Oil cylinder protective device for main pressure roller of hydraulic profile steel straightening machine

The invention specifically discloses an oil cylinder protective device for a main pressure roller of a hydraulic profile steel straightening machine. The oil cylinder protective device comprises the main pressure roller, and is characterized by further comprising an oil cylinder bottom plate, an outer protective sleeve, an inner protective sleeve and an oil cylinder, wherein the oil cylinder bottom plate provides enough acting force to the oil cylinder; the periphery of the outer side of the cylinder body of the oil cylinder is equipped with the inner protective sleeve; the outer side of the periphery of the inner protective sleeve is equipped with the outer protective sleeve; after the oil cylinder completely extends out, the inner protective sleeve and the outer protective sleeve have superposition in certain dimension, so that the inner protective sleeve and the outer protective sleeve define a sealed space, profile steel oxide skins or other impurities are prevented from entering,and an oil cylinder pisto