Friction engagement device for work vehicle and work vehicle

A friction engagement device for a work vehicle, the friction engagement device comprising:

• a rotating shaft;
• a plurality of first friction plates that rotate with the rotating shaft;
• a plurality of second friction plates arranged to face the first friction plates;
• an oil chamber to which hydraulic fluid is supplied;
• a piston movably provided between an engagement position and a release position, the piston engaging the first friction plates and the second friction plates at the engagement position, the piston releasing the first friction plates and the second friction plates at the release position, and the piston being pressed toward the engagement position by hydraulic pressure of the oil chamber;
• a first return spring that
• contacts the piston from the engagement position to a standby position between the release position and the engagement position and urges the piston toward the release position;
• and
• a second return spring that
• contacts the piston from the engagement position to the release position and
• urges the piston toward the release position,
• a center axis of the first return spring being arranged to coincide with a center axis of the rotating shaft, and
• a center axis of the second return spring being arranged to coincide with tire center axis of the rotating shaft.