Stainless Steel Belleville Washer Standard: DIN9250 Type: Butterfly Washer

Compared to standard spring washers, these have stronger serrations (ridges) and a unique curve on their surface, demonstrating their true value in harsh vibration environments.
1. Basic Usage
Usage is very simple, but orientation is important.
? Where to place: Place between the bearing surface of the bolt (or nut) and the object being tightened.
? Orientation: Face the ridged side (the raised side) towards the bolt head, and the valley side towards the object.
? Tightening: As the bolt is tightened, the butterfly washer is compressed and tries to flatten. The **force to return (repulsive force)** at this time strongly presses the bolt's threads, creating frictional resistance.
2. Main Applications
Often used in places where loosening is absolutely unacceptable and vibration is severe.
? Automotive and motorcycle suspension: Areas subjected to subtle vibrations from the engine and impacts during driving.
? Industrial and machine tools: Devices incorporating motors or rotating parts that are constantly exposed to vibration.
? Electrical contacts and terminal blocks: Places where constant pressure needs to be applied to prevent contact failure due to aging.
? Elevators and railway-related equipment: Critical safety components where safety is paramount and maintenance frequency needs to be minimized.
3. Benefits of Butterfly Washers
Why use these instead of regular flat washers or spring washers?
? High holding power: The unevenness of the surface slightly bites into the mating material, physically preventing rotation.
? Space saving: Because they are very thin, a high locking effect can be achieved even in areas where the bolt's underhead length is short.
? Bolt protection: The load is evenly distributed around the circumference, reducing uneven stress on individual bolts.
Precautions for Use
Butterfly washers enhance their effectiveness by biting into the mating material, so they may scratch the surface of the object (paint, etc.). Also, if the mating material is very hard (e.g., hardened steel), they may not bite in sufficiently to provide adequate effectiveness.