CN110410024B

CN110410024B - Variable tooth width screwed joint

Info

Publication number: CN110410024B
Application number: CN201910582410.4A
Authority: CN
Inventors: 潘志勇; 刘永刚; 韩礼红; 余志�; 龙岩; 路彩虹; 韩军; 王蕊
Original assignee: China National Petroleum Corp; CNPC Tubular Goods Research Institute
Current assignee: China National Petroleum Corp; CNPC Tubular Goods Research Institute
Priority date: 2019-06-28
Filing date: 2019-06-28
Publication date: 2021-09-28
Anticipated expiration: 2039-06-28
Also published as: CN110410024A

Abstract

The invention discloses a tooth width-variable threaded joint which comprises an external thread joint and an internal thread joint, wherein the external thread joint and the internal thread joint are respectively provided with an external thread meshing section and an internal thread meshing section; the tooth width of the large end part of the internal thread is smaller than the tooth space width, the tooth space width of the external thread meshed with the large end part of the internal thread is larger than the tooth width of the internal thread, and the tooth width of the external thread meshed with the large end part of the internal thread is smaller than the tooth space width of the internal thread, so that a certain tooth side clearance exists after the internal thread and the external thread are meshed at the large end part of the large end part, and the uniform distribution of the force after the screwing-on and the bearing is facilitated.

Description

Variable tooth width screwed joint

Technical Field

The invention belongs to the field of oil drilling, development and production, and particularly relates to a variable tooth width threaded joint.

Background

API (American Petroleum Institute) pipe threads used in the Petroleum industry mainly comprise API standard round threads and API standard buttress threads, and the two threads are widely used in the Petroleum industry due to simple processing and low production cost. As shown in fig. 1, since the API thread is a tapered thread, all thread tooth widths are equal, and all thread tooth groove widths are also equal, when the engaged threaded joint is subjected to an axial force, large stress concentrations are generated at two dangerous sections, namely, at a position of a small end of engagement fig. 1M of the female threaded joint and at a position of a large end of engagement fig. 1N of the male threaded joint, the small end of engagement wall of the female threaded joint is relatively thick, so that the stress risk generated is small, and the stress risk faced by the large end of engagement wall of the male threaded joint is relatively thick. On the other hand, the stress distribution of the thread meshing section is saddle-shaped, namely, the two ends are high and the middle is low, so that the stress of the large meshing end of the male adapter is aggravated. Therefore, in order to enhance the ability of the threaded joint to resist risks, it is necessary to reduce the stress concentration at the large engagement end of the male threaded joint on the one hand, and to optimize the load distribution of the engaged threads on the other hand.

Disclosure of Invention

The invention aims to provide a variable tooth width threaded joint, which reduces stress concentration at the meshing large end of an external threaded joint and enhances the bearing capacity of the threaded joint by optimally setting the tooth width and the tooth space width of threads.

In order to achieve the purpose, the invention adopts the technical scheme that the tooth width-variable threaded joint comprises an external thread joint and an internal thread joint, wherein the external thread joint and the internal thread joint are respectively provided with an external thread meshing section and an internal thread meshing section, the internal thread tooth width of the internal thread joint is different from the tooth space width, the internal thread tooth width is divided into three sections, the internal thread tooth width is larger than the tooth space width section, the internal thread tooth width is equal to the tooth space width section, the internal thread tooth width is smaller than the tooth space width section, and the external thread tooth width of the external thread joint is equal to the tooth space width.

The internal thread tooth width is greater than the tooth space width section and comprises a meshed internal thread small end and an unmeshed internal thread, the tooth width is greater than the API standard thread tooth width, and the tooth space width is less than the API standard thread tooth space width.

The tooth width of the internal thread is equal to the tooth space width and is positioned in the middle of the external thread meshing section, and the tooth width of the thread is equal to the tooth space width of the thread.

The internal thread tooth width is smaller than the tooth space width, the section is located at the large end of the external thread meshing section, the tooth width is smaller than the API standard thread tooth width, and the tooth space width is larger than the API standard thread tooth space width.

The external thread joint is provided with an external thread tooth width section equal to the tooth space width, and the tooth width section is equal to the tooth space width.

The tooth width of the external thread is equal to the tooth width in the tooth space width section and equal to the tooth width of the internal thread in the tooth space width section.

The tooth width of the external thread is equal to the tooth width of the internal thread in the tooth space width section and is equal to the tooth width of the internal thread in the tooth space width section.

The thread pitch of both the pin and the box is equal to the thread pitch of the API standard thread.

The external thread on the external thread joint and the internal thread on the internal thread joint adopt round threads, buttress threads, hook threads or wedge threads.

Compared with the prior art, the invention has at least the following beneficial effects:

the tooth width of the large end part of the internal thread is smaller than the tooth space width, the tooth space width of the external thread meshed with the large end part of the internal thread is larger than the tooth width of the internal thread, and the tooth width of the external thread meshed with the large end part of the internal thread is smaller than the tooth space width of the internal thread, so that a certain tooth side clearance exists after the internal thread and the external thread are meshed at the large end part of the large end part, and the uniform distribution of the force after the screwing-on and the bearing is facilitated.

Drawings

Fig. 1 is a schematic view of a threaded joint assembly.

Fig. 2 is a schematic view of the female adapter of the present invention.

FIG. 3 is a schematic view of a male connection of the present invention.

Wherein: 1-an external thread joint; 2, an internal thread joint, 21, wherein the tooth width of the internal thread is larger than the tooth space width section; 22-the tooth width of the internal thread is equal to the tooth space width section; 23-the tooth width of the internal thread is smaller than the tooth space width section; 11-the tooth width of the external thread is equal to the tooth space width section; 24-an internal thread meshing section and 12-an external thread meshing section; m-the small end of the female adapter; the N-external thread joint is engaged with the big end.

Detailed Description

The invention is further elucidated with reference to the drawing.

As shown in fig. 2 and 3, the tooth width-variable threaded joint of the present invention includes an external threaded joint 1 and an internal threaded joint 2, where the external threaded joint 1 and the internal threaded joint 2 respectively have an external thread meshing section 12 and an internal thread meshing section 24, and the internal thread tooth width of the internal threaded joint 2 is different from the tooth space width, and is divided into three sections, where the internal thread tooth width is greater than the tooth space width section 21, the internal thread tooth width is equal to the tooth space width section 22, the internal thread tooth width is less than the tooth space width section 23, and the external thread tooth width of the external threaded joint 1 is equal to the tooth space width.

The threaded joint 2 is provided with an internal thread with the tooth width larger than the tooth space width section 21, the internal thread with the tooth width equal to the tooth space width section 22 and the internal thread with the tooth width smaller than the tooth space width section 23, so that the stress concentration of the threaded joint is reduced, and the bearing capacity of the threaded joint is enhanced.

The internal thread tooth width is larger than the tooth space width section 21, and comprises a meshed internal thread small end and an unmeshed internal thread, the tooth width is larger than the tooth width of the API standard thread, and the tooth space width is smaller than the tooth space width of the API standard thread; the internal thread tooth width is equal to the tooth space width, the section 22 is located in the middle of the external thread meshing section 12, the tooth width is equal to the tooth space width, the internal thread tooth width is smaller than the tooth space width, the section 23 is located at the large end of the external thread meshing section 12, the tooth width is smaller than the API standard thread tooth width, and the tooth space width is larger than the API standard thread tooth space width.

The external thread joint 1 is provided with an external thread tooth width equal to the tooth space width section 11, and the tooth width is equal to the tooth space width; the tooth width of the external thread is equal to the tooth width of the tooth space wide section 11 and the tooth width of the internal thread is equal to the tooth width of the tooth space wide section 22; the tooth width of the external thread is equal to the tooth width of the internal thread in the tooth space width section 11 and is equal to the tooth width of the internal thread in the tooth space width section 22.

The pitch of the pin 1 and the box 2 is equal to the pitch of the API standard thread.

The external thread on the external thread joint 1 and the internal thread on the internal thread joint 2 adopt round threads, buttress threads, hook threads or wedge threads.

Claims

1. The tooth width-variable threaded joint is characterized by comprising an external threaded joint (1) and an internal threaded joint (2), wherein the external threaded joint (1) and the internal threaded joint (2) are respectively provided with an external thread meshing section (12) and an internal thread meshing section (24), the internal thread tooth width of the internal threaded joint (2) is different from the tooth space width, the internal thread tooth width is divided into three sections, the internal thread tooth width is greater than the tooth space width section (21), the internal thread tooth width is equal to the tooth space width section (22), the internal thread tooth width is smaller than the tooth space width section (23), and the external thread tooth width of the external threaded joint (1) is equal to the tooth space width; the tooth width of the internal thread is equal to the tooth space width section (22) and is positioned in the middle of the external thread meshing section (12); the internal thread tooth width is smaller than the tooth space width section (23) and is positioned at the large end of the external thread meshing section (12), the tooth width is smaller than the tooth width of the API standard thread, and the tooth space width is larger than the tooth space width of the API standard thread.

2. The variable thread joint according to claim 1, wherein the section (21) having the internal thread tooth width larger than the groove width comprises a small end of the internal thread engaged and an internal thread not engaged, the tooth width is larger than the API standard thread tooth width, and the groove width is smaller than the API standard thread groove width.

3. A variable tooth width threaded joint as claimed in claim 1, characterized in that the male connector (1) is provided with a male thread tooth width equal to the tooth space width section (11) and a tooth width equal to the tooth space width.

4. A variable tooth width threaded joint as set forth in claim 3 wherein the male thread tooth width is equal to the tooth width of the tooth space width section (11) and the female thread tooth width is equal to the tooth width of the tooth space width section (22).

5. A variable thread joint according to claim 3 wherein the thread width of the external thread is equal to the tooth width of the internal thread in the tooth-width segment (11) and the tooth width of the internal thread is equal to the tooth width of the tooth-width segment (22).

6. A variable tooth width threaded joint as claimed in claim 1, characterized in that the pitch of the pin (1) and the box (2) are each equal to the pitch of an API standard thread.

7. A variable tooth width threaded joint as claimed in any one of claims 1 to 6, characterized in that the external thread on the external threaded joint (1) and the internal thread on the internal threaded joint (2) are round threads, buttress threads, hook threads or wedge threads.