# US 2008/0188341 A1 · Cycloid limited slip differential and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0188341 A1 - Document ID: US20080188341A1 - Status: Published application - Kind: A1 - Application number: 11/671,478 - Filed: 2007-02-06 - Published: 2008-08-07 - Earliest claimed: 2007-02-06 - Assignees: GM Global Technology Operations LLC - Inventors: Hsu-Chiang Miao; Chi-Kuan Kao - Web page: https://patentgrep.com/patent/US20080188341A1 ## CPC - F16H 25/06: with intermediate members guided along tracks on both rotary members - F16H 48/147: {with driven cam followers or balls engaging two opposite cams} - F16H 48/14: with cams - F16H: GEARING ## Abstract A differential is provided comprising a rotatable differential housing, first and second output members, a first cycloid disk having an epitrochoid groove, a second cycloid disk having a hypotrochoid groove, a coupling disk connected having a plurality of holes each containing a sphere, wherein the spheres are engageable with the grooves for transferring torque between the cycloid disks. A method is also provided for distributing torque in a vehicle having two axles including at least one drive axle, including attaching one axle to a cycloid disk having a continuous epitrochoid groove, attaching another axle to a cycloid disk having a continuous hypotrochoid groove, attaching a rotatable housing to a center coupling disk having a plurality of holes, and positioning a torque transfer sphere that is engageable with the grooves in each of the holes, wherein the spheres are configured for distributing torque along the drive axles. ## Claims ### Claim 1 A differential comprising: a rotatable housing; first and second output members; a first cycloid disk operatively connected to said first output member and having a first cycloid groove; a second cycloid disk operatively connected to said second output member and having a second cycloid groove; a coupling disk operatively connected to said rotatable housing and positioned between said first and second cycloid disks, and having a plurality of holes formed therein; and a plurality of spheres, wherein one of said plurality of spheres is positioned within each of said plurality of holes and is engageable with said first and second cycloid grooves for distributing torque from said rotatable housing between said first and second output members. ### Claim 2 (depends on 1) The differential of claim 1, wherein said first cycloid groove has an epitrochoid profile and said second cycloid groove has a hypotrochoid profile, and wherein each of said plurality of spheres engages said first and second cycloid grooves at the intersection of said profiles formed when one of said profiles is overlaid with the other of said profiles. ### Claim 3 (depends on 1) The differential of claim 1, wherein each of said cycloid disks has a plurality of lobes, and wherein the number of said plurality of holes is equal to the sum of said plurality of lobes. ### Claim 4 (depends on 1) The differential of claim 1, wherein each of said first and second output members is adapted for connection to an axle member selected from the group of a front drive axle and a rear drive axle. ### Claim 5 (depends on 1) The differential of claim 1, wherein said first and second output members are adapted for connection in an all-wheel drive transmission. ### Claim 6 A differential comprising a center coupling disk operatively attached to a rotatable housing and disposed between first and second cycloid disks, wherein said cycloid disks each have a continuous cycloid groove and are operatively attachable to different output shafts, and wherein the differential is configured to selectively distribute torque from said center coupling disk to said different output shafts through a plurality of spheres that are engageable with said cycloid grooves. ### Claim 7 (depends on 6) The differential of claim 6, wherein said center coupling disk has a plurality of circumferential holes each containing a different one of said plurality of spheres. ### Claim 8 (depends on 6) The differential of claim 6, wherein said cycloid grooves include a first cycloid groove having an epitrochoid profile and a second cycloid groove having a hypotrochoid profile, and wherein each of said plurality of spheres engages each of said first and second cycloid disks at the intersection of said profiles when one of said profiles is overlaid with the other of said profiles. ### Claim 9 (depends on 6) The differential of claim 6, wherein each of said cycloid disks has a plurality of lobes, and wherein the number of said plurality of holes is equal to the sum of said plurality of lobes. ### Claim 10 (depends on 6) The differential of claim 6, wherein each of said first and second output members is adapted to be operatively connectable to an axle selected from the group of a front drive axle and a rear drive axle. ### Claim 11 (depends on 6) The differential of claim 6, wherein said different output shafts are adapted for use on an all-wheel drive transmission. ### Claim 12 A method of distributing torque in a vehicle having a pair of axles, the method including operatively attaching one axle to a rotatable first cycloid disk having a surface with a continuous cycloid groove, operatively attaching another axle to a rotatable second cycloid disk having a surface with a continuous cycloid groove, and driveably attaching a rotatable housing to a rotatable center coupling disk having a plurality of holes each positioning a rotatable sphere therein, wherein the spheres are configured to engage with the grooves so that torque may be distributed between the cycloid disks as the spheres are rotated within the grooves when the cycloid disks rotate. ### Claim 13 (depends on 12) The method of claim 12, wherein the first cycloid groove is an epitrochoid and the second cycloid groove is a hypotrochoid. ### Claim 14 (depends on 12) The method of claim 12, wherein said vehicle is an all-wheel drive vehicle.