The utility model provides an electron core fixed disk, includes the disk body, the shape of disk body is circular, the centre of disk body is equipped with the through -hole of electron donating core installation, be equipped with on the disk body along the valve slot of the footpath linear extension of through -hole, the through -hole inner wall is connected with two cards and holds the piece, two cards are held the piece and are the point symmetry for the centre of a circle of through -hole and distribute, and the both sides that the piece is located the valve slot axis are respectively held to two cards, the piece is held including card portion of holding and the circuitous portion continuous with the card portion of holding to the card, the shape of the card portion of holding is oval arc, the card portion of holding is 60 -150 with the centre of a circle coincidence and the radian of through -hole, the arc length of the card portion of holding compares for 1.5 -3 with the radius of through -hole: 1, comparing for 0.2 -0.5 of circuitous the length and the arc length of the card portion of holding: 1. The utility model provides an electron core fixed disk, the electron core passes through the cooperation of joint piece elasticity with the fixed disk, provides good buffering and guard action for the electron core.