GB/T 3478 consists of the following nine parts under the general title Straight cylindrical involute splines - Metric module, side fit:
——Part 1: Generalities;
——Part 2: 30° pressure angle dimensions tables;
——Part 3: 37.5° pressure angle dimensions tables;
——Part 4: 45° pressure angle dimensions tables;
——Part 5: Inspection;
——Part 6: 30° pressure angle M and W values;
——Part 7: 37.5° pressure angle M and W values;
——Part 8: 45° pressure angle M and W values;
——Part 9: Measuring pin.
This part is Part 3 of GB/T 3478.
1 Scope
This part of GB/T 3478 specifies all spine dimensions for straight cylindrical involute splines with fillet root of 37.5° standard pressure angle (hereinafter referred to as 37.5° fillet root).
This part is applicable to side-fitting involute splines with 37.5° pressure angle and module 0.5mm~10mm specified in GB/T 3478.1-2008.
The dimensions tables in this part have been prepared according to the calculation formula(e) given in GB/T 3478.1-2008, Table 3 and using the fundamental test method, with the side fit as H/h.
2 Normative references
The following documents contain provisions which, through reference in this part of GB/T 3478, constitute provisions of this part. For dated references, subsequent amendments to (excluding corrections), or revisions, of any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 1800.1 Geometrical product specifications (GPS) - Limits and fits - Part 1: bases of tolerances, deviations and fits
GB/T 3478.1-2008 Straight cylindrical involute splines - Metric module, side fit - Part 1: Generalities (ISO 4156-1:2005, MOD)
3 Dimensions tables
3.1 See Tables 1~28 for dimensions of splines with 37.5° fillet root, module 0.5mm~10mm and tolerance grades 4, 5, 6 and 7.
3.2 See GB/T 3478.1-2008, Table 25 for limit deviations for the minor diameter of internal splines Dii and tolerances for the major diameter of external splines Dee.
3.3 Tolerances for the major diameter of internal splines Dei and tolerances for the minor diameter of external splines Die shall be selected among standard tolerances IT12, IT13 or IT14 given in GB/T 1800.1.
3.4 In manufacture of internal and external splines using the generating method, the arc radius of root is changeable. The minimum root curvature radius is given in this part, as shown in GB/T 3478.1-2008, Table 26.
3.5 If the selected test method is not a fundamental one, the maximum effective space width and the minimum actual space width, the minimum effective tooth thickness and the maximum actual tooth thickness shall be calculated using the following formulae:
Maximum effective space width Ev max=Emax-λ;
Minimum actual space width Emin=Ev min+λ;
Minimum effective tooth thickness Sv min=Smin+λ;
Maximum actual tooth thickness Smax=Sv max-λ.
3.6 If the side fit of splines is not of H/h, the dimensions of external splines given in dimensions tables shall be calculated using the following formulae:
