In this study, a conductivity-regulated barrel-type permanent magnet eddy current governor is proposed, and a conductor barrel structure scheme consisting of four sections of materials with different conductivities is presented. The torque equation of the barrel-type permanent magnet eddy current governor with the equivalent conductivity as the covariate was established using the separation variable method based on the subdomain model, and the equivalent conductivity function was established to obtain the speed regulation characteristics of the governor under a constant torque load. The influence of the conductivity parameters of the conductor barrel on the speed regulation characteristics was studied by numerical simulation, the influence of the conductivity values of each section of the material on the conductivity function was investigated, and the torque equation and conductivity function were verified by three-dimensional electromagnetic finite element simulation. The results show that the structural scheme of the four-segment combined conductor barrel can realize a continuous change in conductivity with the displacement of the magnet disk, thus realizing continuous speed regulation of the constant torque load, and the speed regulation characteristic of the governor is segmented linearly. Compared with the air gap-regulated disk-type permanent magnet eddy current governor, the conductivity-regulated barrel-type permanent magnet eddy current governor has a wider speed regulation range, a lower unloading torque after overload protection, and can start with its maximum torque, thus enabling heavy-load starting of constant torque loads, speed regulation operation, and unloading overload protection of equipment.

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.

To address the problem of problematic spray design inside mining anchor-digging equipment, a switching seal using a permanent magnet eddy current drive is initially presented here. The layer model of the permanent magnet eddy current structure is established, the subdomain analysis model is introduced, the permanent magnet eddy current structure is divided into six regions along the axial direction, and the boundary equations are established at the interfaces of each region. The vector magnetic potential equations in each region are deduced, along with the electromagnetic torque and axial force equations. The computational results are compared and analyzed with the results of finite element simulation, verifying the accuracy of the theoretical model. The design of experiments is used to verify the feasibility of the switching seal using the permanent magnet eddy current structure.