Appendix 4

The applicant for a certificate shall submit to the approval authority an application for a certificate for an axle family based on the family criteria as indicated in paragraph 3.

An axle family is characterized by design and performance parameters. These shall be common to all axles within the family. The axle manufacturer may decide which axle belongs to an axle family, as long as the family criteria of paragraph 4 are respected. In addition to the parameters listed in paragraph 4, the axle manufacturer may introduce additional criteria allowing the definition of families of more restricted size. These parameters are not necessarily parameters that have an influence on the level of performance. The axle family shall be approved by the approval authority. The manufacturer shall provide to the approval authority the appropriate information relating to the performance of the members of the axle family.

In some cases there may be interaction between parameters. This shall be taken into consideration to ensure that only axles with similar characteristics are included within the same axle family. These cases shall be identified by the manufacturer and notified to the approval authority. It shall then be taken into account as a criterion for creating a new axle family.

In case of parameters, which are not listed in paragraph 3 and which have a strong influence on the level of performance, this parameters shall be identified by the manufacturer on the basis of good engineering practice, and shall be notified to the approval authority.

1. (a)

   Single reduction axle (SR)

2. (b)

   Hub reduction axle (HR)

3. (c)

   Single portal axle (SP)

4. (d)

   Single reduction tandem axle (SRT)

5. (e)

   Hub reduction tandem axle (HRT)

6. (f)

   Same inner axle housing geometry between differential bearings and horizontal plane of centre of pinion shaft according to drawing specification (Exception for single portal axles (SP)). Geometry changes due to an optional integration of a differential lock are permitted within the same axle family. In case of mirror inverted axle casings of axles, the mirror inverted axles can be combined in the same axle family as the origin axles, under the premise, that the bevel gear sets are adapted to the other running direction (change of spiral direction).

7. (g)

   F1Crown wheel diameter (+ 1,5 %/– 8 % ref. to the largest drawing diameter)

8. (h)

   Vertical hypoid offset pinion/crown wheel within ± 2 mm

9. (i)

   In case of single portal axles (SP): Pinion angle with respect to horizontal plane within ± 5°

10. (j)

    In case of single portal axles (SP): Angle between pinion axle and crown wheel axle within ± 3,5°

11. (k)

    In case of hub reduction and single portal axles (HR, HRT, FHR, SP): Same number of planetary gear and spur wheels

12. (l)

    Gear ratio of every gear step within an axle in a range of 2, as long as only one gear set is changed

13. (m)

    Oil level within ± 10 mm or oil volume ± 0,5 litre referring to drawing specification and the installation position in the vehicle

14. (n)

    Same oil type viscosity grade (recommended factory fill)

15. (o)

    For all bearings: same bearing rolling/sliding circle diameter (inner/outer) and width within ± 2 mm ref. to drawing

16. (p)

    F2. . . . .

The parent axle within an axle family is determined as the axle with the highest axle ratio. In case of more than two axles having the same axle ratio, the manufacturer shall provide an analysis in order to determine the worst-case axle as parent axle.

The approval authority may conclude that the worst-case torque loss of the family can best be characterized by testing additional axles. In this case, the axle manufacturer shall submit the appropriate information to determine the axle within the family likely to have the highest torque loss level.

If axles within the family incorporate other features which may be considered to affect the torque losses, these features shall also be identified and taken into account in the selection of the parent axle.