DRILL DRIVE DEVICE FOR AN EARTH DRILLING APPARATUS

Abstract

The invention relates to a drill drive device (10) for an earth drilling apparatus with a spindle arrangement which has an inner spindle unit (20) and an outer spindle unit (40) that is supported in an axially displaceable manner on the inner spindle unit (20) and floating between two spring means (50, 60). According to the invention provision is made in that a first front spring means (50) which is arranged on a drilling tool side comprises a combination of at least a compression coil spring and a first disk spring arrangement (54) and in that a second rear spring means (60) which faces away from the drilling tool side has a second disk spring arrangement (64).

Claims

1. Drill drive device for an earth drilling apparatus with a spindle arrangement which has an inner spindle unit and an outer spindle unit that is supported in an axially displaceable manner on the inner spindle unit and floating between two spring means, wherein a first front spring means which is arranged on a drilling tool side comprises a combination of at least a compression coil spring and a first disk spring arrangement and a second rear spring means which faces away from the drilling tool side has a second disk spring arrangement.

2. Drill drive device according to claim 1, wherein the compression coil spring of the first spring means is retained on the one hand on a radially outward-directed first flange on the external side of the inner spindle unit and on the other hand on a bearing ring which is supported on the outer spindle unit by being axially displaceable and spring-loaded by the first disk spring arrangement.

3. Drill drive device according to claim 1, wherein the second disk spring arrangement of the second rear spring means is retained on the one hand on a radially outward-directed second flange of the inner spindle unit and on the other hand on the outer spindle unit.

4. Drill drive device according to claim 1, wherein a torque transmission means, in particular an axial splined shaft toothing, is arranged.

5. Drill drive device according to claim 1, wherein the first disk spring arrangement and/or the second disk spring arrangement are received in a receiving recess.

6. Drill drive device according to claim 1, wherein on a front side of the inner spindle unit a connecting means for mounting a drill rod element is provided.

7. Drill drive device according to claim 1, wherein the compression coil spring has a smaller spring constant and a larger spring deflection than those of the first disk spring arrangement.

8. Drill drive device according to claim 7, wherein the spring deflection of the compression coil spring is equal to or larger than a thread length of a drill rod element with a connecting thread to be mounted.

9. Drill drive device according to claim 1, wherein on the inner spindle unit a ring-shaped guide slot is formed, into which a sleeve-shaped guide protrusion of the outer spindle unit engages so as to fit.

10. Drilling apparatus, in particular earth drilling apparatus, with at least one drill drive, wherein by the drill drive (5) an outer spindle unit of a drill drive device according to claim 1 is driven.

11. Drilling apparatus according to claim 10, wherein as drilling tool a down-the-hole hammer unit is mounted on a drill rod which can be driven in a rotating manner by means of the drill drive device.

Description

[0021] The invention is described further hereinafter by way of a preferred embodiment illustrated schematically in the drawings, wherein show:

[0022] FIG. 1 a schematic cross-sectional view of a drill drive device according to the invention;

[0023] FIG. 2 an enlarged illustration of the left-hand region of the drill drive device according to FIG. 1; and

[0024] FIG. 3 an enlarged cross-sectional view of the right-hand region of the drill drive device according to FIG. 1.

[0025] A drill drive device 10 according to the invention which is illustrated in FIGS. 1 to 3 is substantially constructed of an inner spindle unit 20 having a tubular base body 22 with an inner duct 23 and a tubular outer spindle unit 40 which is coaxial to the inner spindle unit 20 and surrounds the latter. Via an approximately central torque transmission means 70 a torque is transmitted in a generally known manner via one or several drill drives 5, preferably driven hydraulically, to the outer spindle unit 40 and/or the inner spindle unit 20. The inner spindle unit 20 extends rearwards through the ring-shaped torque transmission means 70 and, at its rear end facing away from a drilling tool, has a rotary feedthrough 12 to transmit at least one fluid from a non-depicted drilling apparatus to the inner duct 23 of the tubular inner spindle unit 20.

[0026] The rotary feedthrough 12 substantially has two main components, namely a rotor 14, which is connected in a torque-proof manner to the inner spindle unit 20 and, facing away therefrom to the rear, a stator 16 which is retained via a torque support 18 on a housing of the torque transmission means 70. The rotor 14 rotates relative to the stationary stator 16, on which a fluid line e.g. for transmitting a flushing or drilling suspension can be attached. The outer spindle unit 40 rotates with the inner spindle unit 20 which is supported in an axially displaceable manner relative to the outer spindle unit 40.

[0027] On a front side of the inner spindle unit 20 directed towards a borehole a radially outward-directed first flange 24 is arranged on which a drilling tool can be releasably fixed by means of a connecting means 25 in a direct or indirect manner via mounted drill rod elements. The drilling tool can in particular be a down-the-hole hammer drilling unit that has one or several axially driven percussion elements.

[0028] To dampen percussive pulses from a down-the-hole hammer drilling unit onto the torque transmission means 70 the drill drive device 10 is provided with a first spring means 50 and a second spring means 60 which will be explained in greater detail hereinafter with reference to FIGS. 2 and 3.

[0029] The first spring means 50 has two spring components, namely a compression coil spring 52 and a first disk spring arrangement 54. The compression coil spring 52 which is coaxial to the drilling axis is retained thereby towards the front on the first flange 24 on the tubular base body 22 of the inner spindle unit 20 and on the other hand on a bearing ring 30.

[0030] The bearing ring 30 can have a first ring 31 and a second ring 32. Here, the first ring 31 is displaceably supported on the external side of the inner spindle unit 20 and, by means of the coaxial first disk spring arrangement 54, is retained in a spring-loaded manner with respect to the outer spindle unit 40, wherein a first pre-tensioning force FTF is exerted by the first disk spring arrangement 54 onto the first ring 31 and thus the bearing ring 30. Via a radially projecting stop the first ring 31 is connected to the second ring 32, on a stair-like step of which the other end of the compression coil spring 52 is retained, wherein via the compression coil spring 52 a pre-tensioning force FDF is exerted onto the first flange 24 and thus onto the inner spindle unit 20.

[0031] The compression coil spring 52 enables a stroke H1 which is considerably larger than a stroke H2 of the first disk spring arrangement 54. Here, by preference, the compression coil spring 52 is provided with a smaller spring constant than the first disk spring arrangement 54. The stroke H1 can in particular be designed to compensate the necessary thread distance or screwing distance when screwing on an additional drill rod element. The stroke H2 of the first disk spring arrangement 54 preferably serves to dampen the axial blows that can be exerted by the drilling tool.

[0032] According to FIG. 3 the coaxial second spring means 60 solely has a second disk spring arrangement 64 which is retained on the one hand on a shoulder of the outer spindle unit 40 and on the other hand on a second flange 28 which is releasably fixed, more particularly screwed onto the external side of the tubular base body 22 of the inner spindle unit 20. By means of a cover ring 42 on the outer spindle unit 40 a second receiving recess 66 is formed, in which the disk springs of the second disk spring arrangement 60 are arranged in a protected manner. Via the second disk spring arrangement 60 a pre-tensioning force FTFZ can be transmitted from the outer spindle unit 40 to the inner spindle unit 20 which can also serve to dampen axial forces of a down-the-hole hammer drilling unit. The cover ring 42 keeps the disk springs 60 under pre-tension when the inner spindle unit 20 is displaced axially towards the right side.

[0033] To ensure guidance a ring-shaped guide slot 34 can be arranged on the external side of the tubular base body 22, into which guide slot a corresponding guide protrusion 44 of the outer spindle unit 40 engages.