Elastic cylindrical pin, also known as spring pin, is a kind of hollow cylindrical body without head, with axial groove and chamfering at both ends, which is used for positioning, connecting and fixing between parts; It needs to have good elasticity and shear strength. The outer diameter of this kind of pin is slightly larger than the assembly hole diameter.
In the fastener system of mechanical assembly, elastic cylindrical pins (also known as "spring pins") have become important components for solving the problems of part positioning, connection and fixation, relying on their unique structure of "headless and hollow, axial slotting" as well as excellent elasticity and shear resistance. They do not require complex installation tools and realize adaptive assembly through their own structural characteristics. They can not only adapt to pin holes with dimensional deviations but also remain stable in vibrating environments. Widely used in automobiles, home appliances, machinery, electronics and other fields, they perfectly balance assembly convenience and connection reliability.
From the perspective of structural design, every detail of the elastic cylindrical pin serves "elastic adaptation" and "stable fastening". Its main body is a headless and hollow cylinder. Compared with solid cylindrical pins, the hollow structure not only reduces weight and material costs but, more importantly, provides space for elastic deformation — when the pin body is squeezed, the hollow cavity can absorb pressure through slight contraction, enabling the pin body to adapt to the dimensional deviations of the pin hole and avoiding assembly difficulties caused by insufficient machining accuracy of the pin hole. Axial slotting is the core design of the elastic cylindrical pin; the slot usually runs through the entire length of the pin body, and some models have rounded corners at the slot opening to reduce stress concentration. This slotted structure endows the pin body with the ability of radial contraction and expansion. During installation, the pin body is squeezed and contracts along the slot, easily embedding into the pin hole; after installation, it automatically expands by virtue of elasticity, fitting closely with the inner wall of the pin hole to form a stable interference fit, effectively preventing loosening. The chamfered design at both ends plays a guiding role, avoiding scratches on the inner wall of the pin hole by the pin end during installation, while reducing insertion resistance to make the assembly process smoother. Especially in automated assembly lines, the chamfered design can improve assembly efficiency and reduce the risk of equipment jamming.
The performance advantages of elastic cylindrical pins are concentrated in "good elasticity" and "reliable shear resistance", and these two characteristics enable them to cope with complex working conditions. Elasticity is the core feature that distinguishes them from ordinary cylindrical pins: when the equipment operates with vibration or temperature changes cause thermal expansion and contraction of parts, the elastic cylindrical pin can absorb stress through its own elastic deformation, avoiding gaps between the pin body and the pin hole, thereby preventing part loosening. For example, in the positioning of synchronizers in automobile gearboxes, the high-frequency vibration during gearbox operation easily causes ordinary cylindrical pins to loosen, while the elasticity of the elastic cylindrical pin can always maintain close contact with the pin hole, ensuring the accurate operation of the synchronizer. Shear resistance ensures connection strength. Elastic cylindrical pins are usually made of high-strength materials such as 65Mn spring steel and stainless steel. After heat treatment processes such as quenching and tempering, their shear strength can reach 300-600MPa, which can bear the transverse load between parts. For instance, in the connection between the motor end cover and the shell in home appliances, the elastic cylindrical pin needs to resist the torque during motor operation, and its shear resistance can ensure that the end cover does not shift due to force, guaranteeing the stable operation of the equipment.
The dimensional design of "the outer diameter being slightly larger than the assembly hole diameter" is the key for elastic cylindrical pins to achieve stable fastening. Generally, the outer diameter of an elastic cylindrical pin is 0.1-0.5mm larger than the assembly hole diameter (the specific difference needs to be adjusted according to the material elasticity and pin hole diameter). This slight interference fit enables the pin body to generate radial expansion force after installation, forming close contact with the inner wall of the pin hole. It not only avoids loosening caused by gaps but also prevents pin hole deformation or pin body fracture due to excessive interference. For example, in the connection of plastic parts, the plastic material has low hardness; if the interference is too large, it is easy to cause the pin hole to crack. However, through the precise outer diameter design of the elastic cylindrical pin, it can ensure fastening while protecting the plastic parts; in the connection of metal parts, a reasonable interference can improve the stability of the connection and meet long-term use needs.
In practical applications, elastic cylindrical pins are applicable to a wide range of scenarios. In the automotive industry, they are used for the positioning of bushings in the chassis suspension system and the connection of door hinges, using elasticity to cope with bumpy road conditions and temperature changes; in the home appliance field, the drum brackets of washing machines and the fixation of air-conditioning compressors all rely on them to achieve stable connections while simplifying the assembly process; in electronic equipment, micro elastic cylindrical pins are used for the positioning of gears in printers and scanners, and their small size and elastic characteristics can meet the assembly needs of precision components; in mechanical manufacturing, the connection of connecting rods in agricultural machinery and the positioning of rollers in textile machinery also need to rely on their shear resistance and elasticity to ensure the reliable operation of equipment in high-intensity operations. In addition, elastic cylindrical pins can also be used for the rapid maintenance of parts. When the pin hole of a part becomes larger due to wear, replacing it with an elastic cylindrical pin with a slightly larger diameter can restore the connection function without reprocessing the part, greatly reducing maintenance costs.
Zhuhai Jiali Hardware Products Co., Ltd., established in 2008, is an enterprise specializing in the production and sales of industrial fasteners. At present, the main products of the company are hexagon screw, hexagon screw, micro screw, set screw, various kinds of nuts, teeth, flat pad, spring pad, split ring, various kinds of colorful washer, 12.9 grade alloy steel high strength screw, hexagon wrench, etc Box spanner can also be customized according to the drawing. Products mainly comply with the national standard, German standard, American Standard, British standard and international standard. The main service industries are automobile, electronics, medical equipment, hardware, machinery, shipping, chemical industry, communication, construction, etc. at the same time, all kinds of information should be complete, welcome to contact us.