Reel unit for spinning reel

A spinning reel comprising:

• a spool;
• a rotor arranged to guide a fishing line on a peripheral surface of the spool, the rotor having a bail arm, pivotable between a line-winding posture and a line-releasing posture, and a bail tripping mechanism arranged to return the bail arm from the line-releasing posture to the line-winding posture, the spool arranged to moved forward and rearward along a spool shaft;
• and
• a reel unit configured to rotatably support the rotor, the reel unit including
• a housing unit including a cylindrical portion, a first flange portion and a mechanism accommodating space, the cylindrical portion disposed on a front portion the housing unit so that the center of the cylindrical portion coincides with the center of a rotation shaft of the rotor, the first flange portion arranged behind the cylindrical portion, the first flange portion having a substantially semicircular shape and the center that coincides with the center of the cylindrical portion, the mechanism accommodating space formed in a rear side of the first flange portion;
• a lid portion having a second flange portion with a substantially semicircular shape, the second flange portion forming a circular shape with the first flange portion, the first and second flange portions arranged behind and forming a gap with a rear surface of the cylindrical portion, the lid portion detachably coupled to the housing unit so as to cover the mechanism accommodating space;
• a rod attachment leg portion disposed on either the housing unit or the lid portion;
• and
• a returning member detachably mounted in the gap between the cylindrical portion and the second flange portion, the returning member returning the bail arm from the line-releasing posture to the line-winding posture, the returning member includes a plate-like arranging portion and a protrusion, the arranging portion disposed in the gap between the cylindrical portion and the second flange portion, the protrusion gradually protruding from a front side of the arranging portion to face the first flange portion along the line-winding direction of the rotor, the protrusion has a first sloped surface contactable with the bail tripping mechanism.