Beginning of supporting length of hub keyway

For the determination of the effective surface pressure according to DIN 6892, only the prismatic part of the key is considered as load-bearing. The supporting length of the key is therefore determined automatically from the key shape, length and width.

If the hub is too narrow and/or not positioned centrically on the key, the supporting length of the hub keyway may be smaller than the supporting length of the key. In this case, the supporting length of the shaft keyway may also be smaller (see DIN 6892:2012 Section 6.1.2.1).

Unless otherwise specified by the user, the hub is assumed to be centered on the key and the supporting length of the hub keyway is automatically calculated on the basis of the supporting length of the key and the hub width.

If this is not the case, the user can specify:

• the supporting length of the hub keyway l_2tr, and
• the distance between the beginning of the feather key/shaft keyway and the beginning of the supporting length of the hub keyway d_2tr.