[MOC] Fluid Drive Bus Mk1

[HarmanMotor]

Hi all,

I'm new here to the forums and would like to showcase to you my latest MOC, a bus which is based loosely off the AEC Regal MkIV. This has taken me approximately six months from prototype to completion.

Like the original bus, this MOC also features a fluid flywheel ("fluid drive"), which is filled with 40W silicon oil. This smoothly transmits the power from the E-motor to the gearbox.

The bus is controlled via IR remote controls (for steering, throttle and gear shift).

I've included some links to media below, including photos, video, a PDF manual and a link to the post I made on my own blog.

Hope you enjoy!!!

Link to blog post

Link to PDF Operator's Manual

Edited August 1, 2014 by HarmanMotor

[Pat-Ard]

Hi Harman,

ans welcome on EB... A very nice bus you built...

One question, what wheels did you use? Are they originally black?

Pat

[TheItalianBrick]

Very cool idea!! The bus looks ugly as hell but I the looking was not the point!

I have two remarks: first would be nice (if possible) to achieve the same "smooth" effect with just LEGO parts.

the second thing is, as you are using "oil" I would build a converter so you can swap from "forward" and "backward"....

Anyway I really enjoyed the video and all the technical explanations!!!! :tongue:

[Rockbrick]

wow and thanks for educating me in the wonderful ways of fluid couplings !

the PDF manual is a work of art in itself - reminds me of old motor manuals you'd get with your car in the 1960s when you were expected to do most of the maintenance

[HarmanMotor]

Hi Gents,

Thanks for the comments! Pat, thanks for the welcome. These wheels were originally light grey and I repainted them in "British Green".

@TheItalianBrick Yes I will admit the bus isn't the prettiest thing around...I would have liked to have used more green bricks in its construction however and you're right, the looks weren't high on my list of priorities haha. ;)

Re: the smooth driving effect, this is main benefit of using the fluid flywheel. The drive is transmitted using silicon oil and any shocks from the gear changes etc are cushioned by the fluid also - much like a real-life automatic transmission in a car. Unfortunately Lego haven't made any parts that I could use for this purpose thus far, so I've had to improvise in this area (incidentally, the contents of the fluid flywheel contains Lego parts, it's only the blue casing itself I've had to improvise and needs to be sealed as much as possible as it contains oil which is flung around pretty violently. :o

Not 100% sure what you mean by "converter", however the bus can be driven forwards or backwards via the remote IR controller by issuing forward/reverse commands to the e-motor. If I had more space I could have implemented a dedicated reverse gear however it seemed a bit redundant when I can easily reverse the motor via the IR controller.

Glad you guys enjoyed the vid and the manual also!

Cheers

Edited August 1, 2014 by HarmanMotor

[Pat-Ard]

Hi Harmon,

thanks for the info...

Pat

[TheItalianBrick]

Hi Harman. no worries. So talking about "hydrostatic transmissions" (or converter) we mean an oil trasmission that having only one direction as input can swap the output direction from forward to backward (and actually neutral aswell), It's an "easy" concept, made with 2 valves that control the direction of the fluid. Normally the conbine harvesters use it cos it's smooth and gives an high manouvrability.

basically the engine goes always on and only one direction (input) then the converter drives the fluid (oil) back, neutral or forward.

Enjoy!

Plus, the reason why this big machines uses this sort of CVT transmission it's not all about comfort, but truction. Cos using a conventional clutch there is a moment where the engine (input) and the wheels (output) are not connected, and this means loss of traction!!! So all the movements are smoot, gear shifts too and no loss of traction!

This is what we should build in lego! I'm getting closer with my next MOC, but it's more based on a "gearing" concept rather than a "oil" transmission....it meas it has it's limitations....but still cool ideas!!!

[HarmanMotor]

Ahh yes I get you now, hydraulic motors and the like. =) I've seen this type of transmission used on crane vehicles and railroad shunters also. I've heard that the hydrostatic transmission can also function as an effective brake when the operator wishes to slow down. It would be interesting to build a hydrostatic transmission with hydraulic motors such as these, but my mind boggles a bit if I'm going to consider using oil, as in, the process of keeping everything sealed under pressure and not cause a mess on the living room wooden floor haha. The concept you talk about using gears sounds interesting...do you have any posts on that project elsewhere?

For the moment, my bus sets out to achieve its objective of having a 'simple' fluid coupling which is very similar to its real-world examples (note that this is not a torque converter, only a simple fluid flywheel).

My next vehicle may be a Greyhound "Scenicruiser" bus with two motors and two fluid couplings (very similar to the real-world twin-engined prototype). That's going to be a challenge and a half...

Cheers!

[TheItalianBrick]

Hello harman. Yes the hydrostatic transmission works also as a brake, but conventional disk brakes are necessary anyway when we talk about heavy machiney!

Anywya....now what you should do in my opinion is to use a double cuopling system and 2 valves that controls the oils directions, maybe having a differential between the 2 outputs in order to avoid damages parts due to the oil pressure.

I know it's not nice to work with oil at home :tongue: but you could use plastic floor covers or things like that!! :laugh:

About my solution, hopefully I'll be releasing it after the summer. Unfortunately it turned at being very busy at moment so I've go other priorities....but fingers are crossed!!!

[HarmanMotor]

Haha yes unfortunately I will probably need approval from the council (my wife) before I go any further down that path, but who knows! I already have a fluid drive vehicle running successfully throughout the house. No mess as yet thankfully! :D

I look forward to seeing your project...in the meantime it's Winter here (down in Australia) so I have quite a bit of time indoors to think about these things (and hopefully not lose too much of my hair in the process! lol)

Cheers

[grum64]

Hello Harman and welcome to Eurobricks

You certainly know how to make an entrance.

While I'm vaguely familiar with fluid drives, implementing a fluid drive transmission on a Lego MOC is something I've not come across before and certainly not something I thought I'd see.

Your MOC is, as my learned friend TheItalianBrick so eloquently put it, 'ugly as hell' but as you say appearance wasn't your prime objective. I look forward to seeing your future builds.

The .pdf manual you've done is very informative with everything being explained clearly making it very easy to understand. It's brilliantly done, genuinely as good as anything you could buy anywhere.

You Sir, are a Genius!

[HarmanMotor]

Thanks grum! Muchly appreciate the comments!!

Yes I was hoping to make the operator's manual informative enough, but without getting bogged down with too much detail at the same time...although having said that, some crazy part of me wants to draft up a 'factory' or 'shop' manual for this beast, but the thought of pulling it all apart just to document it just doesn't sit well with me right now. Maybe later...heh.

Glad you guys enjoyed this. I have a strange feeling of wanting to start on my next MOC asap, now that this one is 'out of the way'. I don't believe in dismantling my MOCs so this one is going onto the shelf (once I find make room for it!)...

Cheers

[Rishab N]

Interesting build and a nice concept

[Phoxtane]

What do the internals of the fluid drive unit look like?

[HarmanMotor]

Thanks for the comments.

Phoxtane, I don't have a sample fluid coupling dismantled at the moment to show exactly the internal parts (the case is 'permanently sealed' once assembled and must be broken apart if it needs to be disassembled), but I have provided design/concept images below.

It's very simple, basically the fluid drive case contains Technic pulleys (part 4185)...at least one each for the input and output side of the coupling. The input and output sides are not physically connected in any way, but the whole job is filled half-full with oil.

I am experimenting with using different types of pumps and turbine designs, (rather than using the pulleys with circular holes) to better transmit the driving force. For the moment the pulleys perform the job well enough.

In the future I may look at developing a 'lockup clutch' to physically lock the coupling input and output sides together when the vehicle is travelling at higher speeds for better 'battery economy'.

Edited August 3, 2014 by HarmanMotor