# US 11,441,615 B2 · Clutch adjustment system with wear resistant features for back driving prevention > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,441,615 B2 - Document ID: US11441615B2 - Status: Granted - Kind: B2 - Application number: 17/275,869 - Filed: 2019-09-13 - Published: 2022-02-24 - Granted: 2022-09-13 - Earliest claimed: 2018-09-13 - Assignees: Eaton Intelligent Power Limited - Applicants: Eaton Intelligent Power Limited - Inventors: Mark Charles Barnholt - Web page: https://patentgrep.com/patent/US11441615B2 ## CPC - F16D 13/757: {the adjusting device being located on or inside the clutch cover, e.g. acting on the diaphragm or on the pressure plate} - F16D 13/75: Features relating to adjustment, e.g. slack adjusters - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES ## Abstract A friction clutch for a motor vehicle includes an adjustment mechanism compensating for wear of a friction disk. The adjustment mechanism (40) includes a first cam ring (52) rotatably fixed and a second cam ring (54) rotatable relative to the first cam ring (52). Both cam rings (52,54) have a plurality of cam surfaces configured such that rotation of the second cam ring (54) relative to the first cam ring (52) varies a height of the adjustment mechanism (40). A torsion spring (60) applies a biasing force to the second cam ring (54). A back drive prevention assembly (70) includes a back drive spring (80) attached to the pressure plate and first cam ring (52) to prevent back drive of the second cam ring (54) through a baffle (62) including a plurality of cam teeth (72) formed on a bottom surface of the baffle (62). The cam teeth (72) are formed at an angle A relative to a bottom surface of the baffle (62) decreasing displacement and loads of the back drive spring (80). ## Claims ### Claim 1 A friction clutch for a motor vehicle coupling an engine flywheel to a transmission comprising: an adjustment mechanism compensating for wear of a friction disk coupling the engine flywheel and transmission, the adjustment mechanism including: a first cam ring rotatably fixed with respect to a pressure plate, a second cam ring rotatable relative to the first cam ring and both cam rings having a plurality of cam surfaces configured such that rotation of the second cam ring relative to the first cam ring varies a height of the adjustment mechanism, and a torsion spring applying a biasing force to the second cam ring promoting rotation of the second cam ring relative to the first cam ring; a back drive prevention assembly including a back drive spring attached to the pressure plate and first cam ring to prevent back drive of the second cam ring through a baffle including a plurality of cam teeth formed on a bottom surface of the baffle; wherein the cam teeth are formed at an angle A relative to a bottom surface of the baffle from a proximal end of the cam teeth to a distal end of the cam teeth decreasing a load applied to the back drive spring and reducing displacement of the back drive spring. ### Claim 2 (depends on 1) The friction clutch of claim 1 wherein the angle A is from 2.0 to 6.0 degrees. ### Claim 3 (depends on 1) The friction clutch of claim 1 wherein the plurality of cam teeth are formed radially about the bottom surface of the baffle in at least one location. ### Claim 4 (depends on 3) The friction clutch of claim 3 wherein the plurality of cam teeth extend from 20 to 40 degrees on the bottom surface of the baffle from a proximal end to a distal end of the plurality of cam teeth. ### Claim 5 (depends on 1) The friction clutch of claim 1 wherein the plurality of cam teeth are formed radially about the bottom surface of the baffle at multiple separated locations. ### Claim 6 (depends on 5) The friction clutch of claim 5 wherein the plurality of cam teeth extend from 20 to 40 degrees on the bottom surface of the baffle at the various locations from the proximal end to the distal end of the plurality of cam teeth. ### Claim 7 (depends on 1) The friction clutch of claim 1 wherein the back drive spring includes a base portion having a slot formed therein for attaching to the second cam ring, the back drive spring including a teeth engaging arm extending from the base at an angle defining a pivot. ### Claim 8 (depends on 7) The friction clutch of claim 7 wherein the teeth engaging arm extends from the base at a side surface of the base and extends along a medial portion to an engagement end that engages the cam teeth. ### Claim 9 (depends on 1) The friction clutch of claim 1 wherein the angle A is from 2.0 to 6.0 degrees and a load of the back drive spring at a new position differs in an amount of 1N from a load of the back drive spring at a worn position. ### Claim 10 (depends on 1) The friction clutch of claim 1 wherein the angle A is from 2.0 to 6.0 degrees and a displacement of the back drive spring at a new position differs in an amount of 0.5 mm from a displacement of the back drive spring at a worn position. ### Claim 11 A friction clutch for a motor vehicle coupling an engine flywheel to a transmission comprising: an adjustment mechanism compensating for wear of a friction disk coupling the engine flywheel and transmission, the adjustment mechanism including: a first cam ring rotatably fixed with respect to a pressure plate, a second cam ring rotatable relative to the first cam ring and both cam rings having a plurality of cam surfaces configured such that rotation of the second cam ring relative to the first cam ring varies a height of the adjustment mechanism, and a torsion spring applying a biasing force to the second cam ring promoting rotation of the second cam ring relative to the first cam ring; a back drive prevention assembly including a back drive spring attached to the pressure plate and first cam ring to prevent back drive of the second cam ring through a baffle including a plurality of cam teeth formed on a bottom surface of the baffle; wherein the cam teeth are formed at an angle A of from 2.0 to 6.0 degrees relative to a bottom surface of the baffle from a proximal end of the cam teeth to a distal end of the cam teeth decreasing a load applied to the back drive spring and reducing displacement of the back drive spring.