Custom golf cart

[Oldskool 6,585]

1 hour ago, Handy Don said:

 

If it had squared corners, it’d be about 6.8 gallons. Since it’s a bit beveled on the sides, figure 6.5.

Nice!

Remember that gas weighs about 6 lbs per gallon (plus the tank itself) so you’ll need strong supports!

Thanks for the calculations Don. That should be plenty of fuel for this.

 

Yes a must on the mounts. Plus adding in the fact of being on the back end. 

[bmsgaffer 2,043]

Watch those generator gas tanks. Just had to replace one on my generator that rusted between the seam and started seeping fuel. Not sure if it had a bad weld or was just tired. Dang thing had less than 10 hours on it. 

 

Edit to note: The inside of the tank looked mint, so I never suspected it. Just started seeping out enough to keep the bottom of the tank looking 'wet' with no drips, just fumes. 

Edited March 6, 2023 by bmsgaffer
Add note.

[Oldskool 6,585]

5 hours ago, bmsgaffer said:

Watch those generator gas tanks. Just had to replace one on my generator that rusted between the seam 

 

 Just started seeping out enough to keep the bottom of the tank looking 'wet' with no drips, just fumes. 

Good to know. Thanks. I'll pressure check that one. I may have a plastic one. Maybe I'll try to find it. 

[Handy Don 10,703]

13 hours ago, Oldskool said:

Thanks for the calculations Don. That should be plenty of fuel for this.

 

Yes a must on the mounts. Plus adding in the fact of being on the back end. 

I’m confident this will be up to your usual high standards. 

Edited March 6, 2023 by Handy Don

[Oldskool 6,585]

@Handy Don what are your thoughts on a hydraulic motor turning an automotive standard type transmission for this build?

[Pullstart 59,958]

I’m not Handy or Don, but I’d say as long as the motor has the umph to turn the transmission, and as long as it has a pillow block bearing somewhere to support the input shaft, it should do the trick!

[Oldskool 6,585]

1 hour ago, Pullstart said:

I’m not Handy or Don, but I’d say as long as the motor has the umph to turn the transmission, and as long as it has a pillow block bearing somewhere to support the input shaft, it should do the trick!

I'm curious of the mph vs speed vs torque from such a set up. 

Not knowing much about hydraulics

gal. vs preasure. I'm not sure how big of a motor would be necessary.

[Handy Don 10,703]

1 hour ago, Oldskool said:

I'm curious of the mph vs speed vs torque from such a set up. 

Not knowing much about hydraulics

gal. vs preasure. I'm not sure how big of a motor would be necessary.

i know that you “acquired” several hydraulic motors on a big Toro mower. Gonna go dig that up to remind myself of what they could do.

 

I can think of three things to look at in the setup you envision:

- motor output capability (horsepower it can deliver to the rear end at what pressure and across what working range of RPM)

- RPMs needed for the rear end to get the speed desired from the cart

- pump capacity (volume and pressure) it can deliver

 

To me, it is an idea worthy of some calculations, for sure.

For example, if the motors you have are possibles but maybe individually too weak, perhaps slaving two together to drive a single input to the rear end would work (assuming adequate pump volume & pressure).

 

[8ntruck 6,445]

 Start with deciding what you want the vehicle to do - speed, climbing ability, etc.  Will also need the tire diameter and transmission gear ratios to work out input torque and rpm. 

[Oldskool 6,585]

7 hours ago, 8ntruck said:

 Start with deciding what you want the vehicle to do - speed, climbing ability, etc.  Will also need the tire diameter and transmission gear ratios to work out input torque and rpm. 

20mph-ish would be fine.

I believe the tires are 26in.

and if memory serves me correctly the rear is 3.73

I'm not sure at the moment which transmission I have but here are the available ratios.

[Pullstart 59,958]

I had a thought.  How would you disconnect the hydro motor from the trans for coasting?  I don’t believe they like to be driven by the vehicle… so it would be quite urgent stops from back pressure wouldn’t it?

[Handy Don 10,703]

1 hour ago, Pullstart said:

I had a thought.  How would you disconnect the hydro motor from the trans for coasting?  I don’t believe they like to be driven by the vehicle… so it would be quite urgent stops from back pressure wouldn’t it?

Depends on the motor/pump combination, of course, but this is one part of why hydrostatics have bypass valving built in.

[8ntruck 6,445]

I'll grind on those numbers this afternoon after I walk the dog.

 

@Pullstart - I'm in Mi for a quick trip.  You see me wave when I flew by last night?

 

Just sitting here drinking espresso while waiting for home test Covid result.

 

ALL RIGHT!  It is negative!  

 

Looks like those anti viral horse pills they prescribed helped.

[Pullstart 59,958]

7 minutes ago, 8ntruck said:

 - I'm in Mi for a quick trip.  You see me wave when I flew by last night?

 

Did you bring all this white fluffy stuff?

[Handy Don 10,703]

3 hours ago, Handy Don said:

Depends on the motor/pump combination, of course, but this is one part of why hydrostatics have bypass valving built in.

In a recent thread (below), I posted how the acceleration valves in an Eaton 1100 could affect un-powered movement. Sunstrands have “overpressure” bypass valving for the pump circuit but I’m fairly sure not for the motor side. The Sunstrands also have a manual bypass valve to allow pushing.

Absent something like these, an engaged hydraulic pump/motor combo is much like having a geared tractor be in gear--always directly coupled (there is nearly always going to be a small amount of internal fluid “leakage” past both the pump and the motor internals--the makers accept this loss since it reduces internal friction/wear and also helps cool the mechanicals).

 

 

 

[Oldskool 6,585]

5 hours ago, Pullstart said:

I had a thought.  How would you disconnect the hydro motor from the trans for coasting?  I don’t believe they like to be driven by the vehicle… so it would be quite urgent stops from back pressure wouldn’t it?

 

3 hours ago, Handy Don said:

Depends on the motor/pump combination, of course, but this is one part of why hydrostatics have bypass valving built in.

The coasting aspect wasn't even a thought. Good point. That could make it even harder for the wife to drive.

 

Maybe a selectable bypass valve could be incorperated?

 

I'm grasping at straws here so please bear with me lol

[Pullstart 59,958]

3 minutes ago, Oldskool said:

 

The coasting aspect wasn't even a thought. Good point. That could make it even harder for the wife to drive.

 

Maybe a selectable bypass valve could be incorperated?

 

I'm grasping at straws here so please bear with me lol

You could still run a clutch.  That would be cool.  Easier to shift on the fly, or what have you.

[Oldskool 6,585]

6 minutes ago, Pullstart said:

You could still run a clutch.  That would be cool.  Easier to shift on the fly, or what have you.

One of my first thoughts was a belt drive clutch to the 3speed. 

Then the thought of possibly a CVT clutch to the trans.

Then I had a thought of using a WH hi/lo transaxle with the axle shaft driving a driveshaft.

Although I think the WH would never give me any usable speed worth the effort

[Pullstart 59,958]

12 minutes ago, Oldskool said:

One of my first thoughts was a belt drive clutch to the 3speed. 

Then the thought of possibly a CVT clutch to the trans.

Then I had a thought of using a WH hi/lo transaxle with the axle shaft driving a driveshaft.

Although I think the WH would never give me any usable speed worth the effort

Well, I know one power transmission system that doesn’t work… 

 

 

[Handy Don 10,703]

41 minutes ago, Pullstart said:

Well, I know one power transmission system that doesn’t work… 

 

Actually, its the small final drive pulley that put the kibosh on the snow tractor, IMO. But if you’re fed up with it, I think a lot of those parts might fit really nicely in the golf cart mod! 

 

A pedal linked to the motion control valve on the hydro pump/motor setup would drive a lot like a hybrid electric car that uses strong regeneration to decelerate. Case and other GTs used a setup like this on some models. Very strong and reliable but the knock was that they could be sensitive to control at start/stop because they didn’t have acceleration valves (Eaton had a patent on the economical version of those valves and wasn’t sharing!) They had to use fairly wide-bore valves to allow more fine control and they get pricey.

 

A torque converter drive coasts quite well because it “auto shifts” to the “highest gearing” when the vehicle speed overruns the engine speed and above that you get belt slip. No useful engine braking, of course!

 

[Oldskool 6,585]

3 hours ago, Pullstart said:

Well, I know one power transmission system that doesn’t work… 

 

I have one of those as well. I don't  really need two

[Pullstart 59,958]

Has @tractorchick Kate seen “The Yeti”?

 

 

https://www.wheelhorseforum.com/topic/89905-project-snow-drift/

 

Edited March 10, 2023 by Pullstart

[Oldskool 6,585]

14 minutes ago, Pullstart said:

Has @tractorchick Kate seen “The Yeti”?

 

 

https://www.wheelhorseforum.com/topic/89905-project-snow-drift/

 

I do not think so.

[Oldskool 6,585]

I did have about 30min in the shop tonight before things got in the way.

A good start on the dash. I may just polish to a lite luster, maybe machine turn it. Possibly another finish if I can find a different process.

[8ntruck 6,445]

Ok.  Been number crunching.

 

A 26" tire will run at 259 rpm at a vehicle speed of 20 mph.

 

You will need to turn the input shaft of the 3.73 diff at 966 rpm to do that.

 

If I were building this, I would use the 'three line' version of thetrans.  Those ratios give calculated speeds at 966 rpm input speed as:

 

1st gear - 5.7 mph

2nd gear - 10.5 mph

3rd gear - 20 mph

 

966 rpm axle input speed is the key number for design going forward.

 

If you are planning on using the hydro motors from the 'big Toro mower', we will need to know what kind of gearing was between the hydro motor to see what the original operating range was for the motors.  Motor displacement and pump displacement would be handy numbers to have for the next level of calculations.

 

@Pullstart I was trying to stay ahead of that system as I was travelling yesterday.  I think the system was drafting me!