DEVICE FOR GENERATING OSCILLATIONS FOR A CONSTRUCTION MACHINE AND METHOD OF OPERATION

Abstract

The invention relates to a device for generating oscillations for a construction machine, comprising a housing, a piston which is movable back and forth in a working chamber in the housing between a first return point and a second return point, a pressurized fluid supply through which in each case pressurized fluid can be fed into and discharged from the working chamber via at least one actuatable control valve in the region of the first return point and the second return point, wherein the piston can be induced into a reciprocating motion in order to generate the oscillations, and a control unit which is configured to actuate the at least one control valve and by means of which the movement of the piston in the working chamber is controllable and variable. According to the invention, it is provided that the control unit is configured to control the piston in a first operating mode for generating oscillations and in a second operating mode for generating impact pulses, wherein a strike surface is formed on at least one end side of the working chamber, onto which surface the piston strikes when it reaches at least one return point in order to generate an impact pulse.

Claims

1. A device for generating oscillations for a construction machine, comprising a housing, a piston which is movable back and forth in a working chamber in the housing between a first return point and a second return point, a pressurized fluid supply by means of which in each case pressurized fluid can be fed into and discharged from the working chamber via at least one actuatable control valve in the region of the first return point and/or the second return point, wherein the piston can be set into a reciprocating motion in order to generate the oscillations, and a control unit which is configured to actuate the at least one control valve and by means of which the motion of the piston in the working chamber is controllable and variable, wherein the control unit is configured to actuate the piston in a first operating mode for generating oscillations and in a second operating mode for generating impact pulses, wherein a strike surface is formed on at least one end side of the working chamber, onto which surface the piston strikes when it reaches at least one return point in order to generate an impact pulse.

2. The device according to claim 1, wherein the control valve is configured as a solenoid valve.

3. The device according to claim 1, wherein a measuring device is provided for determining a position of the piston in the working chamber.

4. The device according to claim 3, wherein the measuring device comprises a linear sensor.

5. The device according to claim 1, wherein a frequency and/or a stroke of the piston can be set and adjusted by means of the control unit.

6. The device according to claim 1, wherein the control unit comprises a program memory in which control programs for controlling the piston can be stored.

7. The device according to claim 1, wherein the control unit comprises a selection device by means of which an operating mode can be selected by an operator manually and/or automatically from a detected operating state.

8. The device according to claim 1, wherein the working chamber is formed with two end sides each having one strike surface, onto which the piston alternately strikes in order to generate impact pulses.

9. A construction machine, wherein a device for generating oscillations and impact pulses according to claim 1 is arranged.

10. The construction machine according to claim 9, wherein this machine is configured as a drilling rig for earth and/or rock drilling.

11. The construction machine according to claim 9, wherein the device for generating oscillations and impact pulses is arranged on a rotary drive for rotationally driving a drilling tool, and a damping element is arranged between the rotary drive and the drilling tool or drill pipes.

12. A method of operating a device according to claim 1, in which a piston is moved back and forth in a working chamber in a reversing manner between a first return point and a second return point, wherein the piston is set into a reciprocating motion by means of a pressurized fluid and at least one actuatable control valve, in order to generate the oscillations, and the pressurized fluid is introduced into and discharged from the working chamber in the region of the first return point and/or the second return point, and the at least one control valve is actuated by means of a control unit, wherein the movement of the piston in the working chamber is controllable and variable, wherein the control unit is configured to actuate the piston in a first operating mode for generating oscillations and in a second operating mode for generating impact pulses, wherein a strike surface is formed on at least one end side of the working chamber, onto which surface the piston strikes when it reaches at least one return point in the second operating mode, in order to generate an impact pulse.

13. The method according to claim 12, wherein an operating mode is selected and set by means of a selection device.

14. The method according to claim 12, wherein the device for generating oscillations and impact pulses is used on a drilling rig with a drilling tool which can be driven in rotation, the device is operated in the second operating mode during sinking-by-drilling a borehole into soil or rock, wherein impact pulses are exerted on the drilling tool, and the device is operated in the first operating mode when the drill pipes are pulled out of the borehole, wherein the drilling tool is induced to oscillate.

15. The method according to claim 12, wherein an operating state, in particular a sinking-by-drilling or a pulling of a drilling tool in a drilling rig, is detected by means of at least one detection device, and an operating mode is automatically selected and set by the selection device depending on the detected operating state.

Description

[0034] The invention is explained further with reference to preferred exemplary embodiments, which are shown schematically in the drawings. The drawings show in:

[0035] FIG. 1 a schematic cross-sectional view of a device according to the invention, and

[0036] FIG. 2 another schematic cross-sectional view of a device according to the invention.

[0037] FIG. 1 schematically shows a drill drive assembly 1 for a drilling rig, which assembly is equipped with a device 10 according to the invention for generating oscillations and impact pulses. The drive assembly 1 may comprise an enclosure 5 that can accommodate all functional components. A drill pipe 12, which can carry a drilling tool 13 at its distal end, protrudes from the enclosure 5. The drill pipe 12 can be set into a rotary motion about the axis of the drill pipe 12 by means of a drive 14, such as a hydraulic motor, via a transmission 15. The drive 14 and the transmission 15 may form a so-called drill drive.

[0038] A damping element 25 can be arranged between the drill drive and the drill pipe 12 in order to dampen oscillations and shocks being transmitted to the drill drive. A cutting edge of the drilling tool 13 can remove material at the bottom of the hole by means of the rotary movement of the drilling tool 13.

[0039] In accordance with the invention, the device 10 is mounted on the transmission 15 with a housing 16, which is essentially configured to generate oscillations and impact pulses. The housing 16 can be mounted via rubber elements 17 which dampen the transmission of the generated vibrations from the housing 16 towards the enclosure 5. The drill drive can be displaceably mounted in an axial guide 11. Furthermore, the transmission 15 can be operated in a manner decoupled from the vibration generation of the device 10. In this case, in an exemplary manner, the vibration generated can be transmitted directly to the drill pipes 12 and thus to the drilling tool 13 via a shaft, which shaft can be led through an output shaft configured as a hollow shaft. The rotary motion generated by the transmission 15 can be transmitted from the hollow shaft to the drill pipes 12 and thus to the drilling tool 13 via a toothing or any tooth profile that decouples the generated axial vibration from the transmission. The damping element 25 provides for an additional vibration decoupling. Alternatively, the shaft can also transmit the rotary motion and a hollow shaft the generated vibration.

[0040] The device 10 comprises a piston 18 which is displaceably mounted in a working chamber 20 of the housing 16, wherein the piston 18 divides the working chamber 20 into two pressure chambers. These pressure chambers in the working chamber 20 can be alternately supplied with a pressurized fluid, in particular a hydraulic fluid, via a pressurized medium supply. The pressurized fluid can be provided in a pressurized fluid line P and alternately fed into and discharge from the pressure chambers on either side of the piston 18 by means of a control valve 19.

[0041] The control valve 19 can, for example, be an electromagnetically actuated 2/4-way valve. However, any other appropriate valves can also be used, e.g. with rotating valve spools, proportional valves and/or servo valves. The respectively non-pressurized chamber on the piston 18 can be alternately connected to a pressure-less tank line T via the control valve 19. This alternating pressurization of the piston 18 causes it to be induced to a reversing motion between two return points in the working chamber 20.

[0042] A position of the return points and a frequency of the piston 18 can be controlled and set via the control valve 19 by a control unit 30, in particular with a memory programmable logic control (MPLC).

[0043] The current position of the piston 18 can be detected and transmitted to the control unit 30 via a measuring device 32 on the working chamber 20, which is not shown in detail. The actual stroke and the frequency of the piston 18 can also be determined, checked and set as variables derived from this.

[0044] In particular, a first control program for carrying out a first operating mode and a second control program for carrying out a second operating mode are stored in the control unit 30. In the first operating mode, the control unit 30 actuates the control valve 19 in such a way that the piston 18 is moved back and forth without contact with the two end faces of the working chamber 20. In this way, an oscillation can be generated in the first operating mode without a strike contact.

[0045] If the second operating mode is set on the control unit 30 via a selection device (not shown in greater detail), the pressure medium supply takes place via the control valve 19 in such a way that the piston 18 strikes in a contacting manner at least against the lower end side of the working chamber 20, which is configured as a strike surface 22, in order to generate impact pulses. In this way, impact pulses can be transmitted to the drill pipes 12 and the drilling tool 13 during drilling.

[0046] FIG. 2 shows a further drive assembly 1 according to the invention for a drilling rig, in particular for earth or rock drilling with the device 10 according to the invention, wherein mainly a connection of drill pipes 12 with the drill drive and the device is illustrated. A torque is transmitted by a drive 14, which is only schematically indicated, via a transmission 15 with a hollow output element to a so-called insertion element 21. The insertion element 21 is connected to the tubular drill pipes 12 in an axially displaceable but in a torque proof manner. On a top side of the insertion element 21, oscillation or impact pulses can be transmitted to the insertion element 21 and thus to the drill pipe 12 via the device 10, which is only indicated schematically.

[0047] The insertion element 21 is axially displaceable in the hollow output element of the transmission 15, but is arranged in a torque proof manner, for example via suitable spline groove toothing. An annular damping element 25 is arranged between the drill drive with the transmission 15 and the upper end of the drill pipes 12. The annular damping element 25 can have a disk spring assembly 26, as schematically indicated in FIG. 2. This can provide at least largely an oscillation/impact decoupling between the drill pipes 12 and the drill drive.

[0048] In the assembly according to the invention, the control unit 30 can ensure, in particular when pulling the drill pipes 12 out of the borehole, in a schematically indicated soil, that no impact pulses are exerted on the drill pipes during the pulling movement. This is particularly gentle on the illustrated damping element 25, which is susceptible to impact pulses during the pulling movement. This can significantly extend the service life of the damping element.