Scrap bin motor

Help Support HMEM:

itowbig

Well-Known Member
Joined
Mar 2, 2008
Messages
737
Reaction score
5
i just dont get it for some reason how it works
 

dvbydt

Well-Known Member
Joined
Oct 27, 2010
Messages
114
Reaction score
4
Sid,

Compressed air flows into the stator spindle via the copper tube, then via the transfer port to the two pistons. These are forced appart moving about 5mm. At maximum stroke (the rotor has moved about 90 degrees) the air is cut off and the pressure is bled off via the exhaust port in the outer sleve. The rotor has now moved 180 degrees and the cycle is repeated.

The rotor is about 45mm OD, the pistons are 8mm and the rollers are Delrin.

Ian
 

cfellows

Well-Known Member
Project of the Month Winner
Joined
Aug 25, 2007
Messages
3,891
Reaction score
708
Interesting application. Took me awhile to figure out what the pistons look like, but I think I've got it.

Chuck
 

itowbig

Well-Known Member
Joined
Mar 2, 2008
Messages
737
Reaction score
5
i still dont get how it works but it is cool looking.
 

dvbydt

Well-Known Member
Joined
Oct 27, 2010
Messages
114
Reaction score
4
Thanks for taking an interest. Not very good at explaining how it works, sorry, perhaps this is better. I didn't do any drawings, just made it up from scrap bits.

Ian



Air Path.jpg
 

itowbig

Well-Known Member
Joined
Mar 2, 2008
Messages
737
Reaction score
5
OH ok now i see how the thing works those little wheel are pistons hahaha
i just could not for the life of me figger out how that worked .
Thank you for that. it makes sence now
 

cfellows

Well-Known Member
Project of the Month Winner
Joined
Aug 25, 2007
Messages
3,891
Reaction score
708
That's really a pretty elegant little engine with some nice design features. I particulaly like the slotted cylinder sides to keep the rollers oriented correctly. Wonder how well it would scale up?

Chuck
 

dvbydt

Well-Known Member
Joined
Oct 27, 2010
Messages
114
Reaction score
4
itowbig,

I'm pleased I managed to get the idea across.

Chuck,

It should scale up OK, but would probably need ball races rather than plastic rollers. It did cross my mind that the rotor might make a centrifugally supercharged, uniflow, 2 stoke a possibility, but just a pipe dream!

The reason I was experimenting with porting was for a small air driven V8, but the elegant ball valve exhaust ports on your opposed 4, has caused a redesign and that engine is on hold for the time being.

Ian
 

cfellows

Well-Known Member
Project of the Month Winner
Joined
Aug 25, 2007
Messages
3,891
Reaction score
708
Glad you are trying the ball valve design. It's fun to see how other people adapt it to their own designs.

Chuck
 

imagineering

Well-Known Member
Joined
Dec 6, 2010
Messages
96
Reaction score
13
What is the actual shape of the Rotor cavity - is it 3 holes at offset spacing, or is it a more complex set of curves?

Murray.
 

dvbydt

Well-Known Member
Joined
Oct 27, 2010
Messages
114
Reaction score
4
Murray,

Yes, just 3 bores. The concentric one done on the lathe, the two offsets done at the same setup on the mill with a
flycutting tool.

Ian
 

imagineering

Well-Known Member
Joined
Dec 6, 2010
Messages
96
Reaction score
13
Hi Ian,

Could you post a few basic dimensions please - this one intrigues ???

Murray
 

dvbydt

Well-Known Member
Joined
Oct 27, 2010
Messages
114
Reaction score
4
Murray,

Drawing of the rotor for you, should give you most of the information. I didn't do any drawings before I started, just made it up as I went along, so the drawing is just measurements of the completed motor. Important is the 5mm hole size as it gives the correct spacing of 45 degrees for the porting.

Ian

RotorImage.jpg
 

imagineering

Well-Known Member
Joined
Dec 6, 2010
Messages
96
Reaction score
13
Thanks Ian, it's now on my 'to-do' list.
Am I right in assuming that the Porting Holes go all the way through the Rotor Shaft, (making 4 in total)?

Murray
 

dvbydt

Well-Known Member
Joined
Oct 27, 2010
Messages
114
Reaction score
4
Murray,

Two holes and two slots - the inlet transfer ports that get covered by the outer sleeve.

Ian
 

crueby

Project of the Month Winner!!!
Project of the Month Winner
Joined
Mar 9, 2010
Messages
596
Reaction score
702

That is the coolest thing. You were thinking outside the room holding the bag that the box was in!
 

dvbydt

Well-Known Member
Joined
Oct 27, 2010
Messages
114
Reaction score
4
With the number of views of this thread, I figured this little experimental air motor had earned a mount and a dust cover.

Ian

Dust Cover.jpg
 
2

Latest posts

Top