Expanded timing between gear trains of differentials
AssigneeZexel-Gleason USA, Inc.
InventorShiro Ichiki
Life of this patent
Estimating the term…
Abstract
A gear differential having multiple gear trains interconnecting a pair of output shafts is provided with an arrangement of gearing having an expanded relationship between tooth numbers of the gearing for fitting the gear trains into mesh. The gearing includes two side gears (20 and 21) coupled to respective output shafts and three pairs of combination gears (24 and 25, 26 and 27, and 28 and 29) for interconnecting the two side gears. Each of the combination gears includes a middle gear portion (40) and two end gear portions (42 and 44). The middle and end gear portions have respective numbers of teeth that share a greatest common factor (GCF) that is more than one but less than the number of teeth in the middle gear portion.
Claims12
A differential having compound planetary gearing assembled without reference marks applied to the gears comprising:
- a housing rotatable about a pair of drive shafts;
- side gears disposed within said housing for rotation with said drive shafts;
- pairs of combination gears separately interconnecting said side gears for rotation in equal amounts but in opposite directions with respect to said housing;
- each of said combination gears including a first gear portion for meshing with one of said side gears and a second gear portion for meshing with another combination gear;
- each of said side gears including "N.sub.s " number of teeth, said first gear portion of each combination gear including "N.sub.c1 " number of teeth, said second gear portion of each combination gear including "N.sub.c2 " number of teeth, and said numbers of teeth N.sub.c1 and N.sub.c2 in the first and second combination gear portions having a greatest common factor "GCF" that is greater than one but less than said number of teeth N.sub.c1 in the first combination gear portions;
- and
- each of said side gears being independently rotatable with respect to said housing through a predetermined amount of backlash "B" in degrees,
- wherein said factor GCF, said number of gear teeth N.sub.c2 in the second gear portions, and said number of side gear teeth N.sub.s are related to backlash B according to the following inequality:
- ##EQU8## .
A differential gear assembly comprising:
- a housing rotatable about a pair of drive shafts;
- side gears disposed within said housing for rotation with said drive shafts;
- pairs of combination gears separately interconnecting said side gears for rotation in equal amounts but in opposite directions with respect to said housing;
- each of said combination gears including a middle gear portion for meshing with one of said side gears and two end gear portions for meshing with another combination gear;
- said two end gear portions having respective spur gear teeth that are indexed with respect to each other through one-half circular pitch of said end gear portions;
- and
- at least one but not all teeth of said middle gear portions having midpoints of circular tooth thickness that lie equidistantly between corresponding midpoints of said spur gear teeth that span said one-half circular pitch index between the end gear portions.
Dependencies are inferred from the claim text.