Hydraulic cylinder of novel seal structure

The invention provides a hydraulic cylinder of a novel seal structure. The hydraulic cylinder comprises a cylinder body, a cylinder cover, a piston, a piston rod and seal pieces. The cylinder cover comprises a front end cover and a rear end cover which are connected to the two ends of the cylinder body respectively. The piston rod is connected with the piston to form a piston assembly. The piston assembly is arranged in the cylinder body in a penetrating mode. The front end of the piston assembly is connected with the front end cover. The rear end of the piston assembly is connected with the rear end cover. The seal pieces are arranged between the front end cover and the cylinder body and between the rear end cover and the cylinder body respectively. A thermal insulating sleeve is arranged on the periphery of the part, provided with the corresponding seal piece, of the cylinder body. An annular groove is formed in the middle of the thermal insulating sleeve. After installation, a cavity is formed between the annular groove and the cylinder body. The part, provided with the corresponding seal piece, of the cylinder body is isolated from the outer world through sealing air at the two ends of the hydraulic cylinder, heat transmission is prevented from being conducted between the sealed part and the outer world through sealing air according to the air thermal insulation principle, and therefore the aim of lowering the temperature of the sealed part is achieved, the effect on preventing the seal rings from aging is achieved, oil leakage is effectively prevented, and the work performance of the hydraulic cylinder and the movement stability of hydraulic execution elements are improved.