Uni work - Brake assembly done

[adamskiTNR]

Thought i'd post up my uni work in engineering, thought it may be of interest to people in this section.
It's an upright i designed last year for a formula student race car.
This year i am designing and optimising the hub assembly, but that's a work in progress.

[wadoryu]

Nice mate

[Tom5190]

Looks good which uni?

[adamskiTNR]

Cheers, Brighton

[Tom5190]

Sweet, we got pushed over onto Catia now for some reason for final year.

[adamskiTNR]

I really want to get some hours on catia. Its what i'll be using in industry, but its just too dam expensive to get a load of licences for uni computers.

[Harv]

Looks mint that mate!

I've done a very similar thing within Solidworks but designing the unequal A arms and hub assembly for our SAE car (LJMU). Currently completing a project with FEA to optimise a piston including removing as much material as possible but keep the structural integrity and principal stress distributions the same.

What year you in? I'm half way through my final year project (although I'm doing a masters so another year to go yet) on simulating a FSAE car and comparing the results to data logged information. Still trying to get my model up and running to give tyre loadings within 5% of the calculated loadings. Its a right bitch to get close though haha!

[Tom5190]

Originally Posted by adamskiTNR

I really want to get some hours on catia. Its what i'll be using in industry, but its just too dam expensive to get a load of licences for uni computers.

Catia is alot better imo for the basic creation of designs and making parts/assemblies/cutter paths etc however i still prefer SW for FEA etc and ive also had some issues transfering models from catia to SW which is abit gash.

[manta]

can you do all my cad work for my assignment?

I'll pay you in massages.

Happy endings included.

[adamskiTNR]

In my second year at the moment. Best of luck with tyre modelling. I haven't tried it myself, but seen the calc's and vehicle models with them in and anything slightly dynamic is just a massive ball ache

[adamskiTNR]

Okey dokey. Got my initial hub built up with bearings preload spacer etc. It is a slightly unconventional design, as it uses a face spline as retention for all 6 DOF's. Thought i may as well jump at it and see what i can design this way. This shows the first draft of the face, though i haven't finalised/decided on the rear hub fixing yet.

[axsaxoman]

what is dof ,looks more like a ramp from an lsd

[adamskiTNR]

Directions of freedom

[adamskiTNR]

Te problem i have is that standard centre lock systems are shit. The compliance in the system is huge. And they fret badly.
A face spline sorts all the issues, but creates new ones, such as the braking force now adds load longitudinally to the wheel nut. Would still be easy to revert to a standard drive peg design.

[axsaxoman]

ah, so its a drive flange to mount the road wheel on with single center nut fixing.
the main problem with centre fixing is the amount of expansion in the hub you have to allow for with the heat from brakes ,which is why the they have to be a loose fit ,but clamp up well.
looks like it should work ,not usre how the flat faces will cnetralise the wheel --maybe same basic shape but with tapered flats to cnetralise the wheel and not rely on tight fit on centre post and with a flat bal race built into the wheel nut between the taper and the nut to reduce frivtion ,so clamping troque is real value

[adamskiTNR]

The wheel will not touch the central shaft. The faces are tapered downwards and towards each other to centralise. This also prevents the problem with expansion as the clamping will remain pretty constant from the flat faced wheel nut, and the flange face will remain constant. The point is that no part of the wheel will be touching the flat faces or the bottom of the grooves. So that the taper effect doesn't bottom out

[adamskiTNR]

*Dramatic reveal music* It's complete!... well... the initial draft is. I still need to run numerous stress tests on the components.
As you can see in the picture it uses a large rear plate to fix the frontal section into place. This plate has been the bane of my life. Running test after test to try and get it to hold the clamping force (31500N over a 24mm diameter area.) Not pleasant numbers. This clamping force is so high compared to some of the other loads the hub will experience, but is often overlooked as just "bolting the thing together". I am happy to get it into aluminium form eventually. It was alu, then it broke, i made it thicker, it broke. So i went to steel, it broke, i made it thicker, it worked! But by now was 162g (the main hub component is 212g!) So i changed the design completely. It is now a nice 63g part. I have the option of this design in alu, or a nice thinner design in titanium 4v, but that stuff isn't cheap so aluminium it is.
It should be interesting to see how the braking forces will vector from the angled faces of the hub, be it good or bad.

[greyjasper51]

Have you had any problems with the ball roller bearings being spaced apart such as a high breaking force... Because the bearings have a pre load spacer in there setting them apart the outer will take much much more of a beating due to the leverage effect and the pivot point witch would be the rear bearing... Again the same problem with high cornering speeds it will want to push the center of the bearings through... Have you though about tapered needle rollers?

It was just a though

[adamskiTNR]

Don't worry, I have the actual bearings in the cad model now, you cant see them in these pics as they are just config parts. The bearings are a paired set of deep groove angular contact bearings, so only work in one direction. Similar to a taper setup, but without the assembly limitations.

[adamskiTNR]

But yes the outer bearing will see more loading being the fulcrum, but is unavoidable. They will be lifed as such.
an example http://www.scots-bearings.co.uk/file...ll-bearing.jpg