Drill shank sleeve assembly, rock drill and method

Abstract

A shank sleeve assembly, a rock drill, and a method. The assembly (26) is mountable around a shank adapter (8) in a rock drill (6) and comprises a shank bushing (27) having a two-piece configuration comprising a first bushing part (27a) and a second bushing part (27b) connectable against each other. The assembly also includes a bearing bush (30) that can be arranged to surround the two-piece shank bush and to allow rotation between the shank bush and the bearing bush.

Description

TECHNICAL FIELD

[0001] The invention relates to a drill bit sleeve assembly of a rock drill, and it comprises a split sleeve surrounding a shank adapter.

[0002] The invention also relates to a rock drill and a method of providing a drill bit liner having a two-piece construction.

[0003] The field of the invention is defined more closely in the preamble of the independent claims. BACKGROUND

[0004] In mines and other work sites, different types of rock drills are used. The rock drill is provided with one or more booms, and the rock drill is arranged at the distal end of the boom. The rock drill comprises a percussion device provided with a percussion piston configured to provide percussion pulses to a drill tool via a shank adapter. The shank adapter is configured to transfer the percussion pulses and torque from the rock drill to the drill tool. The shank adapter can be axially supported by means of a drill bit liner. Depending on the construction of the rock drill and the size of the shank adapter, it can be necessary to use a split drill bit liner to allow installation and disassembly. However, in known solutions, some drawbacks have been detected, particularly in terms of wear of the drill bit liner. SUMMARY

[0005] The object of the invention is to provide a novel and improved drill bit sleeve assembly, rock drill and method.

[0006] The drill bit sleeve assembly according to the invention is characterized by the features described in the characterizing part of the first independent device claim.

[0007] The rock drill according to the invention is characterized by the features described in the characterizing part of the second independent device claim.

[0008] The method according to the invention is characterized by the features described in the characterizing part of the independent method claim.

[0009] The idea of the disclosed solution is to assemble a two-piece drill bit liner to surround a shank adapter of a rock drill, and to surround the drill bit liner with a bearing sleeve. This arrangement allows rotation of the drill bit liner.

[0010] In other words, the drill bit liner has a split construction comprising at least two matching liner parts, which are surrounded by separate bearing sleeves providing support for the liner parts.

[0011] An advantage of the disclosed solution is that the two-piece shank bushing is rotatable when the bushing component is properly supported by means of the bearing bushing. Allowing the shank bushing to rotate is beneficial because it enables even wear distribution on the surface of the shank bushing component. The moving shank adapter does not continuously direct wear to the same surface area of the shank bushing, and also reduces wear of the shank adapter. Proper support provided by the surrounding bearing bushing ensures smooth rotation of the shank bushing component. Improved wear resistance means longer service life of the shank bushing and less maintenance work.

[0012] According to an embodiment, the two-piece shank bushing is rotatably mounted relative to the bearing bushing. In other words, the connection between the two-piece shank bushing and the surrounding bearing bushing allows rotational movement between them.

[0013] According to an embodiment, the shank sleeve assembly has no rotational surfaces between the shank bushing and the bearing bushing. However, there are rotational surfaces on the outer surface of the bearing bushing to allow rotation of the assembly. An advantage of this solution is that there are jointless even surfaces at the rotational connection of the assembly. In addition, the manufacturing and dimensional accuracy of the two-piece components is not critical because they are rotating.

[0014] According to an embodiment, the connection between the two-piece shank bushing and the bearing bushing allows only limited axial relative movement between them. In other words, relative rotation between the shank bushing and the bearing bushing is prevented, but axial movement can occur. The connection may, for example, comprise splines or other forms of surfaces that transmit torque but allow axial movement.

[0015] According to an embodiment, the components of the two-piece shank bushing are immovably mounted to the bearing bushing. For example, the components of the shank bushing can be fixed to the bearing bushing by means of screw fastening.

[0016] According to an embodiment, there is a clearance fit between the two-piece shank bushing and the bearing bushing.

[0017] According to an embodiment, the assembly is supported to a flushing housing, which is part of the frame structure of the rock drilling rig. The flushing housing forms a space around the defined part of the shank adapter and allows flushing fluid to be fed to the flushing fluid channel of the shank adapter via the space.

[0018] According to an embodiment, the disclosed solution allows the use of an increased diameter of the rotational joint of the assembly, which is advantageous in terms of rigidity and wear resistance.

[0019] According to an embodiment, the solution also allows the use of a shank adapter with a shoulder, i.e. a shank adapter that implements so-called "shoulder-driven contact" on a threaded rock drilling tool coupling.

[0020] In this document, the bushing can also be referred to as a sleeve, i.e. the bushing is a longitudinal piece having an inner periphery and an outer periphery.

[0021] According to an embodiment, the bearing bushing comprises a rotating surface on its outer periphery and is rotatably mounted. In other words, rotation can occur between the split shank bushing and the bearing bushing, as well as between the bearing bushing and the structure surrounding the bearing bushing. Thus, two rotary joints are provided. An advantage of this embodiment is that the rotational movement in the shank sleeve assembly is split into two rotary joints, i.e. the inner and outer periphery of the bearing bushing, whereby wear can be reduced compared to a situation where only one rotary joint is implemented. When the rotational movement of the shank adapter is shared by two rotary joints, less rotational movement is directed to a single rotary joint and less wear occurs.

[0022] According to an embodiment, the rotating surface of the bearing bushing comprises a rotationally symmetrical outer surface.

[0023] According to an embodiment, the bearing bushing has a uniform, non-split construction, whereby it has a solid structure that can provide rigid support for the shank bushing, which has a split construction. The bearing bushing forms a shell-like structure around the shank bushing.

[0024] According to an alternative embodiment, the bearing bushing is not a rotatable part, but is supported to the surrounding frame part, so that it does not move during operation of the rock drill. In this embodiment, the rotation occurs between the inner surface of the bearing bushing and the shank bushing.

[0025] According to an embodiment, the shank sleeve assembly further comprises a wear bushing that can be arranged to surround the bearing bushing. In other words, the assembly comprises three consecutive sleeve-like parts that are arranged one inside the other, i.e. there are three separate nested sleeves around the shank adapter, namely: the shank bushing, the bearing bushing and the wear bushing. The bearing bushing is indirectly supported to the frame via the wear bushing. An advantage of this embodiment is that the wear bushing is a wear part that is easy to replace, which can be replaced when needed. The wear bushing provides protection for the frame surrounding the assembly. Replacing the wear bushing is much easier and less costly compared to replacing or repairing the frame or replacing the bearing bushing. Another advantage of the separate wear bushing is that it can be designed according to the specific situation without the fundamental limitations related to the frame construction. Thus, the material, shape and other features can be chosen more freely.

[0026] According to an embodiment, the assembly comprises four parts in total, which include a one-piece wear bushing, a one-piece bearing bushing, and two halves of a split shank bushing.

[0027] According to an alternative embodiment, the assembly does not have any separate wear-resistant bushing. In this case, the frame is provided with a space for accommodating the bearing bushing, i.e. the bearing bushing is directly supported to the frame.

[0028] According to an embodiment, one end of the wear-resistant bushing comprises a flange, which protrudes inwards and provides a support axial surface for the bearing bushing. In other words, the flange of the wear-resistant bushing can be used as an axial stop element and can partly define the space for the bearing bushing to rotate in.

[0029] According to an embodiment, the flange of the wear-resistant bushing is configured to determine the axial clearance for the bearing bushing. In case of too large axial clearance due to wear, the original clearance setting can be restored by replacing the wear-resistant bushing. Furthermore, by selecting wear-resistant bushings of different sizes, the axial clearance can be influenced.

[0030] According to an embodiment, the bearing bushing comprises an inwardly facing shoulder at the first end portion of the bearing bushing. The shank bushing comprises a first end facing the drilling direction. Furthermore, a face surface at the first end of the shank bushing can be mounted against the shoulder of the bearing bushing. In other words, the parts of the split shank bushing are supported axially against the shoulder of the bearing bushing and are thus properly supported against the even surface of the shoulder in the axial direction.

[0031] According to an embodiment, the first and second bushing parts of the shank bushing can be fastened to each other so that they together form an integral part in use. When the bushing parts are assembled and fastened together, the parts do not expand radially away from each other during use. In this way, the designed clearance is preserved and the shank bushing works in the designed way.

[0032] According to an embodiment, the bushing parts of the shank bushing are fastened to each other by means of screws or other fastening elements. An alternative is to provide the coupling surfaces of the parts with shape-locking elements or structures.

[0033] According to an embodiment, the solution can also comprise at least one sealing element, such as an O-ring arranged on the outer surface of the bearing bushing. The sealing element can be used to direct the lubrication fluid for the assembly in a desired way.

[0034] According to an embodiment, the at least one sealing element, such as an O-ring, on the bearing bushing can be arranged on the outer surface of the bearing bushing and can be used to facilitate the installation of the assembly.

[0035] According to an embodiment, the disclosed solution also relates to a rock drill comprising a frame, an impact device for generating impact pulses, a bit adapter for receiving the impact pulses and transmitting them as stress waves to a drill tool, which is connectable to the bit adapter, a rotation device for turning the bit adapter about its longitudinal axis, and a bit sleeve assembly comprising a bit sleeve having a split construction, which surrounds the bit adapter and is configured to transmit axial forces between the frame and the bit adapter. Furthermore, the bit sleeve assembly is a bit sleeve assembly according to the features disclosed in this document.

[0036] According to an embodiment, the disclosed solution also relates to a method of providing a rock drill with a rotary bit sleeve. The method comprises providing a bit sleeve having a two-piece construction, which comprises a first sleeve part and a second sleeve part, and arranging the sleeve parts to surround a bit adapter of the rock drill. The method further comprises surrounding the bit sleeve with a separate bearing sleeve and allowing the two-piece bit sleeve to rotate about its longitudinal axis relative to the bearing sleeve.

[0037] According to an embodiment, the method further comprises supporting the bearing sleeve in a rotatable manner relative to a frame of the rock drill.

[0038] According to an embodiment, the method further comprises supporting the bearing sleeve to the frame of the rock drill by means of a separate wear sleeve, which surrounds the bearing sleeve.

[0039] According to an embodiment, a shoulder contact bit adapter is implemented.

[0040] According to an embodiment, an alternative bottom contact bit adapter is implemented. In this case, the coupling head of the bit adapter comprises coupling threads and does not have a shoulder.

[0041] In this document, the terms "split" and "split construction" refer to a structure having a non-continuous edge or circumference. The structure can be split or disassembled in the radial direction into at least two parts or annular segments. Thanks to the two-part construction of the bit sleeve, the bit sleeve can be installed and removed in the radial direction regardless of the size and shape of the bit adapter.

[0042] The above-disclosed embodiments can be combined to form a suitable solution having the desired features among the above-mentioned features. BRIEF DESCRIPTION OF DRAWINGS

[0043] Some embodiments are described in more detail in the attached drawings, in which:

[0044] Figure 1is a schematic side view of a rock drill for use in face drilling,

[0045] Figure 2 is a schematic view of a hydraulic rock drill,

[0046] Figure 3 is a schematic side view of a front part of a rock drill,

[0047] Figure 4 is a schematic cross-sectional side view of a front part of a rock drill and a bit adapter provided with a shoulder,

[0048] Figure 5 is a schematic cross-sectional detail C of the bit sleeve arrangement of Figure 4

[0049] Figure 6 is a schematic cross-sectional side view of a front end of a rock drill provided with a bit sleeve arrangement that can be mounted and dismounted from the rear side direction,

[0050] Figure 7 is a schematic cross-sectional detail D of the bit sleeve arrangement of Figure 6

[0051] Figure 8 is a schematic view of a bit bushing having a two-piece construction,

[0052] Figure 9 is a schematic cross-sectional side view of a front end of a rock drill provided with a bottom-contact bit adapter,

[0053] Figure 10 is a schematic cross-sectional side view of a front end of a rock drill provided with a bit sleeve arrangement having one support sleeve for a bit bushing, and

[0054] Figure 11 is a schematic cross-sectional detail E of the bit sleeve arrangement of Figure 10

[0055] For the sake of clarity, the attached drawings show some embodiments of the disclosed solution in a simplified manner. In the drawings, the same reference numbers indicate the same elements. DETAILED DESCRIPTION

[0056] Figure 1 ​​​A rock drill rig 1 intended for use in face drilling is shown. The rock drill rig 1 comprises a movable carrier 2 and at least one drill boom 3 connected to the carrier 2. A drilling unit 4 is located at a distal end portion of the drill boom 3, which drilling unit 4 is provided with a feed beam 5 and a rock drill 6 supported on the feed beam 5. A drill tool 7 is connectable to the rock drill 6. The rock drill 6 comprises a bit adapter 8 at a front end FE of the rock drill 6 for connecting the drill tool 7. The rock drill 6 further comprises a percussion device 9 and a rotation device 10. By means of a feed device 11, the rock drill 6 can be moved on the feed beam 5 towards a drilling direction A. During drilling, impact pulses are generated by means of the percussion device to the rotating bit adapter 8, which transmits the impact pulses and torque to the drill tool 7. A flushing agent flow is delivered through a hollow structure to the bit adapter 8 and all the way through the drill tool 7 to the bottom of the drilled hole for flushing away drill cuttings from the drilled hole.

[0057] Figure 2 A rock drill 6 is disclosed, which comprises a body 12, a percussion device 9, a rotation device 10 and a gear box housing 13. At a front end FE of the body 12 is mounted a flushing housing 14 and a bit adapter 8. A flushing agent, such as water, is delivered to the flushing housing 14 or flushing head by means of a flushing channel 15. The flushing housing 14 comprises a frame 16 which can be mounted to the gear box housing 13 in a removable manner.

[0058] The percussion device 9 can comprise a percussion piston for generating impact pulses in an impact direction to the bit adapter 8. The rotation device 10 rotates the bit adapter 8 about its longitudinal axis together with a transmission inside the gear box housing 13.

[0059] Figure 3 A front end FE of the rock drill when detached from the gear box housing is disclosed. The front end FE comprises a flushing housing 14 through which the bit adapter 8 is mounted. At a rear end of the frame 16 of the flushing housing 14 is a mounting surface 17 which can be mounted against a matching mounting surface on the gear box housing. The bit adapter 8 comprises splines 18 or corresponding transmission surfaces at a rear end portion thereof. When the flushing housing 14 is mounted in place, the splines 18 are in contact with the gears of the gear box housing. An impact surface 19 of the bit adapter 8 is configured to receive impact pulses from the percussion device. At the opposite other end of the bit adapter 8, there is a connection device 20 comprising a connection thread 21. In this case, the bit adapter 8 is of the shoulder contact type and comprises a shoulder 22 against which the end of a drill tool is supported when the drill tool is connected. As is shown by the arrow in Figure 4 As is shown by the arrow in Fig. 2, the flushing housing 14 comprises a feed port 23 for feeding flushing fluid to the drill tool via a flushing space 24 and a flushing channel 25 of the bit adapter 8.

[0060] Figure 4 A shank sleeve assembly 26 is disclosed, which is mounted around the shank adapter 8 and comprises a shank bushing 27 provided with an inwardly protruding shoulder 28 for providing axial support to the shank adapter 8. The shank bushing 27 has Figure 8 a two-piece construction as disclosed in Figure 4 and Figure 5 Detail C in presents that the shank sleeve assembly 26 further comprises a bearing bushing 30, which can be arranged to surround the two-piece shank bushing 27. This construction allows for a well supported rotation between the shank bushing 27 and the bearing bushing 30. The bearing bushing 30 comprises a rotational surface 31 on its outer circumference. The shank sleeve assembly 26 further comprises a wear bushing 32, which is arranged to surround the bearing bushing 30. At the rear end of the wear bushing 32 there is a flange 33, which protrudes inwardly and provides a support axial surface for the bearing bushing 30. The front end of the wear bushing 32 is supported against an axial surface formed on the frame 16.

[0061] Figure 6 and Figure 7 Detail D in Figure 4 discloses a different solution than the one shown in Figure 5 and Figure 4 The difference is that there is no wear bushing, but instead the bearing bushing 30 is directly supported to the frame 16. The front end of the bearing bushing 30 is supported axially against a shoulder 34 formed in the frame, and the rear end is supported by means of a locking element 35, such as a locking ring. The disclosed mounting direction of the shank sleeve assembly 26 is from the rear end side, while in Figure 5 and the disclosed solution the mounting of the shank sleeve 27 and the bearing bushing 30 is from the front end side.

[0062] Figure 5 Figure 7 Further it is shown that the bearing bushing 30 comprises an inwardly facing shoulder 36 at a first end portion of the bearing bushing 30. The shank bushing 26 is supported against the shoulder 36.

[0063] Figure 9 A different solution than the one shown in Figure 4 is disclosed, the difference being that the shank adapter 8 is of a different type and does not have any shoulder. The shank sleeve arrangement 26 can be as disclosed in Detail C in Figure 5 .

[0064] Figure 10A solution different from the one shown in Figure 6 The solution differs from the one shown in

[0065] In the cross-sectional view in Figure 4 , 6 , 7, 9 and 10, it is not possible to see that the shank sleeve 27 has a split construction. However, this split construction is shown in Figure 8 The parts or halves 27a, 27b can be bolted together, for example, or can be connected to each other in any other way, such as by means of a form fit, for example. The halves 27a, 27b together define an axial opening in which the shank adapter can be mounted. The construction of the bearing sleeve 27 and the wear sleeve 30 can be monolithic, without a split construction.

[0066] The drawings and the related description are intended only to illustrate the idea of the application. In its details, the application can vary within the scope of the claims.

Claims

1. A drill adapter sleeve assembly (26) capable of being mounted around a drill adapter (8) in a rock drill (6), in The sleeve assembly (26) includes a shank bushing (27), the shank bushing (27) having an inner surface facing the shank adapter (8) and provided with an inwardly protruding shoulder (28), and the shank bushing (27) includes an outer surface; The shank bushing (27) has a two-piece construction, comprising a first bushing component (27a) and a second bushing component (27b), both of which are provided with coupling surfaces (29) capable of being connected against each other in a radial direction; and The shank sleeve assembly (26) further includes a bearing bushing (30) which can be arranged to surround the two-piece shank bushing (27); It is characterized by At a first end of the bearing bushing (30), the bearing bushing (30) includes an inwardly facing shoulder (36); and The shank bushing (27) includes a first end facing the drilling direction; Thereby, the end surface of the shank bushing (27) at the first end can be mounted against the shoulder (36) of the bearing bushing (30).

2. The assembly according to claim 1, characterized in that The two-piece shank bushing (27) is rotatably mounted relative to the bearing bushing (30).

3. The assembly according to claim 1, characterized in that Only limited axial movement is allowed between the two-piece shank bushing (27) and the bearing bushing (30).

4. The assembly according to claim 1, characterized in that The components of the two-piece shank bushing (27) are all immovably mounted to the bearing bushing (30).

5. Assembly according to any one of the preceding claims 1 to 4, characterized in that The bearing bushing (30) includes a rotation surface (31) on an outer circumference of the bearing bushing and allows the bearing bushing (30) to be rotatably mounted.

6. Assembly according to any one of the preceding claims 1 to 5, characterized in that The shank sleeve assembly (26) further includes a wear resistant bushing (32) which can be arranged to surround the bearing bushing (30).

7. The assembly according to claim 6, characterized in that One end of the wear-resistant bushing (32) includes a flange (33) that protrudes inwardly and provides a supporting axial surface for the bearing bushing (30).

8. Assembly according to any one of the preceding claims 1 to 7, characterised in that The first bushing component (27a) and the second bushing component (27b) are removably fastened to each other to form together a unitary piece.

9. A rock drill (6), comprising: Frame (12, 16); An impact device (9), the impact device (9) is used to generate an impact pulse; a shank adapter (8), the shank adapter (8) being used to receive the shock pulse and transmit the shock pulse as a stress wave to the drilling tool (7), the drilling tool (7) being connectable to the shank adapter (8); A rotating device (10) for rotating the shank adapter (8) around its longitudinal axis; and A shank sleeve assembly (26), the shank sleeve assembly (26) including a shank bushing (27) having a split structure, the shank bushing (27) surrounding the shank adapter (8) and being configured to transmit axial force between the frame (16) and the shank adapter (8); It is characterized by The shank sleeve assembly (26) is a shank sleeve assembly according to any one of the preceding claims 1-8.

10. A method of providing a rotary drill tail bushing (27) for a rock drill (6); in, The method comprises: Providing the shank bushing (27) with a two-piece construction, the two-piece construction comprising a first bushing component (27a) and a second bushing component (27b); and arranging the bushing components (27a, 27b) to surround the shank adapter (8) of the rock drill (6); and Surrounding the shank bushing (27) with a separate bearing bushing (30); It is characterized by providing the bearing bushing (30) with an inwardly facing shoulder (36) at a first end of the bearing bushing (30); The shank bushing (27) has a first end facing the drilling direction; and The end surface of the shank bushing (27) at the first end is mounted against the shoulder (36) of the bearing bushing (30).

11. The method according to claim 10, characterized in that The two-piece shank bushing (27) is allowed to rotate relative to the bearing bushing (30) about the longitudinal axis of the shank bushing (27).

12. The method according to claim 10, characterized in that preventing rotational movement between the two-piece shank bushing (27) and the bearing bushing (30); and Limited axial relative movement between the two-piece shank bushing (27) and the bearing bushing (30) is permitted.

13. The method according to claim 10, characterized in that The components of the two-piece shank bushing (27) are immovably mounted to the bearing bushing (30).

14. The method according to any one of the preceding claims 11 to 13, characterized in that The bearing bushing (30) is rotatably supported relative to a frame (16) of the rock drill.

15. The method according to claim 14, characterized in that The bearing bushing (30) is supported to the frame (16) by means of a separate wear bushing (32) surrounding the bearing bushing (30).

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