An oil leakage-proof and air-permeable cap and a speed reducer

Abstract

The application discloses an oil-leakage-proof and air-permeable cap and a speed reducer, and relates to the technical fields of mechanical sealing and air permeation. The oil-leakage-proof and air-permeable cap is used for being installed on a box body and comprises an oil inlet, an elongated channel, an oil storage chamber and an oil return structure. The oil inlet is communicated with the elongated channel, the elongated channel is communicated with the oil storage chamber, and the oil return structure is used for connecting the oil storage chamber with the box body. The aperture of the oil inlet is smaller than that of the elongated channel. The application reduces the aperture of the oil inlet to inhibit the oil liquid from rushing in, promotes the condensation of oil gas through the elongated channel, temporarily stores the oil liquid through the oil storage chamber, and guides the oil liquid back to the box body through the oil return structure. While the air permeation function is ensured, the oil leakage problem of the air-permeable cap is fundamentally solved. The application further discloses a speed reducer comprising the oil-leakage-proof and air-permeable cap.

Description

Technical Field

[0001] This invention relates to the field of mechanical seal and venting technology, and more specifically, to an oil-leakage-proof venting cap and a speed reducer. Background Technology

[0002] During operation, enclosed transmission devices such as speed reducers and gearboxes generate energy losses due to internal gear meshing and bearing rotation. These losses are converted into heat, causing the internal temperature of the housing to rise. Increased temperature leads to more intense movement of gas molecules within the housing, resulting in increased gas pressure. If this high-pressure gas is not released in time, it will accelerate the aging of internal parts and increase the risk of lubricating oil leakage.

[0003] In existing technologies, conventional vent caps employ a straight-through, large-opening structure with an internal one-way valve, utilizing the pressure difference between the inside and outside to regulate the internal air pressure of the housing. However, this structure has significant drawbacks: on the one hand, the high-temperature atomized oil and gas inside the housing condenses on the inner wall of the vent cap, forming oil droplets that eventually leak from the vent cap outlet; on the other hand, when the gears rotate, they push the liquid oil against the vent cap, potentially causing a large influx of liquid oil into the vent cap, which in turn forces the one-way valve open, leading to oil leakage.

[0004] Therefore, how to effectively solve the oil leakage problem of the breathable cap is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide an oil leak-proof vent cap and a speed reducer including the oil leak-proof vent cap, so as to solve the oil leakage problem caused by oil vapor condensation and oil inrush in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides an oil leak-proof and breathable cap for installation on a housing, comprising: an oil inlet, an extended channel, an oil storage chamber, and an oil return structure.

[0007] The extended channel connects to the oil inlet. The oil storage chamber connects to the extended channel. The oil return structure connects the oil storage chamber to the housing. The diameter of the oil inlet is smaller than the diameter of the extended channel.

[0008] In the above structure, the reduced inlet diameter effectively decreases the impact force when oil rushes in, preventing leakage caused by a large amount of oil instantly impacting the one-way valve. Simultaneously, the extended channel provides a longer oil-gas flow path, allowing the high-temperature atomized oil-gas to fully diffuse, cool, and condense on the inner wall of the channel. The design of the inlet diameter being smaller than the extended channel diameter allows the oil-gas to rapidly expand and diffuse after entering the extended channel, further promoting condensation. The oil storage chamber temporarily stores the oil that has accumulated after condensation and rushing in, preventing direct leakage from the vent cap. The oil return structure guides the oil accumulated in the storage chamber back to the tank, achieving oil recycling and fundamentally eliminating oil leakage.

[0009] Preferably, the diameter of the oil inlet is 1 mm to 1.5 mm, and the diameter of the extended channel is 1.5 mm to 2 mm.

[0010] The above numerical range represents the optimal parameter interval determined by the inventors through extensive experimental verification. The inlet diameter is controlled at 1-1.5 mm, ensuring smooth flow of oil and gas mist while effectively suppressing the impact force of liquid oil influx. The extended channel diameter is controlled at 1.5-2 mm to ensure sufficient diffusion and condensation of oil and gas, while preventing channel blockage.

[0011] Preferably, the oil return structure includes an oil return groove and an oil guide line disposed in the oil return groove.

[0012] The combination of the return oil trough and the guide oil line creates a capillary flow effect, allowing the oil accumulated in the oil storage chamber to flow back to the tank continuously and stably without the need for additional power.

[0013] Preferably, the oil guide wire is a flexible fiber bundle.

[0014] Flexible fiber bundles have good capillary liquid absorption properties and flexibility, making them easy to install and fix in the oil return tank, and can adapt to oil return tank structures of different shapes.

[0015] Preferably, the oil storage chamber is located at the outlet end of the extended channel.

[0016] By placing the oil storage chamber at the outlet end of the extended channel, the condensed oil can naturally collect at the bottom of the oil storage chamber under gravity, facilitating the oil return structure to guide and recover the oil.

[0017] The present invention also provides a speed reducer, comprising: a housing and an oil leak-proof vent cap as described above. The oil leak-proof vent cap is installed on the housing, and the oil inlet communicates with the interior of the housing.

[0018] The aforementioned reducer uses the leak-proof vent cap of the present invention, which can effectively solve the problem of oil leakage from the vent cap, improve the operational reliability and cleanliness of the reducer, and reduce maintenance frequency and lubricating oil consumption.

[0019] Preferably, the oil return structure connects the oil storage chamber with the interior of the housing.

[0020] The oil return structure directly connects the oil storage chamber to the inside of the tank, ensuring that the condensed and recovered oil can be directly returned to the oil sump in the tank, thus realizing the recycling of lubricating oil. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a schematic diagram of the overall structure of the oil-proof and breathable cap of the present invention.

[0022] Figure 2 This is a schematic diagram of the assembly structure of the oil guide line and oil return groove of the oil return structure of the present invention.

[0023] Figure 3 This is a cross-sectional view of the oil-proof and breathable cap of the present invention.

[0024] Figure 4 This is a three-dimensional structural diagram of the oil-proof and breathable cap of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0026] This invention provides an oil leak-proof vent cap and a speed reducer including the oil leak-proof vent cap. The specific structure of the oil leak-proof vent cap will be described in detail below.

[0027] like Figures 1 to 4 As shown, this embodiment provides an oil leak-proof vent cap for installation on a housing (e.g., a gearbox housing). The oil leak-proof vent cap mainly includes: an oil inlet 10, an extended channel 11, an oil storage chamber 12, and an oil return structure 13.

[0028] The oil inlet 10 is located at the bottom of the leak-proof vent cap (i.e., the end closest to the housing) and is used to connect to the internal space of the housing. The diameter of the oil inlet 10 is designed to be relatively small, smaller than the diameter of the extended channel 11 described below.

[0029] By reducing the diameter of the oil inlet 10, the impact force and inflow of liquid oil into the vent cap when subjected to external impact or severe vibration can be effectively reduced. According to fluid mechanics principles, under the same pressure difference, fluid flow rate is directly proportional to the flow cross-sectional area (Q∝A). When the diameter of the oil inlet 10 is reduced, the cross-sectional area decreases, and the inflow of oil flow rate is significantly reduced, thereby preventing a large amount of oil from instantly impacting and opening the one-way valve inside the vent cap, thus suppressing the risk of oil leakage at the source. At the same time, the reduced diameter has minimal impact on gaseous oil mist molecules. Since the mean free path of gas molecules is much larger than that of oil droplets, the oil mist can still smoothly pass through the oil inlet 10 into the vent cap, ensuring the normal venting and pressure relief function of the tank.

[0030] The extended channel 11 is connected above the oil inlet 10 (i.e., at the end away from the housing). The extended channel 11 is designed to have a longer axial length and its diameter is larger than that of the oil inlet 10.

[0031] The extended channel 11 provides a longer oil and gas flow path. When high-temperature oil and gas mist enters the extended channel 11 from the inlet 10, on the one hand, because the aperture of the extended channel 11 is larger than that of the inlet 10, the oil and gas mist expands and diffuses rapidly after entering, reducing pressure and temperature; on the other hand, as the oil and gas mist flows upward along the extended channel 11, it comes into full contact with the inner wall of the channel, and heat is dissipated outward through the pipe wall, achieving efficient cooling and condensation. The longer the extended channel 11, the more complete the condensation of the oil and gas mist, thus converting most of the oil mist into liquid oil droplets before entering the oil storage chamber 12, reducing the possibility of subsequent leakage. In addition, even if liquid oil rushes in under impact, the longer path of the extended channel 11 provides sufficient buffer distance, allowing the kinetic energy of the oil to gradually dissipate, further weakening its impact on the one-way valve.

[0032] The oil storage chamber 12 is connected above the extended channel 11 (i.e., the outlet end of the extended channel 11). The internal volume of the oil storage chamber 12 is larger than the volume of the extended channel 11, and it is used to temporarily store the oil that has accumulated after condensation and after influx.

[0033] The oil storage chamber 12 serves as a buffer storage space, capable of receiving all oil flowing in from the extended channel 11 (including condensed oil droplets and a small amount of incoming liquid oil), preventing oil from directly overflowing from the vent of the vent cap. Simultaneously, the oil storage chamber 12 provides a centralized collection area for oil return, allowing the oil to naturally collect at the bottom of the chamber under gravity, facilitating the return oil structure 13 for diversion and recovery. Without the oil storage chamber 12, condensed oil droplets would adhere directly to the vicinity of the vent, eventually dripping or spraying out under gravity or airflow, causing oil leakage.

[0034] The oil return structure 13 is located at the bottom or lower side of the oil storage chamber 12, and is used to connect the oil storage chamber 12 with the inside of the tank, so as to guide the oil accumulated in the oil storage chamber 12 back to the tank.

[0035] The oil return structure 13 forms a dedicated channel for oil to return to the tank. Through this structure, the oil accumulated in the oil storage chamber 12 is no longer "waste oil" with nowhere to go, but is actively guided back to the tank's oil sump, achieving the recycling of lubricating oil. This not only completely solves the oil leakage problem but also reduces lubricating oil consumption and lowers maintenance costs. Simultaneously, the continuous guiding effect of the oil return structure 13 keeps the oil storage chamber 12 at a low liquid level, avoiding the risk of excessive oil accumulation and overflow from the vent, forming a complete closed loop of "entry-condensation-storage-return".

[0036] In this embodiment, the diameter of the oil inlet 10 is smaller than the diameter of the extended channel 11. This dimensional relationship is one of the key features for achieving the technical effect of the present invention.

[0037] As mentioned earlier, the "small orifice" design of the oil inlet 10 is used to control the inflow of liquid oil, while the "large diameter" design of the extended channel 11 is used to promote the expansion and condensation of oil and gas. The "small inlet, large outlet" structure formed by the two functions combines the dual functions of preventing inflow and condensation. Specifically, when oil and gas mist enters the extended channel 11 with a large diameter from the small-diameter oil inlet 10, it undergoes adiabatic expansion. The increased volume leads to a decrease in pressure and temperature, accelerating the condensation and precipitation of oil and gas. This effect cannot be achieved in a single-diameter straight-through vent cap.

[0038] Based on the above basic structure, as a preferred embodiment, the diameter of the oil inlet 10 is 1 mm to 1.5 mm, and the diameter of the extended channel 11 is 1.5 mm to 2 mm.

[0039] The inventors systematically optimized the aperture parameters of the oil inlet 10 and the extended channel 11 through extensive simulation experiments and prototype testing. Experiments show that: When the diameter of the oil inlet 10 is greater than 1.5 mm, the impact force of the liquid oil rushing in increases, and the risk of oil leakage rises. When the diameter of the oil inlet 10 is less than 1 mm, the air resistance increases and the internal pressure of the box rises. When the diameter of the extended channel 11 is less than 1.5 mm, the oil and gas expansion space is insufficient, and the condensation effect decreases. When the diameter of the extended channel 11 is greater than 2 mm, the overall size of the vent cap increases, and the installation space requirement increases.

[0040] Therefore, limiting the diameter of the oil inlet 10 to 1-1.5 mm and the diameter of the extended channel 11 to 1.5-2 mm is the optimal parameter range that achieves a balance between anti-surge effect, condensation efficiency and air permeability.

[0041] like Figure 2 As shown, in a preferred embodiment, the oil return structure 13 includes an oil return groove 15 and an oil guide line 14 disposed in the oil return groove 15.

[0042] The oil return groove 15 is located at the bottom of the oil storage chamber 12 and is a long, narrow groove that extends along the bottom wall of the oil storage chamber 12 toward the bottom of the vent cap, eventually connecting with the oil inlet 10 or directly into the interior of the tank. An oil guide line 14 is placed inside the oil return groove 15. The diameter of the oil guide line 14 is slightly larger than the width or depth of the oil return groove 15, so that the oil guide line 14 is slightly compressed and secured within the oil return groove 15, ensuring both a secure hold and allowing for oil flow.

[0043] The oil return groove 15 and the oil guide line 14 together constitute a capillary flow system. The oil guide line 14 itself has a porous fiber structure, which can use capillary effect to absorb the oil at the bottom of the oil storage chamber 12 and transport it downward along the oil return groove 15. Even if the vent cap is tilted or vibrating, the capillary force can still maintain the continuous return flow of the oil, which is not limited by the direction of gravity. At the same time, the oil return groove 15 provides precise positioning and fixation for the oil guide line 14, preventing the oil guide line 14 from shifting or falling off during use. The tiny gap between the oil guide line 14 and the oil return groove 15 provides a channel for gas flow, avoiding the impact of the ventilation function due to complete blockage of the oil return structure 13.

[0044] In a preferred embodiment, the oil guide 14 is a flexible fiber bundle. Specifically, the oil guide 14 can be made of natural fiber materials (such as cotton rope or wool rope) or synthetic fiber materials (such as polyester rope, nylon rope, or polypropylene rope).

[0045] The flexible fiber bundles possess excellent capillary absorption properties, enabling rapid adsorption and transport of oil. Simultaneously, the flexible fiber bundles exhibit good flexibility and compressibility, facilitating insertion into the oil return groove 15 during installation. After slight compression, they adhere tightly to the inner wall of the oil return groove 15, ensuring reliable fixation while preventing damage to the vent cap body due to rigid contact. Furthermore, the multi-strand structure of the fiber bundles provides multiple parallel capillary channels, ensuring that even if some fibers are blocked by oil, other fibers can still maintain the oil return function, providing redundancy and reliability.

[0046] Experimental verification: Using cotton rope as the oil guide line 14, a 48-hour continuous operation test was conducted under simulated working conditions, and no visible oil droplets leaked from the exhaust port of the vent cap.

[0047] In a preferred embodiment, the oil storage chamber 12 is located at the outlet end of the extended channel 11. In other words, the oil storage chamber 12 is an enlarged area at the end of the extended channel 11, forming a stepped or trumpet-shaped transition structure.

[0048] The oil storage chamber 12 is positioned at the outlet end of the extended channel 11, allowing the oil flowing out of the extended channel 11 (whether it's condensed oil droplets or incoming liquid oil) to directly enter the oil storage chamber 12 under inertia, without splashing onto the exhaust port. Simultaneously, under gravity, the oil naturally flows downwards and collects at the bottom of the oil storage chamber 12, precisely at the inlet of the return oil structure 13, achieving an "automatic oil collection" effect. Furthermore, this design ensures that the bottom wall of the oil storage chamber 12 is lower than the lowest point of the extended channel 11's outlet, creating a certain "oil storage depth." Even if the return oil speed temporarily lags behind the inlet oil speed, the oil storage chamber 12 can still hold a certain amount of oil without overflowing, thus acting as a buffer.

[0049] The present invention also provides a speed reducer, which includes a housing and an oil-proof and vent cap as described in any of the above embodiments.

[0050] Specifically, a mounting hole is made on the top or upper side wall of the reducer housing, and the oil leak-proof vent cap is installed in the mounting hole. After installation, the oil inlet 10 of the oil leak-proof vent cap connects to the internal space of the housing, and the extended channel 11, the oil storage chamber 12, and the oil return structure 13 are all located outside the housing or partially embedded in the housing wall. The oil return structure 13 connects the oil storage chamber 12 with the inside of the housing, and directly guides the recovered oil back to the housing oil sump.

[0051] The reducer equipped with the leak-proof vent cap of this invention allows hot oil vapors generated inside the housing to be smoothly discharged during long-term operation, maintaining pressure balance inside and outside the housing. Simultaneously, condensed oil droplets and accidentally injected liquid oil are captured by the oil storage chamber 12 and automatically returned to the housing via the oil return structure 13, achieving "zero leakage" operation. Compared to reducers using traditional vent caps, the reducer of this invention significantly reduces oil leakage failure rates, extends lubricating oil replenishment cycles, and significantly improves the cleanliness of the equipment operating environment, reducing safety hazards and environmental problems caused by oil leaks.

[0052] Experimental verification: The oil-proof vent cap of this invention was installed on a certain type of speed reducer and operated continuously under rated load, with simulated impact loads applied during operation. Experimental results showed that there was no oil leakage at the vent cap's exhaust port, the oil level in the oil storage chamber 12 remained stable, and the oil return rate and inlet rate of the oil return structure 13 reached dynamic equilibrium. In contrast, the same type of speed reducer using a conventional straight-through vent cap showed significant oil leakage after operation under the same conditions.

[0053] Installation method: The first step is to place the oil guide line 14 into the oil return tank 15. The length of the oil guide line 14 should be slightly longer than the oil return tank 15, so that both ends of the oil guide line 14 extend into the bottom of the oil storage chamber 12 and the inside of the tank respectively, ensuring that the oil can be continuously transported from the oil storage chamber 12 to the tank.

[0054] The second step is to install the oil return structure 13 assembly with the oil guide line 14 onto the vent cap body. Specifically, the oil guide line 14 is pressed into the oil return groove 15 so that the oil guide line 14 fits tightly against the inner wall of the oil return groove 15.

[0055] The third step is to install the assembled oil leak-proof and vent cap into the pre-set mounting holes in the box, and tighten the fixing nuts or threaded connections to ensure a reliable seal.

[0056] Precautions for use: Regularly check the capillary suction performance of the oil guide wire 14. If the oil guide wire 14 is found to be hardened or blocked due to long-term use, it should be replaced in time. Regularly check the oil storage chamber 12 for carbon deposits or impurities, and clean it if necessary. After the initial installation, it is recommended to observe for 1-2 operating cycles to confirm that the oil return structure 13 is working properly and there is no blockage or poor return flow.

[0057] Industrial applicability The oil-proof vent cap and reducer of the present invention have a simple structure, low manufacturing cost, and convenient installation and maintenance. They can effectively solve the oil leakage problem of vent caps in closed transmission devices such as reducers and gearboxes, and have broad industrial application prospects.

[0058] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made based on the inventive concept of the present invention and the contents of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields, should be included within the protection scope of the present invention.

Claims

1. A leak-proof and breathable cap (1) for installation on a housing, characterized in that, include: One oil inlet (10); An extended channel (11) is connected to the oil inlet (10); An oil storage chamber (12) connected to the extended channel (11); and An oil return structure (13) is provided for connecting the oil storage chamber (12) with the housing. The diameter of the oil inlet (10) is smaller than the diameter of the extended channel (11).

2. The leak-proof and breathable cap according to claim 1, characterized in that, The diameter of the oil inlet (10) is 1 mm to 1.5 mm, and the diameter of the extended channel (11) is 1.5 mm to 2 mm.

3. The leak-proof and breathable cap according to claim 1, characterized in that, The oil return structure (13) includes an oil return groove (15) and an oil guide line (14) disposed in the oil return groove (15).

4. The leak-proof and breathable cap according to claim 3, characterized in that, The oil guide line (14) is a flexible fiber bundle.

5. The leak-proof and breathable cap according to claim 1, characterized in that, The oil storage chamber (12) is located at the outlet end of the extended channel (11).

6. A speed reducer, characterized in that, include: A box; as well as The oil leak-proof vent cap as described in any one of claims 1 to 5, wherein the oil leak-proof vent cap (1) is installed on the housing, and the oil inlet (10) communicates with the interior of the housing.

7. The speed reducer according to claim 6, characterized in that, The oil return structure (13) connects the oil storage chamber (12) with the interior of the box.

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