The geometry of a 30° pressure angle involute spline relies on strict mathematical relationships. If you are calculating dimensions or auditing a PDF data sheet, use these primary formulas to verify accuracy: ) and Pitch (
Involute Splines Guide (Scribd) : Provides detailed breakdowns of reference diameters and interchangeability. Doppler Gear TechBit: DIN 5480 Spline Decoder
The defining characteristic of a DIN 5480 spline is a . Pressure angles of 37.5° and 45° are covered by the ISO 4156 standard, and splines from these two standards are not interchangeable.
A typical DIN 5480 designation, such as DIN 5480 – W 120 x 3 x 38 x 8f , provides a complete dimensional profile: : Denotes a Shaft ( Welle ) or Hub ( Nabe ). 120 : The reference diameter in millimeters. 3 : The module ( ), indicating the tooth size. 38 : The number of teeth ( din 5480 spline dimensions pdf verified
The standard specifies the methods for verifying and inspecting spline dimensions, including:
) must be calculated based on the module to ensure contact happens near the pitch circle. 2. Composite Go/No-Go Gauging
db=d×cos(30∘)d sub b equals d cross cosine open paren 30 raised to the composed with power close paren p=π×mp equals pi cross m DIN 5480 Dimensions Data Table (Reference Selection) The geometry of a 30° pressure angle involute
) : This is a central design value, often chosen to match standard bearing bores, which remains independent of the module. : Profile modification (
rule: Multiply the number of teeth by the module. Does it match the pitch diameter (
db=d×cos(30∘)=z×m×0.866025d sub b equals d cross cosine open paren 30 raised to the composed with power close paren equals z cross m cross 0.866025 Major and Minor Diameters Pressure angles of 37
If your engineering work requires compliance (e.g., automotive, aerospace, defense), a scraped PDF from a Chinese forum is unacceptable. Here is the verified process:
Official German standards are sold by Beuth Verlag . A verified PDF will either have a visible Beuth watermark or a license header. If it is a pure scan from a library, treat it as a reference only, not a master source.
DIN 5480 allows two root forms: "flat root" (deep cut) and "fillet root" (generated). The PDF must clearly state which dimension table applies. Using a flat root dimension on a fillet root tool will break the tool.