High-strength drill rod joint with equidistant arc surfaces

Abstract

The invention discloses a high-strength drill rod joint with equidistant arc surfaces. At present, two drill rod joints, namely a conical threaded joint and a hexagonal joint, exist at home and abroad. The "high-strength drill rod joint with the equidistant arc surfaces" uses the equidistant arc surfaces to transmit torque and uses a cylindrical surface to center; stress concentration exists in sharp corners arranged in the threads in the conical threaded joint and a hexagon of the hexagonal joint; the "equidistant arc surfaces" for transmitting the torque of the drill rod joint is free of sharp edges and sharp corners, free of stress concentration and high in fatigue strength; no sealing ring is arranged in the conical threaded joint and the hexagonal joint correspondingly, and a sealingring is arranged at the drill rod joint, so that silt can be prevented from invading the drill rod joint, and the service life of the drill rod joint can be prolonged; wear-resistant alloy layers or sliding sleeves and the like are spray and welded on the surface of the conical threaded joint and the surface of the hexagonal joint correspondingly, and are in sliding friction with sleeves to greatly abrade the sleeves; and a "roller pin antifriction sleeve" is arranged on the drill rod joint, and a roller pin is in rolling friction with a sleeve, so that the abrasion of the sleeve is reduced, and the service life is prolonged.

Description

technical field [0001] The invention is a new type of drill pipe joint - a high-strength drill pipe joint with equidistant circular arc surfaces. Background technique [0002] The two ends of the drill pipe joint are connected to the drill pipe to transmit power to the drill bit. At present, there are two types of drill pipe joints used at home and abroad, conical threaded joints ( figure 1 ) and hexagonal connector ( figure 2 ). [0003] Existing problems: There are pitch errors and taper errors in the cooperation between the external thread and the internal thread of the conical threaded joint, uneven contact between each thread surface, and stress concentration. The fillet radius at the root of the thread is very small, only 0.4-0.6mm, and there is a large stress concentration. There is no sealing device for the conical thread joint, and mud and sand enter between the threads, which accelerates the wear and failure of the thread. In the hexagonal joint, the hexagon i...

AI Technical Summary

Problems solved by technology

[0003] Existing problems: There are pitch errors and taper errors in the cooperation between the external thread and the internal thread of the conical threaded joint, uneven contact between each thread surface, and stress concentration

The fillet radius at the root of the thread is very small, only 0.4-0.6mm, and there is a large stress concentration. There is no sealing device for the conical thread joint, and mud and sand enter between the threads, which will accelerate the wear and failure of the thread

In the hexagonal joint, the hexagon is used to transmit torque, and there is a large stress concentration on the contact surface between the outer hexagon and the inner hexagon during rotation ( image 3 ), the size error and misalignment deviation of the six aspects of processing are relatively large, and the fit gap between the outer hexagon and the inner hexagon is large, causing vibration when rotating at a high speed, and the vibration generates an impact load to accelerate the wear of the six aspects; the fit clearance is large, and sand enters the joint Faster hexagonal joint fatigue wear failure

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