Optimization of an eddy current type magnetic floor hinge

Floor hinge is a kind of building construction materials. A floor hinge is used to absorb undesirable mechanical impact in the case of opening and closing the door. Consequently, the door can be operated smoothly. The problem of a conventional hydraulic floor hinge is that damping torque varies so much for seasons due to the large temperature dependency of the viscous coefficient of oil. Hence, the hydraulic floor hinge is particularly designed to allow users to adjust the damping force. However, most of users such as building managers feel annoyed about adjusting it. In this paper, a magnetic floor hinge is suggested to overcome the problem. The magnetic floor hinge uses a magnetic damper which absorbs magnetically undesirable mechanical impact. Compared with the hydraulic floor hinge the magnetic floor hinge has some advantages: One is there exists no wear in the magnetic damper since the disk rotates between the magnets without contact. Another is the deviation of damping torque is very small for seasons due to the low temperature dependency of the conductivity of the disk to which the magnetic damping torque is proportional. To begin with, the analytical models are obtained for the damping torque and the recovering torque. By using the analytical models, the cost optimal design is carried out so that its results should satisfy the Standard requirements with the lowest cost. Finally, the results of the analysis and the design are compared with those of experiments and validated.