# US 12,222,031 B2 · Lubrication mechanism and balance piston for a high speed clutch > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,222,031 B2 - Document ID: US12222031B2 - Status: Granted - Kind: B2 - Application number: 18/158,566 - Filed: 2023-01-24 - Published: 2024-07-25 - Granted: 2025-02-11 - Earliest claimed: 2023-01-24 - Assignees: Deere & Company - Applicants: Deere & Company - Inventors: Randall L. Long; Kyle K. McKinzie; Lloyd D. Martin - Web page: https://patentgrep.com/patent/US12222031B2 ## CPC - F16H 57/0473: {Friction devices, e.g. clutches or brakes} - F16D 25/0638: with more than two discs, e.g. multiple lamellae - F16D 25/123: {in view of cooling and lubrication} - F16H 57/0412: {Cooling or heating; Control of temperature} - F16H 57/043: {within rotary parts, e.g. axial channels or radial openings in shafts} - F16D 2127/02: Release mechanisms - F16D 2300/06: Lubrication details not provided for in group F16D13/74 - F16H: GEARING - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES ## Abstract A lubrication mechanism is provided for a transmission unit having a balance piston. The lubrication mechanism is movable between a closed position when a clutch assembly is disengaged which prevents cooling flow of lubrication to a clutch pack of the clutch assembly, and an open position when the clutch assembly is engaged which provides for a cooling flow of lubrication to the clutch pack. In both positions, lubrication is supplied to a balance piston cavity between the clutch assembly and the balance piston. ## Claims ### Claim 1 A transmission unit of a work vehicle comprising: a drive shaft; a housing surrounding the drive shaft and rotatable therewith; a gear rotatably mounted around the drive shaft; a clutch assembly provided around the drive shaft and including a clutch piston and a clutch pack, the clutch pack provided in a clutch pack cavity provided between the housing, the clutch piston and the gear and being coupled to the housing and to the gear, wherein a clutch piston cavity is provided between the housing and the clutch piston and is configured to receive fluid under pressure to move the clutch piston into contact with the clutch pack; a balance piston provided around the drive shaft, wherein a balance piston cavity is provided between the clutch piston and the balance piston and the balance piston cavity receives fluid under pressure; and a cooling fluid shutoff piston mounted in a passageway of the clutch piston, wherein the passageway is open to the balance piston cavity, wherein the cooling fluid shutoff piston is configured to be in a closed position which blocks a lubrication supply opening of the passageway through which fluid is supplied to the clutch pack cavity when the clutch piston is disengaged from the clutch pack, and wherein the cooling fluid shutoff piston is configured to be in an open position which opens the lubrication supply opening when the clutch piston is engaged with the clutch pack and a first fluid pressure is within the clutch piston cavity. ### Claim 2 (depends on 1) The transmission unit of claim 1, wherein the cooling fluid shutoff piston is further configured to be in the closed position when the clutch piston is engaged with the clutch pack and a second fluid pressure is within the clutch piston cavity, wherein the second fluid pressure is greater than the first fluid pressure. ### Claim 3 (depends on 1) The transmission unit of claim 1, wherein the drive shaft has a first fluid supply passage therethrough which is configured to supply fluid to the clutch piston cavity, and the drive shaft has a second fluid supply passage therethrough which is configured to supply fluid to the balance piston cavity. ### Claim 4 (depends on 3) The transmission unit of claim 3, wherein the passageway is in fluid communication with the second fluid supply passage. ### Claim 5 (depends on 4) The transmission unit of claim 4, wherein the second fluid supply passage further supplies fluid to the lubrication supply opening. ### Claim 6 (depends on 5) The transmission unit of claim 5, wherein the passageway is in fluid communication with the balance piston cavity and the lubrication supply opening. ### Claim 7 (depends on 3) The transmission unit of claim 3, further comprising a valve which is operable to control the fluid pressure within the first fluid supply passage. ### Claim 8 (depends on 1) The transmission unit of claim 1, further comprising a valve which is operable to control the fluid pressure within the clutch piston cavity. ### Claim 9 (depends on 1) The transmission unit of claim 1, wherein the balance piston is mounted in a pocket of the clutch piston. ### Claim 10 (depends on 1) The transmission unit of claim 1, wherein the cooling fluid shutoff piston is engaged with the housing when the clutch piston is disengaged from the clutch pack. ### Claim 11 (depends on 1) The transmission unit of claim 1, further comprising a return spring mounted between the clutch piston and the balance piston. ### Claim 12 (depends on 11) The transmission unit of claim 11, wherein the cooling fluid shutoff piston includes an enlarged head and an elongated shaft, and further comprising another return spring mounted between the enlarged head and the clutch piston. ### Claim 13 (depends on 1) The transmission unit of claim 1, wherein the balance piston is fixed with respect to movement along a longitudinal axis of the drive shaft. ### Claim 14 (depends on 1) The transmission unit of claim 1, wherein a portion of the balance piston is housed inside of the clutch piston. ### Claim 15 (depends on 1) The transmission unit of claim 1, wherein a plurality of cooling fluid shutoff pistons are mounted in respective passageways of the clutch piston. ### Claim 16 A transmission unit of a work vehicle comprising: a drive shaft having a clutch fluid supply passage and a balance fluid supply passage therethrough; a housing surrounding the drive shaft and rotatable therewith; a gear rotatably mounted around the drive shaft; a clutch assembly provided around the drive shaft and including a clutch piston and a clutch pack, the clutch pack provided in a clutch pack cavity provided between the housing, the clutch piston and the gear and being coupled to the gear and to the housing, wherein a clutch piston cavity is provided between the housing and the clutch piston and is configured to receive fluid under pressure through the clutch fluid supply passage to move the clutch piston into contact with the clutch pack; a balance piston mounted within a pocket of the clutch piston and encircling the drive shaft, the balance piston being fixed with respect to movement along a longitudinal axis of the drive shaft, wherein a balance piston cavity is provided between the clutch piston and the balance piston and the balance piston cavity receives fluid under pressure through the balance fluid supply passage; and a cooling fluid shutoff piston mounted in a passageway of the clutch piston, wherein the passageway is open to the balance piston cavity, wherein the cooling fluid shutoff piston is configured to be in a closed position which blocks a lubrication supply opening of the passageway through which fluid is supplied to the clutch pack cavity from the balance fluid supply passage when the clutch piston is disengaged from the clutch pack, and wherein the cooling fluid shutoff piston is configured to be in an open position which opens the lubrication supply opening when the clutch piston is engaged with the clutch pack and a first fluid pressure is within the clutch piston cavity, and wherein the cooling fluid shutoff piston is configured to be in the closed position when the clutch piston is engaged with the clutch pack and a second fluid pressure is within the clutch piston cavity, wherein the second fluid pressure is greater than the first fluid pressure. ### Claim 17 (depends on 16) The transmission unit of claim 16, wherein the cooling fluid shutoff piston is engaged with the housing when the clutch piston is disengaged from the clutch pack. ### Claim 18 (depends on 17) The transmission unit of claim 17, wherein the cooling fluid shutoff piston includes an enlarged head and an elongated shaft, and further comprising a return spring mounted between the enlarged head and the clutch piston. ### Claim 19 (depends on 16) The transmission unit of claim 16, further comprising a return spring mounted between the clutch piston and the balance piston. ### Claim 20 (depends on 19) The transmission unit of claim 19, wherein the cooling fluid shutoff piston includes an enlarged head and an elongated shaft, and further comprising another return spring mounted between the enlarged head and the clutch piston.