Universal joint oil seal structure for automobile steering gear

Abstract

The utility model relates to mechanical engineering technical field especially relates to a kind of universal joint oil seal structure for automobile steering gear, including oil seal body, metal framework is embedded in the oil seal body inner wall, annular oil reservoir is equipped in the oil seal body outer wall center;Multiple rectangular oil reservoirs are arranged and set in the oil seal body inner wall and are in the form of circumferential array;Main sealing lip is integrally formed in one end of the oil seal body center;The universal joint oil seal for automobile steering gear provided in the application is innovatively designed, and the comprehensive performance is significantly improved;Effectively solve the problem that traditional oil seal is easy to wear and easy to leak, comprehensively improve the durability and reliability of sealing, significantly prolong the maintenance cycle and use safety of steering gear assembly.

Description

Technical Field

[0001] This utility model relates to the field of mechanical engineering technology, and in particular to a universal joint oil seal structure for automotive steering gear. Background Technology

[0002] In the modern automotive industry, the steering system, as a core assembly determining vehicle handling safety and driving comfort, has always prioritized reliability and durability in its research and development. The universal joint of the steering gear, as a key force-transmitting component connecting the steering gear and the steering tie rod, endures complex impact loads from the road surface, high-frequency reciprocating torsion, and continuous high-speed rotational motion over extended periods. This extreme working environment places extremely stringent requirements on the accompanying oil seal structure. It must not only prevent leakage of the internal lubricating medium but also effectively resist the intrusion of external dust and mud, serving as the last line of defense to ensure the steering system's "blood" doesn't leak and its "health" remains intact. However, existing oil seals used in this area generally suffer from structural shortcomings. Their overall structural strength is insufficient, making them prone to permanent deformation under alternating stress. Furthermore, their internal oil storage space design is simplistic, lacking an effective oil return guidance mechanism. This results in the sealing lip being in a state of dry friction for extended periods, easily leading to accelerated wear, seal failure, and a series of malfunctions such as abnormal noises in the steering system, oil leaks, and corrosion of critical components, severely impacting the overall vehicle's operational quality and safety redundancy.

[0003] Chinese patent discloses a universal joint oil seal with high sealing performance structure (publication number: CN 207377990 U), which includes a skeleton, a body, three main lips and three secondary lips. The secondary lips are triangular protrusions and are located diagonally above the main lips. The skeleton is interference-fitted with the outer ring, and the main lips are tightly fitted with the journal. The universal joint consists of a cross shaft, a dust cover, an inner oil seal, needle rollers, an outer ring, and a gasket. The cross shaft has four journals, each fitted with a dust cover. The dust cover and the outer ring cooperate with each other. An inner oil seal is located between the outer ring and the journal near the opening. Needle rollers are located between the inner sidewall of the outer ring and the journal. A gasket is located between the inner bottom of the outer ring and the journal. However, the overall structural strength of this universal joint oil seal is insufficient, and it is prone to permanent deformation under alternating stress. Furthermore, the internal oil storage space design is simple and lacks an effective oil return guiding mechanism, causing the sealing lip to be in a state of dry friction for a long time. This easily leads to accelerated wear, seal failure, and a series of malfunctions such as abnormal noise in the steering system, oil leakage, and corrosion of key components. Therefore, a universal joint oil seal structure for automotive steering gear is needed. Utility Model Content

[0004] The purpose of this invention is to address the common structural shortcomings of existing oil seals, such as insufficient overall structural strength, susceptibility to permanent deformation under alternating stress, and a lack of effective oil return guidance mechanism in the design of the internal oil storage space. This results in the sealing lip being in a state of dry friction for a long time, which easily leads to accelerated wear, seal failure, and a series of malfunctions such as abnormal noise in the steering system, oil leakage, and corrosion of key components. These issues seriously affect the overall vehicle's operating quality and safety redundancy. Therefore, this invention proposes a universal joint oil seal structure for automotive steering gears.

[0005] The technical solution adopted by this utility model to solve its technical problem is as follows: The universal joint oil seal structure for automotive steering gear of this utility model includes an oil seal body, characterized in that: a metal skeleton is embedded in the inner wall of the oil seal body; an annular oil reservoir is provided at the center of the outer wall of the oil seal body; multiple rectangular oil reservoirs are arranged in a circumferential array on the inner wall of the oil seal body; and a main sealing lip is integrally formed at one end of the center of the oil seal body. Structural stability and deformation resistance: By embedding a metal skeleton inside the rubber, the overall mechanical strength and rigidity of the oil seal are greatly enhanced, making it less prone to twisting or collapse when the universal joint rotates at high speed and bears lateral forces, ensuring the installation stability and long-term geometric accuracy of the oil seal; Dual oil storage lubrication: The annular oil reservoir at the center of the outer wall is combined with the rectangular oil reservoirs arranged in a circumferential array on the inner wall, forming an internal and external linkage oil storage mechanism. This design ensures a continuous supply of lubricating oil film to the main sealing lip and contact interface during universal joint operation, significantly reducing dry friction between the rubber lip and the metal shaft and preventing premature wear and burning due to lack of oil. Integrated sealing function: The main sealing lip and the oil seal body are integrally molded, eliminating the fitting gap that may occur during separate assembly. This not only simplifies the manufacturing process but also makes the sealing lip have better following and fitting force when rotating with the shaft, fundamentally improving the reliability of dynamic sealing and effectively preventing grease leakage.

[0006] Preferably, the outer wall of the root of the main sealing lip is provided with an annular helical spring, and a spring retaining lip is provided on one side of the annular helical spring. The annular helical spring applies a continuous radial preload to the main sealing lip. As the universal joint is used for a long time, the main sealing lip will experience slight wear or the rubber will shrink due to temperature changes. The spring can automatically expand to compensate for the wear of the lip, always maintaining the optimal contact pressure between the lip and the shaft surface, ensuring a long-lasting and constant sealing effect, and solving the problem of ordinary oil seals failing due to wear. The design of the spring retaining lip plays a role in physical limiting and protection. It can firmly restrain the helical spring in the set position like a "circlip", preventing the spring from shifting, flipping, or even falling off under severe vibration or high-pressure oil impact. This ensures the long-term effective operation of the compensation mechanism and avoids the risk of scratching other parts of the universal joint if the spring loosens.

[0007] Preferably, the metal skeleton has an L-shaped cross-section. The metal skeleton is a closed circular ring precision-stamped from high-quality spring steel and is integrally embedded in the center of the oil seal body. The L-shaped cross-section design provides support in two directions. Compared to a flat skeleton, it can more effectively resist the torsional load and alternating stress generated when the universal joint transmits torque, preventing the oil seal from being squeezed and collapsed axially or torn radially, greatly improving the oil seal's resistance to damage under harsh working conditions. The closed circular ring structure, combined with the precision stamping process, ensures that the skeleton has extremely high roundness and flatness. When the oil seal is inserted into the housing, the skeleton acts as a solid support platform, ensuring that the centerline of the main sealing lip is strictly coaxial with the drive shaft, preventing localized wear due to eccentricity, thereby extending the service life of the oil seal and the shaft.

[0008] Preferably, the outer wall of the oil seal body is provided with multiple spiral oil return grooves extending circumferentially and spirally distributed axially, with each spiral oil return groove arranged in an equally spaced array from top to bottom. Utilizing fluid dynamics principles, the spiral oil return grooves generate a pumping effect when the shaft rotates. When a very small amount of lubricating oil attempts to seep out axially, these spiral grooves capture and guide it, forcing it to flow back inward along the spiral path into the gearbox, rather than allowing it to break through the outer surface and enter the atmosphere. While serving the function of oil return, these spiral grooves also increase the contact area between the outer circle of the oil seal and the housing, facilitating micro-airflow, helping to remove heat generated by friction, reducing the operating temperature of the oil seal, slowing down rubber aging, and improving overall durability.

[0009] Preferably, the rectangular oil reservoir has a depth of 0.8mm to 1.5mm and a width of 1.2mm to 2.0mm, with a rounded transition at the bottom. This specific combination of depth and width maximizes the oil storage volume of the inner wall while ensuring sufficient wall thickness for the oil seal rubber body to maintain strength. This allows the oil seal to store enough oil after a long period of shutdown and to quickly release lubrication upon startup, ensuring instantaneous start-up protection. The rounded transition design at the bottom of the reservoir is crucial. It eliminates stress concentration points at sharp corners, preventing the formation and gradual propagation of micro-cracks in the rubber material at the bottom of the reservoir (i.e., "fatigue cracking") under high-pressure oil and cyclic loads, thus ensuring the integrity of the oil reservoir structure and its long-term reliability.

[0010] Preferably, the oil seal body is made of rubber, which is composed of highly elastic, oil-resistant, and wear-resistant fluororubber. Fluororubber has extremely strong chemical inertness, effectively resisting the corrosion of power steering gear oil, grease, and various additives, and will not lose its sealing performance due to swelling or softening. Simultaneously, its wide temperature range ensures that the oil seal remains soft and highly elastic even in extremely cold or high-temperature environments, without hardening or becoming brittle. The use of highly wear-resistant fluororubber combined with an optimized structural design results in extremely low wear rate of the main sealing lip when it moves relative to a rough shaft surface. This not only protects the expensive drive shaft from scratches but also allows the oil seal lip to maintain a sharp sealing edge for a long time, ensuring long-lasting dynamic sealing performance.

[0011] The advantages of this utility model are:

[0012] The universal joint oil seal structure for automotive steering gear provided by this utility model has significant comprehensive technical advantages through its innovative overall design. In terms of structural stability, the L-shaped metal skeleton, precision-stamped from high-quality spring steel, is integrally embedded in the center of the rubber body, greatly enhancing the oil seal's shear resistance and deformation toughness. This allows it to maintain structural integrity even when facing complex torsional loads and impact vibrations of the universal joint, preventing oil seal collapse or misalignment. It ensures that the main sealing lip and shaft system are always precisely aligned, physically eliminating early leakage caused by structural instability. In terms of lubrication and sealing synergy, this design constructs a three-dimensional oil storage system that combines internal and external components. The rectangular oil storage grooves arranged in a circular array on the inner wall and the annular oil storage groove in the center of the outer wall work together to not only store sufficient lubricating medium to cope with the lubrication gap caused by frequent start-stop cycles, but more importantly, in conjunction with the integrally molded main sealing lip and the annular helical spring at its root, a self-healing dynamic sealing interface is formed. The continuous elasticity compensation mechanism of the spring can sensitively offset the wear caused by long-term friction of the lip, always maintaining the optimal sealing specific pressure. This allows the sealing lip to not only tightly fit the shaft surface to prevent medium leakage, but also to avoid abnormal wear due to excessive interference. In terms of fluid conduction and environmental adaptability, the spiral oil return groove on the outer wall cleverly utilizes the pumping effect generated by rotation to forcibly guide the minute amount of lubricating oil attempting to break through the outer circumference back, achieving active leak prevention control while promoting heat dissipation and micro-circulation of air. Furthermore, the use of highly elastic, oil-resistant, and wear-resistant fluororubber as the body material ensures that the oil seal not only resists the erosion of various harsh oils but also maintains stable physical properties over a wide temperature range, effectively preventing rubber aging and cracking. In summary, this oil seal structure, through the robust support of the metal skeleton, the lubrication guarantee of the dual oil reservoirs, the self-healing seal with spring compensation, and the fluid management of the spiral oil return, comprehensively improves the durability and reliability of the universal joint oil seal, fundamentally solving the pain points of traditional oil seals such as easy wear, easy leakage, and short lifespan, significantly extending the maintenance cycle and operational safety of the steering gear assembly. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure of this utility model.

[0015] Figure 2 This is a schematic diagram of the rear structure of this utility model.

[0016] Figure 3 This is a schematic diagram of the right-side structure of this utility model.

[0017] Figure 4 This utility model Figure 3 A cross-sectional view of BB.

[0018] Figure 5 This utility model Figure 4 Enlarged view of I in the middle.

[0019] In the diagram: 1. Oil seal body; 2. Rectangular oil reservoir; 3. Main sealing lip; 4. Spring retaining lip; 5. Annular helical spring; 6. Helical return oil groove; 7. Annular oil reservoir; 8. Metal skeleton. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model. Example

[0021] Please see Figures 1-5 As shown, a universal joint oil seal structure for automotive steering gear includes an oil seal body 1. Its features include: a metal skeleton 8 embedded in the inner wall of the oil seal body 1; an annular oil reservoir 7 at the center of the outer wall of the oil seal body 1; multiple rectangular oil reservoirs 2 arranged in a circumferential array on the inner wall of the oil seal body 1; and a main sealing lip 3 integrally formed at one end of the center of the oil seal body. The structure is stable and resistant to deformation: by embedding the metal skeleton 8 inside the rubber, the overall mechanical strength and rigidity of the oil seal are greatly enhanced, making it less prone to twisting or collapse when the universal joint rotates at high speed and bears lateral forces, ensuring the installation stability and long-term geometric accuracy of the oil seal; dual oil storage and lubrication: the annular oil reservoir 7 at the center of the outer wall and the rectangular oil reservoirs 2 arranged in a circumferential array on the inner wall combine to form an internally and externally linked oil storage mechanism. This layout ensures a continuous supply of lubricating oil film to the main sealing lip 3 and the contact interface during universal joint operation, significantly reducing dry friction between the rubber lip and the metal shaft and preventing premature wear and burning due to lack of oil. Integrated sealing function: The main sealing lip 3 and the oil seal body 1 are integrally molded, eliminating the fitting gap that may occur during separate assembly. This not only simplifies the manufacturing process but also makes the sealing lip have better following and fitting force when rotating with the shaft, fundamentally improving the reliability of dynamic sealing and effectively preventing grease leakage.

[0022] In this embodiment, an annular helical spring 5 is provided on the outer wall of the root of the main sealing lip 3, and a spring retaining lip 4 is provided on one side of the annular helical spring 5. The annular helical spring 5 applies a continuous radial preload to the main sealing lip 3. As the universal joint is used for a long time, the main sealing lip 3 will experience slight wear or the rubber will shrink due to temperature changes. The spring can automatically expand to compensate for the wear of the lip, always maintaining the optimal contact pressure between the lip and the shaft surface, ensuring a long-lasting and constant sealing effect, and solving the problem of ordinary oil seals failing due to wear. The design of the spring retaining lip 4 plays a role in physical limiting and protection. It can firmly restrain the helical spring in the set position like a "circlip", preventing the spring from shifting, flipping, or even falling off under severe vibration or high-pressure oil impact, thereby ensuring the long-term effective operation of the compensation mechanism and avoiding the risk of scratching other parts of the universal joint after the spring loosens.

[0023] In this embodiment, the metal skeleton 8 has an L-shaped cross-section. The metal skeleton 8 is a closed circular ring precisely stamped from high-quality spring steel and is integrally embedded in the center of the oil seal body 1. The L-shaped cross-section design provides support in two directions. Compared to a flat skeleton, it can more effectively resist the torsional load and alternating stress generated when the universal joint transmits torque, preventing the oil seal from being squeezed and collapsed axially or torn radially, greatly improving the oil seal's resistance to damage under harsh working conditions. The closed circular ring structure, combined with the precision stamping process, ensures that the skeleton has extremely high roundness and flatness. When the oil seal is inserted into the housing, the skeleton acts as a solid support platform, ensuring that the centerline of the main sealing lip 3 is strictly coaxial with the drive shaft, preventing localized wear due to eccentricity, thereby extending the service life of the oil seal and the shaft.

[0024] In this embodiment, the outer wall of the oil seal body 1 is provided with multiple spiral oil return grooves 6 extending circumferentially and spirally distributed axially. Each spiral oil return groove 6 is arranged in an array with equal spacing from top to bottom. The spiral oil return grooves 6 utilize the principle of fluid mechanics to generate a pumping effect when the shaft rotates. When a very small amount of lubricating oil attempts to seep out axially, these spiral grooves can capture and guide it, forcing it to flow back inward along the spiral path into the gearbox, instead of allowing it to break through the outer surface and enter the atmosphere. While playing the role of oil return, these spiral grooves also increase the contact area between the outer circle of the oil seal and the housing, which is conducive to micro-airflow, helps to remove the heat generated by friction, reduces the working temperature of the oil seal, slows down the aging rate of the rubber, and improves the overall durability.

[0025] In this embodiment, the rectangular oil reservoir 2 has a depth of 0.8mm to 1.5mm and a width of 1.2mm to 2.0mm, and the bottom of the rectangular oil reservoir 2 has a rounded transition. This specific combination of depth and width maximizes the oil storage volume of the inner wall while ensuring sufficient wall thickness of the oil seal rubber body to maintain strength. This allows the oil seal to store enough oil after a long period of shutdown and to quickly release lubrication upon startup, ensuring instantaneous start-up protection. The rounded transition design at the bottom of the reservoir is crucial. It eliminates stress concentration points at sharp corners, preventing the formation and gradual propagation of micro-cracks in the rubber material at the bottom of the reservoir (i.e., "fatigue cracking") under high-pressure oil and cyclic loads, thereby ensuring the integrity of the oil reservoir structure and its long-term reliability.

[0026] In this embodiment, the oil seal body 1 is made of rubber, which is composed of highly elastic, oil-resistant, and wear-resistant fluororubber. Fluororubber has extremely strong chemical inertness, effectively resisting the corrosion of power steering gear oil, grease, and various additives, and will not lose its sealing performance due to swelling or softening. Simultaneously, its wide temperature range ensures that the oil seal remains soft and highly elastic even in extremely cold or high-temperature environments, without hardening or becoming brittle. The use of highly wear-resistant fluororubber combined with an optimized structural design results in extremely low wear rate of the main sealing lip 3 when it moves relative to a rough shaft surface. This not only protects the expensive drive shaft from scratches but also allows the oil seal lip to maintain a sharp sealing edge for a long time, ensuring long-lasting dynamic sealing performance.

[0027] The implementation principle of this embodiment is as follows:

[0028] Once the oil seal is pressed into the universal joint housing, its internally embedded closed L-shaped metal skeleton 8 (precision-stamped from high-quality spring steel) immediately comes into play. This skeleton, with its excellent rigidity and resistance to deformation, acts as the "inner skeleton" of the oil seal body 1, resisting the radial forces and torques during universal joint operation and preventing the rubber body from collapsing or twisting under high pressure. Simultaneously, the central axis of the skeleton establishes the installation reference for the oil seal, ensuring that the subsequent sealing lip maintains strict coaxiality with the drive shaft, providing a solid physical foundation and precise geometric positioning for the entire sealing system.

[0029] When the universal joint is stationary or in the initial stage of startup, the multiple rectangular oil reservoirs 2 arranged in a circular array on the inner wall of the oil seal (with rounded transitions at the bottom to prevent stress cracking) and the annular oil reservoir 7 at the center of the outer wall together form a three-dimensional lubricating oil storage network. These oil reservoirs are pre-stored with sufficient grease. When the shaft begins to rotate, the lubricating oil in these reservoirs continuously and evenly penetrates to the contact interface between the main sealing lip 3 and the drive shaft under centrifugal force and capillary action, quickly establishing a tough lubricating film. This transforms the original dry metal friction into controllable fluid friction, creating ideal lubrication conditions for dynamic sealing.

[0030] The integrally molded main sealing lip 3, located at one end of the center of the oil seal body, is tightly fitted against the drive shaft surface under the continuous elastic force of the helical spring (annular helical spring 5). With long-term operation of the universal joint, the main sealing lip 3 inevitably experiences slight wear. At this time, the annular helical spring 5 acts as a "dynamic adjuster," automatically compensating for the wear of the lip through its radial expansion force, ensuring a constant contact pressure at the sealing interface. Simultaneously, the spring retaining lip 4, located on one side of the spring, plays a crucial limiting function, firmly locking the helical spring in a predetermined position to prevent displacement or detachment during severe vibrations. This ensures the long-term effectiveness of the wear compensation mechanism and achieves durable and stable sealing performance.

[0031] Under extreme operating conditions or pressure fluctuations, if a small amount of lubricating oil attempts to leak out through the main sealing lip 3, the spiral return oil grooves 6 on the outer wall of the oil seal will begin to play their core guiding role. These grooves, which extend circumferentially and are spirally distributed axially, use the pumping effect generated when the shaft rotates to capture and forcefully guide the lubricating oil attempting to leak out, causing it to flow back inward along the spiral path into the gearbox cavity.

[0032] While all the aforementioned mechanical actions are performed, the oil seal body 1, made of highly elastic, oil-resistant, and wear-resistant fluororubber, serves as the substrate supporting all the aforementioned precision structures, continuously exhibiting its chemical inertness and physical elasticity. It resists the swelling and corrosion of the lubricating oil, adapts to temperature changes caused by the road surface, protects the internal metal skeleton 8 and spring from environmental erosion, and ensures that the entire sealing system maintains structural integrity and functional coordination even under complex and harsh steering conditions, ultimately achieving the goal of long-term reliable sealing.

[0033] 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.

[0034] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.

Claims

1. A universal joint oil seal structure for automotive steering gear, comprising an oil seal body (1), characterized in that: The inner wall of the oil seal body (1) is provided with a metal skeleton (8), and the center of the outer wall of the oil seal body (1) is provided with an annular oil storage groove (7); the inner wall of the oil seal body (1) is provided with multiple rectangular oil storage grooves (2) arranged in a circular array; the center end of the oil seal body is integrally formed with a main sealing lip (3).

2. The universal oil-saving seal structure for automotive steering gear according to claim 1, characterized in that: The outer wall of the root of the main sealing lip (3) is provided with an annular helical spring (5), and a spring retaining lip (4) is provided on one side of the annular helical spring (5).

3. The universal joint oil seal structure for automotive steering gear according to claim 1, characterized in that: The cross-sectional shape of the metal skeleton (8) is L-shaped. The metal skeleton (8) is a closed ring made of high-quality spring steel by precision stamping and is embedded in the center of the oil seal body (1).

4. The universal oil-saving seal structure for automotive steering gear according to claim 1, characterized in that: The outer wall of the oil seal body (1) is provided with a plurality of spiral oil return grooves (6) extending circumferentially and spirally distributed along the axial direction. Each spiral oil return groove (6) is arranged in an array with equal spacing from top to bottom.

5. The universal joint oil seal structure for automotive steering gear according to claim 1, characterized in that: The rectangular oil storage tank (2) has a depth of 0.8mm to 1.5mm and a width of 1.2mm to 2.0mm. The bottom of the rectangular oil storage tank (2) is provided with a rounded transition.

6. The universal oil-saving seal structure for automotive steering gear according to claim 1, characterized in that: The oil seal body (1) is made of rubber sealing body, which is composed of highly elastic, oil-resistant and wear-resistant fluororubber.

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