MRI compatible magnet for cochlear implant
The present invention discloses an MRI compatible magnet for a cochlear implant, comprising a base, an upper shell, a bracket, a magnet, needle rollers and a lower shell, wherein the upper shell and the lower shell form a closed space, and the magnet and the bracket are arranged in the closed space; the magnet is in an axisymmetric polygonal disk shape; the magnetic pole of the magnet is divided into two halves from the top view, one half is an N pole, and the other half is an S pole; the magnet is arranged in the bracket; the bracket is matched with the magnet in shape, and the bracket rotates with the magnet when the magnet rotates axially; a plurality of positioning slots are provided on the outer side face of the bracket; and , the needle rollers are accommodated in the positioning slots, and the needle rollers are cylindrical and can axially roll in the positioning slots without slipping off. The MRI compatible magnet for a cochlear implant provided by the present invention can flexibly rotate on the bracket according to the change of the direction of an external magnetic field, so that the N pole and the S pole of the magnet can be freely switched in the spatial direction, and it is unnecessary to take out the cochlear implant and the internal magnet during examinations in a strong magnetic field such as MRI.
1 . An MRI compatible magnet for a cochlear implant, comprising a base, an upper shell, a bracket, a magnet, needle rollers and a lower shell, wherein,
the upper shell and the lower shell form a closed space, and the magnet and the bracket are arranged in the closed space; the magnet is in an axisymmetric polygonal disk shape; the magnetic pole of the magnet is divided into two halves from a major plane of the magnet, one half is an N pole, and the other half is an S pole; the magnet is arranged in the bracket; the bracket is matched with the magnet in shape, and the bracket rotates with the magnet when the magnet rotates axially; a plurality of positioning slots are provided on an outer side face of the bracket; and, the plurality of positioning slots, with a corresponding plurality of needle rollers, each of the plurality of needle rollers are accommodated in a respective plurality of positioning slots, and the needle rollers are cylindrical and can axially roll along longitudinal axes in the positioning slots without slipping off from the positioning slots.
2 . The MRI compatible magnet for a cochlear implant according to claim 1 , wherein the magnet is wrapped and fixed by the bracket during injection molding.
3 . The MRI compatible magnet for a cochlear implant according to claim 1 , wherein the bracket comprises upper and lower surfaces and a plurality of semicircular balls are arranged on edges of the upper and lower surfaces of the bracket.
4 . The MRI compatible magnet for a cochlear implant according to claim 1 , wherein the positioning slots are U-shaped internal buckles, and the needle rollers are buckled into the respective positioning slots.
5 . The MRI compatible magnet for a cochlear implant according to claim 1 , wherein the magnet is in an octagonal disk shape.
6 . The MRI compatible magnet for a cochlear implant according to claim 1 , wherein internal threads and internal conical surfaces are provided on an inner wall of the base.
7 . The MRI compatible magnet for a cochlear implant according to claim 6 , wherein external threads and external conical surfaces which are matched with the internal threads and the internal conical surfaces of the base in shape are provided on an outer wall of the upper shell; and, when the upper shell is screwed into the base, the internal conical surfaces come into contact with the external conical surfaces to realize clamping fixation.
8 . The MRI compatible magnet for a cochlear implant according to claim 1 , wherein bayonets are provided on the bracket, and edges of the polygonal disk-shaped magnet are exposed at the bayonets.
9 . The MRI compatible magnet for a cochlear implant according to claim 1 , wherein U-shaped slots are formed on an outer wall of the base.
10 . The MRI compatible magnet for a cochlear implant according to claim 1 , wherein a flange is arranged in a middle position of an exterior of the base, and positioning holes are formed on the flange.