Drill drive assembly

Abstract

The invention relates to a drilling drive arrangement for a double drill rod assembly with an outer rod assembly and an inner rod assembly, which is arranged at least in sections within the outer rod assembly along a drilling axis, with an outer rod assembly drive for rotatingly driving the outer rod assembly, a first carrier unit on which the outer rod assembly drive is arranged, an inner rod assembly drive for rotatingly driving the inner rod assembly, wherein the inner rod assembly drive is arranged axially offset from the outer rod assembly drive, a second carrier unit on which the inner rod assembly drive is arranged, and a displacement device with which the inner rod assembly drive with the second carrier unit is axially displaceable relative to the outer rod assembly drive with the first carrier unit.According to the invention, it is provided that the displacement device has at least one guide rod with a fixed piston section, wherein the guide rod is fixedly attached either to the first carrier unit or to the second carrier unit, that on the at least one guide rod at least one actuating cylinder housing with a piston cavity is mounted and guided in a slide-like manner, in which the piston section of the guide rod is arranged and which can be pressurized with a pressurized fluid in order to move the actuating cylinder housing along the guide rod, and that the second carrier unit or the first carrier unit, to which the at least one guide rod is not fixedly attached, is attached to the actuating cylinder housing.

Description

[0001] The invention relates to a drill drive arrangement for a double drill string with an outer string and an inner string, which is arranged at least sectionally within the outer string along a drill axis, comprising an outer string drive for rotating the outer string, a first support unit on which the outer string drive is arranged, an inner string drive for rotating the inner string, wherein the inner string drive is arranged axially offset from the outer string drive, a second support unit on which the inner string drive is arranged, and a displacement device with which the inner string drive with the second support unit is axially displaceable relative to the outer string drive with the first support unit, according to the preamble of claim 1.

[0002] For drilling in overburden and unstable soils, drilling rigs or drill drive systems are frequently used that feature independent drives for the rotation of a casing or outer casing and an inner drill string. These drill drive systems for such double drill strings are often referred to as double-head drilling rigs. With double-head drilling rigs, it is advantageous if the inner drill string can be shifted relative to the outer, tubular drill string (the casing) in the longitudinal direction of the drilling axis. This not only facilitates screw connections during string installation and removal but also offers further drilling-related advantages. For example, the drill bit at the end of the drill string can be positioned ahead or behind the ring drill bit on the casing, depending on the type of soil encountered during drilling.

[0003] In a double-head drilling rig, the drive for the outer casing is typically the "front" drive, facing the borehole. The drive for the inner drill string is the "rear" drive located behind it. A rod-shaped drill string adapter is guided through the hollow shaft of the front drive so that both connection points, for example, threaded connections, for both the outer casing and the inner drill string are located "in front" or "below" the "front" drive, respectively, to ensure easy access when changing the drill string.

[0004] The relative displacement function of the rear drive is achieved by mounting this drive on its own carriage, which can also be called a tandem carriage. This carriage can be displaced relative to a base carriage on which the front drive is mounted, in the direction of the drilling axis. A positioning element, typically consisting of at least one hydraulic cylinder, is used for this displacement. This cylinder is attached to both the base carriage and the tandem carriage. Such generic drilling drive arrangements with this displacement device for relative displacement of the drives are known, for example, from documents DE 19930504 B4, DE 3503893 C1, DE 8509145 U1, DE 19732479 C1, and DE 202007001858 U1.

[0005] In a special form, which emerges from DE 10005475 A1, the actuator in the form of a hydraulic cylinder is on the one hand firmly connected to the base slide, and on the other hand rotatably connected to the rotary feedthrough, the so-called flushing head, of the rear drive for the drill string.

[0006] Another known embodiment, according to EP 0860580 B1, involves a drive for the drill string having a carriage that, like the carriage of the front drive, is guided directly on a carriage. In this case, there is an adjusting element that can position the rear carriage relative to the front carriage. The feed system of the drill carriage is only attached to the front carriage.

[0007] In all known designs, the functions of displacement and linear guidance of the tandem slide as a support unit for the rear drive are separate, and a second slide (tandem slide) is usually required. With this design, the mountings for the actuator, the linear guides, and the tandem slide, or at least guide surfaces, must be manufactured and installed on the rear rotary drive.

[0008] The invention is based on the Task The basis is to specify a drilling drive arrangement for a double drill string which has a particularly efficient and compact design.

[0009] The problem is solved according to the invention by a drill drive arrangement having the features of claim 1. Preferred embodiments of the invention are specified in the dependent claims.

[0010] In the drilling drive arrangement according to the invention, the displacement device has at least one guide rod with a fixed piston section, wherein the guide rod is fixedly attached either to the first support unit or to the second support unit, wherein at least one actuating cylinder housing with a piston cavity is slidably mounted and guided on the at least one guide rod, in which the piston section of the guide rod is arranged and which can be pressurized with a fluid to displace the actuating cylinder housing along the guide rod, wherein the guide rod extends through the piston cavity, and wherein the second support unit or the first support unit is attached to the actuating cylinder housing, to which the at least one guide rod is not fixedly attached.

[0011] The design according to the invention results in a significant simplification of the drilling drive assembly. A functional separation between the guide and the actuating element is, in effect, eliminated. According to the invention, the displacement device comprises at least one guide rod with a piston section arranged thereon. The guide rod is attached either to the first support unit for the outer linkage drive or to the second support unit for the inner linkage drive. Instead of a separate tandem slide, an actuating cylinder housing with an inner piston cavity is mounted directly on the at least one guide rod in a slide-like manner. The piston section on the guide rod lies within the inner piston cavity of the actuating cylinder housing and thus directly forms an actuating element for the displacement device.By pressurizing the inner piston cavity of the actuator housing with a pressurized fluid, it can preferably be moved reversibly along the guide rod. The other support unit is attached to the actuator housing, but is not directly and rigidly connected to the piston rod.

[0012] In addition to the considerable structural simplification, the geometric accuracy, in particular the alignment of the axes of the inner linkage drive and the outer linkage drive, can be significantly improved, for example, since the play of the neck bushings of an actuating cylinder can be tolerated much more tightly than the play that a tandem slide would have to have compared to a basic slide.

[0013] The arrangement according to the invention can in particular comprise a so-called synchronizing cylinder, which can also be referred to as a synchronous or steering cylinder. Technically, this is a double-acting hydraulic linear actuator with a cylinder housing and a guide or piston rod protruding from the housing, sealed on both sides. The at least one synchronizing cylinder can preferably have mounting points for the rotary drive, in particular for the internal linkage drive, on the actuator housing. Likewise, fastening elements for attachment to the other support unit, in particular the first support unit for the external linkage drive, can be arranged at the free ends of the guide rod.

[0014] A preferred embodiment of the invention consists in at least two guide rods, each with an actuating cylinder housing, being arranged, the actuating cylinder housings preferably being rigidly connected to one another. The arrangement of two or more guide rods increases the guiding accuracy of the linear guide thus formed. Furthermore, an actuating cylinder housing can be arranged on each additional guide rod, so that correspondingly higher actuating forces can be generated for moving the support units with the drives relative to each other. In principle, guide rods or other linear guides could also be arranged without an additional actuating cylinder housing to increase the guiding accuracy.

[0015] According to a further development of the invention, it is advantageous that the at least one guide rod is fixedly attached to the first support unit with the outer linkage drive, wherein the second support unit with the inner linkage drive is slidably mounted and guided along the at least one guide rod.

[0016] The first support unit with the external linkage drive can itself be designed as a slide, in particular as a so-called base slide, which can be guided along a mast or carriage. The second support unit with the internal linkage drive can be slidably mounted relative to the first support unit. Thus, the second support unit is slidably mounted relative to the first support unit with the external linkage drive. This allows the internal linkage to be axially displaced relative to the external linkage, the so-called protective tube, according to a predetermined travel path.

[0017] In principle, the at least one guide rod can be fixed at one end to one of the support units, so that the guide rod has a free end. According to one embodiment of the invention, a particularly stable arrangement is achieved by the at least one guide rod having two opposing end sections, which are either both attached to the first support unit or both to the second support unit. Thus, both ends of a guide rod are attached to either the first or the second support unit. This results in a particularly stable arrangement of the guide rod on one of the support units, allowing the other, movable support unit to be guided very precisely.

[0018] The guide rod can have any suitable cross-section, in particular a square or polygonal cross-section. A cylindrical guide rod with a circular cross-section is particularly preferred.

[0019] A further advantageous embodiment of the invention lies in the fact that the piston section of the guide rod divides the piston chamber in the actuator housing into two separate pressure chambers, each of which can be pressurized with a pressure fluid to enable the actuator housing to be moved reversibly along the guide rod. The pressure fluid can be, for example, compressed air or, preferably, hydraulic oil. Appropriate connections and lines for the pressure fluid are arranged on the actuator housing, so that the individual pressure chambers can be selectively pressurized or vented with the pressure fluid via a suitable control and / or valve device. In this way, a desired position of the actuator housing can be set and maintained along the guide rod.

[0020] A particularly good guiding characteristic is achieved according to a further development of the invention by the fact that the actuator cylinder housing has at least one, preferably two, guide sections, which are designed to fit the outer diameter of the guide rod in order to form a linear guide. The at least one guide section can, in particular, be designed as a guide or sliding bushing, which is guided appropriately on the guide rod. Especially when two or more guide rods are arranged, a very precise, virtually backlash-free linear guide can thus be efficiently achieved.

[0021] The at least one guide section can be made of a suitable low-friction material, such as bronze or brass. If necessary, one or more sealing rings can also be incorporated into the at least one guide section, ensuring that the piston cavity of the actuator housing is pressure-tight.

[0022] According to a further development of the invention, it is preferred that the inner rod drive and / or the outer rod drive comprises one or more drive motors and / or an impact unit. Preferably, one or two drives can be arranged. With an impact unit, which can be arranged particularly on the rear inner rod drive, additional impact impulses for rotary percussion drilling can be applied.

[0023] A particular advantage is that the at least one drive motor is designed as an electric motor, a pneumatic motor, or a hydraulic motor. In principle, other drive motors can also be used, which can generate a rotary drive for the inner or outer linkage. The aforementioned motors enable a particularly compact design.

[0024] The drives can be designed as a direct drive for directly driving the respective linkage. According to one embodiment of the invention, it is particularly advantageous for the inner linkage drive and / or the outer linkage drive to comprise one or more gearboxes. The gearbox can, in particular, be designed as a reduction gearbox, which allows for increased torque at a reduced speed.

[0025] The drilling drive arrangement according to the invention can, in principle, be used wherever a double drill string with outer and inner rods is driven in a rotating manner.

[0026] According to one embodiment, the invention comprises a drilling rig with a carrier unit and a mast or carriage, along which a drilling drive assembly for a double drill string is slidably mounted, wherein the drilling drive assembly is designed according to the invention. By using the drilling assembly according to the invention in a drilling rig, particularly for drilling in earth and rock, the advantages described above can be achieved with the drilling rig.

[0027] The carrier device can be equipped with a mast that is essentially vertically oriented during operation or with a carriage that is relatively freely adjustable in space. A carriage can also be used to set the drilling axis in an essentially horizontal or inclined position. The inner and outer drill strings are preferably arranged coaxially.

[0028] In principle, the drilling rig can be designed as a stationary drilling rig. However, after further development, it is particularly preferred that the carrier unit be mobile, especially with a crawler chassis.

[0029] The invention is further explained below with reference to preferred embodiments, which are shown schematically in the drawings. The drawings show: Fig. 1 a side view of a drilling drive arrangement according to the invention in a first operating state; Fig. 2 a top view of the drilling drive arrangement of Fig. 1from above; Fig. 3 a side view of a drilling drive arrangement according to the invention in a second operating state; Fig. 4 a top view of the drilling drive arrangement of Fig. 3 from above; and Fig. 5 an enlarged cross-sectional view of a displacement device of the drilling drive assembly according to the Figures 1 to 4 .

[0030] According to the Figures 1 and 2 A drilling drive arrangement 10 according to the invention has a first carrier unit 20, which can be designed in a slide-like manner with a lower slide guide 22 for guiding along a linear guide on a mast or carriage of a carrier device.

[0031] On the first support unit 20, an external drill rod drive 30 is attached for rotating a partially indicated tubular external drill rod 20 around a drill axis 1. The drill rod drive 30 can be configured as shown in the illustration. Figures 1 and 2two drive motors 32 which together drive a first gearbox 34, via which a torque is transmitted to the outer linkage 2 via a corresponding linkage connection.

[0032] Coaxial to the tubular outer rod 2 is an inner rod 4, which extends through the outer rod drive 30 to an inner rod drive 50 located behind it in the direction of the drilling axis 1. The inner rod drive 50 may preferably also have two drive motors 52, which, via a common second gearbox 54, drive the inner rod 4 in a rotation about the drilling axis 1. The direction of rotation of the outer rod 2 and the inner rod 4 can be the same or different.

[0033] For axial displacement of the inner rod drive 50 with the inner rod 4 relative to the outer rod drive 30 with the outer rod 2, according to the illustrated embodiment, the inner rod drive 50 is arranged on a second support unit 40, which can be displaced via a displacement device 60 in the direction of the drilling axis 1 relative to the first support unit 20 with the inner rod drive 50.

[0034] In the Figures 1 and 2 The drilling drive arrangement 10 is shown in a first operating state in which the inner rod drive 50 with the second support unit 40 has been moved into a rear position in which the inner rod drive 50 is further spaced away from the outer rod drive 30.

[0035] In the illustrated embodiment, the displacement device 60 comprises two guide rods 62 arranged parallel to each other, each of which is attached at its two free ends to the slide-like first support unit 20. A cylindrical or box-shaped actuating cylinder housing 70 is slidably mounted on each guide rod 62, the two actuating cylinder housings 70 being rigidly connected to each other via the second support unit 40 and the internal linkage drive 50.

[0036] The second support unit 40 can be axially displaced by the internal linkage drive 50 and the internal linkage 4 using the displacement device 60. Figures 3 and 4 The drilling drive arrangement 10 is shown in a second operating state, in which the inner rod drive 50 with the second support unit 40 is moved from the rear position according to the Figures 1 and 2has been moved into a forward position in which the inner linkage drive 50 is located near the outer linkage drive 30.

[0037] The design and function of an actuating cylinder housing 70 of the displacement device 60 are described in more detail in connection with Fig. 3 explained.

[0038] According to Fig. 3The actuator housing 70 has an inner piston cavity 72 through which the guide rod 62 extends axially. A piston section 64 is formed in a central region of the guide rod 62, which in the illustrated embodiment consists of two disk-shaped sections with two radial seals 66 arranged between them. The piston section 64 divides the piston cavity 72 in the actuator housing 70 into two pressure chambers 73, 74 that are pressure-tight from each other. The individual pressure chambers 73, 74 can be selectively pressurized or vented with a pressure fluid, in particular hydraulic oil, by means of schematically indicated pressure fluid lines 80, in order to effect a controlled displacement of the actuator housing 70 relative to the guide rod 62 and thus of the internal linkage drive 50.

[0039] In addition to its actual displacement function, the actuator cylinder housing 70 also performs a guiding function. In the illustrated embodiment, a first guide section 75 and a second guide section 76 are formed, each of which may have a guide bushing 79. The inner openings of the guide bushings 79, together with the outer circumference of the preferably cylindrical guide rod 62, can form a sliding fit and thus a linear guide. One or more sealing rings 78 can be arranged on each of the two guide sections 75, 76 to seal the respective adjacent pressure chambers 73, 74 against the outside atmosphere. The displacement device 60 thus designed can also be described as a synchronous cylinder, which performs both a displacement function and a linear guide function.

[0040] For example, fastening eyes 68 can be provided at the free ends of the respective guide rod 62 as fastening elements in order to fasten the guide rod 62 to the corresponding support unit, here the first support unit 20, on both sides.

[0041] Compared to a conventional actuating device on a drill drive assembly for a double drill string, the drill drive assembly 10 according to the invention achieves a more compact and overall lighter design. This saves space and weight, which, particularly with regard to a conventional arrangement of the drill drive assembly 10 on a mast or carriage, reduces the risk of tipping and enables an increase in the maximum achievable drilling depth.

Claims

1. Drilling drive assembly for a double drill string comprising an outer drill string (2) and an inner drill string (4), which is arranged at least in sections inside the outer drill string (2) along a drilling axis (1), comprising - an outer drill string drive (30) for rotationally driving the outer drill string (2), - a first carrier unit (20), on which the outer drill string drive (30) is arranged, - an inner drill string drive (50) for rotationally driving the inner drill string (4), wherein the inner drill string drive (50) is arranged axially offset relative to the outer drill string drive (30), - a second carrier unit (40), on which the inner drill string drive (50) is arranged, and - a displacement device (60) by means of which the inner drill string drive (50) together with the second carrier unit (40) is axially displaceable relative to the outer drill string drive (30) together with the first carrier unit (20), characterized in that - the displacement device (60) comprises at least one guide rod (62) with a stationary piston section (64), wherein the guide rod (62) is fixedly mounted either on the first carrier unit (20) or on the second carrier unit (40), - on the at least one guide rod (62), at least one actuating cylinder housing (70) having a piston cavity (72) is mounted and guided so as to be slidably displaceable in a carriage-like manner, in which the piston section (64) of the guide rod (62) is arranged and which can be acted upon with a pressure fluid for displacing the actuating cylinder housing (70) along the guide rod (62), wherein the guide rod (62) extends through the piston cavity (72), and - the second carrier unit (40) or respectively the first carrier unit (20) is arranged on the actuating cylinder housing (70), on which the at least one guide rod (62) is not fixedly mounted.

2. Drilling drive assembly according to claim 1, characterized in that at least two guide rods (62) each having an actuating cylinder housing (70) are arranged, wherein the actuating cylinder housings (70) are preferably fixedly connected to one another.

3. Drilling drive assembly according to claim 1 or 2, characterized in that the at least one guide rod (62) is fixedly mounted on the first carrier unit (20) with the outer drill string drive (30), wherein the second carrier unit (40) with the inner drill string drive (50) is mounted and guided so as to be displaceable along the at least one guide rod (62).

4. Drilling drive assembly according to one of claims 1 to 3, characterized in that the at least one guide rod (62) has two opposite end regions, which are either both fastened to the first carrier unit (20) or both fastened to the second carrier unit (40).

5. Drilling drive assembly according to one of claims 1 to 4, characterized in that the piston section (64) of the guide rod (62) divides the piston cavity (72) in the actuating cylinder housing (70) into two pressure chambers (73, 74) separated from one another, which can each be acted upon with a pressure fluid for reversibly displacing the actuating cylinder housing (70) on the guide rod (62).

6. Drilling drive assembly according to one of claims 1 to 5, characterized in that the actuating cylinder housing (70) comprises at least one, preferably two, guide sections (75, 76), which are designed to match an outer diameter of the guide rod (62) for forming a linear guide.

7. Drilling drive assembly according to one of claims 1 to 6, characterized in that the outer drill string drive (30) and / or the inner drill string drive (50) comprises one or more drive motors (32, 52) and / or a percussion unit.

8. Drilling drive assembly according to claim 7, characterized in that the at least one drive motor (32, 52) is designed as an electric motor, a compressed-air-driven motor, or a hydraulic motor.

9. Drilling drive assembly according to one of claims 1 to 8, characterized in that the outer drill string drive (30) and / or the inner drill string drive (50) comprises one or more gear units (34, 54).

10. Drilling rig comprising a carrier vehicle, and a mast or a feed frame, along which a drilling drive assembly (10) for a double drill string is mounted so as to be displaceable, characterized in that the drilling drive assembly (10) is designed according to one of claims 1 to 9.

11. Drilling rig according to claim 10, characterized in that the carrier apparatus is designed to be movable, in particular with a crawler undercarriage.

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