Sprint Washer/Split washer
Material: stainless steel 304316, grade 8.8 high strength and grade 12.9 high strength
It can also support non-standard customization.
In fastening systems composed of bolts and nuts, vibration is an "invisible killer" that causes screw loosening. As an elastic anti-loosening component, the spring washer, with its characteristics of "deformation energy storage and continuous anti-slip", has become a key element for addressing vibration conditions in fields such as machinery, construction, and electronics. Among them, Germany's DIN127 and China's GB93 are two mainstream standards. Although they share the same core function, they have different focuses in structural details and application scenarios, jointly building a "protective wall" for fastening reliability.
I. Product Definition: An Elastic Anti-Loosening Tool
A spring washer is essentially an elastic annular thin sheet, usually made by stamping metal plates and subjecting them to heat treatment. It has a through-hole in the center that matches the bolt shank diameter, with its edge in a wavy or spiral shape (commonly single-lug, double-lug, or spiral structure). Its core value lies in "anti-loosening": when the bolt is tightened, the washer is compressed to generate elastic deformation, forming a continuous axial preload. This offsets the torque attenuation caused by vibration and prevents the bolt from loosening due to frequent vibration.
Different from the "pressure distribution" function of flat washers, the core of spring washers is "active anti-loosening": flat washers passively increase the contact area, while spring washers actively maintain fastening pressure through their own elasticity. They are especially suitable for high-frequency vibration scenarios such as motors, water pumps, and automobile chassis. For example, the high-frequency vibration generated during motor operation easily causes the end cover bolts to loosen; after installing a spring washer, the elastic deformation of the washer can continuously "press" the bolt, reducing the risk of loosening.
II. Standard Specifications: Differences and Commonalities Between DIN127 and GB93
Spring washers of both standards are classified by "nominal bolt diameter" (M1.6-M64) to ensure compatibility with fasteners, but there are differences in structure and precision:
Commonalities: Both require washers to have good elasticity (rebound rate ≥ 80% after compression), with the material mostly being 65Mn spring steel (hardness HRC42-48). The surface needs anti-rust treatment (galvanizing, black oxide coating, etc.), and the gap between the central hole diameter and the bolt shank diameter is ≤ 0.3mm to prevent washer deviation.
Differences: DIN127 is divided into "Class A" (precision type) and "Class B" (ordinary type). Class A washers have a thickness tolerance of ±0.05mm and a surface roughness of Ra ≤ 1.6μm, suitable for scenarios with high precision requirements such as automobile engines and precision instruments; Class B has slightly lower precision and lower cost, mostly used in construction steel structures. GB93 has a single precision grade, with a structure closer to DIN127 Class B. However, the free height of GB93 washers is slightly higher (e.g., the free height of an M8 washer is approximately 3.5mm for GB93 and 3mm for DIN127), providing stronger elasticity and making it more suitable for heavy machinery with severe vibration.
In addition, DIN127 allows tiny burrs (≤ 0.1mm) on the washer edge, while GB93 requires complete removal of burrs to avoid scratching connected parts, giving it an advantage in scenarios with high surface protection requirements such as electronic equipment.
III. Anti-Loosening Principle: "Continuous Force Application" Through Elastic Deformation
The anti-loosening logic of spring washers is based on "elastic deformation and enhanced friction", realized in three steps: When the bolt is tightened, the washer is squeezed by the nut and the connected part, and the wavy or spiral structure generates elastic deformation to store elastic potential energy; when vibration occurs, the bolt tends to loosen, and the washer releases elastic potential energy to generate a reverse axial force, maintaining the bolt preload; at the same time, the tiny serrations (designed in some models) on the washer edge and contact surface increase the friction coefficient, further preventing bolt rotation. This forms a dual anti-loosening effect of "elastic energy storage + friction anti-slip".
For example, if only flat washers are used for automobile chassis bolts, the loosening probability is approximately 25% after 3 months of vibration; when matched with GB93 spring washers, the loosening probability can be reduced to less than 5%, which clearly demonstrates the significant anti-loosening effect of spring washers.
IV. Application Scenarios: "Necessary Components" for Vibration Environments
The application scenarios of spring washers focus on "high-frequency vibration" or "load variation" conditions, mainly covering three fields:
Industrial Machinery Field: The connection between the casing and base of motors, water pumps, and fans needs to withstand continuous vibration. DIN127 Class A spring washers, with their high-precision compatibility, can avoid anti-loosening failure caused by washer deviation; the hydraulic pipeline fixing of construction machinery such as excavators and loaders involves severe vibration and large loads. The high elasticity of GB93 spring washers can adapt to load fluctuations and ensure no pipeline leakage.
Automotive and Transportation Field: The bolt connections of automobile chassis suspension systems and wheel hubs need to cope with road 顛簸 vibration. Spring washers are used in combination with flat washers ("flat washer + spring washer"), which not only distributes pressure but also prevents loosening; the connection between the pedals and frame of bicycles and electric vehicles has small loads, but the vibration caused by frequent pedaling easily loosens the screws. Small GB93 spring washers (M5-M8) can effectively solve this problem.
Electronic and Home Appliance Field: The motor fixing screws of washing machines and outdoor air conditioner units generate high-frequency vibration during operation. Spring washers can prevent noise or component damage caused by screw loosening; the fasteners of outdoor photovoltaic brackets need to resist wind-induced vibration. DIN127 Class B spring washers, combined with galvanizing treatment, can both prevent loosening and rust, adapting to outdoor environments.
V. Materials and Usage Precautions
In terms of materials, the mainstream is 65Mn spring steel, which has a balanced combination of elasticity and strength, suitable for most scenarios; stainless steel (304/316) spring washers have strong corrosion resistance and are used in humid environments such as marine equipment and medical devices, but their elasticity is slightly inferior to that of 65Mn; copper alloy washers are suitable for electronic equipment to avoid electrochemical corrosion.
Precautions for use: Spring washers should be used in combination with flat washers (spring washer on the nut side, flat washer on the connected part side) to avoid direct contact between the spring washer and easily deformable materials (such as plastic); they cannot be reused, as the elasticity of deformed washers decreases, reducing the anti-loosening effect by half; the specification must match the bolt—oversized or undersized washers will cause anti-loosening failure.
As the "anti-loosening guardian" of fastening systems, although spring washers (DIN127 and GB93) have a simple structure, they have become indispensable components in vibration environments due to their core values of "active anti-loosening and vibration adaptation". When selecting, it is necessary to consider precision requirements, vibration intensity, and environmental factors to maximize their anti-loosening effect and ensure that every fastening is stable and reliable for a long time.