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.

Dual clutch transmission system, vehicle and method of cooling. A dual clutch transmission system, including coaxial first and second engageable and disengageable torque transmitting assemblies, configured to be installed in a power train of a vehicle, the system including a main flow path for supply of cooling fluid, wherein the main flow path branches into a first flow path for supply of cooling fluid to the first torque transmitting assembly, and a second flow path for supply of cooling fluid to the second torque transmitting assembly, wherein the system includes a third flow path for supplying cooling fluid, which is discharged from the second torque transmitting assembly, to the first torque transmitting assembly, the third flow path preferably being arranged within a space defined by a housing of the dual clutch transmission system.

Dual clutch transmission system, vehicle and method of cooling. A dual clutch transmission system, including coaxial first and second engageable and disengageable torque transmitting assemblies, configured to be installed in a power train of a vehicle, the system including a main flow path for supply of cooling fluid, wherein the main flow path branches into a first flow path for supply of cooling fluid to the first torque transmitting assembly, and a second flow path for supply of cooling fluid to the second torque transmitting assembly, wherein the system includes a third flow path for supplying cooling fluid, which is discharged from the second torque transmitting assembly, to the first torque transmitting assembly, the third flow path preferably being arranged within a space defined by a housing of the dual clutch transmission system.

The automatic transmission has, on an axis of a power transmission shaft: a one-side clutch including a plurality of friction plates; and an other-side clutch including a plurality of friction plate. A pressing section of a piston of the one-side clutch and a pressing section of a piston of the other-side clutch are arranged to overlap each other in an axial direction. On one side in the axial direction of the plurality of friction plates of the one-side clutch, a radial section of the piston of the one-side clutch and a radial section of the piston of the other-side clutch are arranged in parallel in the axial direction. Pressure-receiving sections of the pistons of the one-side clutch and the other-side clutch and bearing sections of the pistons of the one-side clutch and the other-side clutch are aggregated and arranged on a radially inner side.

A dual clutch transmission includes an input shaft having a first clutch having a first input disc carrier, a first output disc carrier, a first force transfer region, and a first actuation piston. The transmission includes a second clutch having a second input disc carrier, a second output disc carrier, a second force transfer region, and a second actuation piston. A first sub-transmission includes a first sub-transmission input shaft and a second sub-transmission has a second sub-transmission input shaft. The input shaft, the first input disc carrier, and the second input disc carrier are connected to one another for fixedly conjoint rotation. The first output disc carrier is connected to the first sub-transmission input shaft for fixedly conjoint rotation. The second output disc carrier is connected to the second sub-transmission input shaft for fixedly conjoint rotation. The second sub-transmission input shaft is arranged coaxially with and radially surrounding the first sub-transmission input shaft.

A dual clutch transmission includes an input shaft having a first clutch having a first input disc carrier, a first output disc carrier, a first force transfer region, and a first actuation piston. The transmission includes a second clutch having a second input disc carrier, a second output disc carrier, a second force transfer region, and a second actuation piston. A first sub-transmission includes a first sub-transmission input shaft and a second sub-transmission has a second sub-transmission input shaft. The input shaft, the first input disc carrier, and the second input disc carrier are connected to one another for fixedly conjoint rotation. The first output disc carrier is connected to the first sub-transmission input shaft for fixedly conjoint rotation. The second output disc carrier is connected to the second sub-transmission input shaft for fixedly conjoint rotation. The second sub-transmission input shaft is arranged coaxially with and radially surrounding the first sub-transmission input shaft.

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 hydraulic circuit for a vehicle driving device includes an oil pump, a clutch oil passage, a cooling oil passage, a pressure regulating valve, and a shift valve. The cooling oil passage guides oil to a cooled portion of a vehicle. Supply of oil to the clutch oil passage and the cooling oil passage is switched by switching of the pressure regulating valve and the shift valve. The cooling oil passage includes: a shaft center cooling oil passage which supplies cooling oil to a shaft center of a rotation shaft of an electric motor mounted on the vehicle; and a cooling oil passage shift valve which switches presence/absence of supply of oil to the shaft center cooling oil passage.

A hydraulic circuit for a vehicle driving device includes an oil pump, a clutch oil passage, a cooling oil passage, a pressure regulating valve, and a shift valve. The cooling oil passage guides oil to a cooled portion of a vehicle. Supply of oil to the clutch oil passage and the cooling oil passage is switched by switching of the pressure regulating valve and the shift valve. The cooling oil passage includes: a shaft center cooling oil passage which supplies cooling oil to a shaft center of a rotation shaft of an electric motor mounted on the vehicle; and a cooling oil passage shift valve which switches presence/absence of supply of oil to the shaft center cooling oil passage.

A dual clutch transmission includes an input shaft and a first clutch, which has a first input disc carrier, a first output disc carrier, a first force transfer region, and a first actuating piston. The transmission has a second clutch having a second input disc carrier, a second output disc carrier, a second force transfer region, and a second actuating piston. The transmission includes a first partial transmission having a first partial transmission input shaft, and a second partial transmission having a second partial transmission input shaft. The input shaft, the first input disc carrier, and the second input disc carrier are non-rotationally connected to one another. The first output disc carrier is non-rotationally connected to the first partial transmission input shaft. The second output disc carrier is non-rotationally connected to the second partial transmission input shaft. The second partial transmission input shaft is arranged coaxially and radially surrounding the first partial transmission input shaft.