Badger_McLetcher
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| posted on 6/4/09 at 01:12 AM |
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Need advice on custom upright design
Hey guys, I've been looking for some uprights for my project car (a replica c3 corvette) for a while now and ended up buying some 300zx hubs.
However I'm not that happy with them so I thought I'd run this idea past your expertise  I've had the idea for these in my head
for a while now but have only just got round to making a model of them (plenty of sketches on random pieces of paper though!  ).
The cylindrical centre section is the hub carrier and is a thick walled tube machined out to accept the two bearings (tapered items). This hub
carrier is welded to the two facing plates and then boxed in with the side and diagonal plates. The top and bottom inserts are bolted in (was thinking
that this would allow some variation in castor/camber/kpi by having a variety of blocks on hand with the mounting holes in different locations). The
axle itself is meant to be a screw threaded cortina spindle, the actual hub plate being bolted to what was the spindle side of it (not sure I'm
happy with that arrangement as it puts the threaded section under shear- the version for welding may be the better option).
The model is something I made up this evening and isn't really to size (just meant for proof of concept). I made the model out of 1/8"
sheet- would this be hefty enough?
Would really like some opinions on these.
Cheers guys.
[Edited on 8/4/09 by Badger_McLetcher]
If disfunction is a function, then I must be some kind of genius.
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designer
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| posted on 6/4/09 at 05:35 AM |
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That seems very heavy and a lot of work.
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Mr Whippy
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| posted on 6/4/09 at 06:47 AM |
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Hmmmmmm
Hugely over engineered, could be a hub for a main battle tank...
The angles are wrong for the ball joints, and not a drop of caster either. So you’d have to take the top and bottom plates off to bolt on the ball
joints?
What’s wrong with just using a production car one??? It would have the correct angles and weight about a ¼ of that
Fame is when your old car is plastered all over the internet
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nick205
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| posted on 6/4/09 at 08:04 AM |
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Seems very complex (and heavy) to me when you could take a stock production part to do the same job better. Castor and camber adjustment would be
better built into the actual suspension components - i.e. the wishbone pivot/mounting points.
Just my opinion BTW - perhaps you're trying to achieve something more specific with your design...?
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v8kid
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| posted on 6/4/09 at 08:20 AM |
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Racecar Engineering March 2005 had a quite detailed article on upright design which I found usefull. Also Aurora bearings publish a free article on
sizing rod ends for uprights.
Stanniforth in his articles if you read them closely implies that the outboard pick up points have a less dramatic effect than the positioning of the
upright pickup points and you can verify this for yourself by playing around with the free SLARK programme.
How are you going to tighten the bolts on your tapers?
Like the other chaps it looks a bit heavy to me. 2mm appears to be the norm for a 700kg locost with about 1.2mm for a racer depending on the
intergrity of the design.
Cheers
David
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Badger_McLetcher
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| posted on 6/4/09 at 08:56 AM |
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Havn't got time for a detailed reply atm, but I'll just quickly put the following replies:
-overengineered: Probably! I'm a bit prone to that. The hoped estimate for the car is 1000kg and 500bhp/lbf to begin with (up to 1000bhp when I
can get myself another engine to build) so I tend to build things beefy-though 1/8" steel plate probably is overkill!
-Why not use Production items?: Basically I've got these 300zx hubs but the offset on them (IE BJ-Faceplate distance) is huge, and space for
the wishbones is at a premium on this build (also the reason I didn't want to use Wilwood Prospindles). They're also heavy (about 7kg
each) and seem to have minimal castor. If anyone can point me towards a better 4.5"/114.3mm PCD 5 stud hub/upright I'd gladly have a look
at it!
-No Castor/wrong angle for BJ's: As I said this is more a proof of concept design than a proper one. Castor can very easilly be put in by
altering the mounting holes. Also it's designed for rod ends rather than ball joints (Spigots attached to the inserts).
Right I'm out of time! Input noted and will try to draw up a proper design tonight.
BTW had a quick look for the aurora/slark stuff you mentioned V8kid and turned up nothing? Will have a better look later.
Cheers for the comments guys
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MikeRJ
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| posted on 6/4/09 at 11:50 AM |
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Honda Prelude, Accord and Integra have double wishbone front suspension and 114.3x5 PCD, might be worth a look? Also I think the Lexus is200 is
double wishbone with same PCD.
[Edited on 6/4/09 by MikeRJ]
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Badger_McLetcher
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| posted on 6/4/09 at 12:11 PM |
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quote:
Originally posted by MikeRJ
Honda Prelude, Accord and Integra have double wishbone front suspension and 114.3x5 PCD, might be worth a look? Also I think the Lexus is200 is
double wishbone with same PCD.
[Edited on 6/4/09 by MikeRJ]
I thought only the Prelude Type R had 114.3x5 and the others were 114.3x4? Ta for the IS 200 idea, will have a butchers 
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MikeRJ
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| posted on 6/4/09 at 02:11 PM |
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Probably should have said Accord/Integra Type R, the standard versions are 4x114.3 as you say.
Lots of other Honda stuff is also 114.3x5 (Legend, Shuttle, Civic Type R etc), but not sure if any of them use a double wishbone front suspension.
Virtualy all Lexi use the same size as well, but again the is200 is the only one I know for sure that has double wishbones rather than struts, the
other models may be similar.
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hellbent345
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| posted on 6/4/09 at 03:49 PM |
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yeh as others have said, looks a bit mighty, can you get someone with some fea software to go over it and slim it down, im sure it could be made
thinner and lighter in quite a few places?
EDIT looks like youve got solidworks anyway? try and use cosmosxpress on it with the proper restraints, thatll give you an idea how thin you can make
all the constituent bits
[Edited on 6/4/09 by hellbent345]
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Badger_McLetcher
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| posted on 8/4/09 at 02:41 PM |
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Right, I've finished the redesign. This version uses 16 swg sheet on most sides now and the hub carrier has been redesigned. Projected weight is
about 3.85kg each which is half that of the 300zx items I have. I havn't done any stress analysis on this yet- if someone has access to a
program and wouldn't mind doing it I'd be obliged, otherwise I'm going to have to wait until after my exams and do it manually 
Anyways here's the images. Any better?
BTW hellbent345 I don't have solidworks, I've got a program Uni gave me called SolidEdge. The stress analysis in it is useless!
If disfunction is a function, then I must be some kind of genius.
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WIMMERA
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| posted on 11/4/09 at 12:35 AM |
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If the Honda has the stud pattern you require, fabricate an upright to accommodate the live stub axle and bearing, I used that method to make uprights
from Peugeot 205 bits, it's very simple and effective, use the bore dimensions from the Honda upright to get the right size for the press fit
bearing. I used hollow bar for the bearing housing and 65x35 box for the upper and lower ball joint inserts (similar to your design) .
Wimmera
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