Ground hydraulic drilling jar for deep well and extra-deep well

A ground hydraulic drilling jar for a deep well and an extra-deep well is mainly composed of a lifting sub, an upper hydraulic cylinder, an oil hole, a lower hydraulic cylinder, a piston, a pressure relieving hole, an upper sealing ring, a metal sealing ring, a lower beating rod, a middle sealing ring, a sealing set, a bearing ring, chain rings, a circulating connector, a circulating hole and a safe chain, the pressure relieving hole is drilled in the piston, the upper sealing ring and the metal sealing ring are arranged around the piston, the lower beating rod is in screwed connection with the piston, the lifting sub is in screwed connection with the upper hydraulic cylinder, the oil hole is formed in the upper portion of the upper hydraulic cylinder, the upper hydraulic cylinder and the lower hydraulic cylinder are in screwed connection, the screwed connection positions of the upper hydraulic cylinder and the lower hydraulic cylinder are sealed through the middle sealing ring, the connected lower beating rod and piston are put into the lower hydraulic cylinder from the lower face of the lower hydraulic cylinder, the sealing set is arranged in the lower hydraulic cylinder from the lower end of the lower beating rod in a sleeved mode and is jacked to a circular bead, the bearing ring is arranged on the lower beating rod in a sleeved mode, a buckled special tool hole is machined in the lower face of the bearing ring, screw threads between the bearing ring and the lower hydraulic cylinder are connected, the lower face of the lower beating rod is connected with the circulating connector through screw threads, the circulating hole is formed beside the circulating connector, the chain rings are arranged at the lower end of the lower hydraulic cylinder and on the circulating connector, and the safe chain is connected between the chain rings of the circulating connector and the lower hydraulic cylinder.