Centre differentials with uneven torque split (planetary)
Centre differentials with uneven torque split (planetary)
(OP)
Hi,
I can't get my head around how torque is split unequally using a planetary centre diff(e.g. 30-70% f/r ratio). The fundamental laws of gearing say that for a given gear ratio, the increase in torque is inversely related to the rotational speed. However for 70% of torque to go to the rear axle it must rotate faster than the front axle (as defined by tyre characteristics).
What causes the torque to be split unequally? And how is this linked with the rotational speeds?
I have read design of machinery and Mechanisms and Dynamics of mechanics but still don't understand it.
Thanks a lot!
I can't get my head around how torque is split unequally using a planetary centre diff(e.g. 30-70% f/r ratio). The fundamental laws of gearing say that for a given gear ratio, the increase in torque is inversely related to the rotational speed. However for 70% of torque to go to the rear axle it must rotate faster than the front axle (as defined by tyre characteristics).
What causes the torque to be split unequally? And how is this linked with the rotational speeds?
I have read design of machinery and Mechanisms and Dynamics of mechanics but still don't understand it.
Thanks a lot!
RE: Centre differentials with uneven torque split (planetary)
Now, visualize the bevel gear diff, and unwrap it in your mind, retaining but distorting its topology so that the bevel gears become spur gears. So, it's morphed into a planetary.
Having done that, you can maybe appreciate that if you juggle the gear ratios, the planetary diff can have a split other than 50/50.
Mike Halloran
Pembroke Pines, FL, USA
RE: Centre differentials with uneven torque split (planetary)
First for a 50-50% as found in bevel diff
| Ring
_ = _
Planet 1 | | |Planet2
=---------= Spider
| |
= =
sun1 going to front | | Sun2 going to rear axle
----- ------
And now with sun2 larger, causing larger torque output to the rear?
| Ring
_ = _
Planet 1 | | |Planet2
=---------= Spider
| |
= =
sun1 going to front | | Sun2 going to rear axle
----- |
------
RE: Centre differentials with uneven torque split (planetary)
RE: Centre differentials with uneven torque split (planetary)
Regards
Pat
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RE: Centre differentials with uneven torque split (planetary)
Maybe that is where you're getting tripped up?
Under normal circumstances, the gears aren't moving, so they become little more than odd-looking levers.
RE: Centre differentials with uneven torque split (planetary)
http://www.bib-nakladnistvo.hr/integralediff.pdf
Cheers
Greg Locock
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