Vibration or percussive pulse generating apparatus for construction machine and method of operating the same

Abstract

The invention relates to a device for generating vibrations for a construction machine, comprising a housing, a piston which is reversibly movable back and forth in a working chamber in the housing between a first reversal point and a second reversal point, a pressure fluid supply through which pressure fluid can be introduced and expelled into the working chamber in the region of the first reversal point and the second reversal point via at least one controllable control valve, wherein the piston can be set into a reversing motion to generate the vibrations, and a control unit which is designed to control the at least one control valve and through which the movement of the piston in the working chamber can be controlled and changed.According to the invention, the control unit is designed to control the piston in a first operating mode to generate vibrations and in a second operating mode to generate impact impulses, wherein a striking surface is formed on at least one end side of the working space, against which the piston strikes when reaching at least one reversal point to generate an impact impulse.

Description

[0001] The invention relates to a device for generating vibrations for a construction machine, comprising a housing, a piston which is reversibly movable back and forth in a working chamber in the housing between a first reversal point and a second reversal point, a pressure fluid supply through which pressure fluid can be introduced into and out of the working chamber in the region of the first reversal point and / or the second reversal point via at least one controllable control valve, wherein the piston can be set into a reversing motion to generate the vibrations, and a control unit which is designed to control the at least one control valve and through which the movement of the piston in the working chamber can be controlled and changed, according to the preamble of claim 1.

[0002] The invention further relates to a method for operating a device in which a piston is moved back and forth in a working chamber in a reversing motion between a first reversing point and a second reversing point, wherein, to generate the vibrations, the piston is set into a reversing motion by means of a pressure fluid and at least one controllable control valve, and the pressure fluid is introduced into and out of the working chamber in the region of the first reversing point and / or the second reversing point, and the at least one control valve is controlled by means of a control unit, wherein the movement of the piston in the working chamber is controllable and variable, according to the preamble of claim 11.

[0003] A vibration generator for a construction machine is known from EP 1 728 564 B1. In this known vibration generator, the working space in the housing is divided into two pressure chambers by a working piston. The two pressure chambers are selectively supplied with fluid via an inlet and an outlet.

[0004] Pressure fluid is alternately supplied and discharged, causing the working piston to move in reverse and generate an oscillation. The timed supply and discharge of pressure fluid to the individual pressure chambers is achieved via a complex channel arrangement within the working piston. Additionally, a control piston is slidably mounted within the working piston. Its position relative to the working piston can be precisely adjusted by means of stops projecting from the end faces of the housing, allowing it to open or close specific channels. The supply and discharge of pressure fluid is thus achieved mechanically, with the pressure fluid supply and discharge switching over at predetermined switching points via the predefined channels.

[0005] Comparable mechanical control devices for vibration generators are also described, for example, in GB-A-920,158, US-A-4,026,193, and US-A-4,031,812. All these known devices feature a working piston and a control piston, which, depending on their position in the housing, open or close specific channels, thereby enabling a controlled, alternating supply of pressure to the two opposing pressure chambers to move the working piston.

[0006] A generic vibration generator with a control unit for actuating a control valve is known from DE 30 388 35 A1, US 4 342 255, EP 4 001 510 or EP 3 417 951 A1. EP 3 417 951 A1, which originates from the applicant, teaches that such a control unit can be used in a vibration generator or in a percussion mechanism.

[0007] The invention is based on the TaskThe aim is to specify a device and a method for generating vibrations which are particularly efficient for use on construction machinery.

[0008] The problem is solved, firstly, by a device having the features of claim 1 and, secondly, by a method having the features of claim 11. Preferred embodiments of the invention are specified in the dependent claims.

[0009] The device according to the invention is characterized in that the control unit is designed to control the piston in a first operating mode to generate vibrations and in a second operating mode to generate impact impulses, wherein a striking surface is formed on at least one end side of the working space, against which the working piston strikes when reaching at least one reversal point to generate an impact impulse.

[0010] A fundamental aspect of the invention is to provide a device capable of generating both vibrations and impact impulses. For this purpose, an impact surface is formed on at least one end of the working chamber. Similarly, the piston is provided with a corresponding impact surface and is designed to generate impact impulses. Preferably, the working chamber can have two opposing end faces, each formed with an impact surface. The piston can also be provided with two corresponding impact surfaces. The impact surface is preferably hardened relative to the adjacent wall surfaces.

[0011] According to one aspect of the invention, the control unit is designed such that it is provided or configured with a control program comprising a first operating mode for generating vibrations and a second operating mode for generating impact pulses. In the first operating mode, the piston is controlled in the working chamber such that, during its reversing movement, the piston does not strike any end or face of the working chamber. The reversing movement of the piston thus generates a vibration without impact pulses. The device forms a so-called linear oscillator.

[0012] In the second operating mode, however, the at least one control valve is controlled in such a way that the piston strikes at at least one end of the working space, especially on the side facing the ground in the case of a drilling rig, in a defined manner, thus generating a targeted impact impulse.

[0013] The device can thus be used and operated alternately, depending on the selected operating mode, either as a linear oscillator without impact pulses or as a percussion mechanism with the generation of targeted impact pulses.

[0014] For the device according to the invention, all suitable controllable valves can be used, in particular those that are hydraulically or electrically actuated. According to a further development of the invention, it is particularly advantageous for the control valve to be designed as a solenoid valve. The valve body can be adjusted between an open and a closed position by an electromagnetic arrangement. Intermediate positions can also be set, so that the supply quantity of pressurized fluid to the working chamber can be adjusted. In principle, any pressurized fluid can be used, although hydraulic oil is preferred.

[0015] Another preferred embodiment includes a measuring device for determining the position of the piston in the working chamber. This enables very precise control of the piston, with the measuring device being connected to the control unit.

[0016] The measuring device can also be equipped with any usable sensor for length or position measurement, which may operate optically, capacitively, inductively, magnetically, or in any other way. According to one embodiment of the invention, it is particularly advantageous for the measuring device to have a linear sensor. This is especially useful when the piston moves linearly within the housing between the two reversal points.

[0017] Furthermore, the measuring device may include an elongated first measuring component that extends into the working chamber and into a free space within the piston. Thus, the measuring component is not located behind a wall of the housing, but directly within the working chamber in which the piston moves. For particularly precise position measurement, the elongated first measuring component projects into a corresponding free space within the piston, with the piston preferably sliding along the first measuring component without contact.

[0018] According to a further embodiment of the invention, it is preferred that the control unit allows for the setting and adjustment of the piston's frequency and / or stroke. To change the frequency, the opening and closing times, and optionally the supply of hydraulic energy, can be adjusted by the control unit. The piston's stroke can also be achieved by changing the position of the two reversal points through a corresponding opening and closing of the controllable valves. For this purpose, the control unit preferably has an input interface, for example, an input field. Alternatively, the control unit can be directly operated by an operator via a conventional machine control system.

[0019] Another preferred embodiment of the invention is characterized by the control unit having a program memory in which various control programs for controlling the piston can be stored. This allows for the storage of specific control programs for particular applications. In particular, a control program can be stored with the two operating modes. Furthermore, for example, a high frequency with a small piston stroke can be provided at the beginning of a program, while the piston stroke increases and the frequency decreases over time as the program progresses. Virtually any number of different program sequences for controlling the piston with respect to frequency and stroke can be provided. For example, a program can be provided for rapid advancement or for particularly gentle driving. Programs for specific soil types can also be stored for operation as a construction machine.

[0020] According to the invention, the control unit includes a selection device with which an operating mode can be selected manually and / or automatically by an operator based on a detected operating state. For example, an operator can manually switch between the first operating mode for generating vibrations and the second operating mode for generating impact pulses. The selection device can be part of an operating unit. Alternatively or additionally, the control unit can also automatically initiate a change of operating modes, for example, when certain operating states of a machine on which the device according to the invention is arranged are present.

[0021] According to a further embodiment of the invention, it is preferred that the working chamber is designed with two end faces, each with a striking surface against which the working piston alternately strikes to generate impact impulses. Correspondingly, the piston can also be provided with two corresponding striking surfaces.

[0022] The invention comprises a construction machine characterized in that the device described above is arranged for generating vibrations and impact impulses. In particular, the construction machine can be designed and configured for civil engineering.

[0023] According to one embodiment of the invention, it is particularly advantageous that the construction machine is designed as a drilling rig for drilling into earth and / or rock. The drilling rig has a rotary drive for rotating a drill string and / or drilling tool. The device according to the invention can be arranged on the rotary drive or combined with it.

[0024] If the device is operated without impact contacts to generate vibrations according to the first operating mode, a so-called superimposed drilling technique can be performed. In this technique, the rotary motion of the drill bit is superimposed with a vibration or oscillation motion. These superimposed vibrations can achieve a quasi-liquefaction of the soil, at least in the contact area with the drill bit, leading to improved drilling progress. Applying vibrations can also facilitate the extraction of the drill bit from a borehole.

[0025] If the device for generating impact impulses is operated according to the second operating mode, impact drilling can be carried out. This is particularly advantageous when penetrating harder rock layers.

[0026] It is particularly preferred that the device for generating vibrations and impact impulses is arranged on a rotary drive for rotating a drilling tool, and that a damping element is arranged between the rotary drive and the drilling tool or drill string. The damping element, which may comprise, for example, a disc spring assembly, can help to protect the rotary drive, whereby vibrations or impacts exerted by the device on the drilling tool or drill string are not transmitted to the rotary drive, or are only transmitted in a damped form. The damping element can be designed for torque transmission between the rotary drive and the drilling tool or drill string.Particularly to protect the damping element, it may be useful for the control unit to switch from an operating mode for generating impact impulses to an operating mode for generating vibrations when a drilling tool is pulled.

[0027] The method according to the invention is characterized in that the control unit is designed to control the piston in a first operating mode to generate vibrations and in a second operating mode to generate impact impulses, wherein a striking surface is formed on at least one end side of the working space, against which the working piston strikes when reaching at least one reversal point in the second operating mode to generate an impact impulse.

[0028] The method according to the invention can be carried out in particular with the device described above. The advantages described above result from this.

[0029] The method according to the invention is preferably further developed by means of a selection device in which an operating mode is selected and set. The selection can be made manually by an operator or automatically by a program of the control unit depending on an operating state. Depending on the selected operating mode, the control of the at least one control valve is changed by the control unit so that, according to the first operating mode, vibrations without impact contact or, according to the second operating mode, impact pulses are generated.

[0030] According to a further development of the method, it is also preferred that the device for generating vibrations and impact impulses is used on a drilling rig with a rotating drill bit, which, when drilling a borehole in soil or rock, operates the device in the second operating mode, whereby impact impulses are exerted on the drill bit, and that when the drill bit is withdrawn from the borehole, the device is operated in the first operating mode, whereby the drill bit is set into vibration.

[0031] The method is a drilling process in which a drill bit, with or without drill string, is driven by rotation. Depending on the drilling operation, the rotational movement is superimposed with vibrations or impact pulses. For example, during core drilling, percussion drilling can be performed, combining the rotational movement with impact pulses as described in the second operating mode. For efficient withdrawal of the drill bit from the borehole, the device is switched to the first operating mode, generating vibrations without impact pulses. Axial oscillation of the drill bit during withdrawal reduces friction, making the withdrawal process easier and gentler on the borehole wall and any damping element. This oscillation can occur with or without rotation of the drill bit. The rotation can also preferably be performed as a reversing rotary motion during withdrawal.

[0032] A particularly preferred embodiment of the invention consists in the following: at least one detection device is used to detect an operating state, in particular the drilling or withdrawal of a drilling tool in a drilling rig, and the selection device automatically selects and sets an operating mode depending on the detected operating state. The detection device can, in particular, detect whether drilling (i.e., advancement in the drilling direction) or withdrawal (i.e., a retraction movement from a borehole) is taking place. Depending on this operating state, an automatic switch between the two operating modes can then occur, in particular from generating impact pulses during drilling (according to the second operating mode) to generating vibrations (according to the first operating mode) when withdrawing the drilling tool.

[0033] The detection device can preferably also detect the forward movement and / or the rotational speed and / or the torque of the drilling tool, with the control unit being designed to draw conclusions about the approaching soil layer based on this information. For example, a decrease in rotational speed and forward speed or an increase in torque may indicate that a harder soil layer is encountered. In such a case, the control unit can automatically switch the device to its second operating mode for generating impact pulses.

[0034] If, however, a softer soil layer is detected, the control unit can switch the device to the first operating mode for performing overburden drilling with vibrations. Alternatively, instead of automatic switching, the control unit can also provide a machine operator with a notification or recommendation to change the operating mode via the control unit. Generally, when drilling, it can be selected whether vibrations or impact pulses should be generated. When pulling, vibrations are always generated using the device according to the invention.

[0035] The invention will be further explained with reference to preferred embodiments, which are shown schematically in the drawings. The drawings show: Figure 1 shows a schematic cross-sectional view of a device according to the invention, and Figure 2 shows another schematic cross-sectional view of a device according to the invention.

[0036] The Figure 1 Figure 1 schematically shows a drill drive arrangement 1 for a drilling rig, which is equipped with a device 10 according to the invention for generating vibrations and impact impulses. The drive arrangement 1 can include a housing 5 that can accommodate all functional components. A drill string 12 projects from the housing 5 and can carry a drill bit 13 at its distal end. The drill string 12 can be set into a rotary motion about the axis of the drill string 12 by means of a drive 14, for example a hydraulic motor, via a gearbox 15. The drive 14 and the gearbox 15 can form a so-called drill drive.

[0037] A damping element 25 can be arranged between the drill drive and the drill string 12 to dampen the transmission of vibrations and impacts to the drill drive. A cutting edge of the drill bit 13 can remove material from the bottom of the bore by the rotary motion of the drill bit 13.

[0038] According to the invention, the device 10 with a housing 16, which is essentially designed to generate vibrations and impact impulses, is mounted on the gearbox 15. The housing 16 can be mounted via rubber elements 17, which dampen the transmission of the generated vibration from the housing 16 to the enclosure 5. The drill drive can be slidably mounted in an axial guide 11. Furthermore, the gearbox 15 can be operated decoupled from the vibration generation of the device 10. In this case, for example, the generated vibration can be transmitted directly to the drill string 12 and thus to the drill bit 13 via a shaft, which can be guided through an output shaft designed as a hollow shaft. The rotary motion generated by the gearbox 15 can be transmitted from the hollow shaft to the drill string 12 and thus to the drill bit 13 via a toothed connection or any tooth profile that decouples the generated axial vibration from the gearbox.The damping element 25 provides additional vibration decoupling. Alternatively, the shaft can transmit the rotary motion and a hollow shaft can transmit the generated vibration.

[0039] The device 10 has a piston 18 which is slidably mounted in a working chamber 20 of the housing 16, the piston 18 dividing the working chamber 20 into two pressure chambers. These pressure chambers in the working chamber 20 can be alternately pressurized with a pressure fluid, in particular a hydraulic fluid, via a pressure medium supply. The pressure fluid can be supplied in a pressure fluid line P and alternately introduced into and out of the pressure chambers on both sides of the piston 18 by means of a control valve 19.

[0040] The control valve 19 can be, for example, an electromagnetically actuated 2 / 4-way valve. However, any other suitable valve can also be used, such as those with rotary valve spools, proportional and / or servo valves. The control valve 19 allows the unpressurized chamber on the piston 18 to be alternately connected to a pressureless tank line T. This alternating actuation of the piston 18 causes it to move in a reversing motion between two reversal points within the working chamber 20.

[0041] The position of the reversal points and the frequency of the piston 18 can be controlled and set via the control valve 19 by a control unit 30, in particular with a programmable logic controller (PLC).

[0042] The current position of the piston 18 can be detected via a measuring device 32 (not shown) on the working chamber 20 and transmitted to the control unit 30. The actual stroke and frequency of the piston 18 can then be determined, monitored, and adjusted as derived parameters.

[0043] The control unit 30 contains, in particular, a first control program for executing a first operating mode and a second control program for executing a second operating mode. In the first operating mode, the control unit 30 actuates the control valve 19 such that the piston 18 is moved back and forth without contacting the two end faces of the working chamber 20. In this way, a vibration can be generated in the first operating mode without impact contact.

[0044] If the second operating mode is selected via a selection device (not shown) on the control unit 30, the pressure medium is supplied via the control valve 19 such that the piston 18 makes contact at least with the lower end of the working chamber 20, which is designed as a striking surface 22, to generate impact impulses. In this way, impact impulses can be transmitted to the drill string 12 and the drilling tool 13 during drilling.

[0045] In Figure 2Figure 1 shows a further drive arrangement 1 according to the invention for a drilling rig, particularly for drilling in earth or rock, with the device 10 according to the invention, wherein a connection of a drill string 12 with the drilling drive and the device is clearly illustrated. A torque is transmitted from a drive 14 (only schematically indicated) via a gearbox 15 with a hollow output element to a so-called insertion element 21. The insertion element 21 is in an axially displaceable, but rotationally fixed, connection with the tubular drill string 12. At an upper surface of the insertion element 21, a vibration or impact impulses can be transmitted to the insertion element 21 and thus to the drill string 12 via the device 10 (only schematically indicated).

[0046] The insertion element 21 is axially displaceable within the hollow output element of the gearbox 15, but rotationally fixed, for example by means of a suitable keyway. An annular damping element 25 is arranged between the drill drive with the gearbox 15 and the upper end of the drill string 12. The annular damping element 25 can include a disc spring assembly 26, as shown schematically in Figure 2 This indicates that at least a significant degree of vibration / impact decoupling can be achieved between the drill string 12 and the drill drive.

[0047] In the arrangement according to the invention, the control unit 30 can ensure, particularly when pulling the drill string 12 out of the borehole in a schematically indicated bottom, that no impact impulses are exerted on the drill string during the pulling movement. This protects the damping element 25 shown, which is susceptible to impact impulses during the pulling movement. This can significantly extend the service life of the damping element.

Claims

1. Device for generating oscillations for a construction machine, comprising - a housing (16), - a piston (18) which is movable back and forth in a working chamber (20) in the housing (16) 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 (20) via at least one actuatable control valve (19) in the region of the first return point and / or the second return point, wherein the piston (18) can be set into a reciprocating motion in order to generate the oscillations, and - a control unit (30) which is configured to actuate the at least one control valve (19) and by means of which the motion of the piston (18) in the working chamber (20) is controllable and variable, wherein the control unit (30) is configured to actuate the piston (18) in a first operating mode for generating oscillations and in a second operating mode for generating impact pulses, wherein a strike surface (22) is formed on at least one end side of the working chamber (20), onto which surface the piston (18) strikes when it reaches at least one return point in order to generate an impact pulse, characterized in that the control unit (30) 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.

2. Device according to claim 1, characterized in that the control valve (19) is configured as a solenoid valve.

3. Device according to claim 1 or 2, characterized in that a measuring device (32) is provided for determining a position of the piston (18) in the working chamber (20).

4. Device according to claim 3, characterized in that the measuring device (32) comprises a linear sensor.

5. Device according to any one of claims 1 to 4, characterized in that a frequency and / or a stroke of the piston (18) can be set and adjusted by means of the control unit (30).

6. Device according to any one of claims 1 to 5, characterized in that the control unit (30) comprises a program memory in which control programs for controlling the piston (18) can be stored.

7. Device according to any one of claims 1 to 6, characterized in that the working chamber (20) is formed with two end sides each having one strike surface (21), onto which the piston (18) alternately strikes in order to generate impact pulses.

8. Construction machine, characterized in that a device (10) for generating oscillations and impact pulses according to one of claims 1 to 7 is arranged.

9. Construction machine according to claim 8, characterized in that this machine is configured as a drilling rig for earth and / or rock drilling.

10. Construction machine according to claim 8 or 9, characterized in that the device (10) for generating oscillations and impact pulses is arranged on a rotary drive (14) for rotationally driving a drilling tool, and in that a damping element (25) is arranged between the rotary drive (14) and the drilling tool (13) or drill pipes.

11. Method of operating a device (10) according to any one of claims 1 to 10, in which the piston (18) is moved back and forth in the working chamber (20) in a reversing manner between the first return point and the second return point, wherein the piston (18) is set into a reciprocating motion by means of a pressurized fluid and the at least one actuatable control valve (19), in order to generate the oscillations, and the pressurized fluid is introduced into and discharged from the working chamber (20) in the region of the first return point and / or the second return point, and the at least one control valve (19) is actuated by means of the control unit (30), wherein the movement of the piston (18) in the working chamber (20) is controllable and variable, wherein the control unit (30) is configured to actuate the piston (18) in the first operating mode for generating oscillations and in the second operating mode for generating impact pulses, wherein the strike surface (22) is formed on the at least one end side of the working chamber (20), onto which surface the piston (18) strikes when it reaches at least one return point in the second operating mode, in order to generate an impact pulse. characterized in that an operating mode is selected and set by means of the selection device.

12. Method according to claim 11, characterized in that the device (10) for generating oscillations and impact pulses is used on a drilling rig with a drilling tool (13) which can be driven in rotation, in that the device (10) 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 in that the device (10) is operated in the first operating mode when the drill pipes (13) are pulled out of the borehole, wherein the drilling tool (13) is induced to oscillate.

13. Method according to any one of claims 11 to 12, characterized in that 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 in that an operating mode is automatically selected and set by the selection device depending on the detected operating state.

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