I was thinking again Doug and I decided if Paxton does not need gears
neither
do we. At first I rejected the idea as the balls would be too big and
heavy
for the reduction ratio we need then I realized they don't need to be
balls.
They could be disk with radiused edges. We already have a source of force
to
keep everything in high pressure contact. No springs needed. Namely the
engine
oil pressure annular clutch throw out cylinder. This means it does double
duty
by keeping the CVT in contact and the friction planetary in contact.
Also when the engine oil pressure is released the planetary is disengaged
along
with the CVT. This reduces the inertia load on the turbo charger allowing
it to spin up faster in automotive use.
I suspect the oiling will work better as you don't have a bunch of teeth
zinging
around in several circles at supersonic velocities.
This should cut the cost greatly. No need for expensive high precision
gears.
Paul Lamar
This series of Paxton blower curves says it all. Notice the max HP
capability
of this drive
is 21 HP. Right in the ball park for what we are looking for.
This is an excerpt from the book called Street Supercharging by Pat
Ganahl 1984 and 1992 ISBN 0-931472-17-3 S-A Design Books North Branch Mn
By removing the Paxton impeller and feeding the output of a turbo charger
into
this device
through a small shaft you would have a complete turbo compound unit with
variable speed
belt drive to the e-shaft. At a power level of 150 HP out of a 13B you
could
up
the HP to 170 HP at the same fuel burn. The BSFC would go from the current
.47 to .42 right up there with the best of any aircraft engine on the
market
today. It would do much btter than this when optimized for our needs.
After all this is a 50 year old design.
BTW The efficiency island is rather poor for this compressor because of
the crude impeller design. A modern impeller with inducer could up
this to 70 or 80%.
Paul Lamar
Paul,
Funny about timing. The Paxton blower is a good start. Great. I can
probably sell their impeller to the ninja warriors over here:) Looks a lot
like the "shirukin" they throw. I understand the performance curves well
but
I am little confused on how you intend to use the device for a power
turbine. Run it backwards? I need more info about what you mean about
metal balls
You your enjoyment:
I am still concerned about the amount of friction in all of the 'full
contact' reduction drives.
Last night I found this US patent # 50130409 granted to Mr. William Mabe
Jr.
who made a planetary transmission out of permanent magnetics on a wheel.I
had been playing with the concept two days ago and noticed how our wind
generator rotors when spun in close contact to one another would transmit
torque and behave in much the same way as gears do. I have ordered some
bearings to do a simple test to determine the torque limits between and two
of them. Mr. Mabe was through enough to provide formulaes and charts on
how to size the different magnet ratios though.
The 7:1 looks reasonably easy to mock up with the materials I have at hand.
BTW here is the site for the patent assignee Sundstrand Corp.
http://www.hamiltonsundstrandcorp.com/generic/0,3626,CLI1_DIV22_ETI2766,00.>
h
tml
Doug in Japan
Yes. Instead of the power going in through the belt end and into the
compressor
we can run it backwards and put the power in the compressor end and take it
out the belt end. I'll bet you can find one of these things on E-bay.
BTW I neglected to mention that with a shallow taper angle on the ring
"gear"
(for lack of a better term) and the pinion "gear" not much axial force is
required
to get this type of planetary to work. The wedging action magnifies the
effect
of
the axial force.
See the attached gif below.
As I understand it the problem with magnetic coupling is, when there is a
large
discrepancy in the speeds heating occurs due to eddy currents. Any time you
have heating
in a device that implies a loss of efficiency. This statement is rather
confusing
because I thought the whole idea of the magnetic device was to transmit
torque. Unless of
course they are using a mechanical lock up clutch when the speed of the
driven
member approaches the speed of the driving member. Then things start to make
more
sense as it is a soft start. The web site smells like a stock scam to me.
I seem to have a nose for this sort of thing.
Steel on steel traction drives have been around as long as the locomotive
on iron or steel rails. What is remarkable about dry steel on dry steel
is the well proven coefficient of friction being about .78. Heck a gear
would
only have a coefficient of friction of only one so to speak :)
Paul Lamar
Paul
I understand the point about little wheels on little steel rails very well
thank you. I am trying to understand the bearing load or friction resulting
from clamping pressure you said the object needed. In its new form does the
planetary drive becomes discs with radiused edges rolling in the same axial
plane as a geared planetary drive? The clearance would have to be so fine
as to slip or create heavy loads on the tiny bearings. How would it be
assembled?
Can you send a picture of the Paxton supercharger, or a sketch of what you
mean by the steel ball or flat disc gear box? Don't all moving connections
whether magnetic or mechanical produce heat due to friction inefficiencies.
How much is the question. I'm trying to "narrow down" what 'to much' and
'not much' mean:)
We have to judge the technology and its potential not the company. A lot of
questionably products are on the market but those products sometime contain
parts to fit our challenge.
Doug in Japan
Doug in Japan
OK the bearing issue is a valid one. According to the Torrington Company
Service
Catalog a 50 MM bore ceramic ball bearing with grease lubrication will
experience a
10 degree centigrade heat rise at 30,000 RPM. Cooled light oil lubrication
will reduce this temp rise. The only thing they say in the catalog is "these
bearings are "low torque" with a surface finish of .1 to .2 micro inch AA."
That is the best I can do right at the moment. I need to research this
further.
The 12 mm bearing I am intending on using for the planet wheels is 3MMV99100WM
CR
ceramic superprecision. ABEC 9.
These are designed to accept thrust. Max we are asking from these bearings
is 17,000 RPM and 670 pounds dynamic load rating which is a piece of cake.
Also the
thrust loads are divided by three as all three bearings share the thrust
loads. Since
the RPM of the planet wheels is so modest (for a ceramic bearing) we could go
up a size or two to increase the thrust capability and increase the life.
I also think we might be able to get away with non ceramic bearings in this
position.
For the input shaft I may use six or more of a 12.70 mm needle thrust
bearings with a dynamic load rating of 1290 pounds and a max RPM limit of
19,000 RPM.
By using six units back to back the 100K RPM is reduced to less than 16,000
RPM for each bearing. Needle bearing thrust capability deteriorates rapidly
with increased RPM. If this scheme works it is super low cost as these
bearings
are only pennies apiece. They also require very little room at 2 or 3 mm width
each. I am still looking into this part of it and may decide to use a larger
ceramic ball bearing instead.
One problem with using a friction planetary is the bearings now take the brunt
of the design effort rather than the gears.
Paul
Yes but I think the friction planetary will be a LOT smoother running.
Sounds good.
The power shaft out of the turbine will turn at turbine speeds so we will
have to use similar bearings and oil mist them right?
doug in Japan
If it were not for the thrust required to generate the traction the pinion
would not need bearings. The planets serve as three large ball bearings.
Paul Lamar
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