CN115707850A - Eccentric threaded joint - Google Patents
Eccentric threaded joint Download PDFInfo
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- CN115707850A CN115707850A CN202110962243.3A CN202110962243A CN115707850A CN 115707850 A CN115707850 A CN 115707850A CN 202110962243 A CN202110962243 A CN 202110962243A CN 115707850 A CN115707850 A CN 115707850A
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Abstract
The invention discloses a partial-circle threaded joint which comprises a male end with an external thread and a female end with an internal thread, wherein the male end and the female end are in matched meshed connection, the tooth top between a bearing surface and a guide surface of the external thread is a tooth top fillet part, the tooth bottom between the bearing surface and the guide surface of the external thread is a tooth bottom fillet part, and the angular bisectors of the tooth top fillet part and the tooth bottom fillet part respectively have an included angle A of non-zero degrees with the radial direction. The eccentric threaded joint is convenient to process and difficult to trip, and has high tensile resistance and high air tightness; the eccentric threaded joint can be buckled conveniently and improve the buckling efficiency.
Description
Technical Field
The invention relates to a steel pipe joint, in particular to a threaded joint.
Background
In the field of drilling and developing of underground resources such as petroleum and natural gas, a drill rod is often needed to drill a stratum, then a casing is used for sealing the stratum and fluid in the casing, and oil and gas are conveyed through the oil pipe. Drill pipes, casing pipes and oil pipes are often connected in a threaded manner, and the steel pipes are connected one by one and then lowered into the ground to reach the depth of several kilometers, wherein each pipe is about 10 meters long.
In the API 5B standard, the contract tubing joint should be able to withstand 4 make-up and break-out operations without galling, the API 5C5 standard test procedure specifies that the tubing should be able to withstand 10 make-up and 9 break-out operations without galling, and the casing should be able to withstand 3 make-up and 2 break-out operations without galling. However, in oil pipes and casings used in oil fields, due to the fact that the working conditions are severe, environmental wind and sand, pipe tongs are operated, excessive torsion and the like, the phenomenon of thread gluing happens sometimes when the pipe is disassembled after 1 time of tightening, in addition, after the pipe column is used for a period of time, the pipe column is taken out again and stacked on a ground well site due to various reasons, the inner surface and the outer surface of the pipe often corrode seriously, the surface of a thread cannot be reused due to improper protection reasons such as thread gluing, corrosion and collision, and the pipe column and the casing can be used only after being recovered and cleaned and processed into new threads.
Whether the equipment precision or the technical capability of a processing plant for recycling processing is behind compared with that of the original manufacturing plant, the high-performance airtight high-quality threaded joint is difficult to process, and only conventional threaded joints specified by API standards, such as a plain-end pipe round threaded oil pipe NU, an external thickening round threaded oil pipe EU, a short round threaded sleeve SC, a long round threaded sleeve LC and a buttress threaded sleeve BC, can be processed. The externally thickened EU joint is formed by heating and upsetting the pipe end on the basis of a plain end pipe and then processing threads. But the thickened end part needs to be cut off after the thread is damaged, the thread is machined again at the moment, the length of the thickened end cannot meet the machining requirement, and only the thickened NU joint can be machined into a non-thickened NU joint, but the anti-slipping performance of the round thread NU joint is poor, the tensile property of the joint is only 60% -80% of that of the pipe body, and when the tensile force is increased, the joint is tripped.
The secondary recovery pipes are various in types, some are high-alloy steel with high price, some are low-alloy steel, and some are common carbon steel; the corrosion degrees of the pipes are different, some pipes are not corroded, some pipes are slightly corroded, and some pipes are seriously corroded; the original threaded joints are different, some are thickened at the pipe end, some are air-tight high-quality threads, and some are plain-end pipes. However, the API common thread has lower performance and cannot meet the use requirement, and part of the recovery pipe still hopes to be processed into a joint product with higher performance by using the existing processing equipment.
Based on the above, in order to improve the performance of the threaded joint processed by the secondarily recovered pipe, and simultaneously, in consideration of the advantages and the disadvantages of the existing Round Thread and buttress Thread, the invention designs a partially Round Thread (Deflective Round Thread) joint which is convenient to process and not easy to release, has high tensile resistance and has high air tightness.
The eccentric threaded joint can be buckled greatly and conveniently, and the screwing efficiency is improved; the eccentric threaded joint has excellent performance and very wide applicability, can be used in severe working conditions such as oilfield exploitation, is convenient for subsequent repeated repair, and has good popularization prospect and application value.
Disclosure of Invention
One of the purposes of the invention is to provide a partial round threaded joint which is convenient to process and difficult to trip, has higher tensile resistance and air tightness; the eccentric threaded joint can be buckled conveniently and improve the buckling efficiency.
The eccentric threaded joint has excellent performance and wide applicability, can be effectively applied to severe working conditions such as oilfield exploitation, is convenient for subsequent repeated repair, and has good popularization prospect and application value.
In order to achieve the above object, the present invention provides a partial-round threaded joint, which includes a male end having an external thread and a female end having an internal thread, which are engaged with each other, wherein a tooth crest between a bearing surface of the external thread and a guide surface is a tooth crest fillet, a tooth bottom between the bearing surface of the external thread and the guide surface is a tooth bottom fillet, and respective angle bisectors of the tooth crest fillet and the tooth bottom fillet have a non-zero included angle a with a radial direction.
In the prior art, API oil casing standards specify 10 and 8 threads per inch round threads and 5 threads per inch buttress threads. The round thread is easy to process, gaps are only arranged at the tooth top and the tooth bottom round angle after screwing, and the sealing performance is better after being filled with thread grease. When the thread is buckled, the radial interference is large, thread gluing is easy to occur, and batch thread gluing is easy to occur in the repeatedly used oil pipe; the anti-slippage performance is poor, the tensile strength of the joint is only 60% -80% of that of the pipe body, when the tensile force is increased, the joint is tripped, the pipe column falls into the well, and production accidents are caused, so that the round threads are difficult to use in deep wells and high-pressure wells with worse well conditions. The buttress thread has high tensile property, but the axial tooth width of the thread has a gap of 0.05-0.20 mm after the gaps of the four round corners of the buttress thread exist, and the sealing performance of the buttress thread is not as good as that of a round thread due to the gaps.
Therefore, in consideration of the advantages and the disadvantages of the round thread and the buttress thread, the invention combines the advantages of the round thread and the buttress thread and creates a brand new eccentric threaded joint.
In the invention, the eccentric threaded joint can be ensured to obtain higher tensile resistance and higher air tightness through the reasonable design of the joint structure; the eccentric threaded joint can greatly facilitate the buckling of the male end and the female end, improves the buckling efficiency, and ensures that the male end and the female end are not easy to be tripped.
Further, in the partial circular threaded joint of the present invention, the degree of the included angle B between the bearing surface and the guide surface satisfies: b is more than or equal to 50 degrees and less than or equal to 70 degrees.
Further, in the eccentric threaded joint of the present invention, an included angle between the bearing surface and the guide surface is B, and the degrees of a and B satisfy: b/2-5.71 is less than or equal to A and less than or equal to B/2+5.71.
Further, in the eccentric threaded joint of the present invention, it satisfies:
wherein H represents the radial distance between the virtual intersection point of the bearing surface and the guide surface at the tooth top and the virtual intersection point of the bearing surface and the guide surface at the tooth bottom, p represents the thread pitch, gamma represents the half-cone angle, and the half-cone angle is half of the thread taper.
Further, in the eccentric threaded joint of the present invention, it satisfies:
wherein S is cs Denotes the radial distance, R, between the highest point of the tooth tip fillet and the virtual intersection of the bearing surface and the guide surface at the tooth tip cs The radius of the crest fillet is γ, which represents the half-cone angle, which is half of the thread taper.
Further, in the eccentric threaded joint of the present invention, it satisfies:
wherein S is rs Representing the radial distance, R, between the lowest point of the fillet of the tooth bottom and the virtual intersection of the bearing surface and the guide surface at the tooth bottom rs The fillet radius of the fillet portion of the tooth bottom, γ, represents a half-cone angle, which is half of the thread taper.
Further, in the eccentric threaded joint of the present invention, it satisfies:
wherein h is s Representing the tooth height, H representing the radial distance between the virtual intersection point of the bearing surface and the guide surface at the tooth top and the virtual intersection point of the bearing surface and the guide surface at the tooth bottom, S rs Represents the radial distance, S, between the lowest point of the fillet of the tooth bottom and the virtual intersection of the bearing surface and the guide surface at the tooth bottom rs Representing the radial distance between the lowest point of the fillet of the tooth bottom and the virtual intersection of the bearing surface and the guide surface at the tooth bottom.
Further, in the partial round threaded joint according to the present invention, when the pin and the box are engaged, a clearance is provided between the crest rounded portion of the male screw and the root rounded portion of the female screw, and a clearance is provided between the root rounded portion of the male screw and the crest rounded portion of the female screw.
In the above technical solution of the present invention, after the external thread of the male end and the internal thread of the female end are matched, a slight gap is formed between the tooth crest fillet and the tooth bottom fillet, and the gap is intentionally designed to be small. This is because, when the eccentric threaded joint of the present invention is screwed up, these small gaps can be filled with thread grease, so that the sealing performance of the joint can be effectively improved.
Further, in the eccentric threaded joint of the present invention, the male end and the female end are both pipe fittings; or the female end is a coupling, and the male end is a pipe fitting.
Further, in the eccentric threaded joint of the present invention, the pipe or the coupling satisfies:
when the outer diameter is 60.32-114.30 mm, the tooth height is 1.20mm, the thread pitch is 3.175mm, and the number of teeth per inch is 8;
when the outer diameter is 127.00-219.08, the tooth height is 1.58mm, the thread pitch is 4.23mm, and the number of teeth per inch is 6;
when the outer diameter is 244.48-339.72, the tooth height is 2.00mm, the screw pitch is 5.08mm, and the number of teeth per inch is 5.
In the technical scheme of the invention, aiming at steel pipes with different outer diameters, the eccentric threaded joint of the invention designs 3 different thread counts, and simultaneously selects proper outer diameter, tooth height and thread pitch to improve the applicability. Therefore, the eccentric threaded joint has wide applicability, can be applied to large-caliber steel pipes, and has good application prospect.
Therefore, in the present invention, compared with the prior art, the eccentric threaded joint of the present invention has the following advantages and beneficial effects:
different from the prior art, the invention provides a novel eccentric threaded joint from the design of a joint structure, the eccentric threaded joint is convenient to process and is not easy to trip, and the eccentric threaded joint not only has higher tensile resistance, but also has higher air tightness; the eccentric threaded joint can be buckled conveniently and improve the buckling efficiency.
The eccentric threaded joint has excellent performance and very wide applicability, can be effectively applied to severe working conditions such as oilfield exploitation, is convenient for subsequent repeated repair after failure, and has good popularization prospect and application value.
Drawings
FIG. 1 schematically shows a tooth profile of a male-end external thread of an eccentrically threaded joint according to an embodiment of the present invention.
FIG. 2 schematically shows a profile view of female-end internal threads of a partial round thread joint according to an embodiment of the invention.
Fig. 3 is a schematic diagram showing the structure of the internal and external thread engagement of the partial circular threaded joint according to the present invention in one embodiment.
Figure 4 schematically illustrates a cross-sectional view of a fitting engagement of an offset circular threaded fitting according to an embodiment of the present invention.
FIG. 5 schematically shows a cross-sectional view of a box coupling of an eccentric threaded joint according to the present invention in one embodiment.
Figure 6 schematically shows a cross-sectional view of a male end fitting of an embodiment of the partial round thread joint of the present invention.
Detailed Description
The eccentric threaded joint according to the invention will be further explained and illustrated with reference to specific examples and figures of the description, which, however, do not unduly limit the technical solution according to the invention.
In the present invention, the eccentric threaded joint of the present invention may include: a male end having external threads and a female end having internal threads. The male end and the female end of the eccentric threaded joint can be mutually matched, meshed and connected, the applicability is wide, and the eccentric threaded joint not only has high tensile resistance, but also has high air tightness.
FIG. 1 schematically shows a tooth profile of a male-end external thread of an eccentrically threaded joint according to an embodiment of the present invention.
As shown in fig. 1, in the present invention, the crest between the bearing surface a and the guide surface b of the male thread X at the pin end of the round-off thread joint according to the present invention is a crest fillet, and the root between the bearing surface a and the guide surface b of the male thread is a root fillet. Wherein, the included angle between the bearing surface a and the guide surface B can be set as an included angle B; the respective angular bisectors c of the crest fillet and the root fillet have an included angle a with the radial direction which is not zero.
It should be noted that, in the present invention, the degree of the included angle B can be controlled to satisfy: b is more than or equal to 50 degrees and less than or equal to 70 degrees, and an included angle alpha between a guide surface B of the external thread and the radial direction is not larger than or equal to (B/2 + A), and an included angle beta between a bearing surface a of the external thread X and the radial direction is not larger than or equal to (B/2-A).
From the tests, the coefficient of friction of the thread compound coating was about μ =0.1, and from the friction angle equation arctan μ =5.71, then-5.71 β 5.71, from which the degree of included angle a was calculated to satisfy: b/2-5.71 is less than or equal to A and less than or equal to B/2+5.71.
As can be seen from fig. 1, in the present embodiment, the crest fillet and the root fillet of the partial-round threaded joint of the present invention may both be 60 °, that is, the angle B between the bearing surface a and the guiding surface B may be 60 °; correspondingly, the included angles A between the respective angle bisectors c of the tooth crest fillet part and the tooth bottom fillet part and the radial direction can be preferably 30 degrees; from this calculation, the angle α =60 ° between the guide surface b of the external thread X and the radial direction; the bearing surface a of the external thread X forms an angle β =0 ° with the radial direction.
In the present embodiment, the thread taper of the eccentric threaded joint according to the present invention may be 1.
As can be further seen from fig. 1, in the present embodiment, the tooth tip fillet is tangent to the bearing surface a and the guide surface b, so that Rcs can be set as the fillet radius of the tooth tip fillet; accordingly, the tooth bottom fillet is also tangent to the bearing surface a and the guide surface b on both sides, whereby Rrs can be set to the fillet radius of the tooth bottom fillet.
It can be seen that the external thread X of the eccentric threaded joint according to the present invention satisfies:
where H denotes a radial distance between a virtual intersection of the bearing surface a and the guide surface b at the crest and a virtual intersection of the bearing surface a and the guide surface b at the root, p denotes a thread pitch, γ denotes a half-cone angle, which is half of the thread taper.
Wherein S is cs Denotes the radial distance, R, between the highest point of the tip fillet and the virtual intersection of the bearing surface a and the guide surface b at the tip cs The radius of the crest rounded portion is γ, and represents a half-cone angle, which is half of the taper of the thread.
Wherein S is rs Denotes the radial distance, R, between the lowest point of the fillet of the tooth bottom and the virtual intersection of the bearing surface a and the guide surface b at the tooth bottom rs The fillet radius of the fillet portion of the tooth bottom, γ, represents a half-cone angle, which is half of the thread taper.
Wherein h is s Representing the tooth height, H represents the radial distance between the virtual intersection point of the bearing surface a and the guide surface b at the tooth top and the virtual intersection point of the bearing surface a and the guide surface b at the tooth bottom, S rs Indicating the lowest point of the rounded portion of the tooth bottomRadial distance, S, from the virtual intersection of bearing surface a and guide surface b at the tooth bottom rs The radial distance between the lowest point of the rounded portion of the tooth bottom and the virtual intersection of the bearing surface a and the guide surface b at the tooth bottom is represented.
FIG. 2 schematically shows a profile view of female-end internal threads of a partial round thread joint according to an embodiment of the invention.
As shown in fig. 2, the female-end female thread Y shown in fig. 2 can be engaged with the male-end male thread X shown in fig. 1, so that the female-end female thread Y and the male-end male thread X are substantially identical in structure and have no substantial difference therebetween.
Similarly to the description of the male-end male thread X, the female-end female thread Y shown in FIG. 2 has a radius R of a tip fillet cn Satisfies the following conditions: r is cs ＝R cn (ii) a Fillet radius R of fillet portion of tooth bottom thereof rn Satisfies the following conditions: r is rs ＝R rn (ii) a The radial distance S between the highest point of the tooth top fillet part and the virtual intersection point of the bearing surface a and the guide surface b at the tooth top cn Satisfies the following conditions: s. the cs ＝S cn (ii) a The radial distance S between the lowest point of the round corner part of the tooth bottom and the virtual intersection point of the bearing surface a and the guide surface b at the tooth bottom rn Satisfies the following conditions: s rs ＝S rn (ii) a Height h of tooth n Satisfies the following conditions: h is s ＝h n . Further, in the eccentric threaded joint according to the present invention, the following are also satisfied: r is rs ＝R rn ＜R cs ＝R cn 。
Fig. 3 is a schematic diagram showing the structure of the internal and external thread engagement of the partial circular threaded joint according to the present invention in one embodiment.
As shown in fig. 3, in the present embodiment, the partial round threaded joint according to the present invention has a slight clearance at the tooth crest and tooth root fillet positions after the male thread X and the female thread Y are engaged, and the clearance is intentionally designed to be small. This is because, when the eccentric threaded joint of the present invention is screwed up, these small gaps can be filled with thread grease, so that the sealing performance of the joint can be effectively improved.
It should be noted that both the male end and the female end of the eccentric threaded joint can be selected as a pipe fitting. Of course, in some embodiments, the female end of the offset round thread joint may be selected as a collar and the male end may be selected as a tubular.
In the present invention, the outer diameter of the coupling or pipe fitting of the male and female ends may be preferably controlled to be between 114.3mm and 508 mm. In the prior art, the round thread of the casing in the API standard is 8 threads per inch, the tooth height of the round thread is 1.81mm, and the thread pitch is too small for a casing with a large outer diameter and belongs to a fine thread. The large-diameter casing pipe has low efficiency in processing, low fastening efficiency in an oil field site and easy damage to threads.
Therefore, in the present invention, 3 different thread counts are designed for different outer diameter steel pipes: (1) When the number of teeth per inch is 8 and the tooth height is 1.20mm, the tool is suitable for a coupling or a pipe fitting with the outer diameter of 60.32 mm-114.30 mm; (2) When the number of teeth per inch is 6 and the tooth height is 1.58mm, the composite material is suitable for couplings or pipe fittings with the outer diameter of 127.00 mm-219.08 mm; (3) When the number of teeth per inch is 5 and the tooth height is 2.00mm, the method is suitable for couplings or pipe fittings with the outer diameter of 244.48 mm-339.72 mm. The specific dimensions of the three above-described arrangements of couplings or pipe elements can be seen in table 1 below.
Table 1.
Figure 4 schematically shows a cross-sectional view of the fitting engagement of a partially circular threaded joint according to one embodiment of the invention.
As shown in fig. 4, in the present embodiment, the eccentric threaded joint according to the present invention may be composed of a coupling 1 as a female end and two pipe members 2 as male ends. Wherein, this pipe fitting 2 can be processed at the steel pipe both ends that the external diameter is at 60.32mm to 339.72mm, and pipe fitting 2 all processes has the external screw thread, and coupling 1 both ends process has the internal thread.
In the invention, triangular steel seal marks 25 can be arranged at positions which are away from the two pipe fittings 2 at the two sides of the coupling 1 at the female end by a certain length, the height of the triangular steel seal marks 25 can be controlled between 6.35mm and 9.52mm, and when the section of the coupling 1 covers between the bottom edge and the top point of the triangular steel seal marks 25, the coupling is tightened in place.
FIG. 5 schematically shows a cross-sectional view of a box coupling of an eccentric threaded joint according to the present invention in one embodiment.
As shown in fig. 5, in the present embodiment, a coupling 1 at a female end of an eccentric threaded joint according to the present invention is formed with female threads 11 at both ends thereof, and inner chamfers 12 are formed at both ends of the coupling 1, the inner chamfers 12 being preferably selected to be 65 °, and the thread forming positions at both ends are adjusted to be correct in the middle of the coupling 1 so as to prevent the threads at both ends from being engaged by the random teeth, thereby smoothly transitioning the middle thread of the coupling 1.
Figure 6 schematically shows a cross-sectional view of a male end fitting of an eccentric threaded joint according to an embodiment of the invention.
In this embodiment, as shown in fig. 6, the pipe 2 at the male end of the eccentric threaded joint according to the present invention is provided with an external thread at the pipe end, except for the external thread, which is a straight section 24 and may be composed of a complete thread 21 and an incomplete thread 22. Correspondingly, the tube 2 at the male end is provided with an outer chamfer 23, the outer chamfer 23 preferably being selected to be 60 °.
The eccentric threaded joint can be repaired for the second time after failure and then reused. Considering that the outer surface of the pipe fitting 2 may be rusted to different degrees during secondary repair, the surface of the pipe fitting 2 needs to be turned and stripped, the stripping length is larger than the position of the triangular steel seal mark 25, the stripping outer diameter is adjusted on site according to the rusting degree of the pipe fitting 2, and the stripping outer diameter is equal to the actual outer diameter of the pipe fitting 2 or smaller than the actual outer diameter of the pipe fitting 2 by 1mm. Because the actual outer diameter of the tube 2 will generally be slightly larger than the nominal outer diameter, the stripped outer diameter is preferred to the nominal outer diameter of the tube 2 if the tube is new or only slightly corroded.
To further illustrate the applicability of the eccentric threaded joint of the present invention, the present invention is described with reference to specific examples, and the dimensions of the eccentric threaded joint of the related implementations are shown in table 2 below.
Table 2.
As shown in Table 2, the eccentric threads with 3 different tooth heights, thread pitches and thread counts are designed for oil pipes (60.32-114.30 mm) and casings (127.00-339.72 mm) with different outer diameters. The collar in table 2 is the female end and the casing or tubing is the male end.
Therefore, the threads of the eccentric threaded joint have the advantages of easy processing and high air tightness of API round threads, and also have the advantage of high tensile resistance of the buttress threads, and the threads are not tripped under high tensile resistance.
Meanwhile, in some preferred embodiments, the included angle B between the bearing surface and the guide surface may be set to 60 ° to obtain a large guide surface, which may make the buckling easier.
In addition, the eccentric threaded joint has higher processing efficiency and screwing efficiency, and the thread gluing phenomenon is less prone to occur on coarse threads compared with fine threads.
In summary, different from the prior art, the invention provides a novel eccentric threaded joint based on the design of a joint structure, the eccentric threaded joint is convenient to process and is not easy to trip, and the eccentric threaded joint not only has higher tensile resistance, but also has higher air tightness; the eccentric threaded joint can be buckled conveniently and improve the buckling efficiency.
The eccentric threaded joint has excellent performance and wide applicability, can be effectively applied to severe working conditions such as oilfield exploitation, is convenient for subsequent repeated repair after failure, and has good popularization prospect and application value.
It should be noted that the combination of the features in the present application is not limited to the combination described in the claims of the present application or the combination described in the embodiments, and all the features described in the present application may be freely combined or combined in any manner unless contradicted by each other.
It should also be noted that the above-mentioned embodiments are only specific embodiments of the present invention. It is apparent that the present invention is not limited to the above embodiments and similar changes or modifications thereto which can be directly or easily inferred from the disclosure of the present invention by those skilled in the art are intended to be within the scope of the present invention.
Claims (10)
1. The utility model provides a partial circle screwed joint, its includes that the mutual adaptation meshing connects have the male end of external screw thread and have the female end of internal thread, its characterized in that, the addendum between the loading surface of external screw thread and the spigot surface is tooth top fillet, the tooth bottom between the loading surface of external screw thread and the spigot surface is tooth bottom fillet, the respective angular bisector and the radial direction of addendum fillet and tooth bottom fillet all have the contained angle A of nonzero degree.
2. The eccentric threaded joint according to claim 1, wherein the angle B between the bearing surfaces and the guiding surfaces is in degrees such that: b is more than or equal to 50 degrees and less than or equal to 70 degrees.
3. The offset circular threaded joint of claim 1, wherein the angle between the back-up face and the guiding face is B, and the degrees of a and B are such that: b/2-5.71 is less than or equal to A and less than or equal to B/2+5.71.
4. Eccentric threaded joint according to claim 1, characterized in that it satisfies:
wherein H represents the radial distance between the virtual intersection point of the bearing surface and the guide surface at the tooth top and the virtual intersection point of the bearing surface and the guide surface at the tooth bottom, p represents the thread pitch, gamma represents the half-cone angle, and the half-cone angle is half of the thread taper.
5. Eccentric threaded joint according to claim 1, characterized in that it satisfies:
wherein S is cs Representing the radial distance, R, between the highest point of the addendum fillet and the virtual intersection of the bearing surface and the guide surface at the addendum cs The radius of the crest fillet is γ, which represents the half-cone angle, which is half of the thread taper.
6. Eccentric threaded joint according to claim 1, characterized in that it satisfies:
wherein S is rs Representing the radial distance, R, between the lowest point of the fillet of the tooth bottom and the virtual intersection of the bearing surface and the guide surface at the tooth bottom rs The fillet radius of the fillet portion of the tooth bottom, γ, represents a half-cone angle, which is half of the thread taper.
7. Eccentric threaded joint according to claim 1, characterized in that it satisfies:
wherein h is s Representing the tooth height, H representing the radial distance between the virtual intersection point of the bearing surface and the guide surface at the tooth top and the virtual intersection point of the bearing surface and the guide surface at the tooth bottom, S rs Minimum point of rounded portion of tooth bottomRadial distance, S, between virtual intersection points of the bearing surface and the guide surface at the tooth bottom rs Representing the radial distance between the lowest point of the fillet of the tooth bottom and the virtual intersection of the bearing surface and the guide surface at the tooth bottom.
8. The offset round threaded joint as set forth in claim 1 wherein there is clearance between the crest fillet of the male thread and the root fillet of the female thread and clearance between the root fillet of the male thread and the crest fillet of the female thread when the male and female ends are in meshing engagement.
9. The offset circular threaded joint as set forth in claim 1 wherein said male and female ends are both tubulars; or the female end is a coupling, and the male end is a pipe fitting.
10. The eccentric threaded joint according to claim 1, characterized in that said tubular or coupling satisfies:
when the outer diameter is 60.32-114.30 mm, the tooth height is 1.20mm, the thread pitch is 3.175mm, and the number of teeth per inch is 8;
when the outer diameter is 127.00-219.08, the tooth height is 1.58mm, the thread pitch is 4.23mm, and the number of teeth per inch is 6;
when the outer diameter is 244.48-339.72, the tooth height is 2.00mm, the screw pitch is 5.08mm, and the number of teeth per inch is 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110962243.3A CN115707850A (en) | 2021-08-20 | 2021-08-20 | Eccentric threaded joint |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110962243.3A CN115707850A (en) | 2021-08-20 | 2021-08-20 | Eccentric threaded joint |
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| Publication Number | Publication Date |
|---|---|
| CN115707850A true CN115707850A (en) | 2023-02-21 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110962243.3A Pending CN115707850A (en) | 2021-08-20 | 2021-08-20 | Eccentric threaded joint |
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|---|---|
| CN (1) | CN115707850A (en) |
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2021
- 2021-08-20 CN CN202110962243.3A patent/CN115707850A/en active Pending
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