DE29513580U1 - Vibration damper for a deep drilling machine - Google Patents

Description

-ING. PETER &Kgr;&sgr;&egr;^_. DIPPING. BETER* SOBISCH

PATENT ATTORNEYS.""&Ggr; ^? ! &iacgr;&iacgr;&iacgr;* [[*,,,*

PATENT ATTORNEYS. .

ADMISSIONED BY THE EUROPEAN PATENT OFFICE -'EUROPEAN PATENT ATTORNEYS

Patent Attorneys Rose, Kosel & Sobisch Odastrasse 4a, D-37581 Bad Gandersheim

Odastrasse 4a

D-37581 Bad Gandersheim Germany

Telephone (05382) 40 38 Fax (05382) 40 30 VATNo.: DE 114 770 070

your reference/Your ref.

Please specify/pls.quote: Our reference/Ourref.

2953/27

Date 23 August -1985

BURGSMÜLLER GmbH

DESCRIPTION

Vibration damper for a deep drilling machine

The invention relates to a deep drilling machine according to the preamble of claim 1.

As is well known, the drill pipe is the most flexible structural element in deep drilling machines, and can be excited to bending and torsional vibrations by the drilling process. These vibrations, which can be detected via the sound radiation of the deep drilling machine, not only lead to premature tool wear but also to a deterioration in the energy conversion of the drilling tool. To combat these vibrations, vibration dampers are known which surround the outside of the drill pipe and are inserted into damper lunettes which are arranged so that they can be moved along the drill pipe, whereby the damper lunette is placed along the drill pipe in the area of a vibration structure.

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PS/K/N

Account: NORD/LB, NL Bad Gandersheim (bank code 250 500 QO) ₁ year Opening hours: Mon - Fri 7.30am - 12.30pm and 2pm - 5pm '*

Hanover (bank code 250 100 30), account no. 667 15-307

Ol ches is aimed at in order to achieve an optimal damping effect.

The essence of the known vibration dampers consists of a vibrating mass that coaxially surrounds the drill pipe, is cylindrical on the outside and rotatably mounted in a housing and is coupled to the outside of the drill pipe by means of a damping body made of plastic. The damping body has an outer surface that has a conical shape towards one end and that is in contact with a complementary conical inner surface of the vibrating mass. The inner surface of the damping body is cylindrical and smooth and lies directly against the drill pipe, so that a more or less strong deformation state of the damping body and associated different elastic and damping properties can be achieved by axially displacing the damping body relative to the vibrating mass and the drill pipe. The vibrating mass and the drill pipe form an oscillating system in conjunction with the damping body via which they are connected. By deforming the damping body, the coupling state between the oscillating mass and the drill pipe is changed and in this way the influences that determine the vibration behavior can be taken into account with regard to optimal damping. By means of two hydraulically actuated ring pistons arranged on either side of the oscillating mass, which, when pressure is applied, carry out movements in opposite directions, here directed towards a radial center plane of the arrangement, the deformation state of the damping body can be adjusted continuously according to the difference in the pressures acting on the ring pistons. The ring pistons act

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Oil is applied to pressure rings via axially directed roller bearings, which are in direct contact with the damping body on the front side. Such a vibration damper is known, for example, from the brochure "Instructions for hydraulic vibration dampers", issue date 31.08.1994, from Burgsmüller GmbH, 30625 Hanover.

Since the externally conical damping body in these known vibration dampers is clamped between the pressure rings mentioned, it can only be replaced by completely dismantling the system of ring piston and pressure ring on one side. To set a certain deformation state, the differential pressure is determined, which depends on the drill pipe diameter and other parameters of the drilling process and is necessary for the relative movement of the damping body with respect to the oscillating mass required to achieve a certain tension. To remove the coupling state of the damping body to the drill pipe, it must be ensured by appropriately applying pressure to the pressure chambers of the two ring pistons that the damping body is now moved in the opposite direction relative to the oscillating mass - reducing its deformation state - until the coupling state with the drill pipe is removed. The process of tightening and loosening the damping body is comparatively complex, often does not lead to reproducible results and requires a high degree of care and practical experience.

It is the object of the invention to design a vibration damper of the type described above in such a way that the clamping and releasing process of the damping body is simplified while the damping body can be easily assembled and disassembled. This object is achieved in a

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Ol generic vibration damper by the features of the characterizing part of claim 1.

According to this, the essential feature of the invention is a damper structure that is symmetrical to a radial center plane, whereby this symmetry affects the oscillating mass, the pressure rings arranged on both sides of the center plane, the clamping bush and the damping bush, the latter being designed as a cylindrical body that surrounds the drill pipe. The clamping bush, which can be reduced in diameter, has surfaces on the outside that are symmetrical to the center plane and that taper conically towards the front ends, which are in operative connection with the facing inner surfaces of the pressure rings, so that symmetrical displacement of the pressure rings towards the center plane results in a deformation of the clamping bush that is symmetrical to the center plane and overall a uniform radial deformation of the damping bush - seen along its axis. The damping bush, the clamping bush, the system of pressure rings and the oscillating mass thus form a nested, coaxial arrangement that encloses a central cavity intended for the passage of the drill pipe. The clamping bush projects inwards into this cavity and the damping body is detachably connected to the clamping bush. The damping body can be attached to the clamping bush in such a way that the former can be replaced without dismantling other structural elements of the vibration damper. The clamping bush is in a preferably positively effective rotary connection with the oscillating mass, so that the vibration energy transmitted via the drill pipe in the form of torsional vibrations is essentially dissipated via the damping bush. The overall symmetrical structure of the arrangement is easy to manage.

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Ol de movements of the pressure rings, a consequently simple operation, as well as uniform deformation conditions when tightening and releasing the damping bush.

The features of claims 2 to 4 are directed at the guidance and actuation of the pressure rings. These can be actuated in one direction, namely in the direction of the central plane, using a pressure fluid and are subject to the counteraction of a pressure spring in this direction, via which the required return movement can be initiated after pressure relief. The axially displaceable pressure rings are also connected to the oscillating mass via guide bolts in a rotationally locked manner, whereby these guide bolts also enable the axial movements of the pressure rings mentioned. In addition to the oscillating mass, the masses of the pressure rings and the clamping bush, which move synchronously with it, can thus be excited to torsional vibrations via the damping bush.

To create a rotary connection between the oscillating mass on the one hand and the clamping bush on the other, a series of driving pins are provided, which are connected to the oscillating mass, for example by screw, and engage in a form-fitting manner in corresponding facing holes in the clamping bush.

According to the features of claim 6, the pressure rings are actuated by ring pistons, which can only be moved axially and whose axial force is transmitted to the pressure rings via axially oriented roller bearings. The ring pistons are guided in corresponding ring-cylinder-like receptacles and their respective pressure chambers are always uniformly pressurized in order to move the ring pistons. The required reset

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Oil force is applied via the compression springs already mentioned above, which act on the ring pistons via the pressure rings.

According to the features of claim 7, the oscillating mass has an annular body in its central region, which has bore sections that form external guide surfaces for guiding the pressure rings. These guide surfaces end in the region of a central ring web that is formed radially on the inside of the said annular body. The pressure rings have cylindrical surfaces on the outside that interact with the said guide surfaces.

The radially inner recess of the system comprising the pressure rings and the ring web provided in accordance with the features of claim 8 serves to accommodate the clamping bush, wherein the recess is preferably designed in such a way that an axial play is produced on both sides of the clamping bush.

The damping bushing is fixed axially within the clamping bushing via ring grooves corresponding to the features of claim 9 and a snap ring inserted into them, whereby after loosening this snap ring or a comparable functional element, the damping bushing can be axially removed from the vibration damper.

The damping bushing is preferably designed to be split lengthwise in accordance with the features of claim 10, so that its assembly onto a drill pipe is made significantly easier.

The clamping bush is designed to be slotted according to the features of claim 11 and in this way

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Ql is elastically compressible in the radial direction, whereby the slot arrangement should be such that the most homogeneous deformation and thus the exertion of force - seen in the axial direction - on the damping bush is achieved. The clamping bush can also be designed to be split lengthwise.

To tension the damping body with the vibration damper installed, all that is required is a uniform pressurization of the pressure fluid connections of the vibration damper, whereby the extent of the pressurization depends on the parameters of the drilling process and therefore on the individual case. After the pressure is relieved, the damper is released automatically under the effect of the compression springs acting as return springs.

The invention will be explained in more detail below with reference to the embodiment shown in the drawings. It shows:

Fig. 1 a side view of a deep drilling machine with vibration damper;

Fig. 2 is a longitudinal sectional view of a vibration damper according to the invention;

Fig. 3 an enlarged partial view of a vibration damper in longitudinal section.

In Fig. 1, 1 shows the machine bed of a deep drilling machine in a side view, in which a drill spindle box 2 is supported on a carriage 3, which is moved by means of a drive 4 in the direction of the arrows 5, thus in the longitudinal direction of the deep drilling machine in a defined

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Ol ned manner. For this purpose, the machine bed 1 is equipped with a corresponding guide 6 for the slide 3, not shown in detail in the drawing.

7 designates a clamp for a drill pipe 8, which extends parallel to the machine's longitudinal axis into a drilling oil feed device 9 located at a distance from the drilling spindle box 2 and within this engages with the workpiece 10, which is to be provided with a deep bore and extends coaxially to the drill pipe 8. The workpiece 10 is accommodated in the workpiece clamp 11 of a main spindle box, which is fixedly connected to the machine bed 1. The workpiece 10 can be driven about its axis via a drive 13 attached to the main spindle box 12 and the drill pipe 8 can be driven about its axis via a drive 14 attached to the drilling spindle box 2.

During drilling progress, the slide 3 is advanced by means of the drive 4 in the direction of the workpiece.

During the drilling process, a liquid medium used for lubrication and cooling, here a drilling oil, is fed between the outside of the drill pipe and the inner wall of the bore of the drill bit via the drilling oil feed device, whereby the drilling oil laden with chips flows out in a known manner through the hollow drill pipe 8 and is reused after the chips have been separated, filtered and cooled.

The machine type shown can be operated in different ways, namely with rotating tool

With a stationary tool and a stationary workpiece, with a rotating workpiece and a stationary tool and with a counter-rotating tool and workpiece, whereby these three process variants can be carried out by appropriately activating the drives 13, 14.

As a result of the drilling process, mainly the interactions between the workpiece and the tool, as well as the global elastic and damping properties of the machine bed 1 and all components of the deep drilling machine shown, vibrations of the drill pipe 8 arise, in particular torsional vibrations, but also bending vibrations, which are generally referred to as chattering, which not only result in increased tool wear, but also in an inefficient implementation of the installed machine power in relation to the machining process. These vibrations mainly form as continuous vibrations of the torsional and bendiest structural element, namely the drill pipe 8, so that vibration antinodes and vibration nodes form along its free length. To dampen these vibrations, a vibration damper according to the invention inserted into a damper steady rest 16 serves, the structural design of which will be explained below.

For this purpose, the steady rest 16 is moved along the axis of the drill pipe 8 into the area of a vibration antinode in order to achieve an optimal damping effect. After the position of the vibration antinodes changes as a result of the drilling progress and the resulting change in the boundary conditions of the vibrations of the drill pipe 8, the position of the steady rest 16 must be readjusted with the proviso that its position

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Oil is always arranged at the location of an antinode in order to achieve optimum damping performance despite changing boundary conditions.

To explain the structure of the vibration damper according to the invention, reference is made below to drawing figures 2 and 3.

17 designates a cylindrical housing intended for insertion into the steady rest 16, which has radial formations 18 on both end faces, which form annular stops 19 on the inside - oriented towards the center plane 23 of the housing 17 - for the outer ring of a rolling bearing 20, which serve to support an oscillating mass designed to be rotationally symmetrical with respect to the axis 8 ¹ of the drill pipe 8 within the housing 19.

The oscillating mass 21 has in its central region a solid annular body 22 which extends radially inwards and extends axially symmetrically on both sides of a central plane 23 and forms on the inside two bores 24 which extend coaxially to the axis 8 ¹ in the direction of the central plane 23.

25 designates two pressure rings, which are identical to one another and are arranged symmetrically on both sides of the central plane 23, which have inner surfaces 26 on their radially inward-facing side - again symmetrically with respect to the central plane 23 - which widen conically in the direction of the latter. The pressure rings are held in their position shown in one direction, namely in the direction of the central plane 23, by compression springs 27, one end of which is attached to facing surfaces of the respective pressure ring and the other

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Ol ends rest on an annular web 28 which is coaxial with the axis 8 ¹ and formed on the oscillating mass 21. The annular web 28, in particular its radially oriented annular end faces, form stop surfaces of the bores 24 on both sides of the center plane 23, with the compression springs 27 being supported on these stop surfaces. The compression springs 27 are preferably provided in a uniform circumferential distribution along the end faces of the compression rings 25. The compression rings 25 are thus arranged so as to be displaceable axially with respect to the axis 8 ¹ , counter to the action of the compression springs 27 in the direction of the arrows 29.

To stabilize the axial guidance of the two pressure rings 25, a series of guide bolts 30 are provided - also preferably in a uniform circumferential distribution - which extend parallel to the axis 8' of the oscillating mass 21 and are inserted into aligned holes in the two pressure rings 25 and the ring web 28 and are dimensioned such that the pressure rings 25 can slide in the direction of the arrows 29.

31 designates a clamping bush that can be elastically reduced in diameter and has conical outer surfaces that interact with the inner surfaces 26 of the pressure rings 25 in such a way that the inner diameter of the clamping bush 31 can be reduced when the pressure rings 25 move in the direction of the center plane 23, and vice versa. The clamping bush 31 in turn encloses the damping bush 32, which is made of plastic, for example, and is located directly on the inside of the drill pipe 8, and serves for the direct vibration-technical coupling to the drill pipe 8. The damping bush 32 can be split lengthwise, with the two halves being connected by a

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Oil snap ring 33 held together.

The clamping bush 31 can also be designed to be split lengthwise, whereby it can also be designed with longitudinal slots in order to ensure elastic radial deformability. The clamping bush 31 and the damping bush are designed symmetrically with respect to the center plane 23.

34, 34' designate ring pistons of identical design arranged on both sides of the ring web 22, the associated pressure chambers 35, 35" of which can each be pressurized via pressure medium lines 36, 36'. The pressure medium lines 36, 36' end in coupling pins 37, 37', which are intended and designed for direct interaction with locking couplings 38, 38'.

The pressure chambers 35, 35' mentioned are closed radially on the outside by a ring cylinder 39 protruding into the oscillating mass 21 and on the inside and on the front side towards the outside by a cover component 40. Within the ring chamber radially delimited by the ring cylinder 39 and the cover component 40, the respective ring piston 34, 34' is guided in a sliding manner in the direction of the arrows 29 by means of several sealing rings.

Each of the ring pistons 34, 34' is supported on its front side opposite the respective pressure chamber 35, 35' on an axial roller bearing 41, which is supported on its side facing away from the ring piston 34, 34' on the respective pressure ring 25, 25'. It can be seen from the above statements that pressurization of the respective pressure chamber 35, 35* causes a

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This results in a movement of the respective annular piston 34, 34' directed towards the center plane 23 against the action of the compression springs 27, whereby a return movement of the annular pistons 34, 34', on the other hand, occurs when the compression springs 27 are relaxed.

The cover component 40, the ring cylinder 39 and the formations 18 of the housing 17 are screwed together, with the ring cylinder 39 ending at the front in a flange section 42, which at the same time forms a contact surface on the inside for the outer ring of the rolling bearing 20. 43, 44 respectively designate lubricant supply connections for the rolling bearings 20, 41.

The oscillating mass 21 is provided in the central plane 23 - penetrating the ring web 28 and extending into the clamping bush 31 - with several driving pins 45, which are screwed into a corresponding threaded hole in the ring web 22 - from its outside. These driving pins 45 cause a direct coupling of the oscillating mass 21 to the clamping bush 31, which will be discussed in more detail below.

Finally, 46 designates an eyebolt which is screwed into a threaded hole 47 of the housing 17, but which only serves transport purposes.

As can be seen from the drawings Fig. 2, 3, the pressure rings 25 form on the inside in connection with the inside of the ring web 28, namely symmetrically with respect to the center plane 23, a recess 49 directed radially outwards with respect to the other inner surfaces 48 of the pressure rings 25, into which the clamping bush 31 is inserted while leaving an axial play on both sides.

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Ol The clamping bush 31 forms a cylindrical inner surface 50 on the inside, which is characterized by a circumferential groove 51 in the area of the center plane 23. An annular groove 52 of the damping bush 32 is located directly opposite the groove 51, so that the snap ring 33, which lies partially in the groove 52, forms an axial pull-out protection for the damping bush 32. Because the inner surface 50 of the clamping bush 31 extends radially inwards with respect to the inner surfaces 48 of the pressure rings 25 on both sides, after the snap ring 33 has been released, the clamping bush 32 can be pulled out axially in the direction of the arrows 29, without any other structural elements of the vibration damper having to be dismantled beforehand.

The way such a vibration damper works is that a rotating mass, here the oscillating mass 21, is coupled to the drill pipe via the damping bushing 32, whereby the elasticity and damping properties of the damping bushing 32 are adapted to the individual case by varying the clamping pressure exerted via the pressure rings 25. The drill pipe on the one hand and the oscillating mass 21 on the other hand, in conjunction with the damping bushing 32 that couples them, form an oscillating system of two bodies, whereby the vibration damping is based on the energy dissipation of the damping bushing 32.

For practical use, the vibration damper is connected to a hydraulic system via its connectors 37, 37' after it has been inserted into the damper rest 16, whereby the ring pistons 34, 34' are actuated symmetrically in accordance with the clamping pressure to be exerted on the damping bush 32. The ring

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Ql pistons 34 exert an axially directed force via the roller bearings 41 on the pressure rings 25, which are displaced within the bore 24 against the effect of the compression springs in the direction of the central plane 23 and in this way exert a corresponding force on the clamping bush 31 and thus the damping bush 32 via their inner surfaces 26. The clamping bush 31 is centered and fixed in position by the pressure rings 25 due to its structure, which is symmetrical to the central plane 23, and due to the reduction in diameter of the clamping bush 31 triggered by the clamping pressure, the latter transmits a uniform pressure along the axis 8' to the damping bush 32. The aim here is to set up an oscillating system with spring and damping properties, which in turn depend on the individual case.

A pressure relief of the annular pistons 34 in turn results in a return movement of the annular pistons 34, 34' under the action of the compression springs 27 and a resulting relaxation of the clamping bush 31.

The vibration damper according to the invention is characterized compared to known design solutions by simplified handling, reproducible clamping pressure conditions and in particular simplified replaceability of the clamping bush 32.

Claims (11)

ANS P R.-Q-1C H E 1. Vibration damper for the drill pipe (8) of a deep drilling machine, which is intended and designed for insertion into a damper steady (16), with a housing (17) within which a Oscillating mass (21) is rotatably mounted, which can be coupled to the drill pipe (8) by means of an elastically deformable damping body, with a device for defined elastic deformation of the damping body within the housing (17) in accordance with the elastic and damping properties of the coupling state required between the damping body and the oscillating mass (21), wherein the drill pipe (8) extends coaxially to the damping body, -2-PS/K/N Bank account: NORD/LB, NL Bad Gandersheim (bank code 250 500 00), account no. 22 11*8l70** Giro account: Pdätbank Hannover (bank code 250 100 30), account no. 667 15-3' ■ -- ---« '" nn.i7nni)hr -2- Oil is characterized by - that the device for deforming the damping body consists of a clamping bush (31) which can be elastically reduced in diameter, with respect to a radial center plane (23) and coaxially surrounds the damping body, - that the clamping bush (31) has a conically increasing outer diameter, starting from its two front ends in the direction of the central plane (23), forming two conical outer surfaces, - that the conical outer surfaces of the clamping bush (31) are each operatively connected to pressure rings (25) which are arranged on both sides of the central plane (23) and which can move axially in opposite directions to one another, the inner surfaces (26) of which have conicities complementary to those of the outer surfaces of the clamping bush (31), - that the clamping bush (31) is in a positive connection with the oscillating mass (21) and projects radially inwards from the arrangement of the pressure rings (25) and - that the damping body is designed as a cylindrical damping bush (32) which is detachably arranged within the clamping bush (31). 2. Vibration damper according to claim 1, characterized in - that the pressure rings (25) are directed towards the central -3- -3- Oil plane (23) by a pressure fluid and in the opposite direction by compression springs (27), - wherein a plurality of compression springs (27) are arranged with an axially parallel direction of action along the front sides of the pressure rings (25). 3. Vibration damper according to claim 2,
characterized, - that the compression springs (27) are supported at their ends facing away from the pressure rings (25) on an annular web (28) of the oscillating mass (21). 4. Vibration damper according to claim 3,
marked - by axially parallel guide bolts (30) which penetrate the ring web (28) of the oscillating mass (21) and slide - enabling axial movements of the pressure rings (25) - into facing bores of the
Pressure rings (25) are inserted. 5. Vibration damper according to claim 3 or 4,
marked - by means of driving pins (45) which are inserted into radial bores of the oscillating mass (21), the
penetrate the ring web (28) and, in order to create a rotary connection between the clamping bush (31) and the oscillating mass (21), extend into the clamping bush (31) protrude. -4- • * t · t »."·*♦♦ · ■ ·. -4- Ql 6. Vibration damper according to one of claims 1 to 5, characterized in that - that the pressure rings (25) are supported on their side facing away from the pressure springs (27) or the center plane (23) in the axial direction by means of a rolling bearing (41) on ring pistons (34, 34') and - that the ring pistons (34, 34') are guided in a sliding manner in ring-cylinder-like receptacles, the pressure chambers (35, 35') of which are located at the front ends of the ring pistons (34, 34') facing away from the roller bearings (41). 7. Vibration damper according to one of claims 1 to 6, characterized in that - that the oscillating mass (21) is designed as a cylindrical body on the outside, rotatably mounted in a housing (17), symmetrical with respect to the central plane (23), - that the oscillating mass (21) has in its central region a ring body (22) extending radially inwards, which is provided from both end faces with recesses coaxial to the axis of the entire arrangement, which extend symmetrically up to the ring web (28) and form the guide surfaces for facing outer sides of the pressure rings (25). 8, Vibration damper according to one of claims 1 to 7, -5- Oil is characterized by - that the arrangement of the pressure rings (25) radially on the inside forms a recess (49) delimited by the conical inner surfaces (26) of the pressure rings (25) and the central cylindrical inner surface of the ring web (28), into which the clamping bush (31) is inserted. 9. Vibration damper according to one of claims 1 to 8, characterized in that - that the cylindrical inside of the clamping bush (31) and the facing cylindrical outer side of the damping bush (32) are provided with mutually complementary and opposing annular grooves (51, 52) and - that a snap ring (33) or a comparable functional element is inserted into the annular grooves (51, 52) which fixes the damping bush (32) in an axially positive manner. 10. Vibration damper according to one of the preceding claims 1 to 9, characterized, - that the damping bush (32) is split lengthwise. 11. Vibration damper according to one of the preceding claims 1 to 10, -6- -6- Ol characterized in that the clamping bush (31) is designed with longitudinal slots to increase its radial elasticity.