Dust cover with convex structure for shock absorber

Abstract

The utility model discloses a dust cover of shock absorber with convex structure, including the dust cover body for the sleeve setting in the outer periphery of shock absorber piston rod, the dust cover body is one -end opening and the upper end is closed or semi -closed structure, dust cover body upper end is equipped with the cooperation end for cooperating with dust cover, the cooperation end inner circle face is provided with a plurality of and is used for cooperating with the convex structure of dust cover outer circular face and is protruding to the inside. The utility model can reduce assembly stress greatly, not only can effectively prevent the cracking, and can keep good assembly stability.

Description

Technical Field

[0001] This utility model relates to the field of vibration damper technology, and more specifically to a dust cover for a vibration damper with a convex bulge structure. Background Technology

[0002] Currently, automotive shock absorbers generally use plastic dust covers (usually made of materials such as polypropylene (PP), thermoplastic elastomer (TPE), or nylon (PA). Their main function is to cover the outside of the oil seal to prevent contaminants such as mud, water vapor, and dust from entering the shock absorber, thereby protecting the oil seal and piston rod and extending the service life of the shock absorber.

[0003] In existing technologies, common plastic dust covers, when fitted with dust caps (also known as dust caps) made of metal or plastic, are often fastened using a continuous interference fit (i.e., uniform interference in the 360° circumference). For example, the inner diameter of the upper end of the dust cover is slightly smaller than the outer diameter of the dust cap, and the press fitting is achieved by the elastic deformation of the material.

[0004] However, this design has obvious flaws: 1. Assembly stress concentration: Due to the tight fit around the entire circumference, the upper edge of the plastic dust cover bears a large and evenly distributed circumferential tensile stress during the press-fitting process. Especially in low temperature environments (such as -40℃), the plastic becomes more brittle and is very prone to micro-cracks or even direct cracking at the mating edges. 2. Prone to failure with long-term use: Frequent vibrations during vehicle operation and the lack of stress release paths in the tightly fitted structure throughout the circumference can easily lead to fatigue accumulation and accelerate aging and cracking. 3. Insufficient stability or excessive constraint contradiction: If the interference is reduced to avoid cracking, axial or radial wobbling is likely to occur between the dust cover and the dust cap, affecting sealing and NVH performance; if the interference is increased, the risk of cracking increases significantly.

[0005] Although some solutions have attempted to improve the situation by adding reinforcing ribs or changing material formulations, none have fundamentally resolved the contradiction between "high stability" and "low assembly stress." Therefore, a new structural design is urgently needed to effectively reduce local stress concentration and improve product reliability and environmental adaptability while ensuring assembly stability. Utility Model Content

[0006] The purpose of this invention is to provide a dust cover for a vibration damper with a convex structure. This invention can significantly reduce assembly stress, effectively prevent cracking, and maintain good assembly stability.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a dust cover for a shock absorber with a convex structure, comprising a dust cover body for being fitted onto the outer periphery of the shock absorber piston rod, the dust cover body having an open end and a closed or semi-closed upper end, the upper end of the dust cover body having a mating end for cooperating with a dust cover; the inner circular surface of the mating end has a plurality of inwardly protruding convex bulges for cooperating with the outer circular surface of the dust cover.

[0008] By adopting the above scheme, the contradiction between assembly stress concentration and long-term stability is fundamentally alleviated by replacing the continuous interference fit with local discrete convex humps. Specifically, multiple inwardly protruding humps are set on the inner circular surface of the mating end, generating point-like or small-area contact fits with the outer circular surface of the dust cover. This avoids the circumferential tensile stress concentration caused by the traditional uniform interference fit, ensuring that the assembly force acts only on the local area of ​​the humps instead of being continuously distributed throughout the circumference. This significantly reduces the risk of cracking under low-temperature brittle conditions. Simultaneously, the elastic deformation characteristics of the humps provide the necessary radial fixing force while allowing for slight stress release, effectively suppressing vibration fatigue accumulation. This prevents axial wobbling between the dust cover and dust shield to ensure sealing, and avoids material aging problems caused by excessive constraint.

[0009] The present invention is further configured such that the convex hull is an arc-shaped, rectangular, trapezoidal, or hemispherical structure.

[0010] By adopting the above scheme and defining the specific geometry of the convex hull, the stress distribution mechanism is optimized in a targeted manner, thereby effectively alleviating the problem of local stress concentration during assembly and use.

[0011] The present invention is further configured such that multiple protrusions are evenly distributed in a circumferential array on the inner circular surface of the mating end of the dust cover body.

[0012] By adopting the above scheme, the uniform arrangement of the convex bulge on the inner circular surface of the mating end of the dust cover body is ensured, thereby optimizing the stress distribution during the assembly process and avoiding local stress concentration caused by uneven distribution.

[0013] The present invention is further configured such that the height of the protrusion protruding from the inner wall of the mating end of the dust cover body is 0.1mm to 0.5mm.

[0014] By adopting the above scheme, the specific range of the convex height of the convex hull is defined, and the dimensional parameter design of the convex hull structure is optimized, so as to solve the contradiction between assembly stress concentration and insufficient fastening effect.

[0015] The present invention is further configured such that the circumferential width of the convex bulge along the mating end of the dust cover body is 2mm to 10mm, and the axial length of the convex bulge along the mating end of the dust cover body is 1mm to 5mm.

[0016] By adopting the above solution, the stress distribution and connection stability during the mating process of the dust cover and dust shroud are effectively coordinated by precisely defining the geometric dimensional parameters of the convex hull.

[0017] The present invention is further configured such that the convex bulge and the dust cover body are integrally injection molded and made of polypropylene material.

[0018] By adopting the above solution and through the synergistic design of integrated injection molding process and polypropylene material, the structural weak points in the convex area are effectively eliminated, thereby ensuring the long-term stability of the mating parts of the dust cover and dust shield.

[0019] The present invention is further configured such that the upper end of the mating end of the dust cover body is provided with a limiting flange extending inward, and the lower end of the dust cover body corresponding to the mating end is provided with a plurality of inwardly protruding limiting protrusions. The limiting flange and the limiting protrusions are respectively used to abut against the upper and lower ends of the dust cover to form axial limiting.

[0020] By adopting the above solution, the dust cover is axially limited, which can prevent the dust cover from shaking axially and ensure the stability of the assembly structure.

[0021] In summary, this utility model has the following significant technical effects: 1. Significantly reduces assembly stress: Because the contact area is reduced from a full 360° circumference to several discrete protrusions, the plastic undergoes only localized elastic deformation during press-fitting, resulting in a significant decrease in overall circumferential tensile stress. CAE simulation and field measurements verified that, under -40°C low-temperature press-fitting conditions, the cracking rate decreased from approximately 8% in the traditional design to below 0.2%.

[0022] 2. Effectively prevents cracking and improves durability: The non-contact area between the convex hulls provides stress relief space for the material, avoids continuous circumferential tension, significantly improves fatigue resistance, and extends service life.

[0023] 3. Maintain good assembly stability: When the number of convex bulges is ≥4 and evenly distributed, a stable multi-point support structure can be formed, effectively suppressing the swaying of the dust cover in the radial and circumferential directions. Bench vibration tests show that the product of this invention has no loosening or abnormal noise after 500,000 high-frequency vibrations, and its stability is superior to or equivalent to that of traditional full-circumferential fit designs.

[0024] 4. High compatibility and controllable cost: Simply add a raised bulge structure to the mold; there is no need to change the material or alter the main structure. The injection molding process is fully compatible with existing production lines, and the increase in unit cost is negligible.

[0025] 5. Applicable to multiple vehicle platforms: This design has been successfully applied to shock absorbers for passenger cars, SUVs and light commercial vehicles, proving its good versatility. Attached Figure Description

[0026] Figure 1 This is a perspective view of the entire utility model; Figure 2 This is a cross-sectional view of the entire utility model; Figure 3 for Figure 2 AA section view; Figure 4 This is a schematic diagram of the structure of the dust cover of this utility model.

[0027] In the diagram: 1. Dust cover body; 2. Dust cover; 3. Mating end; 4. Protrusion; 5. Limiting flange; 6. Limiting protrusion. Detailed Implementation

[0028] 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 protection scope of the present utility model.

[0029] Example: As attached Figures 1-4The dust cover for a vibration damper with a convex hump structure shown includes a dust cover body 1 for fitting around the piston rod of the vibration damper. The dust cover body 1 is open at one end and closed or semi-closed at the upper end. The upper end of the dust cover body 1 has a mating end 3 for engaging with a dust cover 2. Multiple inwardly protruding humps 4 are provided on the inner circular surface of the mating end 3 for engaging with the outer circular surface of the dust cover 2. The number of humps 4 is 3 to 8, preferably 6 or 8, and the humps are evenly distributed in a circumferential array on the inner circular surface of the mating end 3 of the dust cover body 1. It should be noted that the number of humps 4 should not be less than 3 (otherwise stable support cannot be formed) nor more than 8 (otherwise it will approach a continuous fit, losing the stress dispersion advantage). By replacing the continuous interference fit around the entire circumference with locally discrete humps 4, the contradiction between assembly stress concentration and long-term stability is fundamentally alleviated. That is, multiple inwardly protruding bumps 4 are set on the inner circular surface of the mating end 3 to generate point-like or small-area contact fit with the outer circular surface of the dust cover 2. This avoids the circumferential tensile stress concentration caused by the traditional uniform interference fit around the entire circumference, so that the assembly force only acts on the local area of ​​the bump 4 rather than being continuously distributed around the entire circumference, thereby significantly reducing the risk of cracking in low-temperature brittle environment. At the same time, the elastic deformation characteristics of the bump 4 provide the necessary radial fixing force while allowing micro-stress release, effectively suppressing the accumulation of vibration fatigue. This prevents axial shaking between the dust cover and the dust cover 2 to ensure sealing, and avoids material aging problems caused by excessive constraint.

[0030] As attached Figures 1-3 As shown, the convex hull 4 has an arc-shaped, rectangular, trapezoidal, or hemispherical structure, preferably a bulge with a rounded transition, to reduce stress concentration. By defining the specific geometry of the convex hull 4, the stress distribution mechanism is specifically optimized, thereby effectively alleviating the problem of local stress concentration during assembly and use.

[0031] The height of the protrusion 4 protruding from the inner wall of the mating end 3 of the dust cover body 1 is 0.1mm to 0.5mm, preferably 0.2mm to 0.3mm. By limiting the specific range of the protrusion height of the protrusion 4, the dimensional parameter design of the protrusion 4 structure is optimized to synergistically resolve the contradiction between assembly stress concentration and insufficient fastening effect.

[0032] The circumferential width of the protrusion 4 along the mating end 3 of the dust cover body 1 is 2mm to 10mm, preferably 4mm to 6mm, and the axial length of the protrusion 4 along the mating end 3 of the dust cover body 1 is 1mm to 5mm, preferably 2mm to 3mm. By precisely defining the geometric dimensions of the protrusion 4, the stress distribution and connection stability during the mating process of the dust cover and dust cap 2 are effectively coordinated.

[0033] The convex bulge 4 is integrally injection molded with the dust cover body 1 and is made of polypropylene (PP) material, with PP+EPDM being the preferred choice due to its low cost and good weather resistance. Through the synergistic design of the integral injection molding process and the polypropylene material, the structural weak points in the convex bulge 4 area are effectively eliminated, thereby ensuring the long-term stability of the mating parts of the dust cover and dust cap 2.

[0034] As attached Figure 2 As shown, the upper end of the mating end 3 of the dust cover body 1 is provided with a limiting flange 5 extending inwardly, and the lower end of the dust cover body 1 corresponding to the mating end 3 is provided with multiple inwardly protruding limiting protrusions 6. The limiting flange 5 and the limiting protrusions 6 are respectively used to abut against the upper and lower ends of the dust cover 2 to form an axial limit. Axially limiting the dust cover 2 can prevent axial shaking of the dust cover 2 and ensure the stability of the assembly structure.

[0035] During assembly, the dust cover forms a point / segment contact interference fit with the outer cylindrical surface of the dust cover 2 through multiple protrusions 4 on its inner wall, rather than the traditional full-circumferential surface contact. The interference amount is controlled at 0.05 mm to 0.2 mm (radial) at a single protrusion 4, and the overall pressing force is significantly lower than that of the traditional design.

Claims

1. A dust cover for a shock absorber with a convex bulge structure, comprising a dust cover body (1) for sleeved on the outer periphery of the shock absorber piston rod, wherein the dust cover body (1) is open at one end and closed or semi-closed at the upper end, and the upper end of the dust cover body (1) is provided with a mating end (3) for cooperating with a dust cover (2); characterized in that: The inner circular surface of the mating end (3) is provided with a plurality of inwardly protruding protrusions (4) for mating with the outer circular surface of the dust cover (2).

2. The dust cover for a vibration damper with a convex bulge structure according to claim 1, characterized in that: The convex hull (4) is an arc-shaped, rectangular, trapezoidal, or hemispherical structure.

3. A dust cover for a vibration damper with a convex bulge structure according to claim 1, characterized in that: Multiple protrusions are evenly distributed in a circular array on the inner circular surface of the mating end (3) of the dust cover body (1).

4. A dust cover for a vibration damper with a convex bulge structure according to claim 1, characterized in that: The height of the protrusion (4) protruding from the inner wall of the mating end (3) of the dust cover body (1) is 0.1mm to 0.5mm.

5. A dust cover for a vibration damper with a convex bulge structure according to claim 1, characterized in that: The circumferential width of the protrusion (4) along the mating end (3) of the dust cover body (1) is 2mm to 10mm, and the axial length of the protrusion (4) along the mating end (3) of the dust cover body (1) is 1mm to 5mm.

6. A dust cover for a vibration damper with a convex bulge structure according to claim 1, characterized in that: The convex bulge (4) is integrally injection molded with the dust cover body (1) and is made of polypropylene material.

7. A dust cover for a vibration damper with a convex bulge structure according to claim 1, characterized in that: The upper end of the mating end (3) of the dust cover body (1) is provided with a limiting flange (5) extending inward. The lower end of the mating end (3) of the dust cover body (1) is provided with a plurality of inwardly protruding limiting protrusions (6). The limiting flange (5) and the limiting protrusions (6) are respectively used to abut against the upper and lower ends of the dust cover (2) to form an axial limit.

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