Drill string component for noise control during percussion drilling

1. Drill string component for positioning between a top hammer drill rig and a drill bit for percussive drilling and including a pipe-shaped element which transfers rotational movements from the drill rig to the drill bit, and which is arranged to enclose at least one rod element of a drill string extending along a longitudinal axis for transferring impact pulses from a percussion drilling machine belonging to the top hammer drill rig to the drill bit, wherein the pipe-shaped element is arranged concentrically surrounding said at least one rod element, and wherein a vibration-damping structure is arranged adjoining to and rotatable with at least a part of an inside of the pipe-shaped element in a space formed inwardly of said inside for reducing emissions of noise from the drill string component when in operation and being outside a bore hole.

2. Drill string component according to claim 1 , wherein the vibration-damping structure is produced from a vibration-damping material which is applied in a layer on at least a part of said inside.

3. Drill string component according to claim 2 , wherein said material is any one from the group: 1) viscoelastic materials of a) amorphous materials, b) materials having amorphous components otherwise being crystalline; 2) composite materials with metallic matrix with particles of a material which is harder compared to the matrix material.

4. Drill string component according to claim 3 , wherein a side of the vibration-damping structure being faced away from the pipe-shaped element is provided with a reinforcing wear-resistant layer.

5. Drill string component according to claim 2 , wherein a side of the vibration-damping structure being faced away from the pipe-shaped element is provided with a reinforcing wear-resistant layer.

6. Drill string component according to claim 1 , wherein the vibration-damping structure is formed as an elongated sleeve, which is inserted into said space and which adjoins against at least a part of said inside.

7. Drill string component according to claim 6 , wherein the elongated sleeve has at least one axially extending through channel for allowing flow of fluid between the drill rig and the drill bit.

8. Drill string component according to claim 7 , wherein the elongated sleeve has an outer shell and inner shell together forming an outer and an inner tube-shaped construction, wherein axially extending distance strips in the form of distance holders are arranged there between.

9. Drill string component according to claim 6 , wherein the elongated sleeve has an outer shell and inner shell together forming an outer and an inner tube-shaped construction, wherein axially extending distance strips in the form of distance holders are arranged therebetween.

10. Drill string component according to claim 6 wherein the pipe-shaped element includes a pipe portion with unchanged section along its length which is welded together with two joining portions at its ends.

11. Rock drilling equipment including a rock drill rig and at least one drill string component according to claim 1 .

12. Drill string component of a drill string for a percussive down-the-hole drilling machine for positioning between a drill rig and the down-the-hole drilling machine, wherein the drill string component Includes a pipe-shaped element which transfers rotational movements from the drill rig to the down-the-hole drilling machine, whereas impact pulses to a drill bit belonging to the down-the-hole drilling machine are transferred through the down-the-hole drilling machine, wherein a vibration-damping structure is arranged adjoining to and rotatable with at least a part of an inside of the pipe-shaped element in a space formed inwardly of said inside for reducing emissions of noise from the drill string component when in operation and being outside a bore hole, wherein the vibration-damping structure is formed as an elongated sleeve, which is inserted into said space and which adjoins against at least a part of said inside, and wherein the elongated sleeve has an outer shell and inner shell together forming an outer and an inner tube-shaped construction, and axially and radially extending distance strips in the form of distance holders arranged therebetween.

13. Drill string component according to claim 12 , wherein the vibration-damping structure is produced from a vibration-damping material which is applied in a layer on at least a part of said inside.

14. Drill string component according to claim 13 , wherein said material is any one from the group: 1) viscoelastic materials of a) amorphous materials, b) materials having amorphous components otherwise being crystalline; 2) composite materials with metallic matrix with particles of a material which is harder compared to the matrix material.

15. Drill string component according to claim 13 , wherein a side of the vibration-damping structure being faced from the pipe-shaped element is provided with a reinforcing wear-resistant layer.

16. Drill string component according to claim 12 , wherein the elongated sleeve has at least one axially extending through channel for allowing flow of fluid between the drill rig and the drill bit.

17. Drill string component according to claim 12 , wherein the pipe-shaped element includes a pipe portion with unchanged section along its length which is welded together with two joining portions at its ends.

18. Rock drilling equipment including a rock drill rig and at least one drill string component according to claim 12 .