Two part fan mounting/shroud idea

iamweasel · Post by **iamweasel** » Sun Feb 01, 2009 5:31 pm

I was thinking here, which I know I shouldn't do, but here goes anyway.

I was thinking about fan mounting, rubber grommets and such, and how those don't work in all places. Such as mounting on a tower heat sink, or when space is truly limited (PSUs and somesuch).

Then I figured fan housings could be made in two parts, use hard plastic (or even metal) for the part of the housing, which cannot deform or the fan blades would hit the housing. That is the "hub", the "rods" connecting the shroud to the hub and a thin inner face of the shroud.

The rest of the shroud (the parts making the fan housing rectangular, that have the holes for screws on them) could be some fairly soft material, I'm thinking squeaky toy soft or even softer, just hard enough so you can drive a typical fan screw into a pre-made hole, as usual, without it deforming so badly that the screw just won't work.

The inner (hard) shroud would then just sit in a round groove in the much softer material. (Or the groove could be in the harder material, whichever is easier to make. :) ) Since the outer material would be soft and deformable you could just slip it over the inner parts they would be held together by friction and the tongue and groove sort of joint.

The softer material could help in absorbing the vibration and prevent it from transferring to the screws and so on. The harder material would keep the fan housing from collapsing onto itself. In the end you could mount it exactly like a regular fan and not need grommets or suspension.

I not sure if this would actually work, or how much more it would cost to make the fan housing in multiple parts, or even if there would be any kind of market for such a structure, but I figured I myself could use a few fans which I didn't need to specifically "soft mount" when that proves to be tricky.

hillkitler · Post by **hillkitler** » Sun Feb 01, 2009 11:00 pm

That's certainly feasible, but it doesn't seem very economical. The prices that a fan company would charge end-users for something like this would be astronomical.

Some around here would say that it's more economical to not use a fan at all...

Fawlters · Post by **Fawlters** » Mon Feb 02, 2009 5:09 am

Good idea, but I'm not too sure the soft rubber would take too well to screws. I might be wrong though. Also, depending on how much interference there is between the hard ring and the soft mount, or how much smaller the soft bit is than the hard part, it could still deform the ring.

It might be easier to make it a three part mount with a soft ring sandwiched between two hard pieces; a fan support structure and the outer screw points.

That's certainly feasible, but it doesn't seem very economical.

Being as all the parts could be injection moulded, which they already are, so long as enough are made they shouldn't be too much more.

I think I might have a play with this idea and see what I can come up with. If I get anything worth showing I'll post a couple of pics.

Fawlters · Post by **Fawlters** » Mon Feb 02, 2009 6:58 am

A model I as a sort of proof of concept, ended up a bit more complex than I intended.
Each corner has its own insulator/absorber that fits over a pin on the centre ring, and the corner piece uses two pins similar to acoustifan soft mounts.

hillkitler · Post by **hillkitler** » Mon Feb 02, 2009 7:21 pm

That's a pretty good rendering Fawlters-- Kudos. I was just thinking that whatever soft material is used as the buffer there, however cheap it may be to produce, might result in greatly increased prices of the final product. This would be due, of course, to the "cool" factor that parts manufacturers play off of.

BillyBuerger · Post by **BillyBuerger** » Mon Feb 02, 2009 8:33 pm

I dunno, Artic Cooling has their fans that are pre soft-mounted that aren't any more expensive then others. Problem with them is that they can only mount in the exhaust position. Can't use them say on the intake of a case. This version would fix that issue. I like it.

xan_user · Post by **xan_user** » Mon Feb 02, 2009 9:04 pm

all rubber/silcone shroud with normal hub inserted.

?

Or bi-injected possibly?

stiff=grey soft=blue

hillkitler · Post by **hillkitler** » Tue Feb 03, 2009 1:21 am

Bi-injection makes the most sense to me.

Fawlters · Post by **Fawlters** » Tue Feb 03, 2009 4:04 am

@hillkitler: Thanks, that was pretty much all I did between the two posts. Still, two hours is fairly short for me when I get playing with CAD

@xan: I was going off iamweasel's idea, hence the solid ring round the fan. Rubber/silicone may, but should not, deform sufficiently to touch the edges of the fan blades. The solid ring stops that being an issue.

My design would have to be triple injected if it were made in one piece, and that would be considerably more expensive. If it was a solid ring and rubber/silicone corners, then that could be bi-injected though and should be cheaper.

A quick note on injection moulding; the more parts to the mould, the more expensive the overall mould is. From a quick look at a tricool, they have at least four, more likely six, parts to the mould. If anyone else wants to check other fans, look for the parting lines, probably round the middle of the shroud and inside the corners.

BillyBuerger · Post by **BillyBuerger** » Sun Feb 15, 2009 6:47 am

Just saw these...

NB-MultiframeÂ® S-Series MF12-P

Looks like they've done something very similar to what you were thinking.

Plekto · Post by **Plekto** » Sun Feb 15, 2009 1:02 pm

I just use the little orthodontic spacers my son has a ton of...