HK1082015B - Device for advancing drillings in the ground - Google Patents

Description

Device for driving a hole in the ground

Technical Field

The invention relates to a device for driving a hole in the ground, comprising a rotationally driven main shaft having a journal, the axis of which forms an acute angle with the axis of the main shaft; the drilling head is rotatably mounted about the axis of the journal and has a circumferential zone which rolls over a corresponding circumferential zone.

Background

Such a device is known from DE 4332113a 1.

For horizontal bores, in particular bores with a diameter of approximately 150mm to 1300mm, but also vertical bores in the ground, drilling devices are used in which a rotatably driven shaft is rotatably mounted in a housing, on the end facing the front wall of the working surface or the bore bottom of which a drilling head is provided.

The drilling head is made different according to the situation of the ground in which the hole shall be drilled. Difficulties often arise when there is a change in the condition of the soil to be cut over the length of the borehole. Rock drilling heads which are usually equipped with rollers, cutters or cutterheads can stick in soft, for example clayey ground, whereas drilling heads which exhibit good drilling properties in clay or loose sand quickly fail due to high wear if they hit rock or large rocks.

This problem is solved in the device known from DE 4332113a1 by imparting an oscillating movement to the drilling head, which exerts a rapid impact on the front wall or the hole bottom of the working surface at a high frequency and thus a high kinetic energy, but at the same time cleans the cut-off cuttings with a high torque and a slow rotational speed, or if the soil on the front wall of the working surface is too soft to be peeled off, scrapes the soil with a high torque. The drilling lead-in (rate of penetration) can be significantly increased by the percussive effect, in particular in hard formations.

In order to produce the oscillating movement, the upper side of the drive spindle of the device rotatably supports the journal of the drilling head facing the front face of the working face at an acute angle to the spindle axis. If the spindle is now driven in rotation, the drilling head is oscillated at a frequency corresponding to the rotational speed of the spindle, the amplitude of the oscillating movement depending on the distance of the oscillation center and the size of the oscillation angle.

In order to produce a slow self-rotation of the drill head, it is provided with an external bevel gear which rolls on an internal bevel gear which is fixed in position during the pivoting movement. The drill head thus generates a rotational speed in the opposite direction to the spindle and has a speed ratio which is dependent on the structural parameters of the outer bevel gear relative to the inner bevel gear. Ratios of 30: 1 to 60: 1 should be achievable.

Although the device known from DE 4332113a1 is suitable for excavating very different ground, it has the disadvantage that the rotational speed of the drill head is not optimal for many soil conditions, since it is mostly too high.

A further disadvantage is that the drill head, which is subjected to considerable wear by the drilling process, is complicated to manufacture due to the external bevel gear, thereby increasing the continuous running costs of such a device.

A further disadvantage is that the intermeshing bevel gears are subject to greater wear due to the entry of stripping material.

A final disadvantage is that especially large cuttings lumps cannot be reliably discharged, easily causing a blockage of the conveying pipe.

Disclosure of Invention

The object of the invention is therefore to further develop the device known from DE 4332113a1 in such a way that it can be used on a wide range of different areas.

To this end, the present invention provides an apparatus for driving a hole in the ground, comprising a rotatably driven main shaft having a journal whose axis forms an acute angle with the axis of the main shaft; and a drilling head rotatably supported about the axis of the journal and having a circumferential zone that rolls over a corresponding circumferential zone, characterized in that: the corresponding circumferential zone can be rotated.

In the device according to the invention, the rotary drive of the drill head is continued by a method which has a circumferential zone which rolls over a corresponding circumferential zone when the spindle rotates. The rotation of the drill head, which is now caused by rolling, is controlled according to the invention in terms of its rotational speed in such a way that the respective circumferential zone itself can be rotated. Thus, depending on the direction of rotation of the respective circumferential zone, a rise or a fall in the total rotational speed of the drill head results while the rotational speed of the spindle remains constant.

The corresponding circumferential zone and the circumferential zone rolling on it may be disengaged in any way that ensures rolling during movement. For ease of manufacture and operational reliability, however, it is preferred that the circumferential region includes an external tooth and the corresponding circumferential region includes an internal tooth.

The counter circumferential region is preferably designed as an internal gear which is arranged concentrically with respect to the spindle axis and can be rotated according to the invention.

With the device known from DE 4332113a1, it has been shown in the past that for many applications the ratio between the oscillation frequency and the rotational speed of the drill head is not optimal. For the rate of penetration, a lower rotational speed of the drill head is mostly advantageous. A preferred embodiment of the device according to the invention therefore envisages that the respective circumferential region can be rotated by means of a planetary gear arrangement which meshes with the spindle. This embodiment has the advantage that it does not require an additional, expensive drive motor in comparison with devices of the same type. This embodiment is also distinguished by a particularly high operational reliability.

However, the respective circumferential region can also be rotated independently of the spindle by means of a separate drive, i.e. the respective circumferential region is not connected to the spindle. It is particularly preferred if the individual drives are designed to be controllable or adjustable, so that the ratio between the rotational speed and the oscillation frequency of the drilling head during operation is adapted to the type of ground to be drilled.

In order to avoid overloading the rotary drive, in particular of the spindle, and to reduce wear, in particular of the drilling head, it is advantageous to provide a device with which the feed rate can be controlled or regulated as a function of the output of the rotary drive of the spindle. This configuration can result in an optimum ratio between the feed and the drive power of the drill head.

If the feed and the rotary drive of the spindle are carried out by means of hydraulic means, means are preferably provided which control or regulate the hydraulic pressures which cause the feed and the rotary drive of the spindle relative to one another. For example, if the pressure of the motor for the rotary drive is not high enough, the hydraulic pressure which causes the feed is reduced until the working pressure of the drive motor for generating the rotary drive is sufficient, and if the pressure of the drive motor is too high, the hydraulic pressure which generates the feed is reduced until the desired pressure is likewise built up on the rotary motor. As a result, an optimum utilization of the device is ensured by this construction, with the greatest possible rate of penetration being achieved without frequent manual adjustment for this purpose.

In a particularly preferred embodiment of the device according to the invention, the drill head is made in multiple parts in such a way that the tool part, which is subject to high wear due to friction with the ground to be cut, can be separated from the bearing part. The operating costs associated with the device for the oscillating movement of the drill head during its rotation are not higher than in the case of a device which is normally operated, because the bevel gears and the bearing elements, which are expensive to produce, of the drill head do not have to be replaced if the drill head is worn. If, as is preferred, the drill head is divided into a central support part and a tool part fixed thereto, the replacement of the tool part results in a considerably shorter change-over time than would be the case if the entire drill head were replaced with conventional devices. The operating costs are reduced on the contrary due to the time efficiency achieved thereby and the resulting increase in the rate of penetration per unit time.

Drill head structures in which the tool part is fixed to the support part by means of screws are particularly preferred. The screws are preferably arranged uniformly on a pitch circle of the bearing part.

In a further development of the device according to the invention, a sealing device is provided which at least substantially seals the bearing device of the drill head, thereby preventing: the wear-increasing cuttings enter the area where the circumferential zone rolls over the corresponding circumferential zone.

In a preferred embodiment of the device according to the invention, the sealing means comprise an elastic bellows. It is used to compensate for the radial relative movement between the drill head support and a flange that does not oscillate but rotates at the speed of rotation of the excavating disk. The flange is preferably sealed with respect to the housing of the device by means of a slide ring seal.

Preferably, the drilling head and the receiving end of the conveying pipe are designed such that the removal of drill cuttings takes place much more efficiently than in the prior art by mechanically feeding those drill cuttings located in front of the receiving end into the conveying pipe by means of an oscillating movement of the drilling head.

If, as is preferred, the drilling head has, on its side facing away from the front wall of the working surface, at least one projection which, by means of the pivoting movement, is at least approximately introduced into the receiving end of the conveying pipe, the drill cuttings are introduced particularly efficiently into the conveying pipe and are conveyed further in the conveying unit by the periodic mechanical pressure.

In order to avoid a possible delay or even a stoppage of the conveying process, despite an effective conveyance, it is advantageous to provide means for breaking up at least the large cuttings pieces in the area of the connection to the receiving end of the conveying pipe.

The device may consist of an actively operating, i.e. self-driven, rock breaking machine. However, the embodiment in which the comminution apparatus comprises a crushing rib which extends very appreciably in the cross-section of the conveying pipe is surprisingly effective and simple to produce and is therefore preferred.

The effectiveness of the duct, i.e. the unloading rate achieved with it, is further increased if the receiving end is made partly circular in cross-section. That is, the receiving end can be arranged in the bore symmetrically to its deepest position along the inner circumference of the bore, so that it is not necessary to overcome the height difference for the "loading" of the receiving end.

The unloading rate can also be increased if the device comprises additional means for blowing conveying air into the space of the drilling head, as is used for pneumatic discharge devices known from the prior art.

Drawings

Embodiments of the apparatus of the present invention are schematically illustrated in the drawings. The attached drawings show that:

FIG. 1 is a longitudinal section of the first embodiment;

FIG. 2 is a longitudinal section of the second embodiment;

FIG. 3 is a view taken along section line A-A in FIG. 2;

fig. 4 is a view taken along section line B-B in fig. 2.

Detailed Description

The apparatus, generally designated 100, comprises a drill head 1 having a cutter portion 30 formed as an excavating disk 2 and a support portion 3. The excavating disk 2 and the support part 3 are fastened to each other by a number of cylindrical screws 4, of which only one is visible in the figure. The cylindrical screws 4 are uniformly distributed on a reference circle with the radius of R. Since the drill head 1 is divided into two worn tool parts 30, after reaching the wear limit, they can be removed at the work site by loosening the screws 4 and replaced with new or repaired tool parts.

The excavating disk 2 is provided with a central blade 5, the tip 6 of which is located on the axis of rotation a of the drill head. In the embodiment shown, the excavating disk 2 has three radially outwardly extending arms 7, 7', 7 ", wherein the arm 7 shown in the upper part of the figure is provided with a number of bits 8.

The drilling head 1 is rotatably supported on the journal 11 of the spindle 12 by the bearing section 3 by means of a bearing arrangement 40, which comprises roller cone bearings 9, 10. The journal 11, which has a substantially cylindrical outer circumferential surface, is formed on the spindle 12 such that its axis B intersects the axis of rotation a at an acute angle ω of approximately 5 °.

The spindle 12 is mounted in a housing 15 so as to be rotatable about an axis of rotation a by means of roller cone bearings 13, 14 and is driven in rotation by a hydraulic motor 16 which is flanged at the end faces. The part of the bearing part 3 facing the excavating disk 2 is designed as a gear wheel, which is arranged concentrically to the axis B of the journal 11 and is referred to below as a wobble gear 17, so that it acts as a circumferential zone 18 which rolls in an internal toothing 20 which acts together in correspondence with the circumferential zone 19 when the spindle 12 rotates.

The internal teeth 20 are formed as an internal gear 21 arranged concentrically with the spindle axis and rotatably supported relative thereto.

The annulus gear has a further internal toothing 22 on the end opposite the internal toothing 20, which is part of a planetary gear arrangement, generally designated 28. The teeth of the portion of the planet gear 23 with the smaller diameter 24 mesh with the internal teeth 22. The larger diameter portion 25 of the planet gear 23 meshes with an external toothing 26 provided on the main shaft 12 and an internal toothing 27 provided in the housing 15, so that the planet gear moves in the same rotational direction around the axis of rotation a during the rotational driving of the main shaft 12. The internal gear 21 then rotates in the opposite direction to the drill head 1, the rotation of which is caused by the rolling of the wobble gear 17 on the internal toothing 20. Of course, by selecting the speed ratio of the planetary gear arrangement 28, the rotational speed of the internal gear 21 relative to the main shaft 12 can be specified, and the ratio of the wobble frequency to the rotational frequency of the drill head is ultimately determined.

In order to seal the support 40 or the interior of the housing 15 with respect to the drill head cavity O, a sealing device 50 is provided. It comprises an elastic bellows 51 which is substantially V-shaped in cross section. It is mounted so that its concave surface faces the drill head 1.

The annular free ends of the bellows 51 each have an outwardly directed thickened region 52, 53, one of the thickened regions 52 being accommodated in a complementarily formed annular groove 54 of the bearing part 3, and the other thickened region 53 being accommodated in an annular groove 55 of a ring 57 which is rotatably mounted relative to the housing by means of ball bearings 56. The bellows 51 thus receives a vertical movement component of the drill head 1 relative to the housing 15, which is caused by the oscillating movement.

Between the ring 57, which is moved around at the oscillation frequency, and the end face of the housing facing it, a slip ring seal 58 is arranged, which prevents dirt from entering the ball bearings 56.

The device, indicated generally at 200 in fig. 2, also comprises a drill head 1 having an excavating disk 2 and a support part 3. The excavating disk 2 and the support part 3 are fastened to each other by means of a number of cylindrical screws 4, of which only two are shown in the figure.

The excavating disk 2 is provided with a central blade 5, the tip 6 of which is located on the axis of rotation a of the drill head. In the embodiment shown the excavating disk 2 has three radially outwardly extending arms 7, 7', 7 ".

The drill head 1 is rotatably mounted on a journal of the spindle by means of a bearing, not shown, via a bearing part 3. The journal having a substantially cylindrical outer circumferential surface is formed on the spindle such that its axis B intersects the axis of rotation a at an acute angle ω.

The spindle itself is rotatably supported about an axis of rotation a in the housing 15 and is rotatably driven by a hydraulic motor.

A conveying channel 110 is provided for discharging the cut-off drill cuttings, the circular inner cross-section of the rear region 111 of the channel being flattened to the drill head cavity O in order finally to open into the drill head cavity O in a receiving end 112 of a part-circular cross-section (see in particular fig. 2 and 3).

In the region of the receiving end 112, provided are crush ribs 113 which extend substantially radially, as can be seen in fig. 2. The crushing ribs 113 are each arranged in pairs such that a small distance of two adjacent crushing ribs 113 is followed by a larger distance. The spacing of the ribs 113 is selected such that the drill cuttings to be discharged are comminuted such that they can be discharged without problems via the conveying channel 110.

In order to deliver the drill mechanically to the receiving end 112 of the conveyor channel 110, projections 9 ', 9 ", 9 * are provided on the ends of the arms 7, 7 ', 7" of the excavating disk 2, the rearward facing surfaces 14 ', 14 ", 14 * of which form the conveying surfaces for the drill cuttings. The surfaces 14', 14 ", 14 * also act as striking surfaces for breaking up the cuttings. The oscillation frequency of the cutting disk is synchronized with the rotational speed itself in such a way that, when one of the arms 7, 7', 7 "passes through, the cuttings are caused to be mechanically pushed into the receiving end 112 of the conveying channel 110.

In order to support the conveying process, the device according to the invention comprises an inlet for blowing conveying air into the cavity O of the drilling head, which is not visible in the drawing. By blowing air into the cavity of the drilling head, an air flow is generated in the feed channel 110, which air flow is indicated by the arrow P.

Claims (20)

1. Apparatus for boring a hole in the ground, comprising a rotatably driven spindle (12) having a journal (11) with an axis (B) forming an acute angle (W) with the axis (A) of the spindle (12);

further comprising a drilling head (1) which is rotatably mounted about the axis (B) of the shaft journal (11) and has a circumferential zone (18) which rolls over a corresponding circumferential zone (19),

it is characterized in that:

the corresponding circumferential zone (19) can be rotated.

2. The apparatus of claim 1, wherein: the circumferential zone (18) has an external toothing and the corresponding circumferential zone (19) has an internal toothing.

3. An apparatus as claimed in claim 1 or 2, wherein: the corresponding circumferential zone (19) is formed by an internal gear (21) arranged concentrically to the axis (A) of the spindle (12).

4. The apparatus of claim 1, wherein: the corresponding circumferential region (19) can be rotated by means of a planetary gear arrangement (28) which is in engagement with the spindle (12).

5. The apparatus of claim 1, wherein: the corresponding circumferential region (19) can be rotated independently of the spindle (12) by means of a separate drive.

6. The apparatus of claim 5, wherein: the individual drives are controllable or adjustable.

7. The apparatus of claim 1, wherein: means are provided by which the feed rate can be controlled or regulated in dependence on the power of the spindle rotation drive.

8. The apparatus of claim 7, wherein: the feed and the rotary drive of the spindle are carried out by means of a hydraulic unit, wherein means are provided which control or regulate the hydraulic pressure used to bring about the feed and the rotary drive of the spindle.

9. The apparatus of claim 1, wherein: the drill head (1) is made in multiple parts, so that the part of the drill head which is worn can be separated from the part of the drill head which supports the drill head on the shaft journal (11).

10. The apparatus of claim 9, wherein: the drill head (1) comprises a central bearing part (3) and a tool part (30) detachably fastened thereto.

11. The apparatus of claim 10, wherein: the tool part (30) is fixed to the support part (3) by means of screws which are distributed uniformly on a graduated circle.

12. The apparatus of claim 1, wherein: a sealing device (50) is provided, which seals the support device (40) at least substantially against the drill head cavity (O).

13. The apparatus of claim 12, wherein: the sealing device (50) comprises an elastic bellows (51).

14. The apparatus of claim 12, wherein: the sealing means comprises a slip ring seal.

15. The apparatus of claim 1, wherein: the device comprises a conveying channel (110) which opens with its receiving end into the cavity (O) of the drilling head, and the drilling head (1) and the receiving end (112) of the conveying channel (110) are designed in such a way that the drill cuttings located in front of the receiving end (112) are mechanically conveyed into the conveying channel (110) by means of an oscillating movement of the drilling head (1).

16. The apparatus of claim 15, wherein: the drilling head (1) has at least one cam (9 ', 9', 9 *) on its side facing away from the front wall of the working surface, said cam being moved into the receiving end (112) of the conveying channel (110) by a pivoting movement.

17. The apparatus of claim 15, wherein: in the area adjacent to the receiving end (112) of the conveying channel (110), means are provided for comminuting at least large pieces of cuttings.

18. The apparatus of claim 17, wherein: the comminution device comprises crushing ribs (113) which extend transversely in the cross section of the conveying channel (110).

19. The apparatus of claim 15, wherein: the receiving end (112) is partially annular in cross-section.

20. The apparatus of claim 15, wherein: means are provided for blowing conveying air into the cavity (O) of the drilling head.