EP3141689A1 - Threaded connection and drilling rod having a threaded connection - Google Patents

Abstract

A threaded connection of an internal thread (20) and an external thread (40), in particular for a drill pipe for rotary impact drilling or vibration boring, in particular for overburden drilling, whose individual boring bars (102, 104) have an end with the internal thread (20) and an end with the external thread (40), wherein both threads (20, 40) each have a first flank (12, 32) and a second flank (14, 34), which is characterized in that the profile of the internal thread (20) has a flattened thread crest (40). 18) and a rounded thread root (16) and the profile of the external thread (40) has a flattened thread crest (38) and a rounded thread root (36) and the first flank (12, 32) is longer than the second flank (14, 34 ).

Description

Field of the invention

The invention relates to a threaded connection and a threaded drill pipe according to the preambles of the independent claims.

State of the art

From the DE 19803304 A1 is a threaded drill pipe for connecting individual drill rods known in which the profile of the external thread has a flattened thread crest and a circular arc-shaped thread root, while the profile of the internal thread has a circular arc thread crest and a flattened thread root.

From the US Pat. No. 5,060,740 is a threaded connection with asymmetrical flanks of the thread pitch for a downhole hammer known. The profile of this threaded connection has an elliptical ground, which can lead to seizure when screwing the connection, because the Profilaussenkanten can collide with the ellipses. A relatively steep inlet edge forms a small area on which the load can be distributed. A larger flank with a shallow angle forms a support flank when the thread is screwed and exerts a very high bearing pressure on the threaded sleeve. This is to prevent the parts of the perforated hammer from accidentally loosening during operation.

From the US 4,799,844 A is a screw assembly having a cylindrical support member, at least one thread extending helically along the cylindrical support member in spaced threads, and a base portion extending between adjacent threads of the thread. The screw construction is characterized in that the base portion has a curvature defined by a portion of an ellipse. A larger flank with a shallow angle forms a supporting flank. This known screw assembly therefore has the same problems as those of US Pat. No. 5,060,740 known threaded connection.

From the US 2010/0018699 A1 and the US 4,040,756 A Furthermore, other thread forms are known in which a relatively steep inlet edge forms a small area on which the load can be distributed and a larger flank forms a supporting flank at a shallow angle.

There are now hydraulic rotary actuators with more than 50 kNm of torque and hydraulic hammers which have more than 1000 Joul impact force at 2000 strokes / min. to reach. In addition, there are more and more vibration drives on the market, which not infrequently at a frequency of 160 Hz flywheels of 36 to. to generate.

All previously known thread profiles can be used only partially under the described conditions of use and are subject to premature wear and fatigue fractures.

task

The object of the invention is to provide a threaded connection, in particular for a drill pipe, which can accommodate a high torque and improves the state of the art.

Another object is to provide a corresponding drill pipe with a threaded connection.

solution

The objects are achieved by the inventions having the features of the independent claims. Advantageous developments of the inventions are characterized in the subclaims, the description and the drawings. The wording of all claims is hereby incorporated by reference into the content of this specification. The inventions also include all reasonable and in particular all mentioned combinations of independent and / or dependent claims.

It is proposed a threaded connection of an internal thread and an external thread, in particular for a drill pipe for rotary impact drilling or vibration drilling, in particular for overlay drilling, the individual drill rods have an end with the internal thread and an end with the external thread, both threads each having a first edge and a Having the second flank, the profile of the external thread, ie seen in longitudinal section, a flattened thread crest and a rounded thread root and the profile of the internal thread a flattened thread tip and a rounded thread base has.

Since the drill pipes are always screwed and loosened with the drill under load, it is particularly advantageous if the load can be distributed over as large a surface as possible. Therefore, the first edge in the profile according to the invention is designed to be larger than the second edge. Thus, the contact surfaces are made as large as possible during the screwing and reduces the surface pressure.

The longer flank is also intended as an inlet flank. As a result, the wear during the screwing can be reduced.

The shorter edge serves as a support flank when the thread is screwed and the threaded connection is thus made. Particularly favorable, a noticeable surface contact can be guaranteed and so the surface pressure and the hole pressure on the sleeve can be reduced. This reduces wear, and it can also meet the requirements of today increasingly powerful drilling rigs, especially the recent lately increasingly on the market urging vibratory drives.

To understand the proposed solution, it helps to understand the approach to anchor drilling. When extending the drill string in the ongoing drilling process, the drill pipes are usually lifted by means of lifting devices (excavator or crane attachment, etc.) on the feed carriages of the drills and placed on the drill string to be extended. It is not necessarily done sensitively. The drive unit of the drill is then approached to the other end of the drill pipe and with the on it Threaded threaded and screwed. The drive unit can consist of one or two drives, which are mounted together on a carriage and often reach a weight of 2500 kg. In addition, feed forces of 5-10 t, which act hydraulically via chain drive on the drive units, must be manually controlled.

These forces can all act upon screwing on the inlet edge of the threads. According to the invention, these edges are therefore designed so that the largest possible area is created in order to minimize the surface pressure. In return, the support flank is steeper than the entry edge designed so that the loosening torque of the threaded connection is not too large and the drill pipe can be easily dismantled.

Since contamination of the threaded connections is always to be expected on a construction site, it is of particular advantage if these contaminants can be distributed in a cavity without causing greater additional tension within the threaded connection. It is therefore of particular advantage if there is enough space between the base of the thread and the profile tip in order to be able to absorb these impurities.

According to a favorable embodiment, the flanks in the profile of thread root to thread crest can each be flattened, in particular straight, be formed.

The rounded root of the thread is particularly advantageous for impact drilling and vibration drilling to prevent cracking germs.

According to a favorable embodiment of the thread root of the external thread and the thread root of the internal thread in the profile be rounded. Due to the rounded thread root, the notch sensitivity of the threaded connection is reduced.

According to a favorable embodiment, the rounding at the root of the thread can have a radius of at most 3 mm, preferably at most 2 mm, particularly preferably 1.6 mm. The large radius of e.g. 1.6 mm in the thread root can advantageously counteract fatigue fractures. In a favorable development of the thread root of the external thread and the thread root of the internal thread may have the same radius. As a result, the surface contact is increased and a locally limited surface pressure is avoided.

According to a favorable embodiment, the thread profile may be conical and each thread root and / or each thread crest along the profile lie on an imaginary line, which may be inclined with an inclination angle against the thread axis. The angle of inclination may be between 0.5 ° and at most 6 °, preferably at most 5 °, particularly preferably 4.5 °. This allows easier insertion of the internal thread in the external thread. Alternatively, the thread profile may be cylindrical. The latter allows larger inner diameter of the threaded connection, higher slopes and thus a higher torque absorption.

According to the invention, the angle of inclination describes the tapering of a conical thread, while the flank angle indicates the angle of the flanks (measured with respect to the central axis), irrespective of the extent to which the threaded design is conical or cylindrical.

According to a favorable embodiment, the first and the second flank can each enclose an angle of more than 70 °. Advantageously, the angle can be at least 75 °, preferably 80 ° in a conical thread profile.

In the case of a cylindrical thread profile, the angle can be at least 90 °, preferably 100 °. The latter allows higher gradients, larger thread diameter and a higher torque absorption.

According to a favorable embodiment, the flank angle of the external thread and the internal thread relative to the first, in particular larger flanks relative to the thread center axis can be at least 20 °. In this case, the flank angle in a conical thread profile with respect to the first, in particular larger flanks relative to the thread center axis at least 35 °, preferably at least 40 °, particularly preferably 43 °. In the case of a cylindrical thread profile, the flank angle can be at least 25 °, preferably 28 °, with respect to the first, in particular larger flanks, relative to the thread center axis. This allows a favorable geometry of the thread, in particular a good torque absorption can be achieved.

According to a favorable embodiment, the flank angle of the external thread and the internal thread relative to the second, in particular smaller flanks relative to the thread center axis can be at least 45 °. In this case, the flank angle in a conical thread profile at least 50 °, preferably at least 55 °, particularly preferably 57 °.

In the case of a cylindrical thread profile, the flank angle can be at least 47 °, preferably at least 50 °, particularly preferably 52 °. This allows a favorable geometry of the thread, in particular a good torque absorption can be achieved.

According to a favorable embodiment, the number of threads can increase with increasing outer diameter of the external thread or the internal thread. Conveniently, in a conical thread profile with diameters of the thread less than 75 mm, a thread, with diameters between 75 mm and 115 mm, preferably between 76.1 mm and 114.3 mm, two threads with pitch 20 and with diameters between 120 mm and 155 mm, preferably between 121 mm and 152.4 mm, three threads with pitch 30 may be provided.

Conveniently, in a cylindrical thread profile with diameters of the thread less than 75 mm, a thread, with diameters between 75 mm and 96 mm preferably between 76.1 mm and 95 mm, two threads with pitch 24, with diameters between 100 mm and 135 mm, preferably between 101.6 mm and 133 mm, three threads with pitch 36, with diameters between 150 mm and 178 mm, preferably between 152.4 mm and 177.8 mm, four threads with pitch 48 and with diameters between 192 mm and 220 mm, preferably between 193.7 mm and 219.1 mm, four threads with pitch 60 may be provided.

Advantageously, the pitch angle is chosen so that a sufficient torque can be transmitted and still sufficient self-locking is present, so that the threaded connections do not solve unintentionally. The pitch angle is suitably adapted to the diameter. With larger diameter more threads are provided and thus larger pitch angle.

According to a further aspect of the invention, a drill pipe for rotary impact drilling is proposed, in particular for Overlay drilling, the individual drill rods having an end with an internal thread and an end with an external thread, with a threaded connection as described above. In this case, both threads each have a first flank and a second flank, wherein the first flanks are larger than the second flanks and the first flanks are in each case the outer flanks of the thread facing the drill rod ends.

Advantageously, the larger flank have a shallow angle against the thread center axis, with conical thread profile, for example, 43 ° and cylindrical thread profile, for example, 28 °. This minimizes wear during bolting of the drill rods. The smaller flank, however, can form the support flank when the thread is screwed, and be inclined at a larger angle to the thread center axis, conical thread profile, for example, 57 ° and cylindrical thread profile, for example, 52 °. The flank angles can vary depending on the purpose.

Further details and features will become apparent from the following description of preferred embodiments in conjunction with the subclaims. In this case, the respective features can be implemented on their own or in combination with one another. The possibilities to solve the problem are not limited to the embodiments. For example, area information always includes all - not mentioned - intermediate values and all imaginable subintervals.

Further advantages emerge from the following description of the drawing. The embodiments of the invention are shown schematically in the figures. The same reference numerals in the individual figures designate the same or functionally identical or with respect to their functions corresponding elements. The figures are merely examples and are not intended to be limiting. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

• Fig. 1 einen Ausschnitt aus einem Profil eines konischen Innengewindes nach einem Ausführungsbeispiel der Erfindung;
• Fig. 2 einen Ausschnitt aus einem Profil eines konischen Außengewindes nach einem Ausführungsbeispiel der Erfindung;
• Fig. 3 einen Ausschnitt aus einer Gewindeverbindung von Innengewinde und Außengewinde aus den Figuren 1 und 2;
• Fig. 4 einen Ausschnitt aus einem Profil eines zylindrischen Innengewindes nach einem Ausführungsbeispiel der Erfindung;
• Fig. 5 einen Ausschnitt aus einem Profil eines zylindrischen Außengewindes nach einem Ausführungsbeispiel der Erfindung; und
• Fig. 6 einen Ausschnitt aus einer Gewindeverbindung von Innengewinde und Außengewinde aus den Figuren 4 und 5;

In detail, for example:

• Fig. 1 a section of a profile of a conical internal thread according to an embodiment of the invention;
• Fig. 2 a section of a profile of a conical external thread according to an embodiment of the invention;
• Fig. 3 a section of a threaded connection of internal thread and external thread of the Figures 1 and 2 ;
• Fig. 4 a section of a profile of a cylindrical internal thread according to an embodiment of the invention;
• Fig. 5 a section of a profile of a cylindrical external thread according to an embodiment of the invention; and
• Fig. 6 a section of a threaded connection of internal thread and external thread of the FIGS. 4 and 5 ;

Numerous modifications and developments of the described embodiments can be realized. Identical or similar elements are numbered in the figures with the same reference numerals.

The FIGS. 1 to 3 show a first embodiment of the invention of a conical threaded connection, in particular for a drill pipe for rotary impact drilling, in particular for Overlay drilling, the individual drill rods having an end with an internal thread 20 and an end with an external thread 40.

FIG. 1 shows a section of a profile of the conical internal thread 20 of a sleeve 10 of one end of a drill rod ∅102. The internal thread 20 of the sleeve 10 surrounds a threaded central axis 22. FIG. 2 shows a section of a profile of the corresponding external thread 40 of a pin 30 with conical thread. The external thread 40 of the pin 30 surrounds a threaded central axis 42.

The inclination angle β against the respective thread center axis 22, 42 is half the cone angle and is preferably less than 5 °, preferably 4.5 °.

The internal thread 20 has a first flank 12 and a second flank 14. The first edge 12 is formed in profile larger than the second edge 14. The first flank 12 is provided as an inlet flank during the screwing, which advantageously reduces the wear. The smaller flank 14, however, serves as a support flank when the internal thread 20 is screwed to the external thread 40 and the threaded connection is made. The two flanks 12, 14 enclose an angle α10 of more than 70 °, in particular the angle α10 in the conical thread is at least 75 °, preferably 80 °.

The profile of the internal thread 20 has a flattened thread crest 18, in particular a straight thread crest 18, and a rounded thread root 16. The radius R10 of the thread base is favorably between 1.5mm and 3.0mm, preferably 1.6mm.

The external thread 40 in FIG. 2 has a first flank 32 and a second flank 34. The first edge 32 is formed in profile larger than the second edge 34. The first flank 32 is provided as an inlet flank during the screwing, which advantageously reduces the wear. The smaller edge 34, however, serves as a support flank when the internal thread 20 is screwed to the external thread 40 and the threaded connection is made.

Further, the external thread 40 has a flattened thread crest 38 and a rounded thread root 36 in profile. The radius R30 of the thread base is favorably between 1.5mm and 3.0mm, preferably 1.6mm.

The two flanks 32, 34 enclose an angle α30 of more than 70 °, in particular the angle α30 in the conical thread is at least 75 °, preferably 80 °.

FIG. 3 shows a section of the threaded connection of the conical internal thread 20 and external thread 40 of the Figures 1 and 2 , Due to the flattenings 50 of the thread crests 18, 38 and the rounded groove bases 16, 36, relatively large cavities 50 form there, which offer space for receiving contaminants such as dust and the like.

The first, larger flanks 12, 32 form a flank angle γ with respect to the thread center axis 22, 42, which is at least 20 °, preferably at least 35 °, preferably at least 40 °, particularly preferably 43 °.

The second, smaller flanks 14, 34 form a flank angle δ relative to the thread center axis 22, 42, at least 45 °, preferably at least 50 °, preferably at least 55 °, particularly preferably 57 °.

The larger flanks 12, 32 are in each case the outer flanks of the threads 20, 40 facing the boring bar ends of the boring bars 102, 104.

The FIGS. 4 to 6 show a first embodiment of the invention of a cylindrical threaded connection, in particular for a drill pipe for rotary impact drilling, in particular for overlay drilling, the individual drill rods 102, 104 have an end with an internal thread 20 and an end with an external thread 40.

FIG. 4 shows a section of a profile of the internal thread 20 of a sleeve 10 of one end of a drill rod 102 with a cylindrical thread. The internal thread 20 of the sleeve 10 surrounds a threaded central axis 22. FIG. 5 shows a section of a profile of the corresponding external thread 40 of a pin 30 with a cylindrical thread profile. The external thread 40 of the pin 30 surrounds a threaded central axis 42.

The internal thread 20 has a first flank 12 and a second flank 14. The first edge 12 is formed in profile larger than the second edge 14. The first flank 12 is provided as an inlet flank during the screwing, which advantageously reduces the wear. The smaller flank 14, however, serves as a support flank when the internal thread 20 is screwed to the external thread 40 and the threaded connection is made. The two flanks 12, 14 enclose an angle α10 of more than 70 °, in particular the angle α10 in the cylindrical thread profile is at least 90 °, preferably 100 °.

The profile of the internal thread 20 has a flattened thread crest 18, in particular a flattened thread crest 18, and a rounded thread root 16. The radius R10 of the thread base is favorably between 1.5mm and 3.0mm, preferably 1.6mm.

The external thread 40 in FIG. 5 has a first flank 32 and a second flank 34. The first edge 32 is formed in profile larger than the second edge 34. The first flank 32 is provided as an inlet flank during the screwing, which advantageously reduces the wear. The smaller edge 34, however, serves as a support flank when the internal thread 20 is screwed to the external thread 40 and the threaded connection is made.

Further, the external thread 40 has a flattened thread crest 38 and a rounded thread root 36 in profile. The radius R30 of the thread base is favorably between 1.5mm and 3.0mm, preferably 1.6mm.

The two flanks 32, 34 enclose an angle α30 of more than 70 °, in particular the angle α30 in the cylindrical thread is at least 90 °, preferably 100 °.

FIG. 6 shows a section of the threaded connection of the cylindrical internal thread 20 and external thread 40 of the FIGS. 4 and 5 , Due to the flattenings 50 of the thread crests 18, 38 and the rounded groove bases 16, 36, relatively large cavities 50 form there, which offer space for receiving contaminants such as dust and the like.

The first, larger flanks 12, 32 form a flank angle γ with respect to the thread center axis 22, 42, which is at least 20 °, preferably at least 25 °, particularly preferably 28 °.

The second, smaller flanks 14, 34 form a flank angle δ relative to the thread center axis 22, 42, which is at least 45 °, preferably at least 47 °, more preferably at least 50 °, particularly preferably 52 °.

The larger flanks 12, 32 are in each case the outer flanks of the threads 20, 40 facing the boring bar ends of the boring bars 102, 104.

reference numeral

102

Boring bar with internal thread

104

Boring bar with external thread

10

sleeve

12

first flank

14

second flank

16

thread base

18

flattening

20

inner thread

22

Threaded central axis

30

spigot

32

first flank

34

second flank

36

thread base

38

flattening

40

external thread

42

Threaded central axis

50

cavity

α10

Angle between flanks

α30

Angle between flanks

β

Inclination angle to thread axis

γ

Flank angle first flank to thread axis

δ

Flank angle second flank to thread axis

R10

radius

R30

radius

Claims (20)

Threaded connection of an internal thread (20) and an external thread (40), in particular for a drill pipe for rotary impact drilling or vibration boring, in particular for overburden drilling, whose individual boring bars (102, 104) have one end with the internal thread (20) and one end with the external thread ( 40), wherein both threads (20, 40) each have a first flank (12, 32) and a second flank (14, 34), wherein the profile of the internal thread (20) has a flattened thread crest (18) and a rounded thread root (16) and the profile of the external thread (40) has a flattened thread crest (38) and a rounded thread root (36), characterized in that the first flank (12, 32) is longer than the second flank (14, 34). Threaded connection according to claim 1, characterized in that the flanks (12, 32, 14, 34), seen in longitudinal section from the thread base (16, 36) to the thread crest (18, 38), are flattened in each case. Threaded connection according to one of the preceding claims, characterized in that the thread root (16) of the external thread (20) and the thread base (36) of the internal thread (40) are formed rounded in longitudinal section seen. Threaded connection according to claim 3, characterized in that the rounding on the thread base (16, 36) has a radius (R10, R30) of at most 3 mm, preferably at most 2 mm, particularly preferably 1.6 mm. Thread connection according to claim 3 or 4, characterized in that the thread root (16) of the external thread (20) and the thread base (36) of the internal thread (40) have the same radius (R10, R30). Thread connection according to one of the preceding claims, characterized in that the thread is conical and each thread root (16, 36) and / or each thread crest (18, 38) lies along a longitudinal section on an imaginary line which is inclined at an angle (β). is inclined against the thread axis (22, 42). Thread connection according to claim 6, characterized in that the angle of inclination (β) is between 0.5 ° and at most 6 °, preferably at most 5 °, particularly preferably 4.5 °. Threaded connection according to one of claims 1 to 5,
characterized in that the thread is cylindrical and each thread root (16, 36) and / or each thread crest (18, 38) lies along a longitudinal section on an imaginary line parallel to the thread center axis (22, 42). Threaded connection according to one of the preceding claims, characterized in that the first and the second flank (12, 14; 32, 34) each include an angle (α10, α30) of more than 70 °. Threaded connection according to claim 9, characterized in that the angle (α10, α30) in a conical thread is at least 75 °, preferably 80 °. Thread connection according to claim 9, characterized in that the angle (α10, α30) in a cylindrical thread is at least 90 °, preferably 100 °. Threaded connection according to one of the preceding claims, characterized in that the flank angle (γ) of the external thread (20) and the internal thread (40) relative to the first flanks (12, 32) relative to the thread center axis (22, 42) is at least 20 °. Thread connection according to claim 12, characterized in that the flank angle (γ) in a conical thread relative to the first flanks (12, 32) relative to the thread center axis (22, 42) is at least 35 °, preferably at least 40 °, particularly preferably 43 ° , Thread connection according to claim 12, characterized in that the flank angle (γ) in a cylindrical thread profile with respect to the first flanks (12, 32) relative to the thread center axis (22, 42) is at least 25 °, preferably 28 °. Threaded connection according to one of the preceding claims, characterized in that the flank angle (δ) of the external thread (20) and the internal thread (40) with respect to the second flanks (14, 34) relative to the thread center axis (22, 42) is at least 45 °. Thread connection according to claim 15, characterized in that the flank angle (δ) in a conical thread at least 50 °, preferably at least 55 °, particularly preferably 57 °. Thread connection according to claim 15, characterized in that the flank angle (δ) is at least 47 °, preferably at least 50 °, more preferably 52 ° in a cylindrical thread profile. Thread connection according to one of the preceding claims, characterized in that the number of threads increases with increasing diameter of the thread (40). Drill pipe for rotary impact drilling, in particular for overburden drilling or vibration drilling, the individual boring bars (102, 104) having an end with an internal thread (20) and an end with an external thread (40), with a threaded connection wherein both threads (20, 40) each have one first flank (12, 32) and a second flank (14, 34), characterized in that the threaded connection is formed according to one of the preceding claims. Drill pipe for rotary impact drilling according to claim 19,
characterized in that the first flanks (12, 32) are longer than the second flanks (14, 34) and the first flanks (12, 32) are each the outer edges of the threads (20, 40) facing the boring bar ends.

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