lengel's TIII Omni GLH progress (used to be spirit r/t)

[Reaper1]

Here's a paper that is specific to figuring out FBD's of geartrains.

http://www.asee.org/documents/sectio...ear-Trains.pdf

[lengel]

I would personally go with steel. I feel it is a bending problem more than a yield problem and all steels have the same general modulus of elasticity, just different yield points. Many times chromoly is used more as a marketing tool as the general public sees it as be superior without really understanding the problem. I agree that you should stick to straight bearings if you can as the passenger side isn't designed very strong axially. That being said I can't remember which direction the gear angle goes as you will only be loading one or the other side......unless you drive in reverse like JT does to break trannys. With a tapered set though, any axial deflection will also decrease preload and could introduce gear separation. Possible this is why straight bearings were used in the first place as the intermediate shaft has a tapered set on each side of it on the input shaft and diff. Just a thought.

If you want anything run through FEA or a deflection comparison done between the AL and steel just let me know Adam.

.

Thanks for your input DJ! I may take you up on that offer.

I'm liking this as a failure mode. At first I thought it made sense...1st gear is a torque multiplication of 12 roughly, the gear teeth are at 45 degree angles so that transmits half the force axially (?). So if the engine is outputting 100ftlbs at launch during wheel hop, you have a 600lb hammer whacking the bearing case at what 4 times a second for 3 to 5 seconds? Ouch.

But now that I think about it, the multiplication is not 12 to one because the ring and pinion arent in the game yet. So its more like 3 to 1 at most (which bearing pocket cracks? the input or int shaft? Which would put it at more like 150 lbs of force. And I'm not sure if 50% of the torque is really transmitted axially. Also, its not really like a hammer per se..its periodic but there are tires and suspension making it less of a "step" impact.

So what is cracking the bearing plate? Maybe its heat expansion reducing bearing clearance negative? Or maybe high torque is distorting the race and causing forces to focus in one spot or another?

I have never crack one yet, but if I remember correctly the web cracks between the intermediate shaft bearing bore and the input shaft bearing bore. It also cracks from the threaded backing plate holes down into the intermediate shaft bearing bore.

It's just the example he pulled the picture from...not a direct comparison to our transmission. It also depends on which way the shafts are spinning.

I don't know if this will work for everybody, but this looks like it's something out of a textbook and has force directions shown.

http://www.google.com/url?sa=t&rct=j...83829542,d.aWw

Thanks for the link!

[Ondonti]

Watch this video, that is what I did previously. The case is clearly supporting the driver side input shaft bearing like its what is taking the load in that shaft. It also makes sense when you look at some of the AWD differentials that only have a large bearing on the passenger side (the side that would load of it went passenger side input, driver side intermediate shaft, then passenger side diff loads). I own a few of these.

I watched the video and applied it to a picture someone posted of the gearsets sitting together (opposite from the picture I refered too). The top of the diff spins FWD in FWD gears (top of tire turns fwd) so the top of the intermediate shaft is spinning backwards and the top of the input shaft is spinning FWD with the engine.

There is also the issue of the passenger sleeve sliding off which is because the transfer shaft moves towards the drivers side when the bearing plate deflects from axial loads. People were previously conjecturing that the bearing was holding the sleeve when hot and preventing it from walking away over time.

The bearing is also pressed on TOWARDS the passenger side BUT if axial forces were toward the passenger side, it would pull the bearing off the shaft. It does the opposite, you want to press the bearing on the opposite direction that forces will go so you are not relying on friction or a clip to hold the bearing in place. Axial forces push the seat of the shaft against the inner race of the drivers ball bearing and the outer race of the ball bearing pushes against the retainer plate. The retainer plate pulls on the aluminum that it is fastened to and causes it to deflect/fail. The clip on the ball bearing is only for people launching in reverse, or wheelhop.

The video is pretty cool. Test rig with one helical gear only held in place by a spring, the other helical gear is solidly located. The more axial load, the more the sprung gear wants to walk away and compress the spring.

[lengel]

Model done.

[acannell]

Model done.

looks awesome!! must be a first...

I wonder why the large counterbore on the right isnt concentric with its bore? Or is that just an illusion

[lengel]

looks awesome!! must be a first...

I wonder why the large counterbore on the right isnt concentric with its bore? Or is that just an illusion

Thanks!
Must be a first for what?
The bore is offset. That is there for snap ring access. On the stock plate that bore intersects with the input shaft bearing bore. This is why I offset it.

[acannell]

Thanks!
Must be a first for what?
The bore is offset. That is there for snap ring access. On the stock plate that bore intersects with the input shaft bearing bore. This is why I offset it.

First solid model of the bearing plate that detailed ever made I would think...

[turboshad]

Can you get two more bolt holes in and thicken the bearing retainer plate a bit? The bearing retainer plate I would make out of 4130 etc. and heat treat it to get a good and hard surface.

[5DIGITS]

Working on the solid model.
With using tapered rollers it will put more load on the passenger side of the case not the end plate side. Straight cut gears would be awesome! Yes with straight cut gear tapered rollers on the intermediate shaft would be the way to go.

For reference only, I have a straight cut gear transmission based on the 525 platform and I will take some photos.
These were made for the IMSA GTU circuit and used within the Kal Showket GTU Daytona, the later Kal '99' Datona and the Joe Varde Champion Spark Plug car.
In conjunction with the straight cut gears, a near 1" diameter input shaft was used along with a tilton multi-disc clutch/automatic flex plate arrangement to greatly minimize inertia while the multi-disc provided the necessary clamp load.
I will post pics of the hardware as I round it all up, just for reference and if it helps.
The trans I have does not have the interchangeable gear pack but later units did.
These had input shaft gears that could be changed and held in place via snap rings to provide a means of controlling the ratio spread, depending on the track requirements.

The cost in doing the straight cut gear arrangement is ridiculous as previously indicated ($30k if recalled correctly back in the 80's for a handful of prototypes) but it did eliminate the axial loading described throughout the this thread.
With this, I do believe "Lengel" is on the right track with the thicker plate as adding welded gussets (both internally and externally) is one of the only few other remaining options.
A few pics of the cars that used the straight cut 525 geared transmissions is included, just for reference.

[Reaper1]

I remember reading the story behind the transmission in the "Wraith" car. It didn't specifically say what was done except that it was highly modified because they kept grenading (525 based). I remember it said they used one of the race transmission companies to get it up to par and it was modified to have a spray bar sort of lubrication/cooling system.

Is this something that found its way onto the GTU cars as well?

A little off topic, but it looks like the power steering pump is driven off of the cam.

[lengel]

Can you get two more bolt holes in and thicken the bearing retainer plate a bit? The bearing retainer plate I would make out of 4130 etc. and heat treat it to get a good and hard surface.

I may be able to get more then two if i countersink the holes and use flat head bolts. What are your thoughts about using flat heads?

For reference only, I have a straight cut gear transmission based on the 525 platform and I will take some photos.
These were made for the IMSA GTU circuit and used within the Kal Showket GTU Daytona, the later Kal '99' Datona and the Joe Varde Champion Spark Plug car.
In conjunction with the straight cut gears, a near 1" diameter input shaft was used along with a tilton multi-disc clutch/automatic flex plate arrangement to greatly minimize inertia while the multi-disc provided the necessary clamp load.
I will post pics of the hardware as I round it all up, just for reference and if it helps.
The trans I have does not have the interchangeable gear pack but later units did.
These had input shaft gears that could be changed and held in place via snap rings to provide a means of controlling the ratio spread, depending on the track requirements.

The cost in doing the straight cut gear arrangement is ridiculous as previously indicated ($30k if recalled correctly back in the 80's for a handful of prototypes) but it did eliminate the axial loading described throughout the this thread.
With this, I do believe "Lengel" is on the right track with the thicker plate as adding welded gussets (both internally and externally) is one of the only few other remaining options.
A few pics of the cars that used the straight cut 525 geared transmissions is included, just for reference.

Wow awesome info and pics. Thanks for sharing! Wish those straight cut gear were not so pricey

[OmniLuvr]

SUBSCRIBED!

plus, not to get off track, but 5digits what "body" car is the first engine pic of, the champion plug charger or the Daytona?

and this thread is full of win! go lengel!

[zin]

I'd like to suggest, if FEA is done, to include 7075 Aluminum in the mix. It's a bit less common, but has a strength similar to mild steel, so but but with the weight savings of AL.

Mike

[lengel]

SUBSCRIBED!

plus, not to get off track, but 5digits what "body" car is the first engine pic of, the champion plug charger or the Daytona?

and this thread is full of win! go lengel!

Thanks!

I'd like to suggest, if FEA is done, to include 7075 Aluminum in the mix. It's a bit less common, but has a strength similar to mild steel, so but but with the weight savings of AL.

Mike

Yes I would like a FEA done with 7075 as well for the same thoughts that you have.

[BadAssPerformance]

I agree it would be good to look at Al options too. beyond mass and strength steel still might have the advantage for flexibility / crack resistance

[lengel]

Can you get two more bolt holes in and thicken the bearing retainer plate a bit? The bearing retainer plate I would make out of 4130 etc. and heat treat it to get a good and hard surface.

Looking at It a little closer today. There's no need to use a flat head bolt. Regular blots will work just fine, and it look like I could add as many bolts as needed. I like the hardened plate idea too.

[Ondonti]

Model done.

What exactly is going on with the bearing retainer plate having only 3 of the 4 original holes? I don't see the one FWD of the input shaft.

[BadAssPerformance]

What exactly is going on with the bearing retainer plate having only 3 of the 4 original holes? I don't see the one FWD of the input shaft.

I think lengel's design incorporates the input shaft retainer directly into the man plat so the backup plate is only needed on the intermediate shaft. I think this is where the discussion is to have more bolts holding it on and c-sink bolts if needed.

[lengel]

^ yes this

[lengel]

Making progress! Got the first side done today with all the bores done and sized. Also test fit it on the trans to make sure the pins lined up.