METAL TUBULAR CONNECTING PART AND METHOD FOR OBTAINING SUCH A PART BY ADDITIVE MANUFACTURING

Abstract

A metal tubular connecting part includes a total axial length, an inner surface, and an outer surface. The inner and outer surfaces delimit a wall, an outer transition surface, and an inner transition surface. The outer transition surface and the inner transition surface delimit a transition thickness of the wall. A first threaded end is defined by a first outer surface portion extending over a first axial length. A second threaded end is defined by a second inner surface portion extending over a second axial length. The sum of the first axial length and the second axial length is less than or equal to the total axial length of the connecting part.

Claims

1-7. (canceled)

8. A metal tubular connecting part having at least an axis of revolution and a total axial length, said connecting part comprising: an inner surface and an outer surface, said inner surface and outer surface delimiting a wall, at least a first outer transition plane and at least a second outer transition plane, both of said outer transition planes being orthogonal to the axis of revolution, at least a first inner transition plane and at least a second inner transition plane, both of said inner transition planes being orthogonal to the axis of revolution, an outer transition surface which has a frustoconical shape defined by an outer transition generatrix having an inclination of angle al to the axis of revolution, said outer transition surface extending from the first outer transition plane as far as the second outer transition plane, an inner transition surface which has a frustoconical shape defined by an inner transition generatrix having an inclination of angle 2 to the axis of revolution, said inner transition surface extending from the first inner transition plane as far as the second inner transition plane, said outer transition surface and inner transition surface delimiting a transition thickness of the wall, a first male or female threaded end, having a first end plane orthogonal to the axis of revolution, a first inner diameter and a first outer diameter, said first end being defined by a first inner surface portion having an inner diameter and extending from the first end plane as far as the first inner transition plane, and by a first outer surface portion having an outer diameter and extending over a first axial length from the first end plane as far as the first outer transition plane, said first inner surface portion having a substantially cylindrical shape defined by a first inner surface generatrix, and said first outer surface portion having a substantially cylindrical shape defined by a first outer surface generatrix, a second male or female threaded end, having a second end plane orthogonal to the axis of revolution, a second inner diameter, and a second outer diameter, said second end being defined by a second inner surface portion having an inner diameter and extending over a second axial length from the second end plane as far as the second inner transition plane, and by a second outer surface portion having an outer diameter and extending from the second end plane as far as the second outer transition plane, said inner surface portion having a substantially cylindrical shape defined by a second inner surface generatrix, said second outer surface portion having a substantially cylindrical shape defined by a second outer surface generatrix, wherein a sum of the first and second axial lengths is less than or equal to the total axial length of the connecting part, and wherein the first end has a first thickness of the wall, the second end has a second thickness of the wall, and the transition thickness satisfies the following equation:
[Math]1max (E1; E2)W1.5max (E1; E2) where: max (E1; E2) represents the largest value selected from the first thickness and the second thickness, and corresponds to the first thickness and to the second thickness when the first thickness and the second thickness are equal.

9. The connecting part according to claim 8, wherein the first end has at least one first non-threaded part, and the second end has at least one second non-threaded part.

10. The connecting part according to claim 9, wherein the first non-threaded part extends over a first non-threaded length from the first inner transition plane, and the second non-threaded part extends over a second non-threaded length from the second inner transition plane.

11. The connecting part according to claim 8, wherein the angles 1 and 2 are both between 10 and 30 inclusive relative to the axis of revolution.

12. The connecting part according to claim 8, wherein the angles 1 and 2 are such that |12|5.

13. The connecting part according to claim 8, wherein the angles 1 and 2 are such that |12|2.

14. The connecting part according to claim 8, wherein the wall is produced wholly or partially by additive manufacturing.

15. A method for obtaining the connecting part according to claim 8, said method comprising: producing the wall wholly or partially by additive manufacturing, and machining the first and second ends.

Description

[0062] Other features and advantages of the invention will become apparent upon examining the detailed description provided hereinbelow, and from the accompanying drawings.

[0063] FIG. 1 shows a diagram of a longitudinal sectional view of a connecting part of the prior art;

[0064] FIG. 2 shows a diagram of a longitudinal sectional view of a connecting part according to one embodiment of the invention;

[0065] The accompanying drawings can be used not only to complement the invention, but also to contribute to the definition thereof, where appropriate. They are not limiting as to the scope of the invention.

[0066] FIG. 1 shows a diagram of a longitudinal sectional view of a connecting part (1) of the prior art. The connecting part comprises an axis of revolution (x), a total axial length (L.sub.T), a wall (7), an inner surface (5) and an outer surface (6), a first threaded end (2) and a second threaded end (3), as well as a transition portion (4).

[0067] The transition portion (4) extends from a first inner transition plane (A.sub.int) as far as a second outer transition plane (D.sub.ext).

[0068] The first end (2) is defined by a first end plane (S1) and a first outer surface portion (P1.sub.ext) which extends over a first axial length (L.sub.1) from the first end plane (S1) as far as a first outer transition plane (D.sub.est).

[0069] The second end (3) is defined by a second end plane (S2) and a second inner surface portion (P2.sub.int) which extends over a second axial length (L.sub.2) from the second end plane (S2) as far as a second inner transition plane (C.sub.int).

[0070] The second inner transition plane (C.sub.int) passes orthogonally through the first outer surface portion (P1.sub.ext). In other words, the first outer surface portion (P1.sub.ext) and the second inner surface portion (P2.sub.int) are superimposed in the part delimited by the second inner transition plane (C.sub.int) and the first outer transition plane (B.sub.est). Thus, the first axial length (L.sub.1) and the second axial length (L.sub.2) are such that the sum thereof is greater than the total axial length (L.sub.T) of the connecting part (1). This results in an excess of material and a significant thickness of the wall (7) in the transition portion (4), in particular in the part defined between the second inner transition plane (C.sub.int) and the first outer transition plane (B.sub.ext) wherein the portions (P1.sub.ext) and (P2.sub.int) are superimposed.

[0071] In order to obtain a smaller and more homogeneous wall thickness in the transition portion of the connecting part, the geometries of the connecting parts of the prior art are insufficient, as an excess of material is always present in the transition portion.

[0072] FIG. 2 diagrammatically shows a longitudinal sectional view of a connecting part (1) according to one embodiment of the invention. The connecting part (1) comprises a first threaded end (2), a second threaded end (3) and a transition portion (4) that connects the ends (2) and (3). Moreover, the part (1) comprises a wall (7) delimited by an inner surface (5) and an outer surface (6).

[0073] The wall (7) includes several portions which can be delimited by end planes and/or transition planes. More specifically, the connecting part (1) shown in FIG. 2 includes a first end plane (S1) and a second end plane (S2), a first inner transition plane (A.sub.int) and a second inner transition plane (C.sub.int), a first outer transition plane (B.sub.ext) and a second outer transition plane (D.sub.ext).

[0074] The first end (2) has a first inner diameter (ID.sub.1) and a first outer diameter (OD.sub.1). The first end (2) extends from the first end plane (S1) as far as the first outer transition plane (B.sub.ext).

[0075] The representation of the threading in the figures is diagrammatic. Typically, the threads of the two ends have inclined faces.

[0076] The first end (2) comprises a first outer surface portion (P1.sub.ext) which extends over a first axial length (L.sub.1). The first axial length (L.sub.1) is greater than an axial length over which extends a first inner surface portion (P1.sub.int).

[0077] The first end (2) further has a first non-threaded part (9) which extends over a first non-threaded length (l.sub.1). The wall (7) of the first end (2) has a first thickness (E1) that is substantially constant over the entire first non-threaded length (l.sub.1). In other words, the first thickness (E1) is substantially constant over the entire portion of wall (7) in which the first inner surface portion (P1.sub.int) and the first outer surface portion (P1.sub.ext) are superimposed.

[0078] The first non-threaded part (9) occupies a position that is proximal to the transition portion (4). In the threaded part of the first end (2), the first thickness (E1) varies according to the dimensioning and geometry of the threads. FIG. 2 shows one embodiment wherein the first end (2) has a female threading, i.e. the inner surface (5) is threaded and the outer surface (6) is not threaded. However, according to the invention, the threading can be present either on the inner surface (5) or on the outer surface (6) of the first end (2). The threaded part of the first end (2) occupies a position that is distal to the transition portion (4).

[0079] The second end (3) has a second inner diameter (ID.sub.2) and a second outer diameter (OD.sub.2). The second inner diameter (ID.sub.2) is less than the first inner diameter (ID.sub.1) and the second outer diameter (OD.sub.2) is less than the first outer diameter (OD.sub.1). The second end (3) extends from the second end plane (S2) as far as the second inner transition plane (C.sub.int).

[0080] The second end (3) comprises a second inner surface portion (P2.sub.int) which extends over a second axial length (L.sub.2). The second axial length (L.sub.2) is greater than an axial length over which extends the second outer surface portion (P2.sub.ext).

[0081] The second end (3) further has a second non-threaded part (8) which extends over a second non-threaded length (l.sub.2). The wall (7) of the second end (3) has a second thickness (E2) that is substantially constant over the entire second non-threaded length (l.sub.2). In other words, the second thickness (E.sub.2) is substantially constant over the entire portion of wall (7) in which the second inner surface portion (P2.sub.int) and the second outer surface portion (P2.sub.ext) are superimposed.

[0082] The second non-threaded part (8) occupies a position that is proximal to the transition portion (4). In the threaded part of the second end (3), the second thickness (E2) varies according to the dimensioning and geometry of the threads. FIG. 2 shows one embodiment wherein the second end (3) has a female threading, i.e. the inner surface (5) is threaded and the outer surface (6) is not threaded. However, according to the invention, the threading can be present either on the inner surface (5) or on the outer surface (6) of the second end (3). The threaded part of the second end (3) occupies a position that is distal to the transition portion (4).

[0083] The first and second ends (2) and (3) are shown in FIG. 2 as both having a female threading, however the present invention also encompasses the case where both ends (2) and (3) have a male threading, as well as the case where one of the two ends (2) and (3) has a female threading and the other a male threading.

[0084] The transition portion (4) extends from the first inner transition plane (A.sub.int) to the second outer transition plane (D.sub.ext). The connecting part (1) thus comprises two wall portions in which the ends (2) and (3) are aligned with the transition portion (4). These two portions are referred to as connection areas. Each of the connection areas is defined by an inner connection radius and an outer connection radius (not shown in the figures) which gives the connection areas a rounded shape. The radius of curvature of this rounded shape, i.e. the connection radius, can be between 20 mm and 80 mm inclusive, preferably between 25 and 65 mm inclusive. More preferably, the connection radii measure 50 mm. The connection radii must comply with these dimensions in order to limit the concentration of stresses, or forces, that are applied to the transition portion (4) when the connecting part (1) is under operating conditions. If not properly dimensioned, these stresses can exceed the yield strength of the connecting part (1).

[0085] The first connection area is delimited by the first inner transition plane (A.sub.int) and the first outer transition plane (B.sub.ext), and the second connection area is delimited by the second inner transition plane (C.sub.int) and the second outer transition plane (D.sub.ext). The first and second connection areas allow the first and second ends (2) and (3) to be gradually connected to the transition portion (4).

[0086] In the connection areas, only one of the inner and outer diameters of the part (1) varies, and the other does not. Thus, in the first connection area, only the inner diameter (ID.sub.1) varies according to a slope with an inclination of angle al to the axis (x). In the second connection area, only the second outer diameter (OD.sub.2) varies according to a slope with an inclination of angle 2 to the axis (x).

[0087] The portion of wall (7) with the transition thickness (W) is located between the two connection areas. More specifically, the portion of wall (7) with the transition thickness (W) extends from the first outer transition plane (B.sub.ext) to the second inner transition plane (C.sub.int). In this portion of wall (7), the inner surface (5) and outer surface (6) are respectively referred to as the outer transition surface (ST.sub.ext) and inner transition surface (ST.sub.int). In contrast to the connection areas, in this portion of wall (7) with the transition thickness (W), the inner and outer diameters both vary. The inner diameter varies according to a slope with an inclination of angle 2 to the axis (x). The outer diameter varies according to a slope with an inclination of angle 1 to the axis (x). The angles 1 and 2 both have a value between 10 and 30 inclusive such that: 10130 and 10230. The difference in inclination between the inner transition surface (ST.sub.int) and outer transition surface (ST.sub.ext) does not exceed 5 degrees inclusive, and preferably does not exceed 2 degrees inclusive, such that: |12|5, preferably |12|2.