1 Scope
This standard specifies the basic types and dimensions of hobs for integral involute splines with the pressure angle of 30° and the modules of 0.5 mm to 10 mm and those with the pressure angle of 45° and the modules of 0.25 mm to 2.50 mm.
This standard is applicable to hobs for straight cylindrical involute splines with basic rack profile as required in GB/T 3478.1 and dimensions as required in GB/T 3478.4 or GB/T 3478.2.
Hobs with the pressure angle of 30° are of A, B and C precision, while hobs with the pressure angle of 45° are of C precision.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments to (excluding corrigendum), or revisions of, any of these publications do not apply. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards. For undated references, the latest edition applies.
GB/T 3478.1 Straight cylindrical involute splines—Modules, basic rack profiles and tolerances (GB/T 3478.1-1995, eqv ISO 4156:1981)
GB/T 3478.2 Straight cylindrical involute splines—30° pressure angle dimensions tables (GB/T 3478.2-1995, neq ISO 4156:1981)
GB/T 3478.4 Straight cylindrical involute splines—45° pressure angle dimensions tables (GB/T3478.4-1995, neq ISO 4156:1981)
GB/T 6132 Milling cutters—Interchangeability dimensions for cutter arbors (GB/T 6132-2006, ISO 240: 1994, IDT)
3 Types and dimensions
3.1 There are two basic types of hobs for involute splines with the pressure angle of 30°: Type I and Type II. Type I is a hob for flat top, which is suitable for machining external splines with flat roots; Type II is a hob for a circular top, which is suitable for machining external splines with fillet root.
Foreword i
1 Scope
2 Normative references
3 Types and dimensions
4 Example of designation
Annex A (Informative) Calculated dimensions of hobs
Annex B (Informative) Axial profile dimensions of hobs
