Building main spindle (bearings)

[promehanik]

I am prepairing for build spindle for small grinding machine. Axial forces will be in both directions. I found this drawing. I would like remove tube which is between inner rings. This get me possibility for change bearing preload (ball bearing with angular contact) during the use. Is this acceptable? Maybe this tube have any influence on rigidity of spindle?

regards,
Promehanik

[RICHARD ZASTROW]

That tube or spacer controls the preload of the angular contact bearings. It also contributes to the rigidity of the spindle assembly.

Dick Z

[mactec54]

promehanik

The tube is needed as it is part of the preload in this design, but the length does not have to be precise as you have the springs which give you the preload ajustment required for these bearings, for a grinding spindle you want a flat belt or a poly-v belt type not the deep vee pully in this design

[promehanik]

I developed new design of spindle for 2 wheel grinding machine. On each end of spindle will be diamond grinding wheel (diameter 200 mm). Please tell me if bearing arrangement is suitable. Inside diameter of bearings is 50 mm.

regards,
promehanik

[RICHARD ZASTROW]

The bearing arrangement seems OK. I'm assuming the bearings are sealed type or there are seals in the final design.

The end with the pulley and a grinding wheel might need an additional bearing to compensate for the heavier radial load.

Dick Z

[promehanik]

In the final design will be seals.

The end with the pulley and a grinding wheel might need an additional bearing to compensate for the heavier radial load.

Maybe is better, that I move pulley on other end of shaft (near the 2 preloaded bearings)?

regards,
promehanik

[promehanik]

I prepeared new design. What do you think abou it?
I want wery precise rotation.

regards,
promehanik

[RICHARD ZASTROW]

promehanic, If all your bearing life etc. calculations are correct, it should work OK.

Remember, high precision work requires high precision bearings. The higher the precision, the higher the price $$$$$$$$$$$$$$$$$$.

Dick Z

[promehanik]

I do not want use matched bearings, because of price (very expensive).
- Please tell me if is possible matched bearings at home?
- Please suggest me any other bearings and arrangement?

On both sides I want precise rotation.

Regards, prom

[RICHARD ZASTROW]

promehanic, You will have to be more specific.

What speed do you intend the spindle to operate?, What is the maximum run out (tir)? What is the radial load? What is the axial load?

What one person thinks is precise may be different than mine or yours.

Keep working at it.

Dick Z

[promehanik]

speed: 3000 rev./min
run out: 0,03 mm
axial force: 200 N
radial force: 200 N

regards, prom

[RICHARD ZASTROW]

prom, next question; what ID @ OD etc. are the bearing dimension requirements?

Dick Z