RU2169824C1 - Shock-absorber positioned above drill bit - Google Patents

Abstract

FIELD: mining industry, drilling of blast holes in open cast. SUBSTANCE: given shock-absorber includes external pipe and internal and centering pipes placed coaxially to it. Springy members coming in the form of packages of disc springs are positioned in internal spaces of external and internal pipes. Torque of drill column is transmitted to drill bit via keys arranged axially between internal and external pipes. EFFECT: reduced vibration of drilling column, prolonged service life of working tool. 2 cl, 1 dwg

Description

 The invention relates to the mining industry and can be used when drilling blast holes with cone bits to reduce dynamic loads on the bit and the rotary-feeding mechanism of the drilling rig.

 A pre-bit shock absorber is installed between the bit and the drill rod.

 It is known that when using plate-shaped shock absorbers in over-the-bottom shock absorbers as spring elements, the shock absorber’s performance and reliability are determined mainly by the reliability of the disk springs, which withstand a certain number of cycles of alternating loads depending on the conditions and design of the shock absorber and its operating conditions.

 Known over-bit shock absorber, including connected telescopic pipes - external, connected to the drill rod, and internal, connected to the chisel, forming a cavity in which disk springs, centering tube, rotation transmission unit, intermediate support and heel with a guide hole for the centering pipe are placed, located in the lower pipe under the Belleville springs (see, for example, A.S. USSR 281323, M.cl. E 21 B 17/07).

 A disadvantage of the known shock absorber is that the belleville springs in it are also not protected from shock loads, and the rigid fixing of the centering tube leads to uneven wear on the surface of the belleville springs and the surface of the centering tube, as a result of which the alignment of the belleville springs, which leads to their breakdown, is violated.

 The closest in technical essence to the described invention is a gouge shock absorber comprising an outer pipe made with the possibility of its connection with a drill rod and an inner pipe telescopically connected with it, made with the possibility of connection with a working tool, cup spring cups placed in the pipes, centering pipe , as well as a device for preliminary deformation of Belleville springs, consisting of a support heel, a support sleeve connected to the outer pipe by means of by, and keys for transmitting torque to the working tool and restrictions limit the operating position of the inner tube, it occupies after preliminary deformation of disc springs (see. Russian patent 2032065, M.kl. E 21 B 17/07).

 The main disadvantages of this shock absorber is that a key of this type is fixed in the keyway by welding. During operation, the pipe and weld seam wear. For this reason, and also under the action of dynamic loads, the keys fall out of the grooves and the shock absorber fails. In addition, such dowels make the inner and outer pipes indistinguishable, which makes it difficult to repair the shock absorber. Further, an inner pipe with a variable diameter, having an outer diameter larger than the inner diameter of the outer pipe directly near the working tool, does not allow the latter to bring it as close as possible to the working tool and thereby increase the landing contact of the two pipes, which can lead to transverse vibrations of the working tool. In addition, this fact does not allow to reduce the length of the shock absorber and to use drill pipes of standard length when working with the shock absorber.

 The basis of the invention is the solution to the problem of creating such an over-bit shock absorber, which with a simpler design would have greater maintainability, greater manufacturability, and would also allow it to be used in conjunction with standard drill pipes.

 The technical result that can be obtained by implementing the invention is that the above-bit shock absorber of the proposed design can be applied without altering the existing equipment, while increasing the operational life of the drilling tool.

 The problem is solved due to the fact that in the above-bit shock absorber, including the outer pipe, made with the possibility of its connection with the drill rod and the inner pipe telescopically connected with it, made with the possibility of connection with the working tool, the tube-shaped centering tube placed in the pipes, as well as device for pre-deformation of Belleville springs, consisting of a support heel, a support sleeve connected to the outer pipe by a thread, and dowels for transmitting torque on the working tool and the limitations of the limiting working position of the inner pipe, occupied by it after the preliminary deformation of the disk springs, the keys are placed in the keyways made in the form of blind holes having an exit to the ends of the outer and inner pipes from the side of the working tool, the axes of these holes are located on the generatrix a cylindrical surface with a diameter equal to the outer diameter of the inner pipe, and an annular groove is made inside the wall of the outer pipe, in which the stoppers for fixing are placed keys in the keyways, each stopper made in the form of an annular sector with a centering protrusion designed to fix the stopper in the part of the keyway facing the end of the inner pipe, while the inner pipe is made with a constant outer diameter.

 Preferably, the blind keyways in the body of the telescopically connected pipes are cylindrical, and the keys are made in the form of circular cylinders.

 It is also advisable to make blind keyways in the body of telescopic connected pipes rectangular in their cross section, and the keys - prismatic.

 The invention is illustrated in the drawing, which shows a cross-section of an overhead damper.

 The pre-bit shock absorber includes a telescopically connected outer pipe 1 made with the possibility of connecting with a drill rod (not shown in the drawing), and an inner pipe 2 made with the possibility of connecting with a working tool (not shown in the drawing). In the cavities of the outer pipe 1 and the inner pipe 2, there are packages of Belleville springs 3 and a centering tube 4. In the cavity of the inner pipe 2 there is a support heel 5, on which one of the packets of Belleville springs 3 rests.

 In the cavity of the outer pipe from the side of its connection with the drill rod, an internal thread is made on which the support sleeve 6 is mounted with a central hole for the passage of the centering pipe 4, on which the intermediate support 7 is rigidly mounted, having the possibility of longitudinal movement in the cavity of the inner pipe 2. Last made with a constant outer diameter along its entire length. The supporting sleeve 6, connected to the outer pipe 1 by means of a thread, the dowels 8, designed to transmit torque to the working tool, together with the supporting heel 5 form a device for preliminary deformation of plate springs.

 The dowels 8 are placed in the keyways (not indicated in the drawing), made in the form of blind holes having access to the ends of the outer 1 and inner 2 pipes from the side of the working tool. The axes of these keyways are located on the generatrices of the cylindrical surface with a diameter equal to the outer diameter of the inner pipe 2, and an annular groove 9 is made inside the wall of the outer pipe 1, in which stoppers 10 are placed for fixing the keys 8 in the keyways. Each of these stoppers is made in the form of an annular sector with a centering protrusion 11, designed to fix the stopper in the part of the keyway facing the end of the inner pipe 2, which is made with a constant outer diameter.

 For greater adaptability of the shock absorber, it is advisable to make blind keyways in the body of telescopically connected pipes cylindrical, obtained, for example, by drilling the outer 1 and inner 2 pipes assembled together. In this case, the dowels are cylindrical in shape.

 An embodiment of keyways with a rectangular cross section is not ruled out. Such grooves can be obtained, for example, by separately milling keyway grooves on both pipes. In this case, the keys can be made prismatic.

 The principle of operation of the above-bit shock absorber is as follows. When drilling, dynamic loads, which are intended to be removed by a supra-bit shock absorber, are generated both by a cone bit as a result of its interaction with the bottom of the well and by a rotating drill stand.

 The intermediate support 7, rigidly mounted on the centering tube 4, has the possibility of axial movement both with respect to the heel 5 and relative to the supporting sleeve 6, and this creates favorable conditions for the operation of the Belleville springs 3 at dynamic loads simultaneously from below - from the side of the working tool and from above - from the side of the drill rod. In this case, the relative displacement of the Belleville springs 3 relative to the centering pipe 4 decreases, which reduces its wear, as well as the wear of the contacting edges of the Belleville springs 3, as a result of which their alignment is not disturbed.

 When drilling wells with a supply to it simultaneously with compressed air used to remove drill cuttings, dust for water suppression, the latter, moving along the walls of the drill rods, enters the internal cavity of the above-bit shock absorber, in which Belleville springs 3 are placed, and fills it. The operation of the Belleville springs in a cavity filled with water creates additional resistance to deformation of the Belleville springs 3 during shock loads when drilling very strong or fractured rocks, which protects the belleville springs from overload and increases the life of the over-the-bottom shock absorber. The absence of an outer collar on the inner pipe 2, allows to minimize its length, which makes it possible to use a shock absorber with rods of standard length.

Claims (3)

 1. A sub-bit shock absorber, including an outer pipe made with the possibility of its connection with the drill rod, and an inner pipe telescopically connected with it, made with the ability to connect with a working tool, cup spring disks placed in the pipes, a centering pipe, a supporting heel, and also a device for pre-deformation of Belleville springs, consisting of a support sleeve connected to the outer pipe by a thread, and dowels for transmitting torque to the working tool and restrictions the specific working position of the inner pipe, occupied by it after preliminary deformation of the Belleville springs, characterized in that the keys are placed in the keyways made in the form of blind holes having an exit to the ends of the outer and inner pipes from the side of the working tool, the axes of these holes are located on the generatrices a surface with a diameter equal to the outer diameter of the inner pipe, and an annular groove is made inside the wall of the outer pipe, in which stoppers are placed to fix the keys in the spo night grooves, each stopper being made in the form of an annular sector with a centering protrusion designed to fix the stopper in the part of the keyway facing the end of the inner pipe, while the inner tube is made with a constant outer diameter.  2. The dampers according to claim 1, characterized in that the blind keyways in the body of the telescopically connected pipes are cylindrical, and the keys are made in the form of circular cylinders.  3. The dampers according to claim 1, characterized in that the blind keyways in the body of the telescopically connected pipes are made rectangular in their cross section, and the keys are prismatic.