Driving shaft ball cage sealing structure, assembling method, driving shaft assembly and automobile

Abstract

The invention relates to a driving shaft ball cage sealing structure, an assembling method, a driving shaft assembly and an automobile. The driving shaft ball cage sealing structure comprises a ball cage, the cup opening end of the ball cage is connected with one end of a sheath, the other end of the sheath is used for being connected with a shaft rod of a driving shaft, the cup opening end of the ball cage is in threaded connection with one end of the sheath, and at least one threaded hole is formed in the cup opening end of the ball cage; the end, connected with the cup opening end of the ball cage, of the protective sleeve is provided with at least one fixing hole corresponding to the threaded hole, a threaded piece penetrates through the fixing hole and is fixedly connected with the ball cage in a threaded mode through the threaded hole, and the part, extending into the ball cage, of the threaded piece serves as an anti-pull-off part of the tripod assembly. And the tripod assembly is prevented from being pulled off.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, specifically to a drive shaft ball cage sealing structure, assembly method, drive shaft assembly, and automobile. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] The drive shaft is a crucial component of a car's transmission system. It transmits power from the powertrain to the wheels, propelling the vehicle forward. It also absorbs suspension travel, causing the axle to reciprocate within the inner CV joint seal and rotate around the pivot point in the outer CV joint. During this movement, the internal components are lubricated by grease sealed within the CV joint seal.

[0004] Current ball cage sealing structures include a ball cage and a rubber sleeve placed between the ball cage and the drive shaft. The rubber sleeve is a commonly used sealing structure and provides resistance to keep the three ball pin assembly inside the ball cage and prevent pull-out. In current ball cage sealing structures, the rubber sleeve is locked to the ball cage with clamps for sealing. Anti-pull-out structures and anchor points are added to the sleeve to prevent the three ball pin assembly from being pulled out.

[0005] In traditional manufacturing processes, clamps are assembled manually, with visual marking to ensure proper assembly. This can easily lead to misassembly, omissions, or incomplete assembly. Furthermore, using clamps to lock the ball cage and sleeve can result in clamp damage or insufficient locking force, leading to poor sealing between the sleeve and the ball cage and potential lubricant leakage. Adding an anti-pull-out structure to the sleeve to prevent the three-ball pin assembly from pulling out increases the structural complexity and manufacturing difficulty of the sleeve. Moreover, the anti-pull-out structure of the sleeve has relatively low pull-out resistance, leaving the three-ball pin assembly at risk of being pulled out. Adding anchor points to the sleeve requires specialized anchoring equipment to process the anchor points on the inside of the ball cage's cup end, increasing equipment investment and processing costs. Additionally, using clamps to fix the sleeve and ball cage has a large rotation diameter, which can easily interfere with surrounding components. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a drive shaft ball cage sealing structure, assembly method, drive shaft assembly, and automobile, thereby overcoming the defects of the current ball cage sealing structure.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, embodiments of the present invention provide a drive shaft ball cage sealing structure, including a ball cage, the cup end of the ball cage being connected to one end of a sheath, the other end of the sheath being used to connect to the shaft of the drive shaft, the cup end of the ball cage being threadedly connected to one end of the sheath, the cup end of the ball cage being provided with at least one threaded hole, the end of the sheath connected to the cup end of the ball cage being provided with at least one fixing hole corresponding to the threaded hole, a threaded component passing through the fixing hole, the threaded component being threadedly fixedly connected to the ball cage through the threaded hole, the threaded component having a portion extending into the interior of the ball cage as an anti-pull-out portion of the three-ball pin assembly.

[0008] Optionally, the cup end of the ball cage is provided with an external thread structure, and the end of the sleeve used to connect to the ball cage is provided with an internal thread structure that matches the external thread structure. The sleeve is threadedly connected to the cup end of the ball cage through the internal thread structure and the external thread structure.

[0009] Optionally, the outer side of the end of the sleeve used to connect the ball cage cup mouth is provided with a platform, a fixing hole is opened on the platform, and a fixing through hole passes through the platform and the sleeve.

[0010] Optionally, the ball cage cup end is provided with multiple threaded holes, which are evenly distributed along the circumferential direction of the ball cage cup end. Correspondingly, the end of the sleeve used to connect the ball cage is provided with multiple fixing holes that correspond one-to-one with the threaded holes.

[0011] Optionally, the sheath adopts a conical corrugated tube structure, with a cylindrical section at the larger end. The cylindrical section is used to fit around the outer periphery of the cup end of the ball cage and is threaded to the cup end of the ball cage. The smaller end is used to connect with the shaft.

[0012] Optionally, the fixing hole is a threaded hole that matches the threaded part.

[0013] Secondly, embodiments of the present invention provide an assembly method for the drive shaft ball cage seal structure described in the first aspect, comprising the following steps: The protective sleeve is fitted onto the shaft of the drive shaft; Lubricating grease was pre-injected into the ball cage; Press the end of the assembled drive shaft, consisting of a three-ball pin assembly and a shaft, into the ball cage. The three-ball pin assembly extends into the ball cage. Then, the outer end of the sleeve used to connect the cup end of the ball cage is fitted onto the outer circumference of the cup end of the ball cage. Rotate the sleeve until the fixing hole of the sleeve is coaxially aligned with the corresponding threaded hole of the cup end of the ball cage. The sleeve and the ball cage are threaded together to form a sealing structure. After passing the threaded part through the fixing hole, it is fixedly connected to the ball cage through the threaded hole. Rotate the threaded part until the length of the part of the threaded part extending into the ball cage reaches the set length. Secure the inner end of the sheath to the shaft.

[0014] Optionally, the inner end of the sheath can be fixedly connected to the shaft of the drive shaft using a clamp.

[0015] Thirdly, embodiments of the present invention provide a drive shaft assembly including the drive shaft ball cage sealing structure described in the first aspect.

[0016] Fourthly, embodiments of the present invention provide an automobile including the drive shaft assembly described in the third aspect.

[0017] The beneficial effects of this invention are as follows: The drive shaft ball cage sealing structure of this invention features a threaded connection between the ball cage and the sleeve. Compared to a clamp connection, the threaded connection offers stronger sealing performance and is less prone to damage, ensuring the sealing structure's tightness and preventing lubricant leakage. Furthermore, the absence of a clamp on the outside of the sleeve saves space and avoids interference with surrounding components. The ball cage has a threaded hole, and the sleeve has a fixing hole. The alignment of the threaded hole and the fixing hole controls the depth to which the sleeve is screwed into the ball cage, thus positioning the connection between the ball cage and the sleeve and ensuring proper assembly to meet requirements and guarantee the sealing structure's tightness. Additionally, threaded components can pass through the threaded hole and the fixing hole. The threaded component can extend into the ball cage to a set length, providing anti-pull-out protection for the three-ball pin assembly. Since the threaded component is a rigid part and is threadedly connected to the ball cage, its anti-pull-out capability is significantly better than the traditional flexible anti-pull-out structure inside the sheath. This avoids the risk of the three-ball pin assembly being pulled out. Moreover, during processing, existing tapping equipment can be used to drill threaded holes in the ball cage, eliminating the need for costly special anchoring equipment to create anchor points on the ball cage, thus significantly reducing equipment investment costs. The threaded component can achieve assembly positioning, ensuring the connection and sealing performance between the sheath and the ball cage, while also preventing the three-ball pin assembly from pulling out. The structure is simple, easy to improve, and has low manufacturing costs. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present invention; Figure 2 This is a cross-sectional view of the overall structure of Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the ball cage structure in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the sheath structure in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the assembly process in Embodiment 2 of the present invention; Among them, 1. ball cage, 2. sheath, 3. bolts; 1-1. External thread structure; 2-1. Cylindrical section, 2-2. Internal thread structure, 2-3. Platform, 2-4. Fixing hole. Detailed Implementation

[0020] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is intended to include the plural form as well. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] In this embodiment, the ball cage (also known as the constant velocity universal joint housing) is a key component used to house the three ball pin assembly and realize torque transmission; the sleeve is a flexible protective cover that covers the outside of the ball cage to seal the lubricating medium and prevent contaminants from entering; the drive shaft, as the core component of vehicle power transmission, connects the gearbox and the wheels and needs to withstand alternating loads, angular deflection and axial extension under complex working conditions.

[0023] Example 1 This embodiment provides a drive shaft ball cage seal structure for use in internal ball cage seal structures, such as... Figures 1-4 As shown, the device includes a ball cage 1 and a sleeve 2. The ball cage 1 has an open side, defined as the cup end. The end of the drive shaft can extend into the ball cage 1 through the cup end. The ball cage 1 is used to house the three ball pin assembly of the drive shaft. The sleeve 2 is made of flexible material and has a conical bellows structure. Its larger end is used to fit around the outer periphery of the cup end of the ball cage 1 and is fixedly connected to the cup end of the ball cage 1. The smaller end of the sleeve 2 is used to be fixedly connected to the shaft of the drive shaft, thereby forming a complete sealed cavity. The formed sealed cavity not only effectively seals the lubricating grease inside the ball cage 1, preventing the lubricating grease from leaking due to centrifugal force, thermal expansion, or pressure gradient, but also effectively isolates the intrusion of contaminants such as mud, water, dust, sand, and salt spray from the external environment, ensuring that the moving parts inside the ball cage 1 are in a good lubrication state for a long time, and significantly extending the service life of the drive shaft assembly.

[0024] In this embodiment, the sheath 2 is made of rubber material, such as oil-resistant, high-temperature resistant, and highly elastic neoprene rubber or hydrogenated nitrile rubber. Neoprene rubber or hydrogenated nitrile rubber has excellent aging resistance, resistance to compression set, and wide temperature range adaptability, making it suitable for use on passenger vehicle platforms. At the same time, the aforementioned neoprene rubber or hydrogenated nitrile rubber can maintain stable physical and mechanical properties and sealing elasticity in a wide temperature range (-40℃ to +150℃), ensuring that the sealing structure does not fail under extreme climatic conditions (such as winter start-up in cold regions or driving in high-temperature desert environments). Those skilled in the art can determine the type of rubber material for the sheath according to actual needs, such as fluororubber (FKM) or silicone rubber (VMQ), which will not be described in detail here.

[0025] Sheath 2 adopts a tapered bellows structure. The tapered bellows structure, through its multi-layer pleated design, gives it good axial expansion and contraction capabilities and angular compensation capabilities. It provides sufficient axial compression and tension stroke, and can maintain uniform wall thickness and reasonable stress distribution when deflected at large angles. This significantly extends service life and maintains sealing integrity, meeting the normal working requirements of vehicle suspension bounce, steering action or uneven road conditions. Moreover, the tapered bellows structure can avoid stress concentration, significantly improving fatigue life and sealing integrity.

[0026] In this embodiment, the ball cage 1 is improved based on the current ball cage. An external thread structure 1-1 is machined on the outer circumferential surface of the cup end of the ball cage 1. The external thread structure 1-1 extends along the axial direction of the ball cage 1. The length of the external thread structure 1-1 along the axial direction of the ball cage 1 needs to meet the sealing requirements after assembly with the protective sleeve 2. The protective sleeve 2 and the ball cage 1 have sufficient mating length in the axial direction to provide sufficient thread engagement area to resist higher internal lubricating grease pressure and external vibration load, so as to form an effective seal. Since different vehicle platforms have different requirements for drive shaft size, the specific length of the external thread structure 1-1 along the axial direction of the ball cage 1 can be flexibly set according to actual engineering needs. It is not described in a limiting way here. The internal structure of the ball cage 1 can adopt the existing technology and will not be described in detail here.

[0027] The sheath 2 is an improvement on the current sheath structure. An internal thread structure 2-2 matching the external thread structure 1-1 is provided on the outer side of the cylindrical section 2-1 at the larger end of the sheath 2. Therefore, after the cylindrical section 2-1 of the sheath 2 is fitted onto the outer periphery of the cup end of the ball cage 1, it can be threadedly connected to the cup end of the ball cage 1, thus completing the integration of mechanical connection and sealing.

[0028] The cup ends of the sleeve 2 and the ball cage 1 are connected by threads for sealing. Compared to the traditional method of sealing with clamps, the axial preload generated during the tightening of the threads on the sleeve 2 and the ball cage 1 is much greater than the radial clamping force generated by the elastic deformation of the clamps. The locking force between the sleeve 2 and the ball cage 1 is stronger, and the threaded connection provides strong resistance to axial pull-out, effectively preventing the sleeve 2 and the ball cage 1 from loosening. Furthermore, the threaded connection has self-locking properties, and even under harsh conditions such as high-frequency vibration, impact loads, or temperature cycling, the threaded connection is not prone to loosening, fretting wear, or sealing failure. This fundamentally solves common failure modes such as clamp loosening, corrosion, breakage, or improper installation, thus ensuring the sealing performance between the sleeve 2 and the ball cage 1 and preventing leakage of lubricating grease inside the ball cage 1. The threaded connection between the sleeve 2 and the ball cage 1 eliminates the need for additional clamps or other auxiliary parts, reducing the number of parts and assembly complexity.

[0029] Therefore, in this embodiment, the cup ends of the sleeve 2 and the ball cage 1 are connected by threads. Utilizing the self-locking characteristics of the threaded pair and the surface contact sealing principle, this not only significantly improves the locking force at the connection point between the sleeve 2 and the ball cage 1, but also ensures that the threaded connection is not prone to loosening or fretting wear during long-term vehicle operation, even when subjected to high-frequency vibration, impact loads, or temperature cycling. In contrast, traditional clamp connections mainly rely on radial pressure generated by elastic deformation to achieve sealing, and their preload easily decays over time. Especially after the rubber ages and shrinks under high-temperature conditions, the sealing performance drops sharply. However, the threaded connection method of the sleeve 2 and the ball cage 1 in this embodiment can always maintain a stable axial clamping force, effectively preventing leakage of the high-viscosity lubricating grease inside the ball cage 1 under centrifugal force or pressure gradient, thereby ensuring long-term reliable lubrication of the lubricating grease.

[0030] The thread engagement length of the sleeve 2 and the ball cage 1 can be set according to actual needs. The thread engagement length of the sleeve 2 and the ball cage 1 of heavy SUVs or light commercial vehicles is greater than that of the sleeve 2 and the ball cage 1 of small passenger cars. The specific thread engagement length can be set according to actual needs, and will not be described in detail here.

[0031] The cup end of the ball cage 1 is provided with at least one first threaded hole. In this embodiment, there are multiple first threaded holes, which are distributed at equal intervals along the circumferential direction of the cup end of the ball cage 1.

[0032] Preferably, three first threaded holes are provided, with adjacent first threaded holes spaced 120° apart circumferentially along the cup mouth end of the ball cage 1.

[0033] The cylindrical section 2-1 of the sheath 2 is provided with a fixing hole 2-4 that matches the first threaded hole. Since there are three first threaded holes, there are also three fixing holes 2-4. The three fixing holes 2-4 correspond one-to-one with the three first threaded holes.

[0034] The fixing hole 2-4 is either a smooth hole or a second threaded hole. Preferably, the fixing hole 2-4 is a second threaded hole. The second threaded hole is completely consistent with the first threaded hole in terms of thread direction, size, tolerance grade, etc., and ensures that the threaded part can pass through the first threaded hole and the second threaded hole and can achieve thread engagement with the first threaded hole and the second threaded hole.

[0035] In this embodiment, when the cylindrical section 2-1 of the sheath 2 is fitted onto the outer circumference of the cup end of the ball cage 1, and the sheath 2 is rotated to make the sheath 2 threadedly connected to the cup end of the ball cage 1, when the sheath 2 is rotated until the fixing hole 2-4 is coaxially aligned with the corresponding first threaded hole, it indicates that the screw-in depth of the sheath 2 relative to the ball cage 1 has reached the requirement. At this time, the thread engagement length between the sheath 2 and the ball cage 1 meets the dual requirements of sealing and strength. Through the setting of the first threaded hole and the fixing hole, the assembly positioning of the ball cage 1 and the sheath 2 is realized, ensuring sufficient thread engagement length. To meet sealing and strength requirements, this design avoids stress concentration at the base of the sleeve or deformation of the bellows due to excessive screwing, and prevents improper assembly of the ball cage 1 and sleeve 2. It ensures the sealing requirements between the ball cage 1 and sleeve 2, effectively eliminating the problems of "under-screwing" or "over-screwing" caused by human judgment errors or automated assembly deviations. It avoids insufficient sealing due to "under-screwing" and excessive compression at the base of sleeve 2, corrugated pipe wrinkling and deformation, or even rubber tearing due to "over-screwing," significantly improving the assembly qualification rate of the ball cage 1 and sleeve 2.

[0036] A threaded component passes through the first and second threaded holes. This threaded component is threadedly connected to the sleeve 2 and the cup end of the ball cage 1 through the first and second threaded holes. The portion of the threaded component extending into the ball cage 1 has a predetermined length, which prevents the three-ball pin assembly inside the ball cage 1 from being pulled out. Specifically, when the drive shaft is subjected to extreme axial tensile force (such as vehicle escaping from a stuck situation, rapid acceleration, or collision conditions), the portion of the threaded component extending into the ball cage 1 can physically block the three-ball pin assembly, preventing it from being accidentally pulled out of the ball cage, greatly improving driving safety.

[0037] The length setting can be adjusted according to actual needs, and will not be described in detail here.

[0038] In this embodiment, the first threaded hole, the second threaded hole, and the threaded component are evenly distributed along the circumferential direction of the ball cage 1 and the sheath 2 to achieve circumferential force balance between the sheath 2 and the ball cage 1, and to avoid the sheath 2 from being skewed or unevenly sealed due to single-point force.

[0039] The three-ball pin assembly is protected against pull-out by using threaded parts, which has high rigidity, fast response and strong impact resistance. This avoids the problem of fatigue failure or loss of function due to softening at high temperature when the anti-pull-out structure is set in the sheath.

[0040] In this embodiment, the threaded component is a bolt 3. The bolt 3 is threadedly connected to the sleeve 2 and the cup end of the ball cage 1 through the first threaded hole and the second threaded hole. The shank of the bolt 3 extends into the ball cage 1 for a set length, which plays a role in preventing pull-out of the three ball pin assembly.

[0041] It is understood that threaded parts can also be threaded columns or other components with threaded structures on their outer surfaces. Those skilled in the art can choose according to actual needs, and will not be described in detail here.

[0042] In this embodiment, the bolt 3 passes through the first threaded hole and the second threaded hole and is threadedly connected to the sleeve 2 and the ball cage 1. The head of the bolt 3 can apply a radial clamping force to the sleeve 2 toward the cup end of the ball cage 1, so that the bolt 3 plays a role in preventing pull-out of the three ball pin assembly on the one hand, and fixes the sleeve 2 and the ball cage 1 radially from the sleeve 2 and the ball cage 1 on the other hand, further improving the fixing strength between the sleeve 2 and the ball cage 1 and preventing the sleeve 2 from being pulled off the ball cage 1.

[0043] The head of bolt 3 is used to fit against the outer side of the end of the ball cage 1 connected to the sleeve 2. In this embodiment, in order to ensure that the head of bolt 3 can stably fit with the end of the sleeve 2, a platform 2-3 is provided on the outer side of the end of the sleeve 2 used to connect to the ball cage. The platform corresponds to the fixing hole 2-4. Since three fixing holes 2-4 are provided, three platforms 2-3 are provided. The platform 2-3 adopts a cubic plate structure, and its outer side is a plane. This plane is parallel to the tangent of the cylindrical segment 2-1 of the sleeve 2, as... The support surface of the bolt head allows the bolt 3 to be set radially along the sleeve 2. When installing the bolt 3, the bolt 3 can be installed in the radial direction of the sleeve 2, avoiding shear damage to the thread pair or local tearing of the sleeve 2 due to oblique force, thus ensuring the structural strength of the sleeve 2. At the same time, the setting of the platform 2-3 forms a locally thickened part at the position where the sleeve 2 is connected to the bolt 3, which enhances the structural strength of the sleeve 2 at the connection of the bolt 3, and ensures that the clamping force of the bolt head on the sleeve 2 is effectively transmitted without damaging the sleeve 2.

[0044] The fixing hole passes through the cylindrical section 2-1 of the platform 2-3 and the sheath 2, with one end extending to the outer side of the platform 2 and the other end extending to the inner side of the cylindrical section 2-1 of the sheath 2.

[0045] Preferably, the fixing hole 2-4 and the platform 2-3 are coaxially arranged to ensure the shortest load transmission path and the least stress concentration. The platform 2-3 and the end of the sheath 2 are integrally connected. During processing, the platform 2-3 and the sheath 2 are an integral structure and are manufactured simultaneously during the rubber injection molding process. No subsequent machining or bonding is required, which not only ensures the structural integrity and sealing performance, but also significantly reduces the manufacturing cost and process complexity.

[0046] The remaining structure of the drive shaft ball cage seal can be achieved using existing technology, and will not be described in further detail here.

[0047] In this embodiment, the ball cage sealing structure uses a threaded connection instead of a clamp connection between the ball cage 1 and the sleeve 2. A first threaded hole and fixing holes 2-4 are added for assembly and positioning. Compared to a clamp connection, the threaded connection between the ball cage 1 and the sleeve 2 provides stronger sealing and is less prone to damage, ensuring the sealing performance of the structure and preventing lubricant leakage. The axially stressed threaded connection between the sleeve 2 and the ball cage 1 has higher tensile and torsional strength than the traditional radial clamp connection, better meeting the stringent requirements of vehicles under complex dynamic loads such as bumpy roads, high-speed cornering, or emergency braking. It effectively prevents the sleeve 2 from falling off under extreme conditions. Furthermore, the elimination of clamps on the outside of the sleeve 2 reduces the number of parts and assembly steps, saves space occupied by clamps, avoids interference with surrounding parts, eliminates noise sources caused by clamps, and reduces quality fluctuations due to the number of parts, all contributing to improved overall vehicle quality. The ball cage 1 has a first threaded hole, and the sleeve 2 has fixing holes, allowing the alignment of the first threaded hole and fixing holes 2-4 to control the screwing of the sleeve 2 into the ball cage. The depth of cage 1 is used to position the connection between the ball cage 1 and the sleeve 2, ensuring proper assembly and precise control of the assembly depth. This guarantees that each assembly meets the sealing performance requirements. Simultaneously, the first threaded hole and fixing holes 2-4 can pass through the threaded component, which extends into the ball cage 1 to a set length, providing anti-pull-out protection for the three-ball pin assembly. Since the threaded component is rigid and threaded to the ball cage 1, replacing the traditional flexible anti-pull-out structure with a rigid structure significantly improves safety redundancy. Therefore, the anti-pull-out capability of the threaded component is significantly greater than... The traditional flexible anti-pull-out structure inside the sheath can avoid the risk of the three-ball pin assembly being pulled out. Moreover, during processing, existing tapping equipment can be used to drill threaded holes in the cup end of the ball cage 1 and the cylindrical section 2-1 of the sheath 2. There is no need to use expensive special anchoring equipment to make anchor points on the ball cage, which significantly reduces the equipment investment cost. The bolts 3 can achieve assembly positioning, ensure the connection and sealing performance between the sheath 2 and the ball cage 1, and also play a role in preventing the three-ball pin assembly from being pulled out. The structure is simple, easy to improve, and has low manufacturing cost.

[0048] It is understood that the ball cage sealing structure of this embodiment can also be used in the external ball cage sealing structure. In the application scenario of external ball cage, it is only necessary to make adaptive adjustments to the thread position, sheath taper and corrugation parameters according to the geometric shape and motion characteristics of the external ball cage. It has strong versatility and will not be described in detail here.

[0049] Example 2 This embodiment provides an assembly method for the drive shaft ball cage seal structure described in Embodiment 1, such as... Figure 5 As shown, it includes the following steps: Step 1: Place the sheath 2 onto the drive shaft. The assembly method between the sheath 2 and the drive shaft can be achieved using existing technology and will not be described in detail here. In this step, the smaller diameter end of the sheath 2 is fitted onto the shaft of the drive shaft, but the sheath 2 and the shaft of the drive shaft are not locked together.

[0050] Step 2: Pre-inject lubricating grease into the ball cage 1. The lubricating grease injection process can be completed by a quantitative grease injection machine. The method of injecting lubricating grease into the ball cage 1 can use existing technology, which will not be described in detail here.

[0051] Step 3: Assemble the three-ball pin assembly at the end of the shaft to form a drive shaft, and then press the end of the drive shaft with the sleeve 2 into the ball cage 1 which was injected with lubricating grease in step 2. At this time, the three-ball pin assembly extends into the ball cage 1.

[0052] The assembly method of the shaft and the three ball pin assembly, as well as the method of pressing the end of the drive shaft into the ball cage, can be achieved using existing technology and will not be described in detail here. This process requires control of the pressing speed and alignment accuracy to prevent damage to the sealing surface of the ball cage cup 1 end or to cause the lubricating grease to be squeezed out.

[0053] Step 4: Move the sleeve 2 so that the cylindrical section 2-1 of the sleeve 2 mates with the cup end of the ball cage 1. Then rotate the sleeve 2. As the sleeve 2 moves, the operator can observe to determine the relative position between the fixing hole 2-4 and the first thread control. The operator rotates the sleeve 2 until the fixing hole 2-4 on the sleeve 2 is coaxially aligned with the corresponding first thread hole on the ball cage 1. At this point, the thread engagement length between the sleeve 2 and the ball cage 1 reaches the target value, the assembly depth is qualified, and the sleeve 2 and the cup end of the ball cage 1 are threadedly connected. This method fundamentally solves the problem of relying on experience to judge whether the sleeve 2 and the ball cage 1 are properly assembled, and improves the assembly qualification rate and product consistency between the sleeve 2 and the ball cage 1.

[0054] Step 5: Insert bolt 3 into the fixing hole 2-4 and the first threaded hole. Bolt 3 is connected to the sleeve 2 and the ball cage 1 through the fixing hole 2-4 and the first threaded hole. Use a torque wrench or power tool to turn bolt 3 until the length of the bolt 3 extending into the ball cage 1 reaches the set length. At the same time, the head of bolt 3 is in contact with the outer side of platform 2-3. The length of the bolt 3 extending into the ball cage 1 should be sufficient to effectively block the maximum axial displacement stroke of the three ball pin assembly, so as to play a rigid anti-pull-out role.

[0055] Step 6: Fix the smaller end of the sheath 2 to the shaft of the drive shaft. In this embodiment, the smaller end of the sheath 2 is fixed to the shaft by a clamp. The fixing method can be any existing technology and will not be described in detail here.

[0056] The assembly method in this embodiment is simple in process and easy to operate. The assembly positioning is achieved by aligning the first threaded hole and the fixing holes 2-4, which greatly reduces the dependence on the operator's skills and is suitable for large-scale industrial production.

[0057] Example 3 This embodiment provides a drive shaft assembly, including the drive shaft ball cage seal structure described in Embodiment 1. In this embodiment, the outer ball cage seal structure and / or the inner ball cage seal structure of the drive shaft assembly both adopt the drive shaft ball cage seal structure of this embodiment. Preferably, both the outer ball cage seal structure and the inner ball cage seal structure of the drive shaft assembly adopt the drive shaft ball cage seal structure described in Embodiment 1. The remaining structures of the drive shaft assembly can adopt the prior art, and will not be described in detail here.

[0058] Example 4 This embodiment provides an automobile equipped with the drive shaft assembly described in Embodiment 3. The automobile can be a gasoline-powered vehicle, a hybrid vehicle, or a pure electric vehicle, and is suitable for various vehicle types such as passenger cars, SUVs, and light commercial vehicles. Due to the use of the sealing structure of this embodiment, the overall vehicle's durability, NVH performance, and maintenance cycle are significantly improved. The remaining structures of the automobile can be constructed using existing technologies and will not be described in detail here.

[0059] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A drive shaft ball cage sealing structure, comprising a ball cage, wherein the cup end of the ball cage is connected to one end of a sheath, and the other end of the sheath is used to connect to the shaft of the drive shaft, characterized in that, The cup end of the ball cage is threadedly connected to one end of the sheath. The cup end of the ball cage is provided with at least one threaded hole. The end of the sheath connected to the cup end of the ball cage is provided with at least one fixing hole corresponding to the threaded hole. A threaded component passes through the fixing hole. The threaded component is threadedly fixedly connected to the ball cage through the threaded hole. The threaded component has a part that extends into the inside of the ball cage as an anti-pull-out part of the three-ball pin assembly.

2. The drive shaft ball cage sealing structure as described in claim 1, characterized in that, The cup end of the ball cage is provided with an external thread structure, and the end of the sleeve used to connect to the ball cage is provided with an internal thread structure that matches the external thread structure. The sleeve is threadedly connected to the cup end of the ball cage through the internal thread structure and the external thread structure.

3. The drive shaft ball cage sealing structure as described in claim 1, characterized in that, The outer side of the end of the sleeve used to connect the ball cage cup mouth is provided with a platform, and the fixing hole is opened on the platform. The fixing through hole passes through the platform and the sleeve.

4. The drive shaft ball cage sealing structure as described in claim 1, characterized in that, The ball cage cup end has multiple threaded holes, which are evenly distributed around the circumference of the ball cage cup end. Correspondingly, the end of the sleeve used to connect the ball cage has multiple fixing holes that correspond one-to-one with the threaded holes.

5. The drive shaft ball cage sealing structure as described in claim 1, characterized in that, The sheath adopts a conical corrugated tube structure, with a cylindrical section at the larger end. The cylindrical section is used to fit around the outer circumference of the cup end of the ball cage and is threaded to the cup end of the ball cage. The smaller end is used to connect with the shaft.

6. The drive shaft ball cage sealing structure as described in claim 1, characterized in that, The fixing hole adopts a threaded hole that matches the threaded part.

7. A method for assembling the drive shaft ball cage seal structure according to any one of claims 1-6, characterized in that, Includes the following steps: The protective sleeve is fitted onto the shaft of the drive shaft; Lubricating grease was pre-injected into the ball cage; Press the end of the assembled drive shaft, consisting of a three-ball pin assembly and a shaft, into the ball cage. The three-ball pin assembly extends into the ball cage. Then, the outer end of the sleeve used to connect the cup end of the ball cage is fitted onto the outer circumference of the cup end of the ball cage. Rotate the sleeve until the fixing hole of the sleeve is coaxially aligned with the corresponding threaded hole of the cup end of the ball cage. The sleeve and the ball cage are threaded together to form a sealing structure. After passing the threaded part through the fixing hole, it is fixedly connected to the ball cage through the threaded hole. Rotate the threaded part until the length of the part of the threaded part extending into the ball cage reaches the set length. Secure the inner end of the sheath to the shaft.

8. The assembly method of the drive shaft ball cage seal structure as described in claim 7, characterized in that, The inner end of the sheath is fixedly connected to the shaft of the drive shaft using a clamp.

9. A drive shaft assembly, characterized in that, It includes the drive shaft ball cage sealing structure as described in any one of claims 1-6.

10. A car, characterized in that, It includes the drive shaft assembly as described in claim 9.

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