The invention relates to a hydraulic locking rotary joint. Two interpenetrating channels are formed in a housing, in one channel, a mandrel is supported by a bearing, a braking piece is installed outside the mandrel, and the mandrel and the housing are relative rotating members of the rotary joint; a miniature
hydraulic cylinder is installed in the other channel, and the back part of a cylinder
barrel is pressed against a disc spring group. When low-pressure oil is introduced into an oil cylinder, the disc spring group is pressed against the cylinder
barrel, so that the braking piece is pressed by the inclined plane of a boss on a cylinder cover on the front end of the cylinder
barrel, the mandrel is tightly held, and the rotary joint is in a locking state; when high-pressure oil is introduced into the oil cylinder, a
piston rod protrudes to withstand a stop pin, the
piston rod stops moving, the cylinder barrel overcomes the thrust of the disc spring group to retract, the inclined plane of the boss on the cylinder cover leaves the braking piece, the mandrel is loosened, and the rotary joint is in a rotatable state. The rotary joint has the advantages of small size, light weight, large locking force, large bearing rotary torque and convenience in control. By adopting the rotary joint, the performance of a rod-shaped serial mechanism, especially an
endoscope bracket and the likecan be obviously improved.