2 Speed Gearbox

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CZal
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Post by CZal » Mon, 25 May 2009, 15:39

Sorry, that last post was a bit off topic... that only applies if you are planning on a 4wd conversion and the transfer case is already there... It's not really the right shape for a RWD gear box...

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Post by acmotor » Mon, 25 May 2009, 17:52

Transfer case may suit city / country pre selection.
CZal wrote: How about your transfer case Tuarn? for those of us who don't mind coming to a complete stop to shift down.... can you shift up while on the move?


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Post by mikedufty » Mon, 25 May 2009, 22:12

The subaru dual range boxes can be shifted on the move. Not sure what they do different to others.
Interesting that in the old part time 4WD subarus the warnings about using 4wd on hard surfaces are really weakly worded, like "if you feel the transmission winding up or the steering resisting you should probably consider changing back to 2WD" whereas in Land cruisers it's more like "don't even look at the 4WD lever while on the bitumen or the car will explode."

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Post by fuzzy-hair-man » Mon, 25 May 2009, 23:14

mikedufty wrote: The subaru dual range boxes can be shifted on the move. Not sure what they do different to others.
Interesting that in the old part time 4WD subarus the warnings about using 4wd on hard surfaces are really weakly worded, like "if you feel the transmission winding up or the steering resisting you should probably consider changing back to 2WD" whereas in Land cruisers it's more like "don't even look at the 4WD lever while on the bitumen or the car will explode."
Perhaps the two issues are related, subarus are generally light with little tyres that given a big force would more easily slip and give before destroying a transfer case, so perhaps subaru could put a dog clutch on the transfer case.

If you are in a LandCruiser or big 4wd you have lots of weight lots of inertia and big wide tyres which means the tyres might be less inclined to slip or scrub off any difference in speed and will instead concentrate on destroying your transfer case.

This might also mean the understeer tendencies of the subaru might be noticable but controllable, but the first warning you might get in a big 4wd might be once it's steered you into a tree?

I guess a parallel could be seen between the gearboxes in some? motorbikes and car gearboxes the motorbikes seem happy enough with dog clutches and not using the clutch for gear changes, car gearboxes need the clutch and synchros etc to handles gear changes.

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Post by aversion » Mon, 25 May 2009, 23:41

Image I probably should have been a bit more detailed with my initial post! Half asleep from sitting through the f1 procession.
Realizing that is is an overdrive (not an underdrive unit) I meant to ask if it would be possible to replace one of the gears to get your required ratio and use that rather than going to the effort (and perhaps expense) of creating a new gearbox from scratch.

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Post by AMPrentice » Wed, 27 May 2009, 17:23

I understand all you need is a highly geared differential on a rwd to use the overdrive that way if you are using say a hilux 5.1 the overdrive will allow
extra legs as the speed rise. Essentially lowering engine revs.
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Post by DeepGreen » Tue, 23 Jun 2009, 04:22

Hi, you I saw a while back you were looking for masterflux siera airconditioning, did you have any luck finding a supplier and prices.

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Post by DeepGreen » Tue, 23 Jun 2009, 04:23

sorry, forgot to put who I was talking to

acmotor ... did you ever find out about masterflux siera airconditioning?

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Post by acmotor » Tue, 23 Jun 2009, 05:51

Did someone wake me up ??? Image Image

I did email masterflux some time back.
Prices were around US$1,000 and they didn't have a 600V version.

This still needed to be plumbed into a system and would be great if you felt so inclined.

http://www.masterflux.com/products/sierra/

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Post by zeva » Tue, 23 Jun 2009, 06:02

We've chatted about them a bit at EV Works meetings and might bring some over. They are a more elegant solution for EVs than reusing the old mechanical compressors but yes, a pretty expensive way to go once you include the necessary inverter.

I'm very interested to pursue reverse cycle A/C in EVs because it's also a great way to heat the cabin (heat pumps are ~3x more efficient than electric heaters!)

I hope to put reverse cycle in my MX5, but will probably just drive the old A/C compressor off the motor's tailshaft via pulley (the cheapest way to go!)

Edit: Actually I have to check the legalities - since my MX5 is direct drive, I wouldn't be able to run the compressor if the car is stationary.. which may be illegal since I couldn't demist the windscreen before driving off! In which case I will indeed have to go for one of the electric compressors.
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Post by Johny » Tue, 23 Jun 2009, 16:06

I think I have posted this before but have you looked at the air conditioning offerings here?
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Post by acmotor » Wed, 24 Jun 2009, 06:58

zeva wrote: ........
Edit: Actually I have to check the legalities - since my MX5 is direct drive, I wouldn't be able to run the compressor if the car is stationary.. which may be illegal since I couldn't demist the windscreen before driving off! In which case I will indeed have to go for one of the electric compressors.


There is no requirement to demist windscreen before driving off ???? just that you "can demist it" since most ICEs would take 5 minutes or more before there is enough heat from hot water demister on a cold day and there is no interlock to stop you driving off !

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Post by woody » Tue, 07 Jul 2009, 20:53

Over in another thread the DIY electric car thread mentions a Suzuki transfer case (Sierra = Samurai)
diyelectriccar wrote:The rear differential has a ratio of 3.8:1. To reduce this, I have used a transfer box from a Suzuki SJ410 (similar to a Samurai). Being normally driven by the gearbox, this should be able to handle the torque. It has a high range reduction of 1.6:1 and low range of 2.5:1 - which is close to perfect for the application.
The transfer box is very light weight - 15kg or so and has bolt together flange type input and output - so very easy to adapt to. I turned up a quick adapter for the motor shaft (keyed) and bolted it straight on to the transfer box.
So acmotor, Red Suzi has one of these. You could take it out, for an increased top speed / reduced acceleration - about the same as a Star/Delta rewind.

Can you shift on the fly? (is your front driveshaft still out?)
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Post by acmotor » Wed, 08 Jul 2009, 01:39

Woody, no shift on the fly or the teeth will fly !

Transfer case in red suzi also has the handbrake drum and speedo pickup integrated so more trouble to remove it and satisfy DPI about the changes.
I have considered removing it but then also lose the 4WD ability. (front shaft is fitted from transfer case to front diff.)

I would not be happy with half the torque at rear wheels so I am going the rewire motor to lower voltage direction. i.e. same torque, double rev, double power. (unless I go for 1/4 voltage then 4x revs, 4x power)(and 4 x controller current)
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Post by Squiggles » Wed, 08 Jul 2009, 03:19

If the handbrake is on the transfer case, would the car roll if you jacked a wheel up when parked on a slope?

I ask because I had thought about having a parking brake on the motor shaft, talked myself out of it as I figured the diff would allow movement when a wheel was off the ground.
Last edited by Squiggles on Tue, 07 Jul 2009, 17:20, edited 1 time in total.

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Post by acmotor » Wed, 08 Jul 2009, 05:49

Yep, but as most zook (and other 4WDs like Landys) know... engage 4WD before jacking, that way 2 wheels (one front and one rear) would have to be off the ground for there to be a problem.

In some 4WDs like disco you should lock centre diff for safe jacking.

I'm not certain of the logic of transfer case handbrakes on some 4WD. Makes sense on a disco with 4 wheel discs but not on sj40 with all drums. Maybe the thinking is because the handbrake effectively operates on all 4 wheels, not just rear ? I just say that REAL 4WDs have transfer case handbrakes because all of mine do !!

All this raises the point again that EVs need two park brakes. Handbrake and parking pawl in a gearbox.
So... desirable option for your 2 speed gearbox topic in this thread. Image
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Post by bga » Fri, 10 Jul 2009, 20:22

The park lock has been bothering me for a while.

EV motors turn freely, so it's like leaving the gearbox in neutral. For direct to diff drive, the problem is more obvious.

I was thinking about how to arrange a 'Park' lock, like an automatic gearbox has. The thought was to bolt a pawl set onto the back of the motor (3PH IM) and a slotted disk to the output shaft. My concern with this is engaging it while rolling with the shock of the pawls dropping in trashing the rear bearing on the motor.

Perhaps a cable actuated disk or drum brake can be put on the back of the motor and serve the purpose of the 'Park' brake. I was thinking of the drum brakes off the rear of a small car, ignore the hydraulics.
With the diff between it and the rear wheels, not very much holding torque (500Nm?) is needed.

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Post by Squiggles » Sun, 12 Jul 2009, 04:07

bga wrote: The park lock has been bothering me for a while.

EV motors turn freely, so it's like leaving the gearbox in neutral. For direct to diff drive, the problem is more obvious.

I was thinking about how to arrange a 'Park' lock, like an automatic gearbox has. The thought was to bolt a pawl set onto the back of the motor (3PH IM) and a slotted disk to the output shaft. My concern with this is engaging it while rolling with the shock of the pawls dropping in trashing the rear bearing on the motor.

Perhaps a cable actuated disk or drum brake can be put on the back of the motor and serve the purpose of the 'Park' brake. I was thinking of the drum brakes off the rear of a small car, ignore the hydraulics.
With the diff between it and the rear wheels, not very much holding torque (500Nm?) is needed.


Some motors have a brake option which is basically what you describe. It still leaves the problem of not being safe if one of the driven wheels is jacked off the ground. The diff will allow the other wheel to rotate and the car could come off the jack....potential disaster.

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Post by Tritium_James » Sun, 12 Jul 2009, 14:05

That's potentially a problem for lots of cars, and if you're jacking a wheel you should always chock the opposite one and not rely on the transmission or handbrake.

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Post by Squiggles » Sun, 12 Jul 2009, 17:33

Absolutely correct, never rely on the transmission and parking brakes are not always the best. Always chock the wheel.
Some cars used to come with wheel chocks in the service kit. Now they come with a 1300 number instead!!

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Post by Sparky Brother » Sun, 12 Jul 2009, 19:47

I was just thinking on the same issue. How about the pawl engaged by and when the hand brake is pulled up. Nobody pulls up the hand brake while driving so no worries on something being destroyed by mistake. And just to stay on the safe side I would add a lock up solenoid to prevent the pawl from getting engaged even by mistake. The release button of the hand brake seems perfectly good for this dual operation.

P.S.
Correction! in this case I suppose I should be talking specifically about my conversion. The fact is the Daihatsu Feroza has drums on the back wheels so I have the option of keeping the hand brake set and the pawl setup will be somewhat the GB in 1st gear with an ICE is.
Last edited by Sparky Brother on Sun, 12 Jul 2009, 09:55, edited 1 time in total.

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Post by grub » Fri, 28 Aug 2009, 00:30

I used to own a little Suzuki 4wd and it had a stand alone transfer case (low and high). Something similar could be used as a gearbox and there is no law (yet) that says you have to use both output shafts.
On a different note, washing machines use a 2 speed gearbox. They have 1:1 direct drive for spinning or go through the box to reduce speed for washing. Not strong enough for a vehicle but the concept is there.

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Post by acmotor » Fri, 28 Aug 2009, 00:36

yep, I have that transfer case in the red suzi. Quite useful at times and incredibly strong (so far). I've put 300+Nm into it.
It also has the advanatage of a drum parking brake on the output shaft.
It is a stand alone with uni joint flanges input and outputs. Image

edit: just can't change ratio on the fly !
Last edited by acmotor on Thu, 27 Aug 2009, 14:37, edited 1 time in total.
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Post by Electrocycle » Fri, 28 Aug 2009, 01:18

grub wrote:On a different note, washing machines use a 2 speed gearbox. They have 1:1 direct drive for spinning or go through the box to reduce speed for washing. Not strong enough for a vehicle but the concept is there.
And some newer washing machines have a large diameter PMAC motor driving the drum directly :)
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Post by EV2Go » Fri, 28 Aug 2009, 03:32

I contacted the guys at Black Box last week and they said they don’t recommend changing gears above 15 kph; I am waiting to hear back if they have any info on a RPM limit instead, since using it directly behind a motor won’t have any gear reduction which it may if it followed a gearbox.
It will take some creative thinking to come up with a gearbox that changes smoothly without a clutch.

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