2WD design thoughts
Hi all! I posted this to another forum [in error] and meant to post it here too, forgot!
Working on building an outfit in the near future and have given a lot of thought to 2WD. I hear a bunch of negatives and complications, but most all say the traction is great so it sounds good to me! Possibly the planned design would be of use to others contemplating 2WD?
I have a complete bike rear wheel/sprocket/brake for hack with bike's original swingarm and shocks. This build will have a PTO at engine, so come off the PTO and across under the chair with a u-jointed driveshaft. Chain drive from driveshaft to sidecar rear wheel or adapt as necessary direct to wheel.
In order to make it usable in full-time 2WD, split driveshaft in two, then mount shafts in bearing supports under chair's frame. On the two adjoining cut ends of each shaft attach clutch plates that will press against each other, as simple flat hubs with friction material on faces.
Mount it all up so that it's adjustable for pressure between the 2 shaft ends with clutch plates. One shaft end may be splined, with that clutch hub internally splined and then spring-loaded, with coil spring pressing aginst a stop collar and the clutch plate hub, to apply constant spring pressure to clutches as needed but with options on spring ratings. Adding a threaded stop collar and threading shaft behind splines provides easy adjustment of spring pressure anytime as desired.
With this setup I can adjust to have full traction up to about 50% of full engine power on hack wheel, give or take, or anywhere up to locked rear. This allows light enough pre-load so that sidecar axle and wheel can slip as needed in turns on hard surfaces, either speeding up or slowing down, as if free-wheeling. Of course I'd expect some clutch plate wear over time, maybe not all that much. This setup would give a whole lot more extra traction power on soft surfaces and hopefully leave everything drivable on hard surfaces? It's CHEAP, EASY, RELIABLE and DIY!
2 U-joints
4 Bearings and supports
1 Shaft cut in two and splined as needed
2 Flat plates [may be the hubs themselves]
2 hubs, 1 splined for shaft splines
2 Friction material
1 Shaft stop collar or welded ring
1 Coil spring
That's about it? List of advantages over other systems:
1] COST: Lowest by far, a couple of $100, not $1,000's!
2] Simplest of all known designs.
3] Ultra-Lightweight, easily under 25 lbs total.
4] True DIY: Ease of building all components at home.
5] Only 1 machining operation required: cut splines.
6] Extreme strength for any horsepower/torque range.
7] Useable on any sidecar-trike or vehicle with 2 wheels that can be driven.
8] Works on any motorcycle ever built with a simple jackshaft PTO added.
9] No limitations on Track Width - 18" to 18', doesn't matter, custom fit.
10] Simplest to adjust or repair on the road, most others not adjustable or repairable on road.
11] Simplest to completely disconnect on road, most others can't be disco'd on road.
12] Extreme Reliability, basic simplicity, fool-proof design with very few parts.
13] Absolute minimum wearing or possibly failing parts.
14] Absolute minimum moving parts.
15] Easily and quickly adjustable for ANY desired traction advantage up to locked rear.
16] No high-priced MANUFACTURER ONLY parts.
17] No parts destined to become obsolete.
18] Parts pricing structure not controlled by Manufacturer or Sales network.
19] No 'Proprietary' Manufactured parts.
20] No complicated and expensive parts, gears, doo-dads etc.
21] Every single part easily carried onboard as a spare.
22] Limited-Slip traction advantage may be changed in minutes or seconds.
Hope it helps some of you to do a 2WD conversion or build one the easy and cheap way!
XLerate - JimmieD.
this following is a high$-option from Germany.
http://www.mobec-international.com/technical/duodrivesuperdrive/03351a9ff30d2fe14.php
I am at the point to equipe my Jawa/Velorex560 rig with a new watercooled 4 stroker engine.
Husquarna 450ccm.
The idea of all wheel drive is in my head for decades and your idea might be doable. But at the moment I cannot visualize it in my head.
(might be because of weeks in paperwork and not on site)
My own idea always for all or two wheel drive always went over hydraulic motors and pumps.
http://www.hydraulicinnovations.com/raccoon.htm
including the original is going over hydraulics for the front wheel drive. So my idea for the sidecar drive would be a front wheel drive used for the sidecar too.
http://www.rokon.com/index.php?p=1_15_Products
Just thoughts that do not let my mind sleep.
Meanwhile I just have to wait for the 4 stroker and many other tasks to get done...
Sven
It's pretty simple, Sven. Just one shaft similar to a Ural drivesahft but cut in half in the middle. Clutch plate/hubs on those cut ends of shafts, pressing together face to face. On one side the shaft is splined and one clutch hub is internally splined, with a stop collar behind that and a coil spring in between. Coil spring presses on lock collar and on clutch hub to apply constant pressure to clutch plate hub and therefore against other clutch plate.
The amount of spring pressure causes the limited slip instead of full time locker. You could also thread that sprung shaft and use a threaded stop collar behind spring for more adjustment on the road or whatever.
One clutch plate hub is rigidly mounted to a shaft, the other slides on a shaft because of splines.
.
In theory Your Idea is good. In reality You will be over forcing your splines and springs way over their limits.
Its feasonable, but needs serious engineering and will possibly become that big that You will not fit it under the sidecar frame.
Think about canabilized multi disc clutches from huge bikes for a small bike.
Lets say two 1500ccm goldwing clutches for a 750ccm bike, just will make up the torque You will need.
Remember Your clutches will have to work after the gear box not in front of it so torque will be a multiple.
In wet clutches a hydraulic/turbine oil without EP extreme pressure aditives is the oil to use. I see it in lathes with mechanical clutch quite often that people think to do something good with
EP additives And they wonder why the lathe spindle slips and overheats. As soon You put in the cheap hydraulic oil And You break in the clutch, troubles disappear in minutes.
Think about another problematic issue: free spinning because of one tire in the air. There a excenter mecanism could help to force to couple both clutches.
I remember a type of automatic clutch in a bottle washing machine that had 2 discs with champhered nests in which were huge ball bearing balls. As soon the tracted disc started to slip too much the disc lifted and forced the clutch to grip stronger on one side and the other disc got loosened.
But It is so many years ago that I cannot remember well the design. But as above mentioned for dry single disc it needed a huge diameter.
Sorry if I disappoint you, but in deed, sit down together with an engineer who is strong in calculations and design layout.
Myself I am bad in calculations, but good at observe actual designs and predict where it will fail just out of experience and optical eye balling.
Good luck with yôur design.
Sven
Thanks for the reply, Sven
I'll have to disagree with you on a few points. Regarding splined shafts stressed over their limits, not so. I have a splined driveshaft on my Cummins 4BTA diesel powered truck of 7,500 lbs, no problems. Another of my vehicles has splined axle shafts and all shaft drive bikes have them. Very common to use splined shafts with far more horsepower and torque than ever found on a bike rig. The trick is in number of splines, total contact surface plus interfence and materials used.
Also there's no problem with stress on clutch springs if they're properly installed and made of quality materials at proper spring rates. If a single spring will not supply adequate force the answer is obvious: use a heavier spring, add more spring, or a second, or a third, including coil springs located inside one another. Other than diaphragm type pressure plates the same basic design is used on all vehicles that have a manual clutch with manual transmission for over 100 years.
Also I never gave any dimensions or materials suggestions and never described any particular splined shaft or spring so it seems impossible to suggest that they will be stressed beyond limits, because I never gave any specification to judge what their limits are?
As for overall size, can't see that as a problem either. Look at a 2WD Ural with driveshaft. These friction plates mentioned don't have to be of large diameter. Their normal job is to transfer maybe 50% of engine power before some slippage might start. They would slip a bit on turns, but would not be spinning furiously. 4" to 5" diameter with proper clamping force is adequate to transfer a whole lot of power to a sidecar wheel that's working together with the other wheel to provide the push. Certainly no problem to have a slight cutaway in body for clearance of clutch discs, or simply put them in the open space between bike and chair.
I believe you're mistaken on the clutch discs and applied torque 'problem'. I have a DANA 60HD rear axle with DANA Power-Lok Limited Slip rear in my truck, that I just rebuilt. This unit is commonly used to power trucks with Cummins Diesel 6BT engines of up to 400 HP and 500 ft/lbs of torque in very extreme conditions with heavy loads, no problems. Those L/S clutch discs are about 4" diameter and 1/8" thick and last on average over 200,000 miles. One may also use one steel hub/disc and only one friction plate, with steel plate running direct to friction plate surface, just like a DANA Limited Slip rearend or any autmotive clutch and pressure plate.
As for suitable lubricant, no lube is needed. No automotive manual transmission uses clutch lubricant. There's no excessive heat involved here, all parts being open to forced-air cooling by motion same as air-cooled engines.
Regarding one wheel in the air, it would turn at the same speed as the wheel that has traction. There should be no stress caused by one wheel in the air.
Regarding outside consultation with an engineer: I've spent my lifetime in Mechanical Engineering, machine design, hands-on fabrication, modification, maintenance and repair, starting with building my first state of the art racing go kart chassis and rebuilding the engine at the age of 12 in 1962 and onward from there. Machines and the study of the way they work and how to improve them, plus years of automotive mechanical design have been my major consuming interest for 50 years. I have considerable direct professional experience with vehicles and machines using all this same technology in very similar applications. It was not a half-baked idea by an inexperienced newcomer to things mechanical but instead a very simple design based on well established and proven mechanical engineering principles.
I hope the design will be of benefit to others to make their lives easier and their projects and motoring experiences more rewarding and bountiful. I have been Blessed in many ways by others and I believe that a good part of a man's journey through life is to reach out and give a hand to others when possible. This was simply intended as a free gift to help others. It wasn't favorably received but what each decides to do with it is their own concern.
Thanks!
.
After many years in the professional auto racing field, fabrication and so forth i am amazed at how many things came into vogue that were actually developed in the 'backyard garage' type atmosphere that eventually became a necessity to go fast. Yes. many times the original idea was taken in by the engineeer types and then taken to the next level of sophitication and improved upon. Moral of the story is that the human brain is a marveloous thing and no one should discount any idea that comes from it just becase the idea seems off the wall. From the other side of the coin the 'educaetd' engineer types can at times be so book smart they close their minds to new ideas..this can be sad in many ways. can't se the forest for th e trees type thing. Have also seen things that looked good on paper but sucked in th ereal world. So it goes....lol.
Yes indeed, well said!
Also, like so many things in life, many times a designer just doesn't know when to stop. Instead of just building a better mouse trap they keep on head scratching and add in
so many features, doo-dads, and farkles that it's impossible to fix without proprietary factory-only part$ and nobody but a reincarnated Einstein can repair it.
In my tiny little world 'MIM' is the rule of the day whenever possible: if I Made It Myself then I can repair it myself, any way I want to, with any parts I want to use. Works for me!
Jimmie,
Sorry to delay that much my response. I wrote it on the computer from my children and until today I am able to use it again. The other day the conection got lost.
So here my response from the other day.
....don´t be offended. You are new to me on this forum and people have to get to know each other.
Specially here in a public forum it is better to be gentle and polite.
My idea as engineer in a developing country is to help other people to do things right, save natural resources, secure employments and prevent accidents. As it is a fact that machine safety and 70% of all costs are defined during the design period, I participate on this forum with my personal experience frecuently.
So please take things calm, I just want to help where I can.
Simply your first comment sounded as it would come from several well inspirited, but not professionally prepared inventors who frequented my machine shop diverse times. And as mentioned, I had the head full of paperwork and then I cannot visualyze as good as when I have my hands on simular pieces as You describe.
As English is not as accurate as German in technical descriptions and diferent people have diferent ways to express themselves, there are a lot of possibilities to misinterpret and one single word can have many meanings like "file" has at least 5 meanings i know of.
Simple example: "Spline" in my language understanding is a simple dull pin (not necessarily out of hardened steel, often even intentionally made out of soft material like brass) which obviously would shear off in an eye blink.
Apparently in yours its a solid multiple milled or forged "star key way" as I used to make on shafts for hospital drying tumblers and washing machines, such one would not have any trouble to handle the force.
As you explained in your post from 29th, it sounds You are out of the area and have all experience and materials needed. Seeing the back ground it turns out to be a whole different story then the first reading inducted.
After rereading: It sounds good => Go for it!
I wish You luck, and would love to see the development and the results, perhaps in some step I can be of help. ...
So far the other days response.
...
Keep things simple is a good approach. Or as I say:"What is not in it cannot break / What cannot be adusted, cannot get disadjusted"
I frecuently come up with too much safety in my designs. Or in the words of a former US-boss, for whom I worked for 3 years:
"Sven, each time I encharge You a row boat, You hand me over a Bismark !"
Well he might have been right, but 98% of my designs still fullfil heavy duty work.
While he flushed his father's factory down the drain....
So far for today.
Best wishes
Sven
Hey, we're good, Sven no problem!
I lived in Europe for a time and the languages drove me nuts!!! Like in Germany, it doesn't much matter if you speak classical German, the locals have their own dialects with so many different local words that you cannot understand them.
In the Frankfurt area I met some young folks and we spent a lot of time together. I quickly found out that they could ONLY speak their local dialect, called 'Frankfurter' dialect, a localized language, and would get stumbled at proper German! Fortunately we could fall back to English and between 3 or 4 languages finally understand each other.
All of life and all of the world is a learning experience.
Yes, the 'splines' are grooves cut in a shaft lengthwise, as going from one end to the other end, and may be about 6" to 8" in length. More splines is stronger than less splines, even if the shaft with less splines has deeper splines or grooves.
You would see splines cut into the end of the driveshaft on a rear-engined car, at the transmission end of shaft. This allows it to slide back and forth as the rear axle moves up and down. Both the driveshaft and the universal joint or u-joint would have splines to let driveshaft move as needed.
