Multi-lip composite oil seal structure

Abstract

The utility model relates to the technical field of sealing elements, in particular to a multi-lip composite oil seal structure which comprises a sleeve arranged outside a shaft body in a sleeved mode, a first carbon steel framework and a second carbon steel framework, the axial section of the first carbon steel framework and the axial section of the second carbon steel framework are both of an L-shaped structure, and the first carbon steel framework and the second carbon steel framework are symmetrically arranged on the periphery of the sleeve. A rectangular inner cavity is formed between the first carbon steel framework and the second carbon steel framework and filled with lubricating grease. According to the technical scheme, the rigidity and the wear resistance are enhanced by arranging the symmetrical carbon steel frameworks, and composite lithium-based lubricating grease is filled between the carbon steel frameworks and a sealing cavity, so that friction is reduced, and a grease barrier is formed; the first sealing lip and the second sealing lip are combined with the spiral flow guide groove to form a multi-stage sealing cavity structure, the spring compensates elastic attenuation of the lips, efficient dust prevention, low friction and deformation resistance are integrally achieved, the service life of the oil seal is prolonged, and the oil seal is suitable for high-pollution working conditions.

Description

Technical Field

[0001] This utility model relates to the field of sealing technology, specifically to a multi-lip composite oil seal structure. Background Technology

[0002] An oil seal is a mechanical component used to seal oil. It isolates the lubricated parts from the output parts in a transmission system, preventing lubricating oil leakage and blocking external dust from entering the lubricated parts. It has the effect of sealing oil internally and preventing dust externally and is widely used in industries such as household appliances, automobile engines, and chemicals.

[0003] Patent publication number CN107327573A discloses a combined dustproof oil seal device, including a sleeve assembly and an oil seal body. The sleeve assembly includes a rubber ring and an L-shaped metal skeleton embedded in one side of the rubber ring. The oil seal body includes a rubber sealing ring, with a static sealing ring extending axially from the outer periphery of the rubber sealing ring. An L-shaped metal skeleton with an axial cross-section is embedded within the rubber sealing ring and the static sealing ring. A dynamic sealing assembly is provided on the inner periphery of the rubber sealing ring, including a main sealing lip extending from the rubber ring body to both sides, a first secondary sealing lip, and a second secondary sealing lip. An annular groove is provided on the outer ring of the main sealing lip, and a spring is installed within the annular groove. The combined dustproof oil seal device provided by this invention can effectively resist external pollutants and is suitable for dusty and highly polluted environments. The carbon steel metal skeleton increases rigidity, making the oil seal less prone to deformation, and the spring provides a certain binding force to the oil seal lip and extends the oil seal's lifespan.

[0004] In the above scheme, the first and second sealing lips are located on the inner diameter of the oil seal body, and there is no corresponding protective setting on the outer diameter of the oil seal body. Therefore, the blocking effect on fine sand or high concentration of dust is limited, and it is difficult to cope with complex polluted environments. Utility Model Content

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the purpose of this invention is to propose a multi-lip composite oil seal structure to improve the sealing strength of the oil seal.

[0006] The objective of this utility model can be achieved through the following technical solutions:

[0007] A multi-lip composite oil seal structure includes a sleeve fitted around the outside of a shaft, wherein the inner wall of the sleeve is clearance-fitted with the shaft, and further includes:

[0008] The first carbon steel frame and the second carbon steel frame both have an L-shaped axial section and are symmetrically arranged on the outer periphery of the sleeve. A rectangular inner cavity is formed between the first carbon steel frame and the second carbon steel frame, and the rectangular inner cavity is filled with grease.

[0009] The first sealing lip and the second sealing lip are respectively disposed at the end junction of the first carbon steel frame and the second carbon steel frame. The root of the first sealing lip and the root of the second sealing lip both extend into the rectangular inner cavity. At least one sealing cavity is formed between the root of the first sealing lip and the second carbon steel frame and between the root of the second sealing lip and the first carbon steel frame, respectively. The sealing cavity is filled with grease.

[0010] A spring is fitted at the base of the second sealing lip.

[0011] In some embodiments of this utility model, a semi-covering component is also included, which partially covers the outer periphery of the first carbon steel frame and the second carbon steel frame.

[0012] In some embodiments of this utility model, the first sealing lip, the second sealing lip, and the semi-encapsulated part are all made of rubber material, and graphene reinforcing agent is added to the rubber material.

[0013] In some embodiments of this utility model, the sealing cavity includes a first sealing cavity and a second sealing cavity, wherein the first sealing cavity and the second sealing cavity are rectangular, square or irregular in shape.

[0014] In some embodiments of this utility model, spiral guide grooves are provided on the contact surface between the first sealing lip and the second carbon steel skeleton, as well as on the contact surface between the second sealing lip and the first carbon steel skeleton.

[0015] In some embodiments of this utility model, the surfaces of the first carbon steel frame and the second carbon steel frame are covered with a chromium nitride coating with a thickness of 3-5 μm and a surface hardness of ≥1800HV.

[0016] In some embodiments of this utility model, the grease is a composite lithium-based grease containing molybdenum disulfide, with a cone penetration of 265-295, a dropping point ≥250℃, and a grease filling amount of 80%-90% of the volume of the rectangular inner cavity.

[0017] In some embodiments of this utility model, the outer surface of the semi-covered part is provided with a serrated anti-slip texture, the texture depth is 0.2-0.4mm, and the texture spacing is 1-2mm.

[0018] The beneficial effects of this utility model are:

[0019] Compared to traditional methods, this technical solution enhances rigidity and wear resistance by setting a symmetrical carbon steel skeleton. The spaces between the carbon steel skeleton and the sealing cavity are filled with composite lithium-based grease to reduce friction and form a grease barrier. The first and second sealing lips are combined with spiral guide grooves to construct a multi-stage sealing cavity structure. Springs compensate for the elasticity decay of the lips, achieving high efficiency dust prevention, low friction, and deformation resistance, thus extending the life of the oil seal and making it suitable for high-pollution working conditions. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 This is an overall sectional view of the present invention;

[0022] Figure 2 This is a cross-sectional view of the first sealing cavity and the second sealing cavity in this utility model.

[0023] In the figure: 1. Sleeve; 2. First carbon steel frame; 3. First sealing lip; 4. Semi-encasing component; 5. Second carbon steel frame; 6. Spring; 7. Second sealing lip; 8. First sealing cavity; 9. Second sealing cavity. Detailed Implementation

[0024] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0025] Example 1:

[0026] like Figure 1 , Figure 2 As shown, in this embodiment, the basic structure of the multi-lip composite oil seal includes a sleeve 1 fitted outside the shaft. The sleeve 1 is made of precision-machined high-strength alloy steel, with an inner diameter tolerance controlled within ±0.02mm and a surface roughness Ra≤0.4μm, ensuring a precise clearance fit with the shaft. This clearance is typically 0.05-0.1mm, ensuring normal shaft rotation while preventing excessive radial movement.

[0027] The oil seal's frame structure consists of a symmetrically arranged first carbon steel skeleton 2 and a second carbon steel skeleton 5. Both skeletons have an L-shaped axial cross-section, are made of SPCC grade carbon steel with a thickness of 1.0-1.5 mm, and are phosphated to enhance adhesion. The first and second carbon steel skeletons 2 and 5 are symmetrically arranged around the outer periphery of the sleeve 1, forming a closed rectangular cavity. The rectangular cavity has a radial width of 3-5 mm and an axial length of 5-8 mm, and is filled with a special grease, forming a grease storage chamber. This symmetrical design not only provides structural balance but also enhances overall rigidity and resistance to deformation.

[0028] The sealing system consists of two key components: a first sealing lip 3 and a second sealing lip 7. The first sealing lip 3 is located at the end junction of the first carbon steel frame 2, with a thickness of 2.0-2.5 mm at the root, gradually thinning to 0.2-0.3 mm at the tip, forming a flexible sealing edge. The second sealing lip 7 is located at the end junction of the second carbon steel frame 5, with a similar structure to the first sealing lip 3, but with a spring 6 fitted at its root. The roots of both sealing lips extend into the rectangular inner cavity, forming a deep-penetrating design.

[0029] Spring 6 is made of stainless steel wire with a diameter of 0.6-0.8 mm. Its inner diameter in the free state is slightly less than 95% of the diameter at its mounting position, providing continuous radial preload to ensure that the second sealing lip 7 remains firmly against the shaft surface. The number of coils of spring 6 is determined according to the oil seal size, typically 0.5-1 times the shaft diameter, to ensure uniform radial pressure.

[0030] When the oil seal is installed on the shaft and begins operation, the first sealing lip 3 acts as the primary dust barrier, directly contacting the shaft surface and forming the first sealing barrier, mainly preventing external dust and impurities from entering. The second sealing lip 7, under the preload provided by the spring 6, adheres tightly to the surface of the second carbon steel frame 5, forming the second sealing barrier, primarily preventing internal lubricating oil leakage. The grease filling the rectangular cavity between the two sealing lips serves a triple function: first, providing continuous lubrication and reducing friction and wear between the sealing lips and the shaft; second, forming a liquid sealing layer to enhance the sealing effect; and third, adsorbing any small impurities that may penetrate, preventing them from further penetrating.

[0031] As the shaft rotates, a small amount of frictional heat is generated at the contact surface between the sealing lip and the carbon steel skeleton, leading to a local temperature increase. This enhances the fluidity of the grease, and through capillary action and the rotation of the shaft, the grease is gradually released from the rectangular inner cavity to the contact surface, continuously providing lubrication. Simultaneously, spring 6 ensures that the second sealing lip 7 maintains appropriate contact pressure even under temperature changes or vibration conditions, preserving an effective seal.

[0032] In this embodiment, the double sealing lip design forms multiple sealing barriers, effectively blocking external contaminants, especially fine sand and high-concentration dust; while the spring 6 preload structure ensures a long-term stable sealing effect, adapts to temperature changes and vibration conditions, and the grease storage system provides continuous lubrication, significantly extending the service life of the sealing lip.

[0033] Example 2:

[0034] This embodiment focuses on optimizing material properties and surface treatment, based on Embodiment 1.

[0035] First, a semi-encasing component 4 was added to the basic structure. This component partially covers the outer periphery of the first carbon steel frame 2 and the second carbon steel frame 5, covering 70%-85% of the outer surface of the frames. The semi-encasing component 4 has a thickness of 1.5-2.5 mm, a hardness of 65-75 Shore A, and its outer surface is equipped with serrated anti-slip patterns. The pattern depth is precisely controlled at 0.2-0.4 mm, the pattern spacing is 1-2 mm, and the serration angle is 45°±5°. This design not only increases the friction with the mounting holes but also effectively expels compressed air during installation, preventing air bubble formation.

[0036] In this embodiment, the first sealing lip 3, the second sealing lip 7, and the semi-encasing component 4 are all made of a specially formulated rubber material. The base rubber material is fluororubber (FKM), with a temperature resistance range of -20℃ to 230℃ and a hardness controlled at 65-70 Shore A. 0.5-1.5 wt% of graphene reinforcing agent is added to the rubber material. The graphene has a multilayer structure with a thickness of 5-10 nm, a lateral dimension of 1-5 μm, and a purity ≥98%. By adding the graphene reinforcing agent, the tensile strength of the rubber material increases from the original 15 MPa to 20 MPa, the wear resistance increases by 30-40%, and the coefficient of friction decreases from 0.4-0.5 to 0.2-0.3. Furthermore, 2-3 wt% of antioxidant and 1-2 wt% of anti-ozone aging agent are added to the rubber formulation to further improve the material's aging resistance.

[0037] The surfaces of the first carbon steel skeleton 2 and the second carbon steel skeleton 5 are covered with a chromium nitride (CrN) coating, with the coating thickness precisely controlled at 3-5 μm and a surface hardness ≥1800 HV. The coating is prepared using physical vapor deposition (PVD) technology, with the deposition temperature controlled at 300-400℃. Process parameters include: chamber vacuum degree ≤5×10⁻⁶. -4 Pa, deposition rate 0.5-1.0 μm / h, substrate bias -80V to -120V. This coating not only has extremely high hardness and wear resistance, with a friction coefficient of only 0.3-0.4, but also excellent corrosion resistance, with a salt spray test duration of over 500 hours.

[0038] The grease is a complex lithium-based grease containing molybdenum disulfide, with a cone penetration precisely controlled within the range of 265-295 (NLGI grade 2) and a dropping point ≥250℃. The molybdenum disulfide content in the grease is 3-5 wt%, and the particle size is controlled within 0.5-2 μm. The base oil is a synthetic ester-based oil with a viscosity index ≥140 and good pumpability at -30℃. The grease filling amount is precisely controlled to 80%-90% of the rectangular cavity volume. This ratio has been precisely calculated and experimentally verified, providing sufficient lubrication reserve while allowing appropriate space for the expansion of the seals due to temperature changes.

[0039] The chromium nitride coating forms a dense protective film on the surface of the skeleton. The coating prevents the skeleton from corroding by blocking oxygen, moisture and corrosive media from contacting the carbon steel substrate, while reducing friction and wear with the rubber sealing lip.

[0040] During operation, when the shaft rotates and generates high temperature or high pressure, the molybdenum disulfide-containing complex lithium-based grease forms a transfer film on the friction surface. Its layered structure (adjacent sulfur atom layers are bonded by weak van der Waals forces) allows the layers to slide easily, providing an extremely low coefficient of friction (0.05-0.1). Even under extreme conditions where the base oil film is squeezed out, this transfer film can still provide effective lubrication.

[0041] Example 3:

[0042] Based on the previous two embodiments, this embodiment focuses on optimizing the sealing cavity structure and sealing lip design to form a complete multi-level protection system.

[0043] In this embodiment, the sealing cavity includes a first sealing cavity 8 and a second sealing cavity 9, which are located between the root of the first sealing lip 3 and the second carbon steel frame 5, and between the root of the second sealing lip 7 and the first carbon steel frame 2, respectively.

[0044] The first sealing cavity 8 adopts a gradient fan-shaped design, narrower on the inner side and wider on the outer side, unfolding in a fan shape, with the volume gradually increasing from the inlet to the depth. Specific dimensions are: axial length 3-5mm, maximum radial width 2.5-3.5mm, and volume approximately 25-40mm³. This fan-shaped design creates a weak centrifugal pump effect during shaft rotation, promoting the flow of grease to the sealing contact surface. The second sealing cavity 9 adopts a semi-elliptical design, with the major axis parallel to the axial direction and the minor axis parallel to the radial direction. The major axis length is 4-6mm, and the minor axis length is 2-3mm. The second sealing cavity 9 also has 3-5 micro-grooves around its perimeter, each groove being 0.5-1.0mm deep and 1.0-1.5mm wide, evenly distributed to increase the grease storage space and improve flow characteristics.

[0045] Spiral guide grooves are formed on the contact surfaces of the first sealing lip 3 and the second carbon steel frame 5, and on the contact surfaces of the second sealing lip 7 and the first carbon steel frame 2. These spiral guide grooves have a depth of 0.3-0.5 mm, a width of 0.5-1.0 mm, and a spiral angle of 30°±5°. The starting end of the spiral guide groove is located inside the sealing cavity, and the ending end points towards the contact area between the sealing lip and the shaft, forming a directional lubricating oil flow channel. The spiral direction is designed to be opposite to the shaft rotation direction, utilizing rotational shear force to transport the grease from the sealing cavity to the sealing contact surface.

[0046] The multi-stage sealing chambers and spiral guide grooves form a complete lubrication circulation system. When the shaft rotates, the grease stored in the sealing chambers is continuously and quantitatively delivered to the contact area between the sealing lip and the shaft through the capillary action and pumping effect of the spiral guide grooves. The fan-shaped design of the first sealing chamber 8 utilizes centrifugal force to assist the flow of grease, while the semi-elliptical design and micro-grooves of the second sealing chamber 9 increase the storage capacity and improve the flow characteristics.

[0047] The reverse design of the spiral guide groove ensures that the grease flows against the direction of centrifugal force, preventing grease loss due to centrifugal force. When the shaft rotates, the spiral groove generates an effect similar to an Archimedes' screw pump, "drawing" the grease from the sealing cavity and directionally delivering it to the sealing contact surface, forming a continuous lubricating oil film.

[0048] As an example, the first sealing cavity 8 and the second sealing cavity 9 are rectangular, square, or irregular in shape.

[0049] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions 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 one or more embodiments or examples.

[0050] The above description is merely an example and illustration of the present utility model. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the utility model or exceed the scope defined in the claims, they should all fall within the protection scope of the present utility model.

Claims

1. A multi-lip composite oil seal structure comprising a sleeve fitted to the outside of a shaft body, the inner wall of the sleeve being in a clearance fit with the shaft body, characterized in that, Also comprising: a first carbon steel skeleton and a second carbon steel skeleton, both of which are L-shaped in axial section, symmetrically arranged on the outer periphery of the sleeve, and a rectangular inner cavity is formed between the first carbon steel skeleton and the second carbon steel skeleton, which is filled with lubricating grease; a first sealing lip and a second sealing lip, respectively arranged at the end of the first carbon steel skeleton and the second carbon steel skeleton, the root of the first sealing lip and the root of the second sealing lip extend into the rectangular inner cavity, and the root of the first sealing lip and the second carbon steel skeleton and the root of the second sealing lip and the first carbon steel skeleton form at least one sealing cavity, respectively, which is filled with lubricating grease; a spring, sleeved on the root of the second sealing lip.

2. The multi-lip composite oil seal structure of claim 1, wherein, Also comprising a half covering, which partially covers the outer periphery of the first carbon steel skeleton and the second carbon steel skeleton.

3. The multi-lip composite oil seal structure of claim 2, wherein, The first sealing lip, the second sealing lip and the half covering are all made of rubber material.

4. The multi-lip composite oil seal structure of claim 1, wherein The sealing cavity includes a first sealing cavity and a second sealing cavity, which are rectangular, square or special-shaped.

5. The multi-lip composite oil seal structure of claim 1, wherein, The contact surface of the first sealing lip and the second carbon steel skeleton and the contact surface of the second sealing lip and the first carbon steel skeleton are both provided with spiral flow grooves.

6. The multi-lip composite oil seal structure of claim 1, wherein The surface of the first carbon steel skeleton and the second carbon steel skeleton is covered with a chromium nitride coating, the coating thickness is 3-5μm, and the surface hardness is ≥1800HV.

7. The multi-lip composite oil seal structure of claim 1, wherein The lubricating grease is a composite lithium-based lubricating grease, the cone penetration is 265-295, the drop point is ≥250℃, and the filling amount of the lubricating grease is 80%-90% of the volume of the rectangular inner cavity.

8. The multi-lip composite oil seal structure of claim 3, wherein The outer surface of the half covering is provided with a zigzag anti-slip pattern, the pattern depth is 0.2-0.4mm, and the pattern spacing is 1-2mm.

Images