​valve (4) to the threaded top cover (16).

4. The air filter regulator for a gearbox according to claim 1, characterized in that, The first porous filter (1) is fixed inside the air inlet (3) by the first snap ring (2).

5. The air filter regulator for a gearbox according to claim 1, characterized in that, A third porous filter (12) is fixed inside the air outlet (11) by a second retaining ring (10).

6. The air filter regulator for a gearbox according to claim 1, characterized in that, A pressure regulating component is provided on the piston (21) at a position away from the piston rod (26). The pressure regulating component is installed inside the threaded bottom cover (6). The threaded bottom cover (6) is installed on the valve body (9). An adjusting component is installed in the threaded bottom cover (6). One end of the adjusting component abuts against the pressure regulating component at a position away from the piston (21). An overflow hole (29) is inclinedly provided on the threaded bottom cover (6).

7. The air filter regulator for a gearbox according to claim 1, characterized in that, The pressure regulating assembly includes a second spring (28) and a pressure regulating support plate (14). One end of the second spring (28) abuts against the piston (21), and the other end of the second spring (28) abuts against the pressure regulating support plate (14). The position of the pressure regulating support plate (14) away from the second spring (28) abuts against the regulating member.

8. An air filter regulator for a gearbox according to claim 7, characterized in that, The adjusting component includes a pressure adjusting screw (23) and a bottom cover locking screw (30). The threaded bottom cover (6) is provided with a threaded hole. The pressure adjusting screw (23) and the bottom cover locking screw (30) are installed in the threaded hole. One end of the pressure adjusting screw (23) is provided with a connecting groove. The inner end of the bottom cover locking screw (30) is installed in the connecting groove. One end of the pressure adjusting screw (23) abuts against the pressure adjusting support plate (14).

9. An air filter regulator for a gearbox according to claim 7, characterized in that, The threaded bottom cover (6) is connected to a second porous filter screen (7) via a third snap ring (22) at the position of the inner port of the threaded hole.

10. An air filter regulator for a gearbox according to claim 9, characterized in that, A one-way membrane (15) is provided between the second porous filter (7) and the threaded hole.

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