We normally specify spur and helical gears with 2.35M whole depth and 2.0M working depth to allow for grinding and shaving if necessary. We have a supplier who is proposing to change whole depth to 2.25M to suit their standard hobs. Everything else: working depth, centre distance, rack shift, pressure angle, helix angle, PCD, number of teeth, material & HT, face width etc remains the same. The gears are case carburised and used in a truck tcase.
My question is whether the gears with 0.25M clearance can be safely meshed with the existing gears with 0.35M clearance? The only problem I can see is that the 2.25M gears will be marginally stiffer in bending and therefore 2.25 and 2.35 teeth will deflect by somewhat different amounts under load, but I think the involute profile should take care of that.
If we can't interchange the new gears with the old then we run into logistics problems, both with controlling spares and because one of the gear designs is used in multiple gearboxes, which means changing all of them if we can't interchange.
My question is whether the gears with 0.25M clearance can be safely meshed with the existing gears with 0.35M clearance? The only problem I can see is that the 2.25M gears will be marginally stiffer in bending and therefore 2.25 and 2.35 teeth will deflect by somewhat different amounts under load, but I think the involute profile should take care of that.
If we can't interchange the new gears with the old then we run into logistics problems, both with controlling spares and because one of the gear designs is used in multiple gearboxes, which means changing all of them if we can't interchange.