# US 11,111,970 B1 · Clutch balance dam with cooling flow valve > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,111,970 B1 - Document ID: US11111970B1 - Status: Granted - Kind: B1 - Application number: 16/952,676 - Filed: 2020-11-19 - Granted: 2021-09-07 - Earliest claimed: 2020-11-19 - Assignees: Schaeffler Technologies AG & Co. KG - Applicants: Schaeffler Technologies AG & Co. KG - Inventors: Nicholas Wurst; Edward Goodwill - Web page: https://patentgrep.com/patent/US11111970B1 ## CPC - F16D 25/0638: with more than two discs, e.g. multiple lamellae - F16D 13/72: Features relating to cooling - F16D 25/123: {in view of cooling and lubrication} - F16D 48/02: Control by fluid pressure - F16D 2048/029: {Hydraulic circuits combining clutch actuation with clutch lubrication or cooling} - F16D 2300/0214: Oil or fluid cooling - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES ## Abstract A clutch assembly includes a shaft, a backing plate fixed to the shaft, a plurality of clutch plates, a hydraulic piston, and a balance dam. The hydraulic piston is sealed to the shaft and axially slidable on the shaft to clamp the plurality of clutch plates against the backing plate to close the clutch assembly. The balance dam is fixed to the shaft and disposed axially between the backing plate and the hydraulic piston. The balance dam has a cooling flow orifice and a cooling flow valve for adjusting cooling oil flow through the cooling flow orifice. In some example embodiments, the cooling flow valve is a reed valve with a displaceable steel plate fixed to the balance dam and preloaded against the balance dam to cover the cooling flow orifice. ## Claims ### Claim 1 A clutch assembly, comprising: a shaft; a backing plate fixed to the shaft; a plurality of clutch plates; a hydraulic piston, sealed to the shaft and axially slidable on the shaft to clamp the plurality of clutch plates against the backing plate to close the clutch assembly; and a balance dam: fixed to the shaft; disposed axially between the backing plate and the hydraulic piston; and comprising: a cooling flow orifice; and a cooling flow valve for adjusting cooling oil flow through the cooling flow orifice. ### Claim 2 (depends on 1) The clutch assembly of claim 1 wherein the cooling flow valve is a reed valve comprising a displaceable steel plate fixed to the balance dam and preloaded against the balance dam to cover the cooling flow orifice. ### Claim 3 (depends on 2) The clutch assembly of claim 2 wherein the displaceable steel plate comprises a bonded seal or a seal coating on an end that covers the cooling flow orifice. ### Claim 4 (depends on 3) The clutch assembly of claim 3 wherein the displaceable steel plate is flat and a thickness of the bonded seal or the seal coating provides a preload of the displaceable steel plate against the balance dam. ### Claim 5 (depends on 2) The clutch assembly of claim 2 wherein the displaceable steel plate is fixed to the balance dam by a rivet. ### Claim 6 (depends on 5) The clutch assembly of claim 5 wherein the rivet is offset from the cooling flow orifice in a circumferential direction. ### Claim 7 (depends on 1) The clutch assembly of claim 1 wherein the hydraulic piston and the balance dam are sealed together to form a first portion of a balance chamber. ### Claim 8 (depends on 7) The clutch assembly of claim 7 wherein the cooling flow valve is preloaded against the balance dam with a force such that the cooling flow valve seals the cooling flow orifice when a fluid pressure in the balance chamber is 0.3 bar. ### Claim 9 (depends on 7) The clutch assembly of claim 7 wherein the hydraulic piston and the balance dam are both sealed to the shaft and the shaft forms a second portion of the balance chamber. ### Claim 10 (depends on 9) The clutch assembly of claim 9 wherein the shaft comprises a radial channel for introducing a fluid into the balance chamber. ### Claim 11 (depends on 10) The clutch assembly of claim 10 wherein the shaft comprises an axial channel hydraulically connected to the radial channel. ### Claim 12 (depends on 7) The clutch assembly of claim 7 wherein: the cooling flow valve is arranged to prevent an outward flow of cooling oil from the balance chamber when the shaft is stationary; and the cooling flow valve is arranged to permit an outward flow cooling oil flow from the balance chamber when the shaft is rotating. ### Claim 13 (depends on 12) The clutch assembly of claim 12 wherein the cooling flow valve is displaced away from the balance dam by a dynamic pressure in the balance chamber when the shaft is rotating, thereby permitting cooling flow out of the balance chamber. ### Claim 14 (depends on 12) The clutch assembly of claim 12 wherein the cooling flow valve is displaced away from the balance dam by hydraulic pressure in the balance chamber when the hydraulic piston is displaced towards the balance dam, thereby permitting cooling flow out of the balance chamber. ### Claim 15 (depends on 1) The clutch assembly of claim 1 further comprising a clutch plate carrier: disposed axially between the backing plate and the balance dam; fixed to the backing plate; and comprising an orifice for allowing a radially flowing cooling oil flow to cool the plurality of clutch plates. ### Claim 16 (depends on 1) The clutch assembly of claim 1 further comprising a resilient element disposed axially between the hydraulic piston and the balance dam urging the hydraulic piston away from the balance dam. ### Claim 17 (depends on 16) The clutch assembly of claim 16 wherein the resilient element comprises a plurality of coil springs. ### Claim 18 (depends on 17) The clutch assembly of claim 17 wherein the plurality of coil springs is disposed about a circumference arranged radially outside of the cooling flow orifice. ### Claim 19 (depends on 1) The clutch assembly of claim 1 further comprising a seal plate, wherein the seal plate and the hydraulic piston are sealed together to form a first portion of a pressure chamber. ### Claim 20 (depends on 19) The clutch assembly of claim 19 wherein the seal plate and the hydraulic piston are both sealed to the shaft and the shaft forms a second portion of the pressure chamber.