Ball joint assembly
By using a clamping spring instead of a traditional retaining clip, the problem of dust cover damage during the assembly of ball joint assemblies is solved, enabling reliable attachment and efficient assembly of the dust cover, and reducing the failure rate and cost.
Patent Information
- Application Number
- CN202510579106.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-05-13
- Filing Date
- 2025-05-07
- Publication Date
- 2025-11-14
AI Technical Summary
During the assembly of existing ball joint assemblies, the use of sharp retaining clip unfolding tools can easily damage the surface of the dust cover, leading to premature wear and failure. Furthermore, the damage is difficult to detect during quality control and assembly, resulting in increased costs and delays.
Instead of traditional retaining clips, clamping springs are used. The clamping springs are flexible and can be unfolded on the dust cover without damaging the surface. Optimized dimensions and characteristics ensure a secure attachment, reduce disassembly force, and are suitable for existing dust cover designs.
It effectively avoids damage to the surface of the dust cover, improves the reliability and efficiency of the assembly process, reduces the failure rate and cost, and simplifies quality control.
Smart Images
Figure CN120946675A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a ball joint assembly according to the preamble of claim 1. Background Technology
[0002] Ball joints are essential components of automotive suspension and steering systems, facilitating multidirectional movement and effectively transmitting mechanical loads between components. Despite their critical role, these joints are frequently subjected to harsh environmental conditions such as dust, debris, moisture, and road contaminants, all of which can significantly degrade their performance and reliability over time. To prevent such damage, dust covers or boots are typically used as protective barriers for ball joints.
[0003] Traditionally, retaining clips (such as flat springs / wire clips) have been the primary means of securing dust covers to ball joints. These clips apply appropriate radial force to ensure proper positioning and function of the dust cover. However, during assembly, the retaining clips need to be expanded so that they can be assembled over the dust cover. For this purpose, sharp clip expanding tools can be used to apply pressure to the retaining clips to expand them, which presents significant challenges. For example, the sharp edges of such tools tend to damage the functional surfaces of the dust cover, leading to premature wear and tear during normal use and potential early failure.
[0004] To avoid premature wear, such as due to damaged surfaces, such damage should be detected promptly. However, detecting damaged dust covers during the assembly process at the production level is challenging and often results in bypassed quality control measures. Furthermore, the manual process of unfolding tools using sharp clamps is prone to a relatively high rate of process failures. This is because the process heavily relies on operators who may overlook damage incurred during assembly. Such negligence can lead to additional costs and production delays. Additionally, when dust covers need to be replaced or repaired, the retaining clip must be pulled from its seating position, resulting in permanent deformation of the standard retaining clip.
[0005] Therefore, the object of the present invention is to provide a ball joint assembly that includes an improved dust cover attachment on the ball joint, thereby avoiding damage to the surface of the dust cover during the assembly process. Summary of the Invention
[0006] This objective is achieved by the ball joint assembly according to claim 1.
[0007] The ball joint assembly includes a ball joint (or ball socket joint) having a ball stud (or ball head pin / ball stud / ball head post / ball stud), the ball stud having a shaft portion and a ball head, wherein the ball head is rotatably retained within a housing (or housing). The housing may have a cap-like structure with a bottom opening and an internal cavity filled with lubricant. The internal cavity is configured to retain the ball head in a rotatable manner.
[0008] The ball joint assembly also includes a dust cover adapted to cover the ball joint. The dust cover includes an upper end and a lower end, wherein the upper end is fixed to the housing, and the lower end is fixed to the shaft portion of the ball joint. For example, the dust cover may engage with a recess provided on the outer peripheral surface of the bottom of the housing. Preferably, the dust cover may have a rim-like structure projecting from the upper end, wherein the rim-like structure is configured to be fixed in the recess of the housing to cover the ball joint.
[0009] To attach a dust cover to a ball joint without damaging its surface, the ball joint assembly includes at least one garter spring disposed at the upper and / or lower end of the dust cover. The garter spring is configured to secure the dust cover to the housing and / or to the shaft of the ball joint, respectively. The proposed garter spring provides a unique technical solution: it securely attaches the dust cover to the ball joint even under significant stress or force. Its flexibility allows for easy expansion over the dust cover without damage, and its removal requires less extraction force than conventional retaining clips. Therefore, using a garter spring to attach the dust cover to the ball joint provides a secure attachment (like previously used retaining clips) while avoiding damage to the dust cover's surface.
[0010] The dust cover may have an annular groove at its upper and / or lower ends to accommodate at least one locking spring. This allows at least one locking spring to be firmly and securely attached to the dust cover, thus providing a more reliable and stable attachment of the dust cover to the ball joint.
[0011] Furthermore, at least one clamping spring can be in the form of a closed ring, or any other deployable form that can be easily unfolded and slid onto the dust cover. Alternatively, at least one clamping spring may have two free ends suitable for connection to each other. Thus, at least one clamping spring can be easily mounted around the dust cover due to its open form, and can then be closed or connected to form a closed ring around the dust cover. Furthermore, the length of the clamping spring can be adjusted by cutting its free ends before connecting the ends. This means that the length of the clamping spring can be adjusted to the appropriate size of the dust cover. This adjustment can increase the clamping force or compression force of the clamping spring around the dust cover to hold it securely in place. To connect the two open ends, the first end of the two free ends can be inserted into the second end of the two free ends. The first end can be formed by reducing the cross-sectional diameter towards the end of the wire coil. Thus, the first end can be easily inserted into the second end, forming a first-end-to-second-end twist.
[0012] When designing a clamping spring to hold the dust cover in place, various characteristics of the clamping spring can be optimized, particularly its dimensions, such as the diameter of the coil wire, the diameter of the spring's cross-section, and / or the length of the wire in its free state. These dimensions or characteristics of the clamping spring can be specifically optimized to improve its flexibility and clamping force, thereby effectively holding the dust cover on the housing and / or the axial portion of the ball joint.
[0013] Therefore, according to one embodiment, the cross-sectional diameter (De) of at least one clamping spring is equal to or less than the inner diameter of the annular groove at the upper and / or lower ends. The cross-sectional diameter can be selected to be similar to that of currently used retaining clips. By selecting a cross-sectional diameter similar to that of currently used retaining clips, this ensures that at least one clamping spring can be easily integrated into existing designs.
[0014] For example, for a specific application, at least one clamping spring may have a cross-sectional diameter (De) equal to or less than 1.8 mm, where De ≤ 1.8 mm. This cross-sectional diameter allows the clamping spring to be fitted within the limited space available on the dust cover. For instance, the dust cover may have a diameter between 16 mm and 33 mm and a thickness between 3.5 mm and 5.4 mm, and a cross-sectional diameter ≤ 1.8 mm can be optimized for fitting within dust covers of these dimensions. Such a cross-sectional diameter also ensures that the clamping spring retains the necessary flexibility (or suppleness) to unfold on the dust cover for removal from the dust cover without premature deformation.
[0015] Furthermore, clamping springs with a cross-sectional diameter ≤1.8mm can have the same dimensions as previously used retaining clips, and therefore can be fitted onto existing dust covers, eliminating the need to design new dust covers. This makes the proposed clamping spring a suitable replacement for traditional retaining clips, thus providing compatibility with a wide range of applications.
[0016] Furthermore, at least one clamping spring may have a wire diameter (d) between 0.1 mm and 0.7 mm, preferably between 0.1 mm and 0.5 mm. The wire diameter can be optimized to enhance the radial force applied by the clamping spring, particularly to provide sufficient force to hold the dust cover on the ball joint.
[0017] According to another embodiment, at least one clamping spring provides a radial force (rf) configured to secure the dust cover to the housing and / or shaft. The radial force applied by the clamping spring is directed radially from the axis of rotation or movement of the dust cover. This is essential for securing the dust cover to the ball joint, even during multi-directional movement of the ball joint. For example, at least one clamping spring can be optimized to provide a radial force value between 45 and 85 Newtons, preferably between 60 and 70 Newtons, to secure the dust cover to the housing and / or shaft. This radial force value can be optimized to be greater than or equal to the radial force value of a conventional retaining clip.
[0018] Furthermore, other dimensions of the clamping spring, such as the number of coils, spring length, spring stiffness, and inner diameter, can be optimized based on the dimensions of the dust cover. For example, the inner diameter (Di) of the clamping spring can be optimized to be equal to the outer diameter of the upper and / or lower ends to ensure proper fit and provide sufficient compressive or clamping force at the upper and / or lower ends of the dust cover. Therefore, by optimizing the dimensions and characteristics of the clamping spring for specific applications, clamping springs of different sizes and dimensions suitable for assembly onto several existing dust covers can be provided.
[0019] The dust cover of the ball joint assembly can have an upper end with an annular diameter larger than that of the lower end. Specifically, the inner diameter of the upper end can be configured to be equal to the outer diameter of the housing, while the inner diameter of the lower end can be equal to the outer diameter of the shaft. This configuration facilitates easy engagement between the upper end and the recess of the housing, as well as easy engagement between the lower end and the shaft portion of the ball joint.
[0020] According to one embodiment, the ball joint assembly includes a first locking spring and a second locking spring, wherein the first locking spring is disposed at the upper end to secure the dust cover to the housing, and the second locking spring is disposed at the lower end to secure the dust cover to the shaft. These first and second locking springs can be optimized to be received within the upper and lower ends, particularly within corresponding annular grooves, thereby ensuring a secure fastening of the dust cover.
[0021] According to another embodiment, the first locking spring differs from the second locking spring in terms of wire diameter and / or radial force. Preferably, the first locking spring can have a larger wire diameter than the second locking spring. For example, the wire diameter of the first locking spring can be between 0.38 mm and 0.42 mm, and the wire diameter of the second locking spring can be between 0.32 mm and 0.37 mm. This is because the first locking spring can be configured to hold the upper end, whose outer diameter is larger than that of the lower end, onto the housing, while simultaneously securing the housing to the ball head. On the other hand, the second locking spring can be configured to directly secure the lower end to the shaft. In this embodiment, the first locking spring requires a greater load capacity, strength, and radial force than the second locking spring to effectively hold a heavier load at the upper end (due to the combination of the housing and the dust cover). Therefore, since the wire diameter affects the load capacity, strength, and radial force, the wire diameter of the first locking spring can be optimized to be larger than that of the second locking spring.
[0022] According to another preferred embodiment, the first clamping spring provides a larger radial force than the second clamping spring. As mentioned above, the upper end of the dust cover can withstand a heavier load than the lower end. Therefore, compared to the second clamping spring, which requires, for example, a radial force between 60 and 64 Newtons to hold the lower end, which has a relatively small outer diameter (e.g., about 16 mm) and a small radial thickness (e.g., about 3.5 mm), to the shaft, the first clamping spring requires a higher radial force (e.g., a radial force between 65 and 70 Newtons) to secure the upper end, which has a larger outer diameter (e.g., about 33 mm) and a larger radial thickness (e.g., about 5.4 mm), to the housing.
[0023] Alternatively, when the upper and lower ends have the same or similar dimensions, the first locking spring can be similar to the second locking spring. Therefore, the dimensions of the first and second locking springs can be optimized based on the dimensions of the dust cover to snugly fit the upper and lower ends and / or apply radial forces to the upper and lower ends, thereby holding the dust cover on the housing and shaft respectively.
[0024] Further preferred embodiments are defined in the dependent claims, as well as in the specification and drawings. Thus, elements described or shown in combination with other elements may exist alone or in combination with other elements without departing from the scope of protection. Attached Figure Description
[0025] Preferred embodiments of the invention are described below with reference to the accompanying drawings, which are merely exemplary and not intended to limit the scope of protection. The scope of protection is defined only by the appended claims.
[0026] The attached diagram shows:
[0027] Figure 1 : Schematic cross-section of a ball joint assembly;
[0028] Figure 2 : Figure 1 A schematic perspective view of the ball joint assembly;
[0029] Figure 3 : Figure 1 and Figure 2 A schematic diagram of the locking spring used in the ball joint assembly; and
[0030] Figure 4 : Figure 2 A cross section of a perspective view.
[0031] Explanation of reference numerals in the attached figures
[0032] 1 ball joint assembly
[0033] 2 spherical pins
[0034] 4-axis section
[0035] 6-ball head
[0036] 7. Housing filled with lubricant
[0037] 8 shells
[0038] 10 dust covers
[0039] 12 First clamping spring
[0040] 14 Second clamping spring
[0041] 16 Upper end
[0042] 18 Lower end
[0043] 20-Fringed Structure
[0044] 22 concavities
[0045] 24 Outer diameter of the upper end
[0046] 26 outer diameter of the lower end
[0047] d. Wire diameter of the clamping spring
[0048] De clamping spring cross-sectional diameter
[0049] Lo clamping spring length
[0050] Di clamping spring inner diameter Detailed Implementation
[0051] In the following text, the same or similar functional elements are indicated by the same reference numerals.
[0052] Figure 1 and Figure 2 A ball joint assembly 1 is shown, comprising a ball joint having a ball stud 2 having a shaft portion 4 and a ball head 6. The ball head 6 is rotatably held within a housing 8 filled with lubricant 7. The ball joint assembly 1 also includes a dust cover 10 adapted to cover and protect the ball joint from harsh environmental conditions such as dust, debris, moisture, or road contaminants.
[0053] The dust cover 10 includes an upper end portion 16 and a lower end portion 18. The upper end portion 16 is configured to be fixed to the housing 8, and the lower end portion 18 is configured to be fixed to the shaft portion 4. The dust cover 10 also includes a rim-like structure 20 projecting from the upper end portion 16. As shown, the rim-like structure 20 can be configured to engage with a recess 22 formed in the housing 8.
[0054] Until now, retaining clips have been used to hold the dust cover onto the ball joint. However, during assembly, an assembly tool is needed to unfold the retaining clip over the dust cover, which can damage the surface of the dust cover due to the sharp edges of the tool. This damage can occur even before the dust cover is secured to the ball joint, leading to premature failure during normal use, or during the removal of the dust cover for replacement. Furthermore, during removal, the previously used retaining clip must be stretched from its position, causing deformation of the retaining clip.
[0055] Therefore, instead of using such a retaining clip, the ball joint assembly 1 described herein includes garter springs 12, 14 for retaining the dust cover 10 securely attached to the ball joint. Figure 1 and Figure 2 As shown, the ball joint assembly 1 may include two clamping springs 12 and 14, which are disposed on the upper end 16 and the lower end 18, respectively, to secure the dust cover 10 to the housing 8 and / or the shaft portion 4. Alternatively, the ball joint assembly 1 may include only one clamping spring, or it may include more than two clamping springs.
[0056] The retaining springs 12 and 14 are flexible and therefore require less force to unfold, allowing them to be easily unfolded from the dust cover 10 without damaging its surface and further preventing deformation of the retaining springs 12 and 14 during disassembly. When replacing the dust cover 10 or servicing the ball joint by removing the dust cover 10, the retaining springs 12 and 14 must be stretched from their seating position to remove them from the dust cover 10. Unlike retaining clips that tend to deform when stretched from their seating position, the retaining springs 12 and 14, due to their flexibility, can be easily unfolded and return to their original shape.
[0057] The locking springs 12 and 14 may be in the form of a closed ring. Alternatively, the locking springs 12 and 14 may be in an open form before assembly. In the latter case, during the unassembled and uncompressed state, the locking springs 12 and 14 are in their unfolded form with two free ends (e.g., Figure 3 (As shown in the diagram). These two free ends can be connected to each other to form a closed loop around the dust cover 10 (as shown in the diagram). Figure 2 (As depicted in the text). Furthermore, the length of the clamping springs can be adjusted by cutting their free ends before connecting the ends, thus allowing them to be sized on the dust cover 10. Therefore, the size of the clamping springs 12, 14 can be easily manipulated by adjusting their length to apply the necessary compressive force around the dust cover 10, thereby firmly holding the dust cover 10 in place.
[0058] Furthermore, the dimensions and characteristics of the clamping springs 12 and 14 (such as cross-sectional diameter, wire diameter, length, inner diameter, and / or radial force) can be optimized to retain the dust cover 10 onto the ball joint. When optimized, the clamping springs 12 and 14 can provide the same functionality as previously used retaining clips. For example, by making the cross-sectional diameter of the clamping springs 12 and 14 equal to or less than 1.8 mm (which can be optimized to resemble the cross-sectional diameter of a retaining clip), similar to previously used retaining clips, the clamping springs 12 and 14 can retain the dust cover in place.
[0059] like Figure 2 and Figure 4 As shown, the dust cover 10 has annular grooves 11 at both its upper end 16 and lower end 18 to accommodate clamping springs 12 and 14. The first clamping spring 12 is accommodated in the annular groove 11 at the upper end 16, and the second clamping spring 14 is accommodated in the annular groove 11 at the lower end 18 of the dust cover 10. Therefore, the first clamping spring 12 secures the upper end 16 to the housing 8, and the second clamping spring 14 secures the lower end 18 to the shaft portion 4.
[0060] In addition, such as Figure 2 As shown, the upper end portion 16 has an outer diameter 24 larger than the lower end portion 18. Therefore, in order to assemble and retain the upper end portion 16 and the lower end portion 18, the wire diameter (d) of the first clamping spring 12 is optimized to be larger than the wire diameter of the lower end portion. This makes the first clamping spring 12 thicker than the second clamping spring 14, thereby providing a greater compressive force and thus allowing it to easily hold the upper end portion 16 with the larger outer diameter 24 onto the housing.
[0061] Preferably, to increase the radial force required to clamp and hold the upper end 16 and lower end 18 to the housing 8 and shaft 4, respectively, the dimensions (such as wire diameter, number of turns, and cross-sectional diameter) of the clamping springs 12 and 14 can be optimized. The first clamping spring 12 may require a larger radial force to clamp and hold the upper end 16 (since the upper end 16 represents a heavier load due to its larger outer diameter) and simultaneously secure it to the housing. The wire diameter affects the stiffness of the clamping springs 12 and 14, which in turn affects the radial force applied by the clamping springs 12 and 14. Therefore, increasing the wire diameter of the first clamping spring 12 increases the radial force of the first clamping spring 12, which is suitable for holding the upper end 16 to the housing 8.
[0062] For example, with an outer diameter of approximately 33 mm at the upper end and approximately 16 mm at the lower end, the wire diameter of the first clamping spring 12 can be optimized to be between 0.38 mm and 0.42 mm to provide a radial force between 65 Newtons and 70 Newtons. The wire diameter of the second clamping spring 14 can be optimized to be between 0.32 mm and 0.37 mm to provide radial forces between 60 Newtons and 64 Newtons, respectively. Therefore, by optimizing the dimensions of the clamping springs 12 and 14 based on the dimensions of the dust cover 10, the clamping springs 12 and 14 can be configured to hold the dust cover 10 in place by snug fitting and applying the necessary radial force for compression or clamping.
[0063] In summary, by using a clamping spring to securely attach the dust cover to the ball joint without damaging the surface of the dust cover, an improved attachment of the dust cover to the housing is provided. The clamping spring has flexibility and radial force, which allows the clamping spring to easily expand and detach from the dust cover without causing any damage to the surface of the dust cover, while also compressing or clamping the dust cover into place.
Claims
1. A ball joint assembly (1), comprising: A spherical joint having a spherical pin (2) having a shaft portion (4) and a ball head (6), wherein the ball head (6) is rotatably held within a housing (8); a dust cover (10) adapted to cover the spherical joint, wherein the dust cover (10) includes an upper end portion (16) and a lower end portion (18), and wherein the upper end portion (16) is fixed to the housing (8), and the lower end portion (18) is fixed to the shaft portion (4). Its features are, At least one locking spring (12, 14) is provided at the upper end (16) and / or the lower end (18), and the at least one locking spring (12, 14) is configured to secure the dust cover (10) to the housing (8) and / or the shaft (4), respectively.
2. The spherical joint assembly according to claim 1, characterized in that, The dust cover (10) has an annular groove (11) at the upper end (16) and / or the lower end (18) for accommodating at least one clamping spring (12, 14).
3. The spherical joint assembly according to claim 2, characterized in that, The cross-sectional diameter (De) of the at least one clamping spring (12, 14) is equal to or less than the inner diameter of the annular groove (11) at the upper end (16) and / or the lower end (18).
4. The spherical joint assembly according to any one of the preceding claims, characterized in that, The at least one locking spring (12, 14) provides a radial force (rf) configured to secure the dust cover (10) to the housing (8) and / or the shaft (4).
5. The spherical joint assembly according to any one of the preceding claims, characterized in that, The ball joint assembly (1) includes a first clamping spring (12) and a second clamping spring (14), wherein the first clamping spring (12) is disposed at the upper end (16) to secure the dust cover (10) to the housing (8), and the second clamping spring (14) is disposed at the lower end (18) to secure the dust cover (10) to the shaft portion (4).
6. The spherical joint assembly according to claim 5, characterized in that, The first clamping spring (12) and the second clamping spring (14) differ in wire diameter (d) and / or radial force (rf).
7. The spherical joint assembly according to any one of claims 5 to 6, characterized in that, The first clamping spring (12) has a larger wire diameter (d) than the second clamping spring (14).
8. The spherical joint assembly according to any one of claims 5 to 7, characterized in that, The first clamping spring (12) provides a greater radial force (rf) than the second clamping spring (14).
9. The spherical joint assembly according to any one of the preceding claims, characterized in that, At least one locking spring (12, 14) includes two free ends adapted to be connected to each other.
10. The spherical joint assembly according to any one of the preceding claims, characterized in that, The housing (8) includes a recess (22), and the dust cover (10) has a flange structure (20) protruding from the upper end (16) and is configured to be fixed at the recess (22) of the housing (8).