Clutch assembly having a hydraulically actuate piston and latching device

A powertrain system comprising:

• a motor having a motor output shaft extending along a central axis;
• a planetary gear set having a planet carrier supporting a plurality of planet gears intermeshed between a sun gear and a ring gear, wherein the sun gear is coaxially connected to the input shaft;
• a first clutch member connected to the ring gear, wherein the first clutch member is rotatable about the central axis;
• a second clutch member co-axially spaced from the first clutch member, wherein the second clutch member is connected to a stationary member such that the second clutch member is non-rotational about the central axis and slidably moveable along the central axis;
• a spring biasing the second clutch member in a first axial direction to engage the first clutch member to prevent the rotation of the first clutch member;
• a piston selectively actuatable to move the second clutch member in the second axial direction overcoming a biasing force of the spring and disengaging the second clutch member from the first clutch member to allow the rotation of the first clutch member;
• and
• a latching device to selectively lock the piston in a fixed position maintaining the disengagement of the second clutch member.

A method of operating a clutch assembly of a transmission, comprising the steps of:

• providing torque to rotate a first clutch member from a reactionary gear of a planetary gear set, wherein the first member clutch is rotated about an axis;
• biasing a second clutch member with a spring along a first axial direction to engage the first clutch member to prohibit the rotation of the first clutch member, wherein the second clutch member is non-rotationally grounded to a stationary member of the transmission;
• selectively actuating a hydraulic piston to overcome a biasing force of the spring such that the second clutch member moves in a second axial direction opposite of the first axial direction to disengage the second clutch member from the first clutch member;
• and
• selectively locking the hydraulic piston in a position to maintain the disengagement of the second clutch member from the first clutch member.