Conical internal thread

Abstract

The invention relates to a tapered inside thread. The root part between teeth is a centering sloping surface, the large diameter end on the upper part of the centering sloping surface is a centering surface in interference fit with the crest of an outside tapered thread, and the included angle beta between the centering sloping surface and a main conical surface is more than 0 and less than alpha which is the inclination angle of the main conical surface. The root part between the teeth of the tapered inside thread adopts a structure with two conical surfaces of the centering sloping surface to form a full thread helical interference surface of which the size can be adjusted by adjusting the stand-off so as to accord with an operating condition requirement, and the generation of the full thread helical interference surface makes loads be evenly distributed on the full length of the thread, a self-locking helical surface is formed and has superior anti-looseness performance; and the tapered inside thread has excellent capability to resist transverse vibration for dealing with frequent vibration and alternating load, is not easy to cause abrasion and fatigue fracture, is suitable for frequent disassemblies, and can interchange with the prior product by only changing the inside thread.

Description

technical field [0001] The invention relates to a thread, especially a tapered internal thread with triangular, trapezoidal, zigzag, etc., which is mainly used in drill pipes, oil pipes, casings and trenchless drill pipes for petroleum, geological exploration and mining. Wait. Background technique [0002] Tapered thread is the necessary way to transmit power and medium for drill pipe, tubing, casing, trenchless drill pipe and other products used in petroleum, geological exploration and development. Drill pipe, tubing, and casing are connected by tapered thread at the end to transmit Power, conveying medium, etc., traditional tapered threads such as API threads and geological threads determine the thread size through the pitch diameter of the thread, and the major diameter of the secondary thread formed is a clearance fit, which is guaranteed by the pitch diameter of the thread; the wireline core drill pipe thread adopts a large Diameter centering, its common disadvantages ...

AI Technical Summary

Problems solved by technology

[0002] Tapered thread is the necessary way to transmit power and medium for drill pipe, tubing, casing, trenchless drill pipe and other products used in petroleum, geological exploration and development. Drill pipe, tubing, and casing are connected by tapered thread at the end to transmit Power, conveying medium, etc., traditional tapered threads such as API threads and geological threads determine the thread size through the pitch diameter of the thread, and the major diameter of the secondary thread formed is a clearance fit, which is guaranteed by the pitch diameter of the thread; the wireline core drill pipe thread adopts a large Diameter centering, its common disadvantages are: small self-locking area, poor anti-loosening effect, uneven load distribution, poor ability to withstand frequent lateral vibration and alternating stress, and thread parts are prone to wear and fracture, especially for rope core drills. The rod wall is thin, so it is necessary to use short teeth and large pitch threads, and the torque is relatively large. The thread is centered with a large diameter, large head interference, small head clearance, uneven force, and more prominent shortcomings

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