Earth drill

Abstract

To provide an earth drill equipped with a swing bearing device capable of correcting lateral inclination of an upper swing body to ensure verticality of a kelly bar.SOLUTION: In a swing bearing device 13, a lower swing bearing case 45, an upper swing bearing case 46, and an intermediate swing bearing case 51 are capable of relatively rotating. The swing bearing device 13 has a lower bearing ball 48 and an upper bearing ball 50 provided corresponding to a swing axis 47 and an inclined axis 49, and an upper bearing case track inclined along which the upper bearing balls roll. A lower running body mounting surface 45a provided in the lower swing bearing case 45 and an upper rotating body mounting surface 46a provided in the upper swing bearing case 46 are parallel to each other, and a swing reference position in which the inclination direction of the inclined axis 49 is aligned with the longitudinal direction of a lower running body and an upper rotating body is determined. During operation, the upper rotating body is inclined relative to the lower running body, and the upper rotating body inclined on the lower running body is rotated to change its inclination direction.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an earth drill, and more particularly to an earth drill having a telescopic kelly bar at its front portion. [Background technology]

[0002] In an earth drill in which a kelly bar is suspended from a wire rope hanging from the tip of a retractable boom, a multi-stage telescopic kelly bar is used, in which multiple kelly bar members with different horizontal cross-sectional sizes are coaxially combined (see, for example, Patent Document 1).

[0003] Fig. 16 shows the structure of the front part of a typical earth drill. In the earth drill, a boom 100 is connected to a rotating body constituting a self-propelled base machine via a support shaft (foot pin), and the boom 100 can be raised and lowered in the front-rear direction (the direction of the arrows X1-X2 in Fig. 16) by applying tension to a wire rope (pendant rope) 101 from a hoisting winch. A wire rope (main hoisting rope) 103 from a main hoisting winch is wound around one of a sheave row 102 supported at the tip of the boom 100, and a kelly bar 105 is rotatably suspended from the tip of this wire rope 103 via a swivel joint 104, and the kelly bar 105 is extended and retracted in the up-down direction (the direction of the arrows Z1-Z2 in Fig. 16) by the winch drive.

[0004] A kelly bar rotation drive device (kelly drive) 108 is provided on a parallel link type front frame 107 supported by a hydraulic cylinder 106 at the base side of the boom 100. A kelly bar 105 is set on the kelly bar rotation drive device 108, and an excavation bucket 109 is attached to the lower end of the kelly bar 105 as an excavation device that rotates integrally with the kelly bar 105 and moves up and down. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-96156 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-mentioned earth drill, before excavation work, for example, the kelly bar rotation drive device 108 is leveled in accordance with the raising and lowering operation of the boom 100, thereby correcting the inclination of the kelly bar 105 set on the kelly bar rotation drive device 108. However, due to the structure of the front part, the direction of such inclination correction is limited to only the front-rear direction, and there is an inconvenience that if the base machine is placed on a slope that is inclined in the left-right direction (the direction of the arrows Y1-Y2 in FIG. 16), there is no means for correcting this on the machine side.

[0007] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide an earth drill equipped with a swivel bearing device capable of correcting the lateral inclination of the upper swivel body to ensure the verticality of the kelly bar. [Means for solving the problem]

[0008] In order to achieve the above object, the earth drill of the present invention is an earth drill including a base machine having a lower traveling body equipped with a crawler and an upper rotating body rotatably provided on the lower traveling body, a boom provided in a hoistable manner at the front of the upper rotating body, a main hoist sheave rotatably supported via a sheave shaft at the tip of the boom, and a kelly bar suspended by a main hoist rope wound around the main hoist sheave, the earth drill including a slewing base that tilts the upper rotating body relative to the lower traveling body and rotates the upper rotating body tilted on the lower traveling body to change the tilt direction. The slewing bearing device includes a lower slewing bearing case provided with a lower running body mounting surface, an upper slewing bearing case provided with an upper slewing body mounting surface, a plurality of lower bearing balls provided in the circumferential direction around a slewing axis extending in a direction perpendicular to the lower running body mounting surface, a plurality of upper bearing balls provided in the circumferential direction around an inclined axis extending in a direction intersecting the slewing axis, and an intermediate bearing assembled between the lower slewing bearing case via the lower bearing balls and between the upper slewing bearing case via the upper bearing balls. a slewing bearing case, a first hydraulic motor that rotates the intermediate slewing bearing case relative to the lower slewing bearing case, and a second hydraulic motor that rotates the upper slewing bearing case relative to the intermediate slewing bearing case, wherein when the lower slewing bearing case, the upper slewing bearing case, and the intermediate slewing bearing case are assembled together, the lower running body mounting surface and the upper rotating body mounting surface are parallel to each other, and the tilt direction of the tilt axis relative to the swing axis is aligned with the front-rear direction of the lower running body and the upper rotating body. a swing reference position is determined, a lower bearing case track along which the lower bearing balls roll under the operation of the first hydraulic motor is formed between the lower swing bearing case and the intermediate swing bearing case, and an upper bearing case track along which the upper bearing balls roll under the operation of the second hydraulic motor is formed between the upper swing bearing case and the intermediate swing bearing case, and when the upper swing bearing case is rotated relative to the intermediate swing bearing case starting from the swing reference position,The upper rotating body mounting surface is inclined relative to the lower running body mounting surface.

[0009] The intermediate swivel bearing case is further divided into two parts, upper and lower, by a plane parallel to the lower running body mounting surface, and the lower part which pairs with the lower swivel bearing case and the upper part which pairs with the upper swivel bearing case are joined to each other by bolting.

[0010] The first hydraulic motor is provided on the lower traveling body and the second hydraulic motor is provided on the upper rotating body. In addition, the first hydraulic motor is provided on the intermediate rotating bearing case and the second hydraulic motor is provided on the upper rotating body. Effect of the Invention

[0011] According to the earth drill of the present invention, the swivel bearing device for rotating the upper rotating body comprises a lower swivel bearing case, an upper swivel bearing case and an intermediate swivel bearing case assembled so as to be rotatable relative to one another, and comprises two axes consisting of a swivel axis and an inclined axis intersecting the swivel axis, a lower bearing ball and an upper bearing ball provided corresponding to the two axes, and an upper bearing case track with an inclination along which the upper bearing ball rolls. The lower running body mounting surface provided on the lower swivel bearing case and the upper swivel bearing case mounting surface provided on the upper swivel bearing case are parallel to each other, and a swivel reference position is determined in which the inclination direction of the inclination axis is aligned with the front-to-rear directions of the lower running body and the upper swivel body. Therefore, in response to the operation of the second hydraulic motor for rotating the upper swivel bearing case, the upper swivel body inclined relative to the lower running body can be tilted, and in response to the operation of the first hydraulic motor for rotating the lower swivel bearing case, the upper swivel body inclined on the lower running body can be rotated to change its inclination direction.

[0012] As a result, when the earth drill is placed on flat ground, it can move to the work site in a traveling position with the upper rotating body held horizontal, as in the conventional case, and if the upper rotating body needs to be rotated, only the operation of the first hydraulic motor is sufficient. On the other hand, when the work site is on a sloping ground with a left or right inclination, the first hydraulic motor and the second hydraulic motor are operated respectively, and the three rotating bearing cases are rotated relatively with the rotation reference position as the starting point, so that the correction angle (the inclination angle of the upper rotating body relative to the lower traveling body) required to level the left and right inclination of the upper rotating body can be generated and applied (the inclination direction is changed) simultaneously or sequentially. In other words, an earth drill equipped with a swivel bearing device that can correct the left and right inclination of the upper rotating body on a sloping ground and ensure the verticality of the kelly bar is achieved. [Brief description of the drawings]

[0013] [Figure 1] 1 is a side view of an earth drill showing an embodiment of the present invention; [Diagram 2] FIG. 13 is a side view of a main part of the base machine at the turning reference position. [Diagram 3] FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. [Diagram 5] FIG. 5 is a cross-sectional view of FIG. 4 . [Figure 6] 6 is a cross-sectional view taken along line VI-VI of FIG. 4. [Figure 7] FIG. 11 is a side view of a main part of the base machine, showing the upper swivel bearing case rotated 180 degrees from the swivel reference position. [Figure 8] FIG. [Figure 9] FIG. 11 is an explanatory diagram showing the attitude of the swivel bearing device at the swivel reference position. [Figure 10] FIG. 11 is an explanatory view showing a state in which the upper swivel bearing case has been rotated 90 degrees from the swivel reference position. [Figure 11]FIG. 11 is an explanatory view showing a state in which the upper swivel bearing case has been rotated 180 degrees from the swivel reference position. [Figure 12] FIG. 11 is an explanatory view showing a state in which the upper swivel bearing case has been rotated 270 degrees from the swivel reference position. [Figure 13] FIG. 11 is an explanatory diagram showing the attitude of the swivel bearing device after the tilt correction in the left-right direction has been performed. [Figure 14] FIG. 4 is a front view of the main part showing the working state of the earth drill. [Figure 15] FIG. 11 is a side cross-sectional view showing a modified example of the swivel bearing device. [Figure 16] FIG. 1 is a perspective view showing the structure of a front part of a typical earth drill. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] 1 to 15 show an example of an earth drill of the present invention. As shown in Figs. 1 and 2, the earth drill 11 includes a base machine (main body) 15, which is made up of a lower traveling body 12 equipped with a crawler and an upper rotating body 14 rotatably mounted on the lower traveling body 12 via a swivel bearing device 13. For ease of understanding, the arrows X1-X2 in the figures indicate the front-rear direction of the lower traveling body 12, that is, the arrow X1 indicates the front (forward direction) and the arrow X2 indicates the rear (rearward direction). The arrow F indicates the front of the upper rotating body 14. That is, although Figs. 1 and 2 are drawn in opposite directions on the paper, both of them show a rotation reference position (described in detail later) where the front-rear direction of the lower traveling body 12 and the front-rear direction of the upper rotating body 14 are aligned in the same direction.

[0015] In the earth drill 11 equipped with such a self-propelled base machine 15, a sheave shaft 17 perpendicular to the length of the boom 16 is provided horizontally on the front surface of the tip of the boom 16 which is provided to be able to be raised and lowered at the front of the upper rotating body 14, and a main winding sheave 18 and an auxiliary winding sheave 19 are rotatably supported on the sheave shaft 17 at a distance from each other. Also, a main winding guide sheave shaft 20 and an auxiliary winding guide sheave shaft 21 perpendicular to the length of the boom 16 are provided horizontally on the left and right coaxially on the rear surface of the tip of the boom 16, and a main winding guide sheave 22 is supported on the main winding guide sheave shaft 20, and an auxiliary winding guide sheave 23 is supported on the auxiliary winding guide sheave shaft 21 at a distance from each other for rotation.

[0016] A main hoisting rope 24 for excavation work, which is paid out from a main hoisting winch (not shown) via a main hoisting guide sheave 22, is wound around the main hoisting sheave 18, and a kelly bar 26 is rotatably suspended from the swivel of the main hoisting rope 24 via a swivel 25, so that the main hoisting winch can extend and retract the kelly bar 26 in the vertical direction (the direction of the arrows Z1-Z2 in FIG. 1). A parallel link type front frame 27 is provided on the base side of the boom 16, and a kelly bar rotation drive device (kelly drive) 28, through which the kelly bar 26 is inserted, is provided at the tip of the front frame 27 in a state supported by a hydraulic cylinder 29. The kelly bar 26 is rotated by the kelly bar rotation drive device 28, which rotates an excavation bucket 30 attached to the lower end of the kelly bar 26.

[0017] Furthermore, an auxiliary hoisting rope 31 for crane operation, which is paid out from an auxiliary hoisting winch (not shown) via an auxiliary hoisting guide sheave 23, is wound around the auxiliary hoisting sheave 19, and an auxiliary hoisting hook 32 is connected to the tail of this auxiliary hoisting rope 31. In addition, a gantry 33 is provided at the rear of the upper rotating body 14 so as to be able to rise and fall.

[0018] The gantry 33 is equipped with a hoisting guide sheave 35 for guiding a hoisting rope 34 paid out from a hoisting winch (not shown). The hoisting rope 34 rises upward from the hoisting winch, passes through the hoisting guide sheave 35, and is passed around a front middle sheave block 36 and a gantry sheave block 37, with the rope end fixed to the gantry sheave block 37. Furthermore, one end of a pendant rope 38, the other end of which is connected to the tip of the boom 16, is connected to the middle sheave block 36, and the boom 16 is raised or lowered by winding up and letting out the hoisting rope 34 with the hoisting winch.

[0019] When performing excavation work using the earth drill 11, the boom 16 is raised to a prescribed angle by the hoisting winch, and then the kelly bar rotation drive device 28 is positioned above the work point. Then, after ensuring that the kelly bar 26 is vertical, the main hoisting rope 24 is let out from the main hoisting winch, the kelly bar 26 suspended by the main hoisting rope 24 is extended, and the kelly bar 26 is rotated by the kelly bar rotation drive device 28, and the excavation bucket 30, which rotates in accordance with this, is pushed into the ground to perform excavation.

[0020] Incidentally, before excavation work, the earth drill 11 performs leveling of the kelly bar rotation drive device 28 in accordance with the raising and lowering operation of the boom 16, thereby correcting the inclination of the kelly bar 26 set on the kelly bar rotation drive device 28. However, in the past, the direction of such inclination correction was limited to the front-rear direction due to the structure of the front part, and there was an inconvenience that if the base machine was placed on a slope that was inclined in the left-right direction, there was no means to correct this on the machine side. Therefore, the earth drill 11 of this embodiment is provided with a swivel bearing device 13 that can correct the inclination of the upper swivel body 14 in the left-right direction.

[0021] 2 to 8, the slewing bearing device 13 is a slewing bearing installed between an upper plate 39a of a track frame 39 in the lower running body 12 and a lower plate 40a of a main frame 40 in the upper rotating body 14 via seat plates 41, 42, 43, 44 of a predetermined plate thickness. A ring raceway is formed between the inner and outer rings of the slewing bearing, in which bearing balls (rolling elements) arranged in two stages, one above the other, are held. Since the upper stage of the two stages has an inclination, during operation, the upper rotating body 14 can be inclined with respect to the lower running body 12 and the upper rotating body 14 inclined on the lower running body 12 can be rotated to change the inclination direction. Although the seat plates 41, 42, 43, 44 are basically circular, for example, disks or annular plates (ring plates) can be used in consideration of the arrangement of hydraulic system components.

[0022] The swivel bearing device 13 mainly includes a lower swivel bearing case 45 having a lower running body mounting surface 45a, an upper swivel bearing case 46 having an upper swivel body mounting surface 46a, a plurality of lower bearing balls 48 provided in the circumferential direction around a swivel axis 47 extending in a direction perpendicular to the lower running body mounting surface 45a, a plurality of upper bearing balls 50 provided in the circumferential direction around an inclined axis 49 extending in a direction intersecting the swivel axis 47 at an intersection P, an intermediate swivel bearing case 51 assembled between the lower swivel bearing case 45 via the lower bearing balls 48 and assembled between the upper swivel bearing case 46 via the upper bearing ball 50, a first hydraulic motor 52 that rotates the intermediate swivel bearing case 51 relative to the lower swivel bearing case 45, and a second hydraulic motor 53 that rotates the upper swivel bearing case 46 relative to the intermediate swivel bearing case 51.

[0023] As shown in Fig. 3, the lower slewing bearing case 45 is an outer wheel side slewing bearing case fixed to the upper plate 39a of the track frame 39 with mounting bolts 54 and nuts 55, and a plurality of bolt holes 45b into which the mounting bolts 54 are inserted are provided so as to form a circumference (Figs. 5 and 6). On the other hand, the upper slewing bearing case 46 is formed to have a similar size in the radial direction (left and right direction in Fig. 3) as the lower slewing bearing case 45, but has a slight thickness in the axial direction (up and down direction in Fig. 3), and is an outer wheel side slewing bearing case fixed to the lower plate 40a of the main frame 40 with mounting bolts 56 and nuts 57. Similarly to the lower slewing bearing case 45, the upper slewing bearing case 46 is also provided with a plurality of bolt holes 46b into which the mounting bolts 56 are inserted so as to form a circumference (Figs. 4, 5 and 6).

[0024] The intermediate slewing bearing case 51 is an inner ring side slewing bearing case that has been subjected to gear machining, and during manufacturing, it is divided into upper and lower two parts by a plane parallel to the lower running body mounting surface 45a, and consists of a lower intermediate case 58 which is the lower part that forms a pair with the lower slewing bearing case 45, and an upper intermediate case 59 which is the upper part that forms a pair with the upper slewing bearing case 46. The lower intermediate case 58 and the upper intermediate case 59 are provided with a plurality of bolt holes 58a, 59a for inserting mounting bolts 60 so as to form a circumference, and are joined to each other by bolt fastening via the seat plate (spacer) 43 with the bolt holes 58a, 59a aligned with each other (FIGS. 4, 5, and 6).

[0025] Between the lower slewing bearing case 45 and the lower intermediate case 58, a lower bearing case raceway is formed in which the lower bearing balls 48 roll under the operation of the first hydraulic motor 52. This lower bearing case raceway is made up of a lower inner case raceway surface 58b and a lower outer case raceway surface 45c which combine to form a circumferential ring raceway surface, and is parallel to the lower running body mounting surface 45a. Meanwhile, between the upper slewing bearing case 46 and the upper intermediate case 59, an upper bearing case raceway is formed in which the upper bearing balls 50 roll under the operation of the second hydraulic motor 53. This upper bearing case raceway consists of an upper inner case raceway surface 59b and an upper outer case raceway surface 46c which combine to form a circumferential ring raceway surface, and when the upper swivel bearing case 46 is rotated relative to the intermediate swivel bearing case 51 starting from the swivel reference position (Figure 2), an inclination is imparted to the upper rotating body mounting surface 46a so that it is inclined relative to the lower running body mounting surface 45a, for example, into a position as shown in Figure 7 (upper rotating body front-up position).

[0026] The first hydraulic motor 52 is installed on the truck frame 39 via a reduction gear mechanism 61, and a small gear (pinion) 62 is attached to the output shaft of the reduction gear mechanism 61. When the first hydraulic motor 52 is operated with the small gear 62 meshed with an internal gear 58c formed on the inner periphery of the lower intermediate case 58, the lower bearing balls 48 roll along the lower bearing case tracks 45c, 58b, and the intermediate slewing bearing case 51 rotates horizontally relative to the lower slewing bearing case 45. This causes the upper rotating body 14 to rotate relative to the lower traveling body 12.

[0027] The second hydraulic motor 53 is mounted on the main frame 40 via a reduction gear mechanism 63, and a small gear (pinion) 64 is attached to the output shaft of the reduction gear mechanism 63. When the second hydraulic motor 53 is operated with the small gear 64 meshed with an internal gear 59c formed on the inner periphery of the upper intermediate case 59, the upper bearing balls 50 roll along the upper bearing case tracks 46c, 59b, and the main frame 40 rotates with an inclination relative to the intermediate slewing bearing case 51 (FIG. 7), as will be described in detail later. As a result, the upper rotating body 14 inclines relative to the lower running body 12.

[0028] 3, in the swivel bearing device 13, with the lower swivel bearing case 45, the upper swivel bearing case 46, and the intermediate swivel bearing case 51 assembled as one unit, the lower running body mounting surface 45a and the upper rotating body mounting surface 46a are parallel to each other, and a swivel reference position is determined in which the tilt direction of the tilt axis 49 relative to the swivel axis 47 is aligned with the front-rear direction (left-right direction in FIG. 3) of the lower running body 12 and the upper rotating body 14. In this embodiment, the tilt angle α between the swivel axis 47 and the tilt axis 49 is set to, for example, 2 degrees, taking into account the tilt correction angle of the upper rotating body 14.

[0029] Similarly, the inclination angle θ1 between the lower bearing case raceways 45c, 58b and the upper bearing case raceways 46c, 59b is set to 2 degrees because it is equal to the inclination angle α of the two shafts 47, 49 that determine the arrangement of the lower bearing balls 48 and the upper bearing balls 50. Then, as can be seen from the fact that the outer peripheral surface 46c of the upper bearing case raceways 46c, 59b is provided on the upper swivel bearing case 46, the inclination angle β between the upper rotating body mounting surface 46a and the upper bearing case raceways 46c, 59b is set to 2 degrees, equal to the inclination angle θ1, and this value does not change even if the orientation (rotation angle) of the upper swivel bearing case 46 with respect to the intermediate swivel bearing case 51 changes. As a result, when the second hydraulic motor 53 is operated and the upper swivel bearing case 46 is rotated 180 degrees from the swivel reference position (Figure 3) and its orientation is reversed back and forth, the main frame 40 rotates with an inclination relative to the intermediate swivel bearing case 51, as shown in Figure 8, and as a result, the inclination angle θ2 (the angle between the lower running body mounting surface 45a and the upper swivel body mounting surface 46a) becomes the sum of the inclination angle θ1 (2 degrees) and the inclination angle β (2 degrees), in other words, the upper swivel body 14 is inclined 4 degrees in the fore-aft direction.

[0030] When the upper rotating body 14 placed at the rotation reference position is rotated 180 degrees by operating the second hydraulic motor 53, the inclination in the front-rear direction relative to the lower traveling body 12 becomes maximum (4 degrees), and in this position (upper rotating body front-up position), no inclination in the left-right direction occurs (Fig. 7). When it is rotated another 180 degrees from here, it returns to the original rotation reference position (Fig. 3). Then, when the rotation direction is counterclockwise and the rotation angles are 90 degrees and 270 degrees, the inclination in the front-rear direction of the upper rotating body 14 becomes an angle (2 degrees) that is half the maximum inclination angle, while the inclination in the left-right direction of the upper rotating body 14 becomes an angle (2 degrees) corresponding to the inclination angle θ1 of the upper bearing case tracks 46c, 59b. In this case, the left and right sides of the upper rotating body 14 face either the mountain side or the valley side of the inclination.

[0031] In the following, for ease of understanding, the change in inclination of the upper rotating body 14 relative to the lower running body 12 will be explained with reference to Figures 9 to 12, which show a simplified representation as a change in inclination of the upper rotating body mounting surface 46a relative to the lower running body mounting surface 45a.

[0032] In the drawing, the X1-X2 axis direction indicates the front-rear direction of the lower traveling body 12, and the Y1-Y2 axis direction indicates the left-right direction of the lower traveling body 12. Arrow F indicates the front of the upper rotating body 14, and arrow LH indicates the left side of the upper rotating body 14. Although not shown in the drawing, the inclination angle (α) between the rotating shaft 47 and the tilting shaft 49 is set to 2 degrees. Furthermore, the upper rotating body mounting surface 46a is disposed on a plane passing through the arrows F and LH.

[0033] 9 corresponds to FIGS. 2 and 3, and shows a rotation reference position where the lower running body mounting surface 45a and the upper rotating body mounting surface 46a are parallel to each other, and the tilt direction of the tilt axis 49 relative to the rotation axis 47 is aligned with the front-to-rear direction (X1-X2 axis direction in FIG. 9) of the lower running body 12 and the upper rotating body 14. Here, when the second hydraulic motor 53 is operated and the upper rotating bearing case 46 is rotated 90 degrees counterclockwise, the upper rotating body mounting surface 46a is inclined at a front-to-rear tilt angle θ2 of 2 degrees and a left-to-right tilt angle θ3 of 2 degrees, as shown in FIG. 10. That is, the upper rotating body 14 is in a front-up attitude and a left-up attitude relative to the lower running body 12.

[0034] When the upper rotating body 14 is rotated by another 90 degrees (a total of 180 degrees), as shown in FIG. 11, the inclination angle θ2 in the front-rear direction becomes 4 degrees, while there is no inclination in the left-right direction. This 180-degree rotated state corresponds to FIG. 7. When the upper rotating body 14 is rotated by another 90 degrees (a total of 270 degrees), as shown in FIG. 12, the inclination angle θ2 in the front-rear direction becomes 2 degrees, and the inclination angle θ3 in the left-right direction becomes 2 degrees. That is, the upper rotating body 14 is in a front-upward posture and a left-downward posture with respect to the lower running body 12. This 270-degree rotated state can be similarly created by rotating the upper rotating body 14 by 90 degrees clockwise from the turning reference position (FIG. 9). In this way, by rotating the upper rotating body 14 by another 90 degrees (a total of 360 degrees), the upper rotating body 14 is returned to the original turning reference position where no inclination occurs (FIG. 9).

[0035] When the earth drill 11 configured in this manner is placed at a work site on a slope where the base machine 15 is inclined left and right, the inclination is detected and the swivel bearing device 13 is hydraulically controlled to generate and apply (change the tilt direction) a correction angle (the tilt angle of the upper rotating body 14 relative to the lower running body 12) required to level the left and right tilt of the upper rotating body 14. Here, the required correction angle can be efficiently obtained within a rotation range of 90 degrees left and right from the rotation reference position, so that rotation range is used when operating the swivel bearing device 13.

[0036] For example, when the base machine 15 is placed on a slope inclined 2 degrees to the left (left downward slope), the swivel bearing device 13 simultaneously operates the first hydraulic motor 52 and the second hydraulic motor 53 to rotate the upper swivel bearing case 46 counterclockwise 90 degrees relative to the intermediate swivel bearing case 51, while rotating the intermediate swivel bearing case 51 clockwise 90 degrees in the opposite direction relative to the lower swivel bearing case 45. Although not shown, when the base machine 15 is placed on a slope inclined 1 degree to the left or right, the rotation angle is half of 90 degrees, that is, 45 degrees.

[0037] Here, when the upper slewing bearing case 46 and the intermediate slewing bearing case 51 are rotated in opposite directions at the same speed, their rotation angles are offset, and as can be imagined from Fig. 13, when the front-rear and left-right directions of the lower running body 12 and the front-rear and left-right directions of the upper slewing body 14 are aligned, that is, when the upper slewing body 14 is stopped in place, the inclination angles θ2, θ3 of the front (F) and left side (LH) of the upper slewing body 14 increase to 2 degrees. As a result, as shown in Fig. 14, a left-upward inclination angle θ3 of 2 degrees is imparted to the upper slewing body mounting surface 46a in the slewing bearing device 13 for the lower running body 12 that is affected by a 2-degree inclined slope (left-downward inclination) G, and as a result, the left-right inclination of the upper slewing body 14 is corrected to a horizontal state.

[0038] In such a left-right horizontal position of the upper rotating body 14, the front-rear position is placed in a front-up position with an inclination angle θ2 of 2 degrees given to the upper rotating body mounting surface 46a, but as a conventional method for correcting the inclination in the front-rear direction, the inclination in the front-rear direction of the kelly bar 26 is corrected by leveling the kelly bar rotation drive device 28 in accordance with the raising and lowering operation of the boom 16. In this manner, with the verticality of the kelly bar 26 secured, the kelly bar 26 is extended by the main hoisting winch and rotated by the kelly bar rotation drive device 28, and the excavation bucket 30, which rotates in accordance with this, is pushed into the ground, whereby an excavation hole (vertical hole) 65 is formed.

[0039] Thus, according to the earth drill 11 of the present invention, the swivel bearing device 13 for rotating the upper swivel body 14 is configured by assembling the lower swivel bearing case 45, the upper swivel bearing case 46, and the intermediate swivel bearing case 51 so as to be rotatable relative to one another, and has two shafts consisting of the swivel shaft 47 and the inclined shaft 49 intersecting the swivel shaft 47, a lower bearing ball 48 and an upper bearing ball 50 provided corresponding to the two shafts 47, 49, and upper bearing case tracks 46c, 59b provided with an inclination along which the upper bearing ball 50 rolls. Since the mounting surface 45a and the upper rotating body mounting surface 46a provided on the upper slewing bearing case 46 are parallel to each other, and the tilt direction of the tilt axis 49 determines a rotation reference position that is aligned with the fore-and-aft direction of the lower running body 12 and the upper rotating body 14, it is possible to tilt the upper rotating body 14 relative to the lower running body 12 in response to operation of the second hydraulic motor 53 which rotates the upper slewing bearing case 46, and to rotate the upper rotating body 14 inclined on the lower running body 12 in response to operation of the first hydraulic motor 52 which rotates the lower slewing bearing case 45, thereby changing its tilt direction.

[0040] As a result, when the earth drill 11 is placed on flat ground, it can move toward the work site in a traveling position with the upper rotating body 14 held horizontally, as in the conventional case, and if the upper rotating body 14 needs to be rotated, it is sufficient to operate only the first hydraulic motor 52. On the other hand, when the work site is on sloping ground G with a leftward or rightward inclination, the first hydraulic motor 52 and the second hydraulic motor 53 are operated, respectively, and the three rotating bearing cases 45, 46, 51 are rotated relatively with respect to the rotation reference position as the starting point, so that a correction angle (the inclination angle of the upper rotating body 14 with respect to the lower traveling body 12) required to level the left-right inclination of the upper rotating body 14 and its application (change of the inclination direction) can be simultaneously or sequentially performed. In other words, the earth drill 11 equipped with the swivel bearing device 13 capable of correcting the left-right inclination of the upper rotating body 14 on the sloping ground G and thus ensuring the verticality of the kelly bar 26 is achieved.

[0041] In addition, the intermediate slewing bearing case 51 is divided into upper and lower halves by a plane parallel to the lower running body mounting surface 45a, and the lower part (lower intermediate case 58) paired with the lower slewing bearing case 45 and the upper part (upper intermediate case 59) paired with the upper slewing bearing case 46 are connected to each other by bolt fastening, so that a conventional slewing bearing device having a slewing shaft 47 can be used as is for the lower part, resulting in excellent manufacturability. Furthermore, since the first hydraulic motor 52 is provided on the lower running body 12 and the second hydraulic motor 53 is provided on the upper rotating body 14, interference between the hydraulic motors 52, 53 can be avoided when the slewing bearing device 13 is in operation, resulting in excellent layout.

[0042] 15 shows a modified example of a swivel bearing device provided in the earth drill of the present invention. In the following description, the same components as those shown in the above embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

[0043] Similar to the above-described embodiment, the swivel bearing device 70 of this modified example is a swivel bearing that rotates three swivel bearing cases relative to one another, starting from a swivel reference position, and includes a lower swivel bearing case 71, an upper swivel bearing case 72 and an intermediate swivel bearing case 73 which are assembled as an integral unit and are configured to be rotatable relative to one another. The swivel bearing device 70 has a first hydraulic motor 52 which rotates the intermediate swivel bearing case 73 relative to the lower swivel bearing case 71, and a second hydraulic motor 53 which rotates the upper swivel bearing case 72 relative to the intermediate swivel bearing case 73.

[0044] As a characteristic configuration of this modified example, the first hydraulic motor 52 is installed in the intermediate slewing bearing case 73 via the reduction gear mechanism 61 in a state in which it is upside down with respect to the above embodiment. The lower slewing bearing case 71 forms an inner ring in relation to the intermediate slewing bearing case 73, and is provided with a lower running body mounting surface 71a, and an internal gear 71b is formed on its inner periphery. As a result, the seat plate 43 interposed between the lower intermediate case 74 and the upper intermediate case 75 constituting the intermediate slewing bearing case 73 also serves as a mounting seat for the reduction gear mechanism 61, and meshes a small gear (pinion) 76 attached to the output shaft of the reduction gear mechanism 61 with the internal gear 71b.

[0045] Furthermore, in this modified example configured in this manner, the same effect can be achieved as when the swivel bearing device 13 of the above-mentioned embodiment is provided, namely, the effect of being able to correct the left-right inclination of the upper rotating body 14 on sloping ground G. Furthermore, in the case of this modified example, since the first hydraulic motor 52 is provided in the intermediate swivel bearing case 73 and the second hydraulic motor 53 is provided in the upper rotating body 14, although measures must be taken to prevent interference between the hydraulic motors 52, 53 (restriction of the rotation range), the control circuit for the hydraulic motors 52, 53, including piping, can be completed on the upper rotating body 14 side, and the installation conditions for the hydraulic motors 52, 53 are also good.

[0046] The present invention is not limited to the above-mentioned embodiments, and the configuration, arrangement, operating conditions, etc. of the swivel bearing device can be appropriately changed according to the specifications of the earth drill. In addition, in the embodiment, the tilt correction on a slope with a leftward slope has been described, but the tilt correction can be performed in the same way even in the case of a slope with a rightward slope, and in that case, the rotation directions of the upper swivel bearing case and the intermediate swivel bearing case are opposite to each other. Furthermore, the tilt correction procedure can be performed by sequentially rotating the upper swivel bearing case and the intermediate swivel bearing case, but by rotating them at the same speed at the same time as in the embodiment, there is an advantage that the tilt correction can be performed efficiently, and since the effect of the rotation inertia force caused by the change in the attitude of the swivel bearing device can be reduced, it is expected that the dedicated parts such as the hydraulic motor can be made smaller. [Explanation of symbols]

[0047] 11...Earth drill, 12...Lower running body, 13...Slewing bearing device, 14...Upper rotating body, 15...Base machine, 16...Boom, 17...Sheave shaft, 18...Main hoist sheave, 19...Auxiliary hoist sheave, 20...Main hoist guide sheave shaft, 21...Auxiliary hoist guide sheave shaft, 22...Main hoist guide sheave, 23...Auxiliary hoist guide sheave, 24...Main hoist rope, 25...Swivel, 26...Kelly bar, 27...Front frame, 28...Kelly bar rotation drive device, 29...Hydraulic cylinder, 30...Drilling Cutting bucket, 31... auxiliary winding rope, 32... auxiliary winding hook, 33... gantry, 34... hoisting rope, 35... hoisting guide sheave, 36... middle sheave block, 37... gantry sheave block, 38... pendant rope, 39... track frame, 39a... upper plate, 40... main frame, 40a... lower plate, 41, 42, 43, 44... seat plate, 45... lower slewing bearing case, 45a... lower running body mounting surface, 45b... bolt hole, 45c... lower outer case raceway surface, 46 ...Upper slewing bearing case, 46a...upper slewing body mounting surface, 46b...bolt hole, 46c...upper outer case raceway surface, 47...slewing shaft, 48...lower bearing ball, 49...tilt shaft, 50...upper bearing ball, 51...intermediate slewing bearing case, 52...first hydraulic motor, 53...second hydraulic motor, 54...mounting bolt, 55...nut, 56...mounting bolt, 57...nut, 58...lower intermediate case, 58a...bolt hole, 58b...lower inner case raceway surface, 58c...internal gear, 59...upper intermediate case, 59a...bolt hole, 59b...upper inner case raceway surface, 59c...internal gear, 60...mounting bolt, 61...reduction mechanism, 62...pinion gear, 63...reduction mechanism, 64...pinion gear, 65...drilling hole, 70...swivel bearing device, 71...lower swivel bearing case, 71a...lower running body mounting surface, 71b...internal gear, 72...upper swivel bearing case, 73...intermediate swivel bearing case, 74...lower intermediate case, 75...upper intermediate case, 76...pinion gear

Claims

1. An earth drill comprising: a base machine having a lower traveling body equipped with a crawler and an upper rotating body rotatably provided on the lower traveling body; a boom provided in a hoistable manner at the front of the upper rotating body; a main hoist sheave rotatably supported via a sheave shaft at the tip of the boom; and a kelly bar suspended by a main hoist rope wound around the main hoist sheave, a slewing bearing device for tilting the upper rotating body relative to the lower traveling body and for rotating the upper rotating body inclined on the lower traveling body to change the tilt direction, The swivel bearing device is a lower slewing bearing case having a lower running body mounting surface; an upper rotating bearing case provided with an upper rotating body mounting surface; a plurality of lower bearing balls provided in a circumferential direction around a pivot axis extending in a direction perpendicular to the lower running body mounting surface; A plurality of upper bearing balls are provided in a circumferential direction around an inclined axis extending in a direction intersecting with the rotation axis; an intermediate slewing bearing case assembled between the lower slewing bearing case and the upper slewing bearing case and the intermediate slewing bearing case and the upper bearing ball are interposed between the intermediate slewing bearing case and the upper bearing ball; a first hydraulic motor for rotating the intermediate slewing bearing case relative to the lower slewing bearing case; a second hydraulic motor for rotating the upper slewing bearing case relative to the intermediate slewing bearing case; a rotation reference position is defined in which, when the lower slewing bearing case, the upper slewing bearing case, and the intermediate slewing bearing case are assembled together, the lower running body mounting surface and the upper rotating body mounting surface are parallel to each other, and the tilt direction of the tilt axis relative to the swing axis is aligned with the front-rear direction of the lower running body and the upper rotating body; A lower bearing case track is formed between the lower slewing bearing case and the intermediate slewing bearing case, in which the lower bearing balls roll under the operation of the first hydraulic motor; An upper bearing case track is formed between the upper slewing bearing case and the intermediate slewing bearing case, in which the upper bearing balls roll under the operation of the second hydraulic motor; The upper bearing case track is inclined so that the upper rotating body mounting surface is inclined relative to the lower running body mounting surface when the upper rotating bearing case rotates relative to the intermediate rotating bearing case starting from the rotation reference position.

2. 2. The earth drill according to claim 1, wherein the intermediate swivel bearing case is divided into two parts, upper and lower, by a plane parallel to the lower running body mounting surface, and the lower part that pairs with the lower swivel bearing case and the upper part that pairs with the upper swivel bearing case are connected to each other by bolt fastening.

3. The first hydraulic motor is provided on the lower traveling body, 3. The earth drill according to claim 1, wherein the second hydraulic motor is provided on the upper rotating body.

4. The first hydraulic motor is provided in the intermediate slewing bearing case, 3. The earth drill according to claim 1, wherein the second hydraulic motor is provided on the upper rotating body.

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