DRIVE DEVICE AND METHOD FOR DRIVING A DRILL ROD

Abstract

The invention relates to a drive device for driving a drill rod, which has an outer rod and an inner rod, with a first rotary drive unit, with which the outer rod can be driven in a rotating manner via an outer drive shaft, a second rotary drive unit, with which the inner rod can be driven in a rotating manner independently of the outer rod via an inner drive shaft, and a vibration unit for generating a vibration, which has a vibration element that can be driven in a vibrating manner. For transmission of the vibration to the outer drive shaft the vibration element is connected via a first transmission unit to the outer drive shaft and for transmission of the vibration to the inner drive shaft the vibration element is connected via a second transmission unit to the inner drive shaft.

Description

The invention relates to a drive device for driving a drill rod, which has an outer rod and an inner rod, in accordance with the preamble of claim 1. Furthermore, the invention relates to a method for driving a drill rod in accordance with the preamble of claim 12.

The drive device comprises a first rotary drive unit, with which the outer rod can be driven in a rotating manner via an outer drive shaft, a second rotary drive unit, with which the inner rod can be driven in a rotating manner independently of the outer rod via an inner drive shaft, and a vibration unit for generating a vibration, which has a vibration element that can be driven in a vibrating manner.

In the method provision is made in that by means of a first rotary drive unit the outer rod is driven in a rotating manner via an outer drive shaft, in that by means of a second rotary drive unit the inner rod is driven in a rotating manner independently of the outer rod via an inner drive shaft and in that by means of a vibration unit a vibration is generated.

The drive device is especially provided for the so-called double-head drilling, in which an outer rod and an inner rod received therein are driven by two independent rotary drive units.

To drive the outer rod the drive device comprises an outer drive shaft which can be coupled with the outer rod. To drive the inner rod the drive device comprises an inner drive shaft which can be coupled with the inner rod.

The outer rod can, in particular, be a drill pipe which stabilizes the ground surrounding the drill-hole as a casing. The inner rod runs inside the outer casing and can have ground working tools for removing ground material and/or a conveyor flight for conveying ground material.

To improve the drilling progress it is known that in addition to the rotary drives a vibration drive is provided with which a vibration or oscillation can be transmitted to the outer rod or the inner rod.

In DE 20 2010 014 478 U1 a drive device for a drill rod is described which has a vibration unit for transmitting an oscillation to the drill rod.

The invention is based on the object to provide a drive device and a method for driving a drill rod which allow for a particularly efficient production of a drill-hole.

In accordance with the invention the object is solved by a drive device having the features of claim 1 and by a method having the features of claim 12.

In the case of the drive device provision is made in accordance with the invention in that for transmission of the vibration to the outer drive shaft the vibration element is connected via a first transmission unit to the outer drive shaft and for transmission of the vibration to the inner drive shaft the vibration element is connected via a second transmission unit to the inner drive shaft.

The method according to the invention is characterized in that the vibration generated by the vibration unit is transmitted via a first transmission unit to the outer drive shaft and via a second transmission unit to the inner drive shaft.

A fundamental idea of the invention resides in the fact that in the case of a drive device having independent rotary drill drives for the outer rod and the inner rod a common vibration unit is provided which generates a vibration or oscillation that is transmitted to both the outer rod and the inner rod. Hence, according to the invention one and the same vibration or oscillation is transmitted to the outer rod on the one hand and to the inner rod on the other hand.

As a result of the invention the need for a second vibration unit is disposed of. Thus, the drive device becomes compact whilst requiring a low amount of power. Moreover, compared to percussive drilling, vibration drilling is quieter and lateral friction is overcome more easily.

The vibration unit comprises a vibration element or a vibration body which is moved up and down in the longitudinal direction of the drill rod, i.e. it oscillates or vibrates. By means of transmission units, which transmit the oscillation or vibration of the vibration element, the vibration body is operatively connected to both rods or both drive shafts.

The drive shafts of the drive device can preferably be driven at different speeds and/or in different directions. The first rotary drive unit exclusively drives the outer rod and the second rotary drive unit exclusively drives the inner rod.

By preference, the vibration unit comprises a non-rotating vibration element, the axial oscillation of which is transmitted via the transmission units to the rotating drive shafts. To transmit the oscillation of the vibration element to the outer rod and the inner rod it is preferred in accordance with the invention that the first transmission unit has at least a first pivot bearing, via which the outer drive shaft is supported in a rotatable manner with respect to the vibration element and that the second transmission unit has at least a second pivot bearing, via which the inner drive shaft is supported in a rotatable manner with respect to the vibration element. The transmission units designed as pivot bearings enable the vibration element to be provided in a non-rotating manner in a housing of the drive device. For the transmission of the vibration the pivot bearings are preferably designed as axial bearings that ensure the transmission of axial forces.

According to the invention it is preferred that via an engaging element, in particular an engaging tooth system, the outer drive shaft and/or the inner drive shaft is supported in an axially displaceable manner on a drive element that drives the drive shaft in a rotating manner. The outer drive shaft and/or the inner drive shaft has an external tooth system, for example, that is in engagement with a tooth system of the drive element. The drive element can be designed, in particular, as a hollow shaft with internal tooth system. By way of the engaging tooth system the outer drive shaft and/or the inner drive shaft is supported in an axially displaceable manner with respect to the drive element. Consequently, the engaging tooth system ensures on the one hand the transmission of a torque to the drive shaft and on the other hand a decoupling of the drive shaft in the axial direction with respect to the drive element so that the vibration of the drive shaft is not transmitted to the drive element or the rotary drive unit.

An especially compact and stable drive device is achieved in that at least one of the rotary drive units and the vibration unit are arranged on a common receiving part or support and in that the vibration unit is supported in an axially movable manner on the common receiving part or support. The rotary drive unit preferably comprises a frame or housing which is firmly connected to the receiving part. Between the vibration unit, more particularly the vibration element, and the receiving part e.g. an elastic element, as for example a rubber bearing, can be arranged. As a result of the decoupling of the vibration unit from the receiving part, a transmission of the vibration via the receiving part to the rotary drive unit is largely avoided.

An advantageous coupling of the vibration unit with both drive shafts can be attained in that the vibration unit is arranged between the first rotary drive unit and the second rotary drive unit.

Furthermore, it is preferred that the first transmission unit is arranged on a first axial side of the vibration element and the second transmission unit is arranged on a second axial side of the vibration element. In this way, an even loading of the vibration unit and a good transmission of the vibration to the drive shafts is achieved.

By preference, the inner drive shaft is passed through the vibration element. This permits the arrangement of the second transmission unit and/or the second rotary drive unit on a side of the vibration unit facing away from the drill rod.

To transmit the axial forces to the inner and/or outer drive shaft it is preferred that the vibration element comprises a bearing seat, of cylindrical shape for instance, on the outer circumference of which the first transmission unit and/or the second transmission unit is arranged. Accordingly, the inner drive shaft and respectively the outer drive shaft preferably have a bearing seat, on the inner circumference of which the corresponding transmission unit is arranged.

To adjust an axial relative position between inner rod and outer rod and/or to change a vibration characteristic it is preferred that an actuator is provided, with which the outer drive shaft is axially adjustable with respect to the inner drive shaft. The actuator is preferably arranged between one of the transmission units and the vibration body. With the actuator the position of the transmission unit can be adjusted with respect to the vibration body. In this way, the respective drive shaft is moved or adjusted axially with respect to the vibration body.

A precise and efficient setting of the relative position between outer and inner drive shaft can be achieved in that the actuator has a positioning cylinder and/or a toothed rack. In particular, the positioning cylinder can be actuated hydraulically and/or electrically. It is also possible that several actuators are distributed in the circumferential direction around the drive shaft.

A compact drive device can be provided in that the first transmission unit and/or the second transmission unit is designed to transmit both the vibration and a torque. In particular, it is preferred that the vibration of the vibration element can be transmitted via the first rotary drive unit and/or the second rotary drive unit to the outer or inner drive shaft. For instance provision can be made for the vibration of the vibration element to be transmitted via a common receiving part to the rotary drive unit and from there via a rotary drive element serving as a transmission unit to the relevant drive shaft. As a transmission unit the drive element therefore transmits both the torque and the vibration to the drive shaft.

In the following the invention will be described further by way of the accompanying schematic drawings, wherein shows:

FIG. 1 a first embodiment of a drive device according to the invention; and

FIG. 2 a second embodiment of a drive device according to the invention.

Identical components or those corresponding to each other are designated in all Figures with the same reference signs.

FIG. 1 shows a drive device 10 for driving a drill rod not illustrated here, which comprises an outer rod and an inner rod received therein.

The drive device 10 has a first rotary drive unit 20 for the outer rod and a second rotary drive unit 30 for the inner rod. The first rotary drive unit 20 comprises an outer drive shaft 22 which can be coupled in a rotationally fixed manner with the outer rod. For this purpose a coupling means is provided in a generally known manner. The outer drive shaft 22 is driven via a drive element 24 by a drive motor 28. The drive element 24 is designed as a hollow shaft with internal tooth system 25. The outer drive shaft 22 is received in the hollow shaft and comprises an engaging tooth system 23 designed as an external tooth system which meshes with the internal tooth system 25 of the drive element 24 so that a torque can be transmitted to the outer drive shaft 22. The engaging tooth system 23 ensures an axial displacement of the outer drive shaft 22 with respect to the drive element 24.

By means of one or several pivot bearings 29 the drive element 24 is supported in a housing 21 of the first rotary drive unit 20. Between the drive motor 28 and the drive element 24 a drive pinion 26 is arranged which meshes with an external tooth system of the drive element 24.

Correspondingly, by means of the second rotary drive unit 30 an inner drive shaft 32 is driven in a rotating manner, which can be coupled in a rotationally fixed manner with the inner rod. Via a drive pinion 36 a drive motor 38 drives a drive element 34 designed as a hollow shaft. The drive element 34 is supported by means of one or several pivot bearings 39 in a housing 31 of the second rotary drive unit 30 and comprises a tooth system 35, via which a torque can be transmitted to the inner drive shaft 32. The inner drive shaft 32 has an engaging tooth system 33 which is in engagement with the tooth system 35. The engaging tooth system 33 and the tooth system 35 enable an axial displacement of the inner drive shaft 32 with respect to the drive element 34.

In the axial direction between the first rotary drive unit 20 and the second rotary drive unit 30 a vibration unit 40 is arranged. The vibration unit 40 comprises at least two rotational masses 41 drivable in opposite directions which set a vibration element 42 into a movement oscillating axially to the drilling or longitudinal axis 12. The rotational masses 41 each have a shaft 43 with an eccentric weight 44. The shafts 43 with the eccentric weights 44 are brought into a synchronized rotational movement so that proportions of unbalanced mass acting radially to the longitudinal axis 12 are mutually compensated and an axially directed up and down movement of the vibration element 42 is generated.

To transmit the vibration generated by the vibration unit 40 to the outer drive shaft 22 a pivot bearing 52 is arranged as a first transmission unit 50 between the vibration unit 40 and the outer drive shaft 22. The inner drive shaft 32 is connected to the vibration element 42 via a second transmission unit 60 which is designed as a pivot bearing 62. The pivot bearings 52, 62 are designed for the transmission of axial forces. Hence, the vibration unit 40 is connected to both drive shafts 22, 32 in an axially fixed manner so that both drive shafts 22, 32 are simultaneously set into oscillation by the vibration element 42.

The first pivot bearing 52 is located on a first axial side of the vibration element 42 facing towards to the drill rod while the second pivot bearing 62 is located on a second axial side of the vibration element 42 facing away from the drill rod. The outer drive shaft 22 has a bearing flange 54 at the end with a bearing seat 56 which is formed by a cylindrical inner lateral surface. The inner drive shaft 32 is passed through a cylindrical passage opening of the vibration element 42 and comprises between its engaging tooth system 33 and the vibration element 42 a bearing flange 64 with a bearing seat 66 for the pivot bearing 62.

The pivot bearings 52, 62 are arranged in the longitudinal direction of the drive shafts 22, 32 between the engaging tooth systems 23, 33 and are each mounted on a bearing seat 46 of the vibration element 42. The bearing seat 46 is formed by a cylindrical outer lateral surface.

The rotary drive units 20, 30 as well as the vibration unit 40 are connected to each other via a common receiving part 70 that can also be referred to as a frame, support or housing. The vibration unit 40 is supported via an elastic element 72 on the receiving part 70.

FIG. 2 shows an alternative embodiment of a drive device 10. In contrast to the embodiment according to FIG. 1 the outer drive shaft 22 and the inner drive shaft 32 are axially adjustable with respect to each other. To this end an adjusting unit with an actuator 48 is provided between the inner drive shaft 32 and the vibration element 42. The bearing seat 46 for the transmission unit 60 is arranged in this case on a bearing ring 47 movable with respect to the vibration element 42. By means of the actuator 48 the bearing ring 47 or the transmission unit 60 can be adjusted axially relative to the vibration element 42 driven in a vibrating manner. In this way, the inner drive shaft 32 can be moved in the axial direction with respect to the vibration element 42. The actuator 48, which is designed by way of example as a positioning cylinder, can set a predetermined distance of the second transmission unit 60 with respect to the vibration element 42. Similarly, it would be possible to adjust the outer drive shaft 22 on the vibration element 42 via an actuator 48.

In the embodiments of the drive device 10 illustrated in FIGS. 1 and 2 the up and down movement of the vibration element 42 is transmitted independently of both rotary drive units 20, 30 to the outer drive shaft 22 and the inner drive shaft 32. However, in a further embodiment of the invention provision can also be made for the entire drive device 10 to oscillate jointly with the rotary drive units 20, 30 and the vibration unit 40 and for the vibrating movement to be transmitted via the rotary drive units 20, 30 to the outer drive shaft 22 and the inner drive shaft 32 respectively. This can be achieved, in particular, in that the drive elements 24, 34 transmit not only a torque to the outer drive shaft 22 or the inner drive shaft 32 but also the vibrating movement.

Claims

1. Drive device for driving a drill rod, which has an outer rod and an inner rod, with wherein

a first rotary drive unit, with which the outer rod can be driven in a rotating manner via an outer drive shaft,

a second rotary drive unit, with which the inner rod can be driven in a rotating manner independently of the outer rod via an inner drive shaft, and

a vibration unit for generating a vibration, which has a vibration element that can be driven in a vibrating manner,

for transmission of the vibration to the outer drive shaft the vibration element is connected via a first transmission unit to the outer drive shaft and

for transmission of the vibration to the inner drive shaft the vibration element is connected via a second transmission unit to the inner drive shaft.

2. Drive device according to claim 1, wherein the first transmission unit has at least a first pivot bearing, via which the outer drive shaft is supported in a rotatable manner with respect to the vibration element, and the second transmission unit has at least a second pivot bearing, via which the inner drive shaft is supported in a rotatable manner with respect to the vibration element.

3. Drive device according to claim 1, wherein via an engaging tooth system the outer drive shaft and/or the inner drive shaft is supported in an axially displaceable manner on a drive element.

4. Drive device according to claim 1, wherein at least one of the rotary drive units and the vibration unit are arranged on a common receiving part and the vibration unit is supported in an axially movable manner on the common receiving part.

5. Drive device according to claim 1, wherein the vibration unit is arranged between the first rotary drive unit and the second rotary drive unit.

6. Drive device according to claim 1, wherein the first transmission unit is arranged on a first axial side of the vibration element and the second transmission unit is arranged on a second axial side of the vibration element.

7. Drive device according to claim 1, wherein the inner drive shaft is passed through the vibration element.

8. Drive device according to claim 1, wherein the vibration element comprises a bearing seat, on the outer circumference of which the first transmission unit and/or the second transmission unit is arranged.

9. Drive device according to claim 1, wherein an actuator is provided, with which the outer drive shaft is axially adjustable with respect to the inner drive shaft.

10. Drive device according to claim 9, wherein the actuator has a positioning cylinder and/or a toothed rack.

11. Drive device according to claim 1, wherein the first transmission unit and/or the second transmission unit is designed to transmit both the vibration and a torque.

12. Method for driving a drill rod, which has an outer rod and an inner rod, in particular by means of a drive device according to claim 1, in which wherein the vibration generated by the vibration unit is transmitted via a first transmission unit to the outer drive shaft and via a second transmission unit to the inner drive shaft.

by means of a first rotary drive unit the outer rod is driven in a rotating manner via an outer drive shaft,

by means of a second rotary drive unit the inner rod is driven in a rotating manner independently of the outer rod via an inner drive shaft, and

by means of a vibration unit a vibration is generated,