Compact planetary differential gear set arrangement

Abstract

A compact planetary differential gear set includes first ( 130 A) and second ( 130 B) sun gears, a first set ( 200 A) and a second set ( 200 B) of planet gears ( 220 ), and a carrier ( 160 ) with a ring gear ( 190 ). Enmeshing gear pairs ( 210 ) are formed from one planet gear from each set. The first and second planet gear sets enmesh the first and second sun gears, respectively. The ring gear does not extend into an annular region containing the planet gears thereby allowing four or more gear pairs to compactly fit into the annular region. The carrier is a weldment and substantially encloses the sun gears and the planet gears permanently. The differential requires no fasteners or post-weld machining and may have a higher capacity, lower cost, smaller size, lower part number count, and/or lower amounts of material compared with conventional differentials. The differential is suited for motor vehicle applications.

1 - 20 . (canceled) 
     
     
         21 . A planetary differential gear assembly having a first input/output, a second input/output, a third input/output, a first bearing mount, and a second bearing mount, the planetary differential gear assembly consisting essentially of:
 a pair of interchangeable first parts, the first parts including a set of gear teeth and an input/output, the input/output of a first one of the pair of first parts being the first input/output of the planetary differential gear assembly, and the input/output of a second one of the pair of first parts being the second input/output of the planetary differential gear assembly;   a pair of interchangeable second parts, the second parts including a bearing mount, a plurality of pin mounts, and a ring gear mount, the bearing mount of a first one of the pair of second parts being the first bearing mount of the planetary differential gear assembly, and the bearing mount of a second one of the pair of second parts being the second bearing mount of the planetary differential gear assembly;   a single third part, the third part including a set of ring gear teeth, the set of ring gear teeth being the third input/output of the planetary differential gear assembly, and the third part including a pair of mounts, a first one of the pair of mounts mounted to the ring gear mount of the first one of the pair of second parts, and a second one of the pair of mounts mounted to the ring gear mount of the second one of the pair of second parts;   a plurality of interchangeable fourth parts, the fourth parts including a set of planet gear teeth and an interior bearing surface, the fourth parts arranged in a plurality of intermeshing planet gear pairs, each of the intermeshing planet gear pairs including a first one of the plurality of fourth parts enmeshed with the first one of the pair of first parts and a second one of the plurality of fourth parts enmeshed with the second one of the pair of first parts;   a plurality of interchangeable fifth parts, the fifth parts including a first portion that mounts in one of the pin mounts of the first one of the pair of second parts, a second portion that mounts in one of the pin mounts of the second one of the pair of second parts, and a bearing surface that rotatably mounts the interior bearing surface of one of the plurality of fourth parts; and   a plurality of welded joints between the first one of the pair of second parts and the third part, between the second one of the pair of second parts and the third part, between the first portion of the fifth parts and the first one of the pair of second parts, and/or between the second portion of the fifth parts and the second one of the pair of second parts.   
     
     
         22 . The planetary differential gear assembly of  claim 21 , wherein the first part is a sun gear. 
     
     
         23 . The planetary differential gear assembly of  claim 21 , wherein the input/output of the first part is internal and the set of gear teeth is external. 
     
     
         24 . The planetary differential gear assembly of  claim 21 , wherein the input/output of the first part includes a spline. 
     
     
         25 . The planetary differential gear assembly of  claim 21 , wherein the set of gear teeth of the first part are a set of straight spur gear teeth. 
     
     
         26 . The planetary differential gear assembly of  claim 21 , wherein the ring gear mount includes a continuous outside cylindrical surface and a shoulder stop that extends radially inwardly from the cylindrical surface. 
     
     
         27 . The planetary differential gear assembly of  claim 21 , wherein each of the pair of mounts includes a continuous inside cylindrical surface and a shoulder stop that extends radially inwardly from the cylindrical surface. 
     
     
         28 . The planetary differential gear assembly of  claim 21 , wherein each of the plurality of fourth parts longitudinally extends between the first one of the pair of second parts and the second one of the pair of second parts. 
     
     
         29 . The planetary differential gear assembly of  claim 21 , wherein the first input/output is adapted to drive a first drive shaft of a vehicle and the second input/output is adapted to drive a second drive shaft of the vehicle. 
     
     
         30 . The planetary differential gear assembly of  claim 21 , wherein the plurality of welded joints introduce only minimal distortion such that no post-weld machining of the planetary differential gear assembly is required. 
     
     
         31 . The planetary differential gear assembly of  claim 21 , wherein none of the first parts and the fourth parts can be removed from the planetary differential gear assembly. 
     
     
         32 . The planetary differential gear assembly of  claim 21 , wherein the plurality of welded joints includes at least one circular welded joint that extends around a circular perimeter and wherein the pair of first parts and the plurality of fourth parts are all positioned within the at least one circular perimeter. 
     
     
         33 . The planetary differential gear assembly of  claim 21 , wherein the first one of the pair of second parts includes a first wall and the second one of the pair of second parts includes a second wall that is spaced from the first wall, wherein each of the plurality of fourth parts longitudinally extends between the first wall and the second wall. 
     
     
         34 . The planetary differential gear assembly of  claim 33 , wherein the first one of the pair of first parts longitudinally extends from the first wall to the second one of the pair of first parts and wherein the second one of the pair of first parts longitudinally extends from the second wall to the first one of the pair of first parts. 
     
     
         35 . A planetary differential gear assembly having a first input/output, a second input/output, a third input/output, a first bearing mount, and a second bearing mount, the planetary differential gear assembly comprising:
 a pair of interchangeable first parts, the first parts including a set of gear teeth and an input/output, the input/output of a first one of the pair of first parts being the first input/output of the planetary differential gear assembly, and the input/output of a second one of the pair of first parts being the second input/output of the planetary differential gear assembly;   a pair of interchangeable second parts, the second parts including a bearing mount, a plurality of pin mounts, and a ring gear mount, the bearing mount of a first one of the pair of second parts being the first bearing mount of the planetary differential gear assembly, and the bearing mount of a second one of the pair of second parts being the second bearing mount of the planetary differential gear assembly;   a single third part, the third part including a set of ring gear teeth, the set of ring gear teeth being the third input/output of the planetary differential gear assembly, and the third part including a pair of mounts, a first one of the pair of mounts mounted to the ring gear mount of the first one of the pair of second parts, and a second one of the pair of mounts mounted to the ring gear mount of the second one of the pair of second parts;   a plurality of interchangeable fourth parts, the fourth parts including a set of planet gear teeth and an interior bearing surface, the fourth parts arranged in a plurality of intermeshing planet gear pairs, each of the intermeshing planet gear pairs including a first one of the plurality of fourth parts enmeshed with the first one of the pair of first parts and a second one of the plurality of fourth parts enmeshed with the second one of the pair of first parts;   a plurality of interchangeable fifth parts, the fifth parts including a first portion that mounts in one of the pin mounts of the first one of the pair of second parts, a second portion that mounts in one of the pin mounts of the second one of the pair of second parts, and a bearing surface that rotatably mounts the interior bearing surface of one of the plurality of fourth parts; and   a plurality of welded joints between the first one of the pair of second parts and the third part, between the second one of the pair of second parts and the third part, between the first portion of the fifth parts and the first one of the pair of second parts, and/or between the second portion of the fifth parts and the second one of the pair of second parts.   
     
     
         36 . The planetary differential gear assembly of  claim 35 , wherein the planetary differential gear assembly consists essentially of the pair of interchangeable first parts, the pair of interchangeable second parts, the single part, the plurality of interchangeable fourth parts, and the plurality of interchangeable fifth parts. 
     
     
         37 . The planetary differential gear assembly of  claim 35 , wherein the each of the interchangeable first parts is a sun gear, the single third part is a ring gear, and the plurality of interchangeable fourth parts are planet gears. 
     
     
         38 . A planetary differential gear assembly having a first input/output, a second input/output, a third input/output, a first bearing mount, and a second bearing mount, the planetary differential gear assembly comprising:
 a pair of interchangeable first parts consisting essentially of a set of gear teeth and an input/output, the input/output of a first one of the pair of first parts being the first input/output of the planetary differential gear assembly, and the input/output of a second one of the pair of first parts being the second input/output of the planetary differential gear assembly;   a pair of interchangeable second parts consisting essentially of a bearing mount, a plurality of pin mounts, and a ring gear mount, the bearing mount of a first one of the pair of second parts being the first bearing mount of the planetary differential gear assembly, and the bearing mount of a second one of the pair of second parts being the second bearing mount of the planetary differential gear assembly;   a single third part consisting essentially of a set of ring gear teeth, the set of ring gear teeth being the third input/output of the planetary differential gear assembly, and the third part including a pair of mounts, a first one of the pair of mounts mounted to the ring gear mount of the first one of the pair of second parts, and a second one of the pair of mounts mounted to the ring gear mount of the second one of the pair of second parts;   a plurality of interchangeable fourth parts consisting essentially of a set of planet gear teeth and an interior bearing surface, the fourth parts arranged in a plurality of intermeshing planet gear pairs, each of the intermeshing planet gear pairs including a first one of the plurality of fourth parts enmeshed with the first one of the pair of first parts and a second one of the plurality of fourth parts enmeshed with the second one of the pair of first parts;   a plurality of interchangeable fifth parts consisting essentially of a first portion that mounts in one of the pin mounts of the first one of the pair of second parts, a second portion that mounts in one of the pin mounts of the second one of the pair of second parts, and a bearing surface that rotatably mounts the interior bearing surface of one of the plurality of fourth parts; and   a plurality of welded joints consisting essentially of welded joints between the first one of the pair of second parts and the third part, between the second one of the pair of second parts and the third part, between the first portion of the fifth parts and the first one of the pair of second parts, and/or between the second portion of the fifth parts and the second one of the pair of second parts.   
     
     
         39 . The planetary differential gear assembly of  claim 38 , wherein the each of the interchangeable first parts is a sun gear, the single third part is a ring gear, and the plurality of interchangeable fourth parts are planet gears. 
     
     
         40 . The planetary differential gear assembly of  claim 38 , wherein the first one of the pair of second parts includes a first wall and the second one of the pair of second parts includes a second wall that is spaced from the first wall, wherein each of the plurality of fourth parts longitudinally extends between the first wall and the second wall, wherein the first one of the pair of first parts longitudinally extends from the first wall to the second one of the pair of first parts, and wherein the second one of the pair of first parts longitudinally extends from the second wall to the first one of the pair of first parts.