Special buckle oil casing sealing structure

The invention discloses a special buckle oil casing sealing structure. An oil casing is in threaded connection with one end of a coupling, and the oil casing and the other end of the coupling are contacted with an anti-excessive-torque shoulder; an annular gap between the oil casing and the middle part of the coupling is a relief groove. The special buckle oil casing sealing structure is characterized in that the relief groove is equipped with a magnetorheological fluid sealing structure, and the magnetorheological fluid sealing structure is composed of an annular permanent magnet, annular magnetic poles, a magnetic fluid and a magnetic conductive sealing shaft; both ends of the annular permanent magnet are provided with the annular magnetic poles, and the magnetic conductive sealing shaft crosses through the annular permanent magnet and the annular magnetic poles; every annular magnetic pole is provided with at least two pole teeth, and two pole teeth symmetrical to the permanent magnet are formed to be a closed magnetic loop through the permanent magnet; every closed magnetic loop fills into the magnetic fluid. By adopting the magnetorheological fluid sealing form, the special buckle oil casing sealing structure can reduce the using cost of the oil casing and reduce the processing precision of the oil casing.