A wet friction disc includes a friction surface and a lubrication groove through which a lubricant supplied to the friction surface flows. The lubrication groove has a plurality of circumferential groove portions that extends in a circumferential direction and a plurality of intersecting groove portions that extends in directions intersecting the circumferential direction. At least one of the circumferential groove portions has a through-hole that extends through the wet friction disc between an opposite surface facing s mating member and a surface on the opposite side in an axial direction.

A wet friction disc includes a friction surface and a lubrication groove through which a lubricant supplied to the friction surface flows. The lubrication groove has a plurality of circumferential groove portions that extends in a circumferential direction and a plurality of intersecting groove portions that extends in directions intersecting the circumferential direction. At least one of the circumferential groove portions has a through-hole that extends through the wet friction disc between an opposite surface facing s mating member and a surface on the opposite side in an axial direction.

Methods and systems for a transmission are provided herein. In one example, a hydraulic system includes a lubrication valve included in a lubricant line and designed to adjust a flow of lubricant to a multi-disc wet clutch. The hydraulic system further includes a clutch line coupled to a clutch control valve, where the clutch line is in fluidic communication with a hydraulic fluid to a clutch actuator of the multi-disc wet clutch and a passive adjustment device of the lubrication valve and where the passive adjustment device transitions the lubrication valve between a limited flow state and an open flow state based on a pressure of the hydraulic fluid in the clutch line.

Methods and systems for a transmission are provided herein. In one example, a hydraulic system includes a lubrication valve included in a lubricant line and designed to adjust a flow of lubricant to a multi-disc wet clutch. The hydraulic system further includes a clutch line coupled to a clutch control valve, where the clutch line is in fluidic communication with a hydraulic fluid to a clutch actuator of the multi-disc wet clutch and a passive adjustment device of the lubrication valve and where the passive adjustment device transitions the lubrication valve between a limited flow state and an open flow state based on a pressure of the hydraulic fluid in the clutch line.

A dual drive, dual clutch accessory drive system for an aircraft including a first input shaft connected to a first pressure spool of a turbine engine. The first input shaft rotates at a first speed. A second input shaft is connected to a second spool of the turbine engine that is distinct from the first spool. The second input shaft rotates at a second speed. An output shaft operatively connected to an aircraft accessory. A first drive path selectively operatively connects the first input shaft with the output shaft. The first drive path includes a first clutch. The first drive path being operable to rotate the output shaft at the first speed. A second drive path operatively connects the second input shaft with the output shaft. The second drive path includes a second clutch. The second drive path is operable to rotate the output shaft at the second speed.

A dual drive, dual clutch accessory drive system for an aircraft including a first input shaft connected to a first pressure spool of a turbine engine. The first input shaft rotates at a first speed. A second input shaft is connected to a second spool of the turbine engine that is distinct from the first spool. The second input shaft rotates at a second speed. An output shaft operatively connected to an aircraft accessory. A first drive path selectively operatively connects the first input shaft with the output shaft. The first drive path includes a first clutch. The first drive path being operable to rotate the output shaft at the first speed. A second drive path operatively connects the second input shaft with the output shaft. The second drive path includes a second clutch. The second drive path is operable to rotate the output shaft at the second speed.

Methods and systems for a transmission are provided herein. In one example, a hydraulic system includes a lubrication valve included in a lubricant line and designed to adjust a flow of lubricant to a multi-disc wet clutch. The hydraulic system further includes a clutch line coupled to a clutch control valve, where the clutch line is in fluidic communication with a hydraulic fluid to a clutch actuator of the multi-disc wet clutch and a passive adjustment device of the lubrication valve and where the passive adjustment device transitions the lubrication valve between a limited flow state and an open flow state based on a pressure of the hydraulic fluid in the clutch line.

Methods and systems for a transmission are provided herein. In one example, a hydraulic system includes a lubrication valve included in a lubricant line and designed to adjust a flow of lubricant to a multi-disc wet clutch. The hydraulic system further includes a clutch line coupled to a clutch control valve, where the clutch line is in fluidic communication with a hydraulic fluid to a clutch actuator of the multi-disc wet clutch and a passive adjustment device of the lubrication valve and where the passive adjustment device transitions the lubrication valve between a limited flow state and an open flow state based on a pressure of the hydraulic fluid in the clutch line.

An intelligent clutch lubrication system includes a first dynamically-lubricated clutch pack, a supply pump, a first lubricant control (LC) valve, and a lubricant flow circuit having a clutch lubrication loop in which the first clutch pack is positioned. When active, the supply pump urges lubricant flow about the lubricant flow circuit and through the clutch lubrication loop. The first LC valve is positioned in the clutch lubrication loop at a location upstream of the first clutch pack, while a controller architecture is operably coupled to the first LC valve. the controller architecture is configured to control the first LC valve to temporarily boost lubricant flow to the first DL clutch pack when moving into an engaged position during operation of the intelligent clutch lubrication system.

An intelligent clutch lubrication system includes a first dynamically-lubricated clutch pack, a supply pump, a first lubricant control (LC) valve, and a lubricant flow circuit having a clutch lubrication loop in which the first clutch pack is positioned. When active, the supply pump urges lubricant flow about the lubricant flow circuit and through the clutch lubrication loop. The first LC valve is positioned in the clutch lubrication loop at a location upstream of the first clutch pack, while a controller architecture is operably coupled to the first LC valve. the controller architecture is configured to control the first LC valve to temporarily boost lubricant flow to the first DL clutch pack when moving into an engaged position during operation of the intelligent clutch lubrication system.