Research on the Design of Mechanically Sealed Switch Based on Permanent Magnet Eddy Current Transmission Characteristic

Aiming at the difficulty in designing the internal spray system inside the telescopic cut-off head of coal mine machinery, this study proposes a mechanical seal switching principle based on the permanent magnetic eddy current effect, which realizes the switching and sealing between the cylinder’s expansion state (without rotation) and the internal spray condition (with rotation). This work can solve the current problem that the inner spray cannot be arranged inside the external rotor structure mining equipment. Firstly, the mechanical seals of the two working conditions are designed, and the requirements for the torque and axial force of the permanent magnet eddy current structure are proposed, and the sealing conditions and mutual switching conditions of the cylinder working condition and spray working condition are revealed. Secondly, the mathematical description of the eddy current magnetic field of the permanent magnet eddy current valve is established, and the calculation equations of the torque and axial force of the permanent magnet eddy current transmission are proposed, and a calculate study is carried out by using the finite element method, and the calculation results show that in the low-slip region, the analysis of the electromagnetic torque and axial force characteristics of the permanent magnet eddy current and the finite element results are in good agreement. Finally, example simulations show that the permanent magnet eddy current switch can realize the sealing and its switching between the two operating conditions as desired, and can realize the low leakage operation.