Generally, in this kind of fishing reel the spool is freely rotatable for casting, with the spool rotating at a higher speed than a fishing line drawn out of the spool causing backlash, whereby the line wound on the spool is entangled or caught in a gap between the spool and a reel frame. In order to solve this problem, a centrifugal brake usually is used to impart a predetermined rotational resistance to the spool. However, a sufficient braking effect has not been achieved with this type of brake and the centrifugal brake, which exerts the braking action by slidable contact of a brake shoe with a brake drum, may have its braking force changed due to wearing of the brake shoe.
There has been proposed a spool braking device using a magnet and a metallic conductor, one of them being rotatable together with the spool and the other being fixed to the reel body so that the rotating field of the rotating member generates an eddy current. Hence, the rotating member, due to Fleming's left-hand rule, is given a magnetic force against its rotation, thereby exerting a braking action on the spool.
This method can increase the braking effect and since there is no contact-portion at the brake member variations in the braking force can be eliminated. However, with this type of mechanism a bearing for the spool shaft becomes magnetized so that the magnetic flux links the bearing and the spool shaft which is made of a magnetic material of high strength, such as stainless steel, thereby increasing the rotational resistance against the rotation of the spool which is integral with the spool shaft.