Universal joint angle on PTO

[fatjay]

Trying to figure out the max safe angle I can run my blower at. I'm working on changing to a hydraulic lift instead of depending on the 3pt. All hte cylinders I see have 6" or more, but I only need 3-4". I figured with 6" I could lift higher, but wouldn't want to lift to high while the blower is spinning and risk damage something.

 

[pmsmechanic]

If you go too high of an angle the pto will start making a rattle that will encourage you to lower the three point hitch to a quieter level. A few seconds of noise won't hurt the pto but running it steady like that will. If you can keep both u-joint angles the same the pto will be quieter.

 

[Texasmark]

If you go too high of an angle the pto will start making a rattle that will encourage you to lower the three point hitch to a quieter level. A few seconds of noise won't hurt the pto but running it steady like that will. If you can keep both u-joint angles the same the pto will be quieter.

That's the essence of the Constant Velocity Joint, like used in front wheel drive vehicles and I/O boat outdrives to name a couple.

I had a JD 530 baler, built in the '60's or thereabouts time frame that had no CV joint but had a U joint at both ends of the baler drive line. It was used with a draw bar adapter that forced the baler connection another foot out from the normal end of the bar. Reason was to keep the drive and driven lengths identical.

Later I downsized to a JD 375 roller and it had a u joint at the baler end of the drive line but had a CV joint at the tractor mounting end which accomplished the same thing without the drawbar adapter requirement.

Keeping the drive and driven paths the same length keeps the "drive and driven angles" (as pms stated) the same and keeps the lead-lag time (drive shaft position vs driven shaft position) to a minimum which is exactly what is accomplished with the CV joint.....so I read from reliable sources.

 

[jmc]

There's quite a bit on Google:

maximum universal joint angle

 

[fatjay]

Sorry I should have specified better. THe snowblower is a front mount, however it's lifted by a cable from the 3pt in the rear, which means I can't opperate htem independently. I'd like to switch the front blower to a hydraulic cylinder so I can put a blade on the 3pt and use them differently.

I googled it quite a bit, but kept getting pushed to jeep sites about angling driveshafts, with nothing conclusive. Some said 15*, some said 30*, some said 5*.

As long as it gives me a rattling warning that's good enough for me I think. Time to find a cylinder, spool valve, and some hoses.

 

[zzvyb6]

Most driveline PTO shafts containing Cardan type (cross) joints are limited for durability reasons to about 20 degrees or so unless the cross bearings are top quality. You can go higher (~30 degrees) IF the input and output shaft connections are co-linear (parallel) and co-planar (in the same 2D plane). This is difficult in many circumstances because the shaft input (or output) shaft is usually connected to an apparatus which does not stay in a plane and/or does not stay co-linear.

If the shafts are not co-planar (parallel but not aligned) a phase angle needs to be built into the inner shaft to correct the torque/moment vectors that define the driveline geometry.

Example of a zero phase shaft wou;d be a prop shaft on a truch where the tranny output is parallel to the rear end pinion and the pinion is lower than the transmission.

Example of a phased shaft in the steering intermediate shaft is FWD cars where the steering column is parallel to the steering gear pinion, but the column is offset to the left (not co-planar), So a phase angle of 10 to 35 degrees is built into the intermediate shaft.

There are several types of CV joints (tripods found in FWD cars to compensate for steer and camber angle changes to the wheel spindle while the transmission stays put) and so called double Cardans, which have two single cross yokes back to back. These will stand higher torque loads than the ball type, are cheaper to make, and do an OK job. You find these all around farm implements which run at several angles and are offset. My Kuhn Combo hay tedder has one of these because it runs two separate tow angles for raking or tedding.

 

[fatjay]

Thank you for that explanation, i'll need to think about it a bit more before I think i'll fully understand it.

 

[Fallon]

I googled it quite a bit, but kept getting pushed to jeep sites about angling driveshafts, with nothing conclusive. Some said 15*, some said 30*, some said 5*.

Fundamentally there isn't any difference in the construction between a drive shaft & PTO shaft. I've seen lifespan charts for PTO shafts around here somewhere. Basically increasing the angle x amount halved the life expectancy of the U joints for every increment. Think X was 5 degrees or something.

 

[Fallon]

Fundamentally there isn't any difference in the construction between a drive shaft & PTO shaft. I've seen lifespan charts for PTO shafts around here somewhere. Basically increasing the angle x amount halved the life expectancy of the U joints for every increment. Think X was 5 degrees or something.

Normand Inverted Snowblower - Page 4

 

[bigdeano]

You can buy spacers to shorten the stroke of hyd cylinders. I've seen them that are split and clamp over the rod so you don't have to take the cyl apart.