5.2.1 Initially,
meshing gears are to be carefully matched on the basis of the accuracy
measurements taken. The alignment is to be demonstrated in the workshop
by meshing in the gearbox without oil clearance in the bearings. Meshing
is to be carried out with the gears locating in their light load positions
and a load sufficient to overcome pinion weight and axial movement
is to be imposed.
5.2.2 The
gears are to be suitably coated to demonstrate the contact marking.
The marking is to reflect the accuracy grade specified and end relief
of helix correction, where these have been applied.
5.2.3 For
gears without helix correction the marking is to be not less than
shown in Table 5.5.1 No load tooth contact
marking.
Table 5.5.1 No load tooth contact
marking
| ISO accuracy
grade
|
Contact marking area
|
| Q ≤ 5
|
40%h
w for 50% b and 20%h
w for a further 40%b
|
| Q ≥ 6
|
40%h
w for 35% b and 20%h
w for a further 35%b
|
Note
1. Where b is face width and
h
w is working tooth depth.
Note
2. For spur gears the values of h
w should be increased by a further 10%.
|
5.2.4 For
gears with end relief of helix correction the marking is to correspond
to the designed no load contact pattern.
5.2.5 A permanent
record is to be made of the meshing contact for purpose of checking
the alignment when installed on board ship.
5.2.6 The
full load tooth contact marking is to be not less than shown in Table 5.5.2 Full load tooth contact
marking.
Table 5.5.2 Full load tooth contact
marking
| ISO accuracy grade
|
Contact marking area
|
| Q ≤ 5
|
70%h
w for 60% b and 50%h
w for a further 30%b
|
| Q ≥ 6
|
60%h
w for 45% b and 40%h
w for a further 35%b
|
Note
1. Where b is face width and
h
w is working tooth depth.
Note
2. For spur gears the values of h
w should be increased by a further 10%.
|