In order to solve the leakage problem of the engineering mechanical hydraulic cylinder, a magnetorheological
fluid (MRF) seal structure with a multistage source is designed. The magnetic f ield in the gap of the sealing
structure is analyzed by ANSYS finite element analysis method, the influence about the number of magnetic
sources and the length of pole teeth on the pressure capability of the MRF seal is studied, and the results are
analyzed. The results show that the suitable number of magnetic sources is 10; The length of the pole teeth with
the best magnetic concentrating effect is 0.7 mm. Then, the influence of the MRF injection volume, reciprocating
speed, reciprocating distance and holding pressure time of the hydraulic cylinder on the MRF sealing
pressure capability is studied. The experimental results show that the maximum pressure capacity can be
achieved when the MRF injection volume is 12 ml. With the increase of reciprocating speed, the pressure
capability of the MRF seal decreases obviously. With the increase of reciprocating distance and holding time,
the sealing pressure capability has no obvious change. Through the finite element analysis and experimental
study of the MRF seal, it is of great significance to develop a device with high sealing performance suitable for
the hydraulic cylinders.