Diff types

[Greg Hermann]

>OK Jim,
>
>Must ask, what's hypoid gearing?  Sounds interesting....
>
>Off-list, if ya must!
>
>Thanks!
>
>Todd....

Straight bevel and spiral bevel (basically the bevel gear analogue to
helical tooth conventional gearing) gearing--the centerline of the pinion
intersects the centerline of the ring gear. Pitch surface (theoretical
tooth contact surface) is a pair of cones. No sliding contact between
teeth--all rolling contact.

Hypoid gearing-the centerline of the pinion passes above or below (usually
below, exception in "RR" (reverse rotation) front axle units). Pitch
surface is a pair of hyperboloids of revolution. Sliding contact exists
between the gear teeth, the further the pinion centerline misses the ring
gear centerline by (for a given ring gear diameter), the more sliding
exists (and the bigger the friction losses and heat build-up become). This
sliding contact is the reason WHY you need a "hypoid" type gear oil, with
the EP (extremee pressure) additive package in it for hypoid gears.

Gleason (in Rochester, NY) is the leading (only??) manufacturer in the
world of machinery for cutting hypoid gears.

Regards, Greg
>
>Jim Davies wrote:
>>
>> On Wed, 2 Jun 1999, SPECTRO COATING CORP. wrote:
>>
>> > Actually - Torsen was the manufacturer - Bob (I think that's his first
>>name)
>> > Gleason invented that differential design. Zexel was the manufacturer
>>last i
>> > knew.
>> >
>> Last name was actually Gleasman, but he changed it to Gleason. Also known
>> for hypoid gearing...