Gap Requirement Between Bush or Hub Flange & Flywheel

Is it a taper fit?

The axial gap is necessary for the hub to climb-over the shaft as the face plate is tightened (else the plate will butt against the shaft face and will not load the hub). This helps in rigid engagement of the taper.

The required gap depends on the axial movement of hub (depends on the taper angle) and the pressure required on the taper.

Typically it should be a few mm when the hub is fully tightened.

However

In case of the hubs that are regularly removed, you may like to have a bit more gap since every time the hub is re-assembled, it moves in a bit further. Especially necessary if the hub is soft material (eg Aluminum)

The loss of engagement length and thus the load carrying capacity.

Yeah its a taper fit,

But this bush can not require frequent opening & fitting,once this is mounted on flywheel it will be re-assembled when overhual occurs, otherwise there is not any chance for re-assembling. i agree that it will have to be open when overhual occurs,this is sure type grip bushing.

Once this is a taper fit hub, the above comment stands.

This is the gap that I mantioned _{(did I ?)} we maintain in all our taper hubs, some with lock plates (where the hub projects out) at some others the shaft has a threading and a lock nut presses the hub.

For us it is a bit large size and we may end up in quite large gaps - a few may be upto 5-10mm also. The smaller ones are of course less.

And by frequent opening means the over-haul/ repair.

Suppose each assembly the hub moves in by 0.5 (again depending on the taper angle, materials etc. And also in first few assemblies as we have seen the movement is larger and then as the profiles mate to each other as well as the contact pressure removes the asperities, the movement stabilises to a low value)

And you expect some 20 dismantling in the hub/shaft life-time. Then the gap must be maintained accordingly. It is decided, at least in our case by experimenting .

I assume that you are referring to Sure Grip tapered bushings?

If so, guest is correct. Once you have torqued all the cap screws there must be a gap otherwise you would not know if you were transferring the applied load to the taper or merely applying it between the faces.

After our internal discussion, we come to know for followings,

bush bolt is designed for holding force, not for torque transmission therefore there must be gap between bush flange & flywheel, if there will not be gap between flywheel & bush flange face then bush bolt will transmit torque & will be shearoff or tear, becz bolt is inserted into bush & flywheel & for holding them only.

from taper angle, torque will transmit from bush to flywheel if there is gap between bush flange & flywheel. so we must have gap between bush flange & flywheel upto 1/16".