CN201756920U

CN201756920U - Variable-taper API threaded oil casing joint

Info

Publication number: CN201756920U
Application number: CN2010202523275U
Authority: CN
Inventors: 王京; 徐志谦; 李毅; 闫龙; 史彬; 骆敬辉; 陈涛; 梅丽; 吕春莉; 吴稀勇; 柳玉伟; 王春河; 张军; 屈强
Original assignee: Tianjin Pipe Group Corp
Current assignee: Tianjin Steel Tube Manufacturing Co., Ltd.
Priority date: 2010-07-09
Filing date: 2010-07-09
Publication date: 2011-03-09
Anticipated expiration: 2020-07-09

Abstract

The utility model provides a variable-taper API threaded oil casing joint, which comprises female threads and male threads. The female threads are arranged at two ends of a box coupling, the male threads are arranged at ends of a casing, the female threads of the box coupling are in screwing connection with the male threads at the ends of the casing, the female threads at two ends of the box coupling are structurally symmetrical, the female threads at two ends of the box coupling are API threads, intermediate diameter of the female threads is variable in taper, an intermediate diameter line of the female threads consists of three connected segments, and the male threads at the ends of the casing are API threads. The taper-variable API threaded oil casing joint has the advantages that in the threaded oil casing joint, taper-variable threads are machined on the box coupling, radial interference magnitude at thread meshed positions of two ends of the box coupling is reduced, thread contact stress at two ends of the joint is decreased, thread contact stress in the middle of the joint is increased, and thread contact stress which is uneven in distribution originally is distributed evenly. The female threads at each end of the box coupling are the API threads, the male threads at the ends of the casing match with the female threads and are also the API threads, and taper of the male threads is 1:16, so that contact stress of the threads is close to uniform in distribution.

Description

Variable conicity API (American Petroleum Institute) thread oil sleeve joint

Technical field

The utility model relates to a kind of technology that is threaded, the petroleum oil that will use when being used for oil drilling, exploitation and production and the variable conicity API (American Petroleum Institute) thread oil sleeve joint of sleeve pipe.

Background technology

The API screw thread is a taper pipe thread, and its tapering is 1: 16 or 1: 12.Since 20th century came out, because its handling ease, low price had obtained using widely at oil gas field.Using and studies show that according to the scene, load distribution on each thread engagement tooth is very inhomogeneous, the threads carry at two ends most load, middle most of screw thread is shared the very load of fraction, so the joint two ends are serious stress concentration districts, be easy to thread gluing and damage, and the screw thread of mid portion are because carrying is very little, much smaller than YIELD STRENGTH, so the ability of material does not obtain maximum performance.

Summary of the invention

At the deficiency on the API helicitic texture, the purpose of this utility model provides a kind of variable conicity API (American Petroleum Institute) thread oil sleeve joint, is beneficial to improve the phenomenon of common API thread compound casing joint load distribution inequality.

For achieving the above object, the technical solution adopted in the utility model provides a kind of variable conicity API (American Petroleum Institute) thread oil sleeve joint, this joint includes the box thread at box cupling two ends and the male thread of cannula tip, the box thread of described box cupling and the male thread of cannula tip are screwed, wherein: the box thread symmetrical configuration at described box cupling two ends is provided with, the box thread of each end is the API screw thread, the middle footpath of this box thread is a taper mutation, the middle line of box thread is made up of three continuous line segments, and the male thread of cannula tip is the API screw thread.

Effect of the present utility model is to use this thread compound casing joint, inhomogeneous at the load distribution on each thread engagement tooth of API screw thread, the threads carry at two ends big load, the characteristics of the very little load of part threads carry broad in the middle, by box cupling being processed into the taper mutation screw thread, reduce the radial interference amount at thread engagement place, two ends, reduce the contact stress of joint two ends screw thread, improve the contact stress of the screw thread at joint middle part, making originally, the thread contact stress distribution of skewness is tending towards even.The box thread of each end is made of the API screw thread, and the male thread of the pipe end that cooperates with box thread is made of the API screw thread, and male thread tapering 1: 16 can make the distribution of contact of screw thread be tending towards even like this.

Description of drawings

Fig. 1 is the structural representation of casing joint of the present utility model;

Fig. 2 is the schematic diagram of the box thread middle line of box cupling of the present utility model.

Among the figure: A-box cupling B sleeve pipe

C-is the taper mutation position D-taper mutation position second time for the first time

E-axis T-tapering is 1: 16 middle footpath

The specific embodiment

Reaching embodiment in conjunction with the accompanying drawings is illustrated variable conicity API (American Petroleum Institute) thread oil sleeve joint structure of the present utility model.

Variable conicity API (American Petroleum Institute) thread oil sleeve joint structure of the present utility model is, this joint includes the box thread at box cupling two ends and the male thread of cannula tip, the box thread of described box cupling and the male thread of cannula tip are screwed, the box thread symmetrical configuration at described box cupling two ends is provided with, the box thread of each end is the API screw thread, the middle footpath of this box thread is a taper mutation, and the middle line of box thread is made up of three continuous line segments, and the male thread of cannula tip is the API screw thread.

The middle footpath tapering of the box thread taper mutation of described box cupling was respectively 1: 20,1: 16 and 1: 12; The taper mutation position of described box thread respectively with preceding 1～5 tooth position of the male thread of cannula tip engagement and the position of back 1～5 pitch thread.

As shown in Figure 1, 2, this variable conicity API (American Petroleum Institute) thread oil sleeve joint structure comprises the box thread of box cupling A and male thread two parts composition of sleeve pipe B.The box thread middle line of box cupling A is made up of three continuous line segments, and tapering was respectively 1: 12,1: 16 and 1: 20 from coupling face to box cupling center.

T among Fig. 2 is a footpath circular arc in former 1: 16, and C and D are respectively the position that tapering begins to change, and E is an axis.The middle line of described taper mutation box thread is made up of three continuous line segments, and tapering was respectively 1: 20,1: 16 and 1: 12, the position of taper mutation respectively with the position of preceding 1～5 tooth position of male end screw-threaded engagement and back 1～5 pitch thread.The taper mutation screw thread can reduce the radial interference amount at thread engagement place, two ends, makes distribution of contact be tending towards even.This structure can be processed on digital control system commonly used.

Claims

1. variable conicity API (American Petroleum Institute) thread oil sleeve joint, this joint includes the box thread at box cupling two ends and the male thread of cannula tip, the box thread of described box cupling and the male thread of cannula tip are screwed, it is characterized in that: the box thread symmetrical configuration at described box cupling two ends is provided with, the box thread of each end is the API screw thread, the middle footpath of this box thread is a taper mutation, and the middle line of box thread is made up of three continuous line segments, and the male thread of cannula tip is the API screw thread.

2. variable conicity API (American Petroleum Institute) thread oil sleeve joint according to claim 1 is characterized in that: the middle footpath tapering of the box thread taper mutation of described box cupling was respectively 1: 20,1: 16 and 1: 12.

3. variable conicity API (American Petroleum Institute) thread oil sleeve joint according to claim 1 is characterized in that: the taper mutation position of described box thread respectively with preceding 1～5 tooth position of the male thread of cannula tip engagement and the position of back 1～5 pitch thread.