Worm gear assembly for drive axle
AssigneeMeritor Heavy Vehicle Systems, LLC
InventorYakov Fleytman
Life of this patent
Estimating the term…
Abstract
A drive axle assembly for a vehicle receives input torque from an engine via an input shaft. The input shaft drives a worm which in turn drives a worm gear. The worm gear includes teeth which engage and drive an axle shaft which in turn drives a vehicle wheel. The teeth of the worm gear are defined by a tooth profile which has two pressure angles, one on each side of the tooth. The worm includes a thread with a thread profile that also has two pressure angles, one on each side of the thread. One of the pressure angles on the thread of the worm is greater than its other pressure angle and one of the pressure angles on the worm gear teeth is greater than its other pressure angle.
Claims15
A drive axle assembly comprising:
- first and second driven wheels;
- first and second axle shafts for driving said first and second wheels respectively, said first and second axle shafts defining a first axis of rotation;
- a worm gear for driving said first and second axle shafts and rotatable about said first axis of rotation, said worm gear having teeth defined by a tooth profile having a first worm gear pressure angle and a second worm gear pressure angle wherein said first worm gear pressure angle is twice said second worm gear pressure angle;
- a worm for driving said worm gear and defining a second axis of rotation substantially perpendicular to said first axis of rotation, said worm including at least one thread having a worm thread profile with a first worm pressure angle and a second worm pressure angle wherein said first worm pressure angle is twice said second worm pressure angle;
- and
- an input shaft for driving said worm, said input shaft rotating about said second axis of rotation.
A worm gear assembly for a drive axle comprising:
- a worm gear rotatable about a first axis of rotation, said worm gear having teeth defined by a tooth profile having a first worm gear pressure angle and a second worm gear pressure angle wherein said first worm gear pressure angle twice said second worm gear pressure angle;
- and
- a worm for driving said worm gear and defining a second axis of rotation substantially perpendicular to said first axis of rotation, said worm including at least one thread having a worm thread profile with a first worm pressure angle and a second worm pressure angle wherein said first worm pressure angle is twice said second worm pressure angle.
A worm gear assembly for a drive axle comprising:
- a worm gear rotatable about a first axis of rotation, said worm gear having teeth defined by a tooth profile having a first worm gear pressure angle and a second worm gear pressure angle wherein said first worm gear pressure angle exceeds said second worm gear pressure angle;
- and
- a worm for driving said worm gear and defining a second axis of rotation substantially perpendicular to said first axis of rotation, said worm including at least one thread having a worm thread profile with a first worm pressure angle and a second worm pressure angle wherein said first worm pressure angle exceeds said second worm pressure angle;
- said thread of said worm being defined by a first curve, a second curve, a third curve, and a fourth curve, wherein said first curve is defined by the equations
- X1=(AC-(b *cos(t*p-M')))*sin(t*k)
- Y1=(AC-(b * cos(t * p-M')))*cos(t*k)
- Z1=b*sin(t* p-M'),
- said second curve is defined by the equations
- X2=(AC-(b *cos(t * p+M")))*sin(t*k)
- Y2=AC-(b * cos(t * p+M")))*cos(t*k)
- Z2=b*sin(t*p+M"),
- said third curve is defined by the equations
- X3=(AC-(b.sup.i *cos(t * p-M')))*sin(t*k)
- Y3=(AC-(b.sup.i * cos(t * p-M')))*cos(t*k)
- Z3=b.sup.i *sin(t* p-M'),
- and said fourth curve is defined by the equations
- X4=(AC-(b.sup.i *cos(t * p+M")))*sin(t*k)
- Y4=(AC-(b.sup.i *cos(t * p+M")))*cos(t*k)
- Z4=b.sup.i *sin(t* p+M"),
- wherein (X1, Y1, Z1), (X2, Y2, Z2), (X3, Y3, Z3), and (X4, Y4, Z4) represent a three dimensional coordinate for the first, second, third, and fourth curves respectively, AC represents a distance between a center for said worm and a center for said worm gear, b represents the pitch radius of said worm gear, t represents a variable from zero to one, p is equal to k divided by the number of said teeth on said worm gear, M' and M" represent angles of a tooth on said worm gear, k is equal to three hundred sixty degrees divided by the number of threads on said worm, and b.sup.i represents a distance greater than b.
Dependencies are inferred from the claim text.