Normally-closed oil-blocking ventilation plug and transmission

Abstract

The invention discloses a normally-closed type oil blocking ventilation plug, and belongs to the technical field of ventilation plugs. The ventilation plug is provided with a connector body serving as a middle device, a dustproof cover is arranged outside the connector body, and the connector body is internally inserted into a transmission. A valve element structure is arranged between the connector body and the dustproof cover and connected with the connector body and the dustproof cover through elastic pieces, an oil absorption rod used for absorbing oil is arranged in the valve element, an oil guide rod is arranged in the connector body, and an oil filter element is arranged on the lower portion of the connector body. Through the arrangement of the structure, three layers of structures for preventing oil liquid from being transmitted outwards are arranged along the transmission from inside to outside, the first layer is the oil filter element, the second layer is the oil guide rod, the third layer is the oil absorption rod, when the dustproof cover is jacked up and gas is transmitted outwards, through the three layers of structures, the exhaust effect can be guaranteed, and meanwhile the exhaust efficiency is improved. And the oil liquid is prevented from being discharged.

Description

Technical Field

[0001] The invention belongs to the technical field of vent plugs and relates to a normally closed oil-blocking vent plug and a transmission. Background Art

[0002] When heavy-duty commercial vehicles and new energy commercial vehicles operate, gear meshing, oil agitation, and temperature fluctuations can cause internal pressure fluctuations. Therefore, a breather plug is installed on the outside of the transmission. By exhausting hot air or taking in cold air, the breather plug maintains internal and external pressure balance, preventing housing deformation, oil seal leakage, or rupture. However, conventional breather plugs cannot prevent transmission oil leakage during ventilation, resulting in frequent oil leakage.

[0003] For example, the Chinese utility model patent with announcement number CN221347804U discloses a normally closed vent plug structure, in which a buffer chamber is set inside the valve body to prevent the oil in the accumulation chamber from directly entering the spring chamber. However, in this technical solution, it is difficult to remove the oil carried in the gas during the process of gas being discharged from the gap into the spring chamber, so the oil may still be discharged from the fitting gap between the valve core and the valve body, resulting in oil leakage. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a normally closed oil vent plug and a transmission to solve the problem that the vent plug in the prior art is difficult to effectively prevent the transmission oil from leaking during ventilation.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A normally closed oil retaining vent plug, comprising: Connector body; An air inlet hole is provided in the joint body along the axis; A dust cover is mounted on the upper part of the connector body; The valve core is installed inside the dust cover, and the lower end is inserted into the air inlet hole; Elastic part, installed between the dust cover and the valve core; The oil suction rod is installed in the valve core, and the end of the space of the valve core for installing the oil suction rod is open; The oil guide rod is fixedly installed in the air inlet hole; The oil filter element is detachably installed at the bottom of the air inlet, below the oil guide rod.

[0006] A further improvement of the present invention is: Preferably, the dust cover and the connector body are snap-fitted together.

[0007] Preferably, the inner wall of the dust cover is provided with an inwardly protruding limiting retaining ring; the outside of the joint body is provided with a second limiting groove and a first limiting groove.

[0008] Preferably, the depth of the first limiting groove is greater than the depth of the second limiting groove, and the width of the first limiting groove is greater than the width of the second limiting groove.

[0009] Preferably, the valve core is divided into an outer part, a middle part and an inner part that are integrally connected; the diameter of the middle part is larger than the diameter of the outer part, and the diameter of the middle part is larger than the diameter of the inner part; the elastic part is sleeved on the outer part, and the inner part is inserted into the air inlet hole.

[0010] Preferably, the inner portion is sheathed with a sealing ring.

[0011] Preferably, the outer side wall of the oil guide rod is provided with a spiral guide groove, and the bottom of the oil guide rod is provided with a drainage groove.

[0012] Preferably, one end of the oil filter core is a connecting end, and the other end is provided with a plurality of ventilation holes.

[0013] Preferably, the oil guide rod and the connector body are interference fit.

[0014] A transmission, wherein a normally closed oil vent plug as described above is installed on the transmission housing.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a normally closed oil-blocking vent plug, which is provided with a joint body as an intermediate device, a dust cover is provided on the upper part of the joint body, and the lower part extends into the interior of the transmission; a valve core structure is provided between the joint body and the dust cover, the valve core is respectively connected to the joint body and the dust cover through elastic parts, an oil suction rod for absorbing oil is provided in the valve core, an oil guide rod is provided inside the joint body, and an oil filter core is provided at the lower part. When the oil and gas pass through the oil filter core, a large amount of oil is blocked outside by the oil filter core to avoid flowing into the interior of the vent plug and causing blockage, and a small amount of oil droplets are not blocked by the oil filter core and flow upward through the four drainage grooves of the oil guide rod along with the gas. When passing through the drainage grooves, the oil droplets in the gas are adsorbed on the surface of the drainage grooves when in contact with the surface of the drainage grooves and flow back downward in liquid form, while the gas continues to flow upward. Furthermore, if some oil droplets still pass over the oil guide rod and reach the top of the oil guide rod, they are absorbed by the oil suction rod in the valve core, and gas accumulates in the cavity. When the gas reaches a certain pressure, the valve core is lifted by the gas, the spring is compressed, and the dust cover moves upward, the dust cover is stretched open, and the gap between the joint body and the dust cover is opened, which increases the efficiency of gas discharge from the gap. During exhaust, the oil suction rod returns to a free extension state, allowing the oil suction rod to further absorb oil. When exhaust is completed, the dust cover returns to its original position, and the oil suction rod is compressed again to discharge the absorbed oil. The internal oil flows along the drainage groove and is discharged from the entire vent plug through the oil filter core and flows back into the box. The present invention constructs a multi-stage, efficient, and coordinated active adsorption and mechanical separation composite oil blocking system. The system can remove as much liquid oil as possible from the gas (especially the gas carrying oil mist during exhaust) before it reaches the valve core fitting gap, thereby solving the technical problem of oil leakage during the ventilation process of the vent plug. At the same time, the optimized valve core structure, sealing design, and limiter mechanism ensure reliable sealing in the normally closed state, effectively preventing dust and water. Ultimately, this design significantly improves the sealing reliability of transmission breather plugs in commercial vehicles (especially heavy-duty and new energy vehicles), extends transmission fluid life, reduces maintenance costs and environmental pollution risks caused by oil leakage, and prevents serious problems such as housing deformation, oil seal failure, or rupture caused by air pressure imbalance.

[0016] Furthermore, the dust cover and the connector body are snap-fitted together so that when the vent plug is in a closed state, the dust cover and the connector body can be firmly connected. When the vent plug is in an open state, the dust cover can move up and down on the connector body to form a gap, which facilitates the discharge of gas.

[0017] Furthermore, in order to achieve a snap-on connection, the dust cover is provided with a corresponding limit ring, and two limit grooves are provided on the connector body, and the limit grooves are provided with different sizes, so that the dust cover and the connector body can fit tightly or form a gap.

[0018] Furthermore, the present invention optimizes the structure of the valve core so that the valve core can play the role of sealing, connecting the dust cover and the joint body, and installing the oil suction rod to promote oil absorption.

[0019] Furthermore, a sealing ring is provided on the valve core so that when the vent plug is in the closed state, the sealing effect can meet the requirements.

[0020] Furthermore, the guide grooves and drainage grooves provided on the oil guide rod can assist in the movement of the oil.

[0021] Furthermore, the interference fit of the oil guide rod and the detachable design of the oil filter element further improve the reliability of the structure and the convenience of maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the parts and positions of the oil-blocking normally closed vent plug (closed state) of the present invention; Figure 2 This is a schematic diagram of the parts and positions of the oil-blocking normally closed vent plug (exhaust state) of the present invention; Figure 3 Schematic diagram of the spiral guide rod and drainage groove of the present invention; Figure 4 Schematic diagram of the oil filter element of the present invention; Figure 5 Schematic diagram of cavity A and cavity B when closed in the present invention; Figure 6 This is a schematic diagram of the vent plug exhausting the present invention; 1. Dust cover; 2. Elastic part; 3. Valve core; 4. Sealing ring; 5. Limiting ring; 6. Connector body; 7. Oil filter core; 8. Oil suction rod; 9. Second limiting groove; 10. First limiting groove; 11. Oil guide rod; 12. First cavity; 13. Second cavity; 601, air inlet; 301, outer part; 302, middle part; 303, inner part; 111, guide groove; 112, drainage groove; 701, vent. DETAILED DESCRIPTION

[0023] The present invention is described in further detail below with reference to the accompanying drawings: The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0024] See also Figure 1 and Figure 2The present invention discloses a normally closed oil-blocking vent plug, comprising a dust cover 1, an elastic member 2, a valve core 3 and a joint body 6 which are arranged in sequence from the outside to the inside; the dust cover 1 is sleeved on the upper part of the joint body 6, the dust cover 1 and the outer part of the joint body 6 are clamped together, one end of the elastic member 2 is fixedly connected to the inner end of the dust cover 1, and the other end of the elastic member 2 is fixedly connected to the valve core 3; a hole is provided in the end of the valve core 3 facing the joint body 6, and an oil suction rod 8 is installed in the hole; an air inlet hole 601 is provided in the joint body 6 along the axial direction, the lower end of the valve core 3 is inserted into the air inlet hole 601, an oil guide rod 11 is installed in the air inlet hole 601, and the lower end of the air inlet hole 601 is detachably connected to the oil filter core 7, and the oil filter core 7 is below the oil guide rod 11.

[0025] Through the arrangement of the above structure, three layers of structures are provided along the direction from the inside to the outside of the transmission to prevent the oil from being transmitted outward. The first layer is the oil filter core 7, the second layer is the oil guide rod 11, and the third layer is the oil suction rod 8. While the gas is transmitted outward, the transmission of oil is prevented.

[0026] In some embodiments of the present invention, the dust cover 1 is snap-fitted to the connector body 6. The dust cover 1 covers and seals the upper portion of the connector body 6, thereby preventing external water and large particles of impurities from entering the vent plug cavity, thereby preventing internal blockage and poor exhaust.

[0027] Furthermore, the inner wall of the dust cover 1 is circumferentially provided with an inwardly protruding retaining ring 5. The exterior of the connector body 6 is provided with a second retaining groove 9 and a first retaining groove 10. The first retaining groove 10 is positioned closer to the transmission housing and the outer edge of the dust cover 1 than the second retaining groove 9. The retaining ring 5 is secured to the two retaining grooves of the connector body 6, ensuring the proper installation of the elastic member 2. The dust cover 1 prevents water and large particles from entering the vent plug cavity, preventing internal blockage and poor ventilation.

[0028] Furthermore, the depth of the first limiting groove 10 is greater than the depth of the second limiting groove 9, and the width of the first limiting groove 10 is greater than the width of the second limiting groove 9; the changes in the depth, width, and surface curvature of the limiting retaining ring 5 match the first limiting groove 10. When the limiting retaining ring 5 is located in different limiting grooves, the overall exhaust efficiency of the vent plug can be adjusted. The dust cover limiting retaining ring is located in different first limiting grooves 10 or second limiting grooves 9 when the vent plug is closed and open, and the exhaust flow rate of the vent plug is changed by the vertical displacement of the dust cover 1. When the entire normally closed oil-blocking vent plug is closed, the elastic part 2 is compressed, and the limit retaining ring 5 can be completely stuck in the first limit groove 10 to prevent movement; when the entire normally closed oil-blocking vent plug is opened, the valve core 3 and the elastic part 2 are pushed outward, the elastic part 2 is compressed, and at the same time, the dust cover 1 is pushed outward. Since the size of the limit retaining ring 5 cannot be fully inserted into the second limit groove 9, a gap is formed between the dust cover 1 and the joint body 6, and the gas can be discharged, thereby increasing the exhaust efficiency.

[0029] In some embodiments of the present invention, the valve core 3 is divided into an integrally connected outer portion 301, a middle portion 302, and an inner portion 303. The diameter of the middle portion 302 is larger than that of the outer portion 301, which in turn is larger than that of the inner portion 303. The elastic member 2 is sheathed on the outer portion 301, and the inner portion 303 is inserted into the air inlet 601. This structural arrangement allows the elastic member 2, when a spring is used, to be securely sheathed on the outer portion 301, with the dimensions of the elastic member 2 matching those of the outer portion.

[0030] In some embodiments of the present invention, the elastic member 2 is a spring that can be mounted on the outer portion 301 , with the outer end of the spring connected to the dust cover 1 and the inner end of the spring connected to the outer portion 301 .

[0031] The valve core 3 and elastic member 2 are the primary moving parts within the vent plug. The valve core 3 provides mounting space for the elastic member 2. The spring is made of conventional 65Mn material, with a wire diameter d ranging from φ0.3 to φ0.5mm, an effective number of turns n ranging from 5 to 10, and an installation height h ranging from 5 to 15mm. This smaller wire diameter ensures the spring can be compressed with appropriate pressure, preventing high pressure inside the transmission.

[0032] In some embodiments of the present invention, the oil suction rod 8 is made of a compressible and deformable material, preferably a cotton swab; the oil suction rod 8 serves as an important component for internal oil blocking, and ensures that excess oil is absorbed, squeezed out and refluxed through its own compression and rebound. When the vent plug is in the closed state, the oil suction rod 8 is compressed and installed in the inner hole of the valve core 3. When the transmission exhaust valve core is pushed open, the oil suction rod 8 returns to its free length from the compressed state, increasing the oil absorption capacity of the oil suction rod 8 and ensuring that the small oil droplets accompanying the exhaust can be effectively absorbed. When the exhaust is completed, the valve core 3 is closed, and the oil suction rod 8 returns to the compressed state again. At this time, the oil absorbed during the exhaust can be squeezed out, thereby refluxing inward.

[0033] See also Figure 5 and Figure 6 In some embodiments of the present invention, a sealing ring 4 is installed on the outside of the inner part 303, and the sealing ring 4 is on the upper side of the joint body 6. When the normally closed oil-blocking vent plug is closed, the sealing ring 4 contacts the upper end of the joint body 6 to seal the gas. Through the setting of the sealing ring 4, when the vent plug is closed, the dust cover 1, the valve core 3 and the joint body 6 are divided into two independent cavities, a first cavity 12 and a second cavity 13. The first cavity 12 is the space between the sealing ring 4, the inner part 303 and the oil guide rod 11 in the air inlet 601, and the second cavity 13 is the space between the sealing ring, the valve core 3, the upper end of the joint body 6 and the dust cover 1. The first cavity 12 is connected to the internal gas of the gearbox, and the second cavity 13 is connected to the outside atmosphere, forming a significant air pressure difference between the inside and the outside.

[0034] Furthermore, the seal ring 4 can be made of rubber materials such as AEM and FKM to ensure sealing performance in both low- and high-temperature operating conditions. Furthermore, the seal ring 4 is designed with a hardness between 50 and 80 IRHD to prevent high-temperature aging or pressure resistance issues, which could even cause transmission oil seal leakage, when the pressure in the second cavity 13 is too high but does not meet the opening pressure.

[0035] See also Figure 3 In some embodiments of the present invention, the oil guide rod 11 is a non-metallic round rod, and the oil guide rod 11 and the connector body 6 form an interference fit. The outer wall of the oil guide rod 11 is provided with a spiral guide groove 111. Four spiral guide grooves 112 are evenly distributed around the bottom of the oil guide rod 11 to guide the oil and gas upward. When the oil in the oil and gas contacts the oil guide rod 11, it contacts the surface of the guide groove 111, collects the oil droplets, and flows inward. The oil guide rod 11 is assembled into the air inlet 601 of the connector body 6 with a small interference fit, preventing the oil and gas from flowing directly out of the gap between the holes, and instead flows upward along the grooves.

[0036] See also Figure 4In some embodiments of the present invention, one end of the oil filter core 7 is a connection end, and the other end is provided with multiple vent holes 701. The end provided with multiple vent holes 701 is frustoconical in shape. The oil filter core 7 is screwed into the air inlet 601 of the connector body 6 via straight threads. The oil filter core 7 is made of sintered metal, and the metal particles have small gaps between them, which ensures that gas can enter while the metal particles block the oil.

[0037] The present invention also discloses a transmission, wherein the transmission housing is equipped with the normally closed oil blocking and venting plug.

[0038] See also Figure 5 and Figure 6 The working process of the oil vent plug of the present invention is as follows: 1) When the transmission is operating, the gears stir the lubricating oil, increasing internal pressure and entraining oil droplets to form oil vapor. As the oil vapor passes through the oil filter, a large amount of oil is blocked, preventing it from flowing into the vent plug. However, a small amount of oil droplets entrained in the gas cannot be blocked by the oil filter 7 and flow outward along with the gas through the guide groove 111 of the oil guide rod 11. Due to the presence of the sealing ring 4, the oil does not enter the second cavity 13 and cause oil leakage in the vent plug. Upon reaching the top of the oil guide rod 11, the oil droplets are absorbed by the oil suction rod 8 in the valve core 3.

[0039] 2) As the internal temperature rises, the gas pressure increases, creating a large pressure differential between the second cavity 13 and the first cavity 12. When the pressure continues to rise to the minimum deformation pressure of the spring, the sealing ring 4 pushes upward, the valve core 3 is opened, and the second cavity 13 is connected to the first cavity 12 to release the gas. When the gas pressure is high enough, the spring is compressed to its maximum deformation, the dust cover 1 is forced to move upward, and the limit ring 5 shifts from the first limit groove 10 to the second limit groove 9. The dust cover 1 is properly stretched, increasing the gap with the joint body 6 and improving the exhaust efficiency. Due to the upward displacement of the dust cover 1, the gap between the valve core 3 and the joint body 6 increases, and the oil suction rod 8 returns to a free state from the compressed state, releasing the volume to absorb more oil, increasing the oil suction efficiency and preventing oil leakage from the vent plug.

[0040] 3) After the exhaust is completed, the dust cover 1 is displaced downward by the drag force of the spring, and the limit ring 5 falls back to the first limit groove 10. The sealing ring 4 separates the connected second cavity 13 from the first cavity 12. The oil suction rod 8 is compressed again to release the absorbed oil. The squeezed oil flows back to the transmission through the guide groove 111 of the oil guide rod 11 and the oil filter core 7, forming a reciprocating motion during the continuous operation of the vent plug to prevent oil leakage.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "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 the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more. In the description of the present invention, a first feature "above" or "below" a second feature may include the first and second features being in direct contact, or the first and second features not being in direct contact but being in contact through another feature between them.

[0042] In the description of the present invention, “on”, “above” and “above” a first feature of a second feature include the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0043] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0044] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0045] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A normally closed oil vent plug, characterized in that: include: Connector body (6); An air inlet (601) is provided in the joint body (6) along the axis; A dust cover (1) is mounted on the upper portion of the connector body (6); The valve core (3) is installed inside the dust cover (1), and the lower end is inserted into the air inlet hole (601); An elastic member (2) is installed between the dust cover (1) and the valve core (3); An oil suction rod (8) is installed in the valve core (3), and the end of the space in which the oil suction rod (8) is installed in the valve core (3) is open; An oil guide rod (11) is fixedly mounted in the air inlet hole (601); The oil filter core (7) is detachably mounted at the lower portion of the air inlet (601) and below the oil guide rod (11).

2. A normally closed oil-blocking vent plug according to claim 1, characterized in that: The dust cover (1) and the connector body (6) are connected by snap-fitting.

3. A normally closed oil retaining vent plug according to claim 2, characterized in that: The inner wall of the dust cover (1) is provided with an inwardly protruding limiting retaining ring (5); the outside of the joint body (6) is provided with a second limiting groove (9) and a first limiting groove (10).

4. A normally closed oil-blocking vent plug according to claim 3, characterized in that: The depth of the first limiting groove (10) is greater than the depth of the second limiting groove (9), and the width of the first limiting groove (10) is greater than the width of the second limiting groove (9).

5. The normally closed oil-blocking vent plug according to claim 1, characterized in that: The valve core (3) is divided into an outer part (301), a middle part (302), and an inner part (30) which are integrally connected; the diameter of the middle part (302) is larger than the diameter of the outer part (301), and the diameter of the middle part (302) is larger than the diameter of the inner part (303); the elastic member (2) is sleeved on the outer part (301), and the inner part (303) is inserted into the air inlet hole (601).

6. A normally closed oil retaining vent plug according to claim 5, characterized in that: The inner portion (303) is sleeved with a sealing ring (4).

7. The normally closed oil-blocking vent plug according to claim 1, characterized in that: The outer side wall of the oil guide rod (11) is provided with a spiral guide groove (111), and the bottom of the oil guide rod (11) is provided with a drainage groove (112).

8. The normally closed oil-blocking vent plug according to claim 1, characterized in that: One end of the oil filter core (7) is a connecting end, and the other end is provided with a plurality of vent holes (701).

9. The normally closed oil blocking vent plug according to claim 1, characterized in that: The oil guide rod (11) and the joint body (6) are interference fit.

10. A transmission, characterized in that: The transmission housing is equipped with a normally closed oil vent plug as described in any one of claims 1 to 9.

Images