Piston guide element, rock drilling machine and method

Abstract

Piston guide element, rock drilling machine and method for supporting a front end portion of a percussion piston of a rock drilling machine. The element (20) comprises at its rear end (24) a brake recess (16). The element further comprises at least one bearing sleeve (29) provided with two axially consecutive sliding bearing sections (As1, As2). Hydraulic fluid is conveyed between the sliding bearing sections by a feeding system (21).

Description

Technical Field

[0001] This invention relates to a piston guide element for a rock drilling machine. The element is designed to provide support for the front portion of the impact piston.

[0002] The present invention further relates to a rock drilling machine and a method for supporting the front end portion of an impact piston.

[0003] The scope of the present invention is further specifically defined below. Background Technology

[0004] Different types of rock drilling rigs are used in mines and other workplaces. These rigs have one or more booms, with the rock drilling machine positioned at the far end of each boom. The rock drilling machine includes an impact device with an impact piston supported on the machine body via a bearing assembly. In hydraulic impact devices, the front bearing of the piston experiences significant pressure spikes, especially when the piston's movement in the impact direction needs to be stopped by a brake recess located at the front of the impact device. Various solutions have been disclosed to eliminate these harmful pressure spikes on the bearings. However, the known solutions exhibit some drawbacks. Summary of the Invention

[0005] The object of the present invention is to provide a novel and improved piston guide element, a rock drilling machine equipped with such an element, and a method for supporting the front end of an impact piston.

[0006] The piston guide element according to the present invention is characterized by the following features.

[0007] The rock drilling machine according to the present invention is characterized by the following features.

[0008] The method according to the invention is characterized by the following features.

[0009] The disclosed solution is based on the idea that the piston guide element is a sleeve-like component that can be installed inside the body of a rock drilling machine between the impact piston and the body. The element includes a first end facing the impact direction and a second end facing the return direction. The second end is provided with a braking recess that can receive the piston's collar. Furthermore, the element includes at least one separate bearing sleeve installed inside the body of the element, and the element is provided with a first axial section and a second axial section. Both sections comprise a sliding bearing material. A first groove is located between the axial sections and on the inner surface of the element, the bottom of which includes at least one radial opening between the bottom of the first groove and the outer surface of the element. Hydraulic fluid can be delivered through the at least one radial opening and the first groove between the two adjacent sliding bearing sections.

[0010] The advantages of the disclosed solution are that the magnitude of the pressure peak directed to the bearing can be reduced when hydraulic fluid is guided between the two axial bearing sections. Furthermore, the bearing temperature can be reduced when hydraulic fluid is delivered to the bearing from locations other than the brake recess. In addition, the disclosed structure is simple and easy to manufacture and install.

[0011] According to an embodiment, the at least one individual bearing sleeve is made of a sliding bearing material. For example, the sliding bearing material can be a suitable metal bearing material.

[0012] According to the embodiments, bronze alloy material is used as the aforementioned sliding bearing material. For example, the bronze alloy may be tin bronze, leaded tin bronze, aluminum bronze, or manganese bronze.

[0013] According to an embodiment, cast iron is used as the material for the sliding bearing. For example, the cast iron can be gray cast iron.

[0014] According to an embodiment, the inner surface of the at least one bearing sleeve includes at least one layer made of at least one sliding bearing material.

[0015] According to an embodiment, the inner surface of the bearing sleeve or bearing section is coated with a sliding bearing material.

[0016] According to an embodiment, the at least one bearing sleeve has a bimetallic construction comprising a sleeve made of steel, with a bronze layer disposed on the inner surface of the sleeve, wherein intermetallic diffusion occurs between the steel and bronze materials. Alternatively, other metallic materials may also be used to form the bimetallic structure.

[0017] According to one embodiment, the element includes a separate bearing sleeve mounted inside the element. Therefore, the bearing sleeve is a single, unified piece and is provided with the first axial section and the second axial section for providing support for the piston.

[0018] According to one embodiment, the element includes two separate bearing sleeves sequentially mounted inside the element. A first bearing sleeve is configured to form the first axial segment, and a second bearing sleeve is configured to form the second axial segment. A first groove is thus located between the first and second bearing sleeves. In this way, the features of the bearing sleeves can be customized as needed.

[0019] According to an embodiment, at least the inner surfaces of the first bearing sleeve and the second bearing sleeve are made of different materials. This allows the sleeve material to be selected as needed.

[0020] According to an embodiment, the outer surface includes a second groove, and the at least one radial opening extends to the bottom of the second groove.

[0021] According to an embodiment, the outer surface includes at least one third groove extending from the second end to the second groove.

[0022] According to the embodiment, except at the second groove, the diameter of the outer surface of the element is equal.

[0023] According to an embodiment, the element includes two outer portions with different outer dimensions. Thus, at the first end is a first outer portion with a first outer diameter. At the second portion is a second outer portion with a second outer diameter. The outer diameters are chosen to enable mounting of the element. In other words, the outer surface of the element has a stepped structure, which facilitates mounting of the element.

[0024] According to an embodiment, the outer surface includes at least one third groove extending from the second end to the second groove. The third groove has a helical configuration.

[0025] According to an embodiment, the outer surface includes at least two helical third grooves, which are positioned at equal angular positions in the cross-section of the element when the element is viewed in the axial direction.

[0026] According to an embodiment, the outer surface includes at least one third groove extending from the second end to the second groove. The third groove has an axial configuration.

[0027] According to an embodiment, the outer surface includes at least three axially oriented third grooves, which are positioned at equal angular positions relative to each other when the element is viewed in the axial direction.

[0028] According to an embodiment, the disclosed solution relates to a rock drilling machine. The rock drilling machine includes a body and an impact device, which includes an impact piston capable of reciprocating in an impact direction and a return direction within the body under the influence of alternately pressurized hydraulic fluid in the working pressure chamber of the impact device. The machine further includes a piston guide element for supporting the front end of the impact piston to the body. The piston guide element includes at least one sliding bearing section and a braking recess for decelerating the impact piston. Hydraulic fluid is supplied between the sliding bearing section and the braking recess. Furthermore, the front end portion of the impact piston is supported by the piston guide element, which includes two consecutive sliding bearing sections. Hydraulic fluid is also supplied between the two consecutive sliding bearing sections. The piston guide element is consistent with the features disclosed in this document.

[0029] According to an embodiment, the portion between the two adjacent sliding bearing sections is connected to the impact pressure system of the impact device.

[0030] According to one embodiment, the impact device includes a first working pressure chamber located at the front end of the impact device. Hydraulic fluid is supplied from the first working pressure chamber between the two adjacent sliding bearing sections.

[0031] According to an embodiment, the portion between the two adjacent sliding bearing sections is connected to the impact pressure system via at least one pressure channel formed in the body of the rock drilling machine. Thus, cooler hydraulic oil can be delivered to the piston guide element compared to the oil in the first working pressure chamber at the front of the impact device.

[0032] According to an embodiment, pressurized hydraulic fluid is delivered from elsewhere outside the brake recess to the portion between the two adjacent sliding bearing sections.

[0033] According to an embodiment, the disclosed solution relates to a method for supporting the front end portion of an impact piston in a rock drilling machine. The method includes supporting the front end of the impact piston to the body of the rock drilling machine via a sleeve-shaped piston guide element, the sleeve-shaped piston guide element including at least one sliding bearing section and a braking recess for decelerating the impact piston. Hydraulic fluid is supplied between the sliding bearing section and the braking recess. The method further includes providing at least one bearing sleeve to the piston guide element and supporting the impact piston via two sliding bearing sections. The hydraulic fluid is guided between the sliding bearing sections.

[0034] According to an embodiment, the piston guide element is cooled by hydraulic fluid supplied between two sliding bearing sections.

[0035] According to an embodiment, the solution also relates to a rock drilling rig. The rig includes a movable frame and one or more drilling booms movably connected to the frame and equipped with a rock drilling unit. The rock drilling unit includes a feed beam and a rock drilling machine movably supported on the feed beam. The rock drilling machine and its operation are consistent with the features disclosed in this document.

[0036] According to embodiments, the disclosed solution can also be implemented in a hydraulic crusher designed for crushing rock materials. The crusher includes a body and an impact device, which includes an impact piston capable of reciprocating in the impact and return directions within the body under the influence of alternating pressurized hydraulic fluid in the working pressure chamber of the impact device. The machine further includes a piston guide element for supporting the front end of the impact piston to the body. The piston guide element includes at least one sliding bearing section and a braking recess for decelerating the impact piston. Hydraulic fluid is supplied between the sliding bearing section and the braking recess. Furthermore, the front end portion of the impact piston is supported by the piston guide element, which includes two consecutive sliding bearing sections. Hydraulic fluid is also supplied between the two consecutive sliding bearing sections. This piston guide element is consistent with the features disclosed in this document.

[0037] The disclosed embodiments can be combined to form a suitable solution having the features required among those described above. Attached Figure Description

[0038] Some embodiments are described in more detail in the accompanying drawings, in which: Figure 1 is a schematic side view of a rock drilling rig used for surface drilling, which is equipped with a drilling unit featuring a hydraulic rock drilling machine. Figure 2 and Figure 3 This is a schematic diagram of a hydraulic rock drilling machine. Figure 4 It is Figure 2 and Figure 3 A schematic cross-sectional top view of a rock drilling machine. Figure 5 yes Figure 4 A schematic cross-sectional view of the details. Figure 6 and Figure 7 This is a schematic diagram of a piston guide element. Figure 8 yes Figure 6 and Figure 7 A schematic end view of the piston guide element. Figure 9 yes Figures 6-8 A schematic cross-sectional view of the piston guide element as seen at section BB. Figure 10 This is a schematic cross-sectional view of the component as seen at the cross-section CC. Figure 11 This is a schematic diagram of a piston guide element with helical grooves on its outer surface. Figure 12This is a schematic cross-sectional view of a piston guide element that includes two axially connected sliding bearing elements. Figure 13 This is a schematic cross-sectional view of a piston guide element, which includes sliding bearing material on the inner surface side of the piston guide element.

[0039] For clarity, the accompanying drawings illustrate some embodiments of the disclosed solution in a simplified manner. In the drawings, similar reference numerals denote similar elements. Detailed Implementation

[0040] Figure 1 shows a rock drilling trolley 1 intended for surface drilling. The rock drilling trolley 1 includes a movable frame 2 and at least one drilling boom 3 connected to the frame 2. A drilling unit 4 is located at the distal end of the drilling boom 3, and the drilling unit 4 is provided with a feed beam 5 and a rock drilling machine 6 supported thereon. A drilling tool 7 can be connected to the drilling machine 6. The rock drilling machine 6 may include a shank adapter located at the front end of the rock drilling machine 6 for connecting the tool 7. The rock drilling machine 6 includes an impact device 8 and a rotating device 9. The rock drilling machine 6 can be moved on the feed beam 5 by the feed device 10. The rock drilling machine 6 may be provided with a piston guide element according to the features disclosed in this document. It should be mentioned that the disclosed piston guide element can be used in any type of hydraulic rock drilling machine utilizing the so-called top hammer principle. Furthermore, the disclosed piston guide element can be used in the impact device of a hydraulic breaker.

[0041] Figure 2- Figure 5 A rock drilling machine 6 is disclosed, comprising a main body 11, an impact device 8, a rotating device 9, a flushing housing 35, a shank adapter 12, and a gearbox 13 mounted at the front end of the main body. The impact device 8 includes an impact piston 14 for generating impact pulses to the shank adapter 12 connected to a tool 7 in the impact direction ID. The piston 14 moves in a reciprocating motion in the impact direction ID and the return direction RD. The shank adapter 12 is located at the front end FE of the drilling machine 6, and the end cap 15 is a distal component located at the rear end RE.

[0042] The front end of piston 14 impacts an impact surface located at the rear end of handle adapter 12. If the handle adapter has moved forward and the impact surface has moved away from the designed impact position, the movement of piston 14 is decelerated by brake recess 16 at the end of the impact motion. Brake recess 16 can receive piston collar 17, and together they can form a closed pressure space. Piston 14 is supported to body 11 by front bearing 18 and rear bearing 19, both of which can be sliding bearings. Front bearing 18 and brake recess 16 are part of piston guide element 20, which is an extended sleeve-like member surrounding the front of piston 14. Element 20 includes two axially connected sliding bearing portions, and between them is a feed system 21 for feeding hydraulic pressure fluid from impact device 14 or from another fluid source. Body 11 may be provided with channels, grooves, or other fluid guiding structures to allow feeding. Alternatively or additionally, a fluid guiding groove or other fluid guiding structure may be located on the outer surface of element 20. Figure 2- Figure 4 Pressure accumulators P1-P4 are also shown, which are part of the hydraulic circuit of the impact device 8. The impact device 8 includes several working pressure chambers for moving the impact piston under the influence of hydraulic pressure. For clarity, in Figure 4 Only the foremost working pressure space 22 is indicated. Working pressure space 22 is continuously connected to the high-pressure system and accumulators P1 and P2 during operation. Feeding system 21 can be connected to working pressure space 22 via the pressure feed path, thereby creating high pressure between the sliding bearing portion of guide device 20. Alternatively, high-pressure hydraulic fluid can be fed from any other location or source. However, this pressure fluid is not guided from the brake recess to feeding system 21. The fed hydraulic fluid may leak through the piston bearing clearance and can be collected at the foreground FE, and then guided to the hydraulic system's discharge line.

[0043] Figures 6-10A piston guide element 20 is disclosed, comprising a first end 23, a second end 24, an outer surface 25, and an inner surface 26. The first end 23 is oriented toward the impact direction ID of the impact piston, while the opposing second end 24 is oriented toward the return direction RD of the impact piston. The second end 24 has a brake recess 16 of a larger diameter on the inner surface 26. The brake recess 16 extends from the second end 24 toward the first end 23 by a first axial distance Ad1. The inner surface 26 includes a first groove 27 located at a second axial distance Ad2 from the brake recess 16. The element 20 has one or more radial openings 28 between the bottom of the first groove 27 and the outer surface 25. The inner surface 26 includes a first axial segment As1 located between the brake recess 16 and the first groove 27, and a second axial segment As2 located between the first groove 27 and the first end 23. Furthermore, the element 20 includes a separate bearing sleeve 29 mounted inside the element 20 and having the first axial segment As1 and the second axial segment As2. The first axial section As1 and the second axial section As2 include sliding bearing material.

[0044] The outer surface 25 of component 20 may include a second recess 30. The at least one radial opening 28 extends to the bottom of the second recess 30. Furthermore, the outer surface 25 includes one or more third recesses 31 extending from the second end 24 to the second recess 30. Hydraulic fluid can flow through the recesses 31 from... Figure 4 The working pressure space 22 shown flows to the guide element 20. The third groove may be axially oriented, and the number of grooves 31 may be one, two, three, four, or even more. (As shown in...) Figure 7 As seen in the image, there may be three evenly spaced grooves 31 around the periphery of element 20.

[0045] In an alternative, the guide element 20 may omit the second groove 30. Thus, the third groove 31' may terminate at the radial opening 28', as... Figure 7 As shown by the dashed line.

[0046] Figure 11 A guide element 20 is disclosed, which corresponds to Figures 5-9 The guide element shown, except that the third groove 31 is not axially oriented, but rather has a spiral structure.

[0047] Figure 12A guide element 20 is disclosed, comprising two separate bearing sleeves 29a and 29b sequentially mounted within the element. The first bearing sleeve 29a is made of a sliding bearing material and configured to form a first axial segment As1. The second bearing sleeve 29b is made of a sliding bearing material and configured to form a second axial segment As2. A first groove 27 is located between the first bearing sleeve 29a and the second bearing sleeve 29b. It can be noted that the bearing sleeves 29a and 29b may have different axial lengths. Furthermore, the bearing sleeves 29a and 29b may be made of different materials and may have other different dimensions. Alternatively, the bearing sleeves 29a and 29b may be similar components.

[0048] Figure 12 Further details are provided regarding the delivery of hydraulic fluid to the second groove 30 or directly to the opening 28 via a dedicated pressure channel 32. The pressure channel 32 may be formed into the body of the impact device and may be arranged to deliver cryogenic hydraulic fluid to the guide device 20, thereby effectively lubricating and cooling the bearing.

[0049] Figure 13 A bearing sleeve 29 is disclosed, comprising an outer base sleeve 33, which may be made of steel, and an internal structure 34, which may be a coating made of a sliding bearing material. Alternatively, the structure may have a dual-material construction, wherein a steel base 33 and a bearing bronze layer 34 are combined.

[0050] The accompanying drawings and related descriptions are intended only to illustrate the ideas of the invention. The invention may vary within the scope of the claims in its details.

Claims

1. A piston guide element (20) for providing support for the front end portion (FE) of a reciprocating impact piston (14) of a rock drilling machine (6); And among them, The piston guide element (20) is a sleeve-shaped component that can be installed inside the body (11) of the rock drilling machine (6) between the impact piston (14) and the body (11); The piston guide element (20) includes a first end (23), a second end (24), an outer surface (25), and an inner surface (26). The first end (23) is intended to face the impact direction (ID) of the reciprocating impact piston (14). The piston guide element (20) is characterized in that the opposite second end (24) is intended to face the return direction (RD) of the reciprocating impact piston (14), and a brake recess (16) with a large diameter is provided on the inner surface (26), and the brake recess (16) extends from the second end (24) toward the first end (23) by a first axial distance (Ad1). The inner surface (26) of the piston guide element (20) includes a first groove (27) located at a second axial distance (Ad2) from the brake recess (16); The piston guide element (20) has at least one radial opening (28) between the bottom of the first groove (27) and the outer surface (25). The inner surface (26) includes a first axial section (As1) located between the brake recess (16) and the first groove (27), and a second axial section (As2) located between the first groove (27) and the first end (23). The piston guide element (20) includes at least one separate bearing sleeve (29) which is mounted inside the piston guide element (20) and is provided with a first axial section (As1) and a second axial section (As2). Furthermore, at least the first axial section (As1) and the second axial section (As2) comprise sliding bearing material.

2. The piston guide element according to claim 1, characterized in that, The bearing sleeve (29) installed inside the piston guide element (20) is a single piece and is provided with the first axial section (As1) and the second axial section (As2).

3. The piston guide element according to claim 1 or 2, characterized in that, The at least one individual bearing sleeve (29) is made of sliding bearing material.

4. The piston guide element according to any one of claims 1-2, characterized in that, The inner surface of the at least one bearing sleeve (29) includes at least one layer (34) made of at least one sliding bearing material.

5. The piston guide element according to claim 1, characterized in that, The piston guide element (20) includes two separate bearing sleeves (29a, 29b) that are mounted consecutively inside the piston guide element (20). The first bearing sleeve (29a) is configured to form the first axial section (As1); The second bearing sleeve (29b) is configured to form the second axial section (As2); and The first groove (27) is located between the first bearing sleeve (29a) and the second bearing sleeve (29b).

6. The piston guide element according to any one of claims 1-2, characterized in that, The outer surface (25) includes a second groove (30), and the at least one radial opening (28) extends to the bottom of the second groove (30).

7. The piston guide element according to claim 6, characterized in that, The outer surface (25) includes at least one third groove (31) extending from the second end (24) to the second groove (30).

8. The piston guide element according to claim 1, characterized in that, The outer surface (25) includes at least one third groove (31') extending from the second end (24) to at least one radial opening (28').

9. The piston guide element according to claim 7 or 8, characterized in that, The at least one third groove (31, 31') has a spiral structure.

10. The piston guide element according to claim 7 or 8, characterized in that, The at least one third groove (31, 31') has an axial configuration.

11. The piston guide element according to claim 6, characterized in that, The outer diameter at the second axial section (As2) between the second groove (30) and the first end (23) is greater than the outer diameter at the first axial section (As1) between the brake recess (16) and the second groove (30), thereby the outer surface (25) of the piston guide element (20) has a stepped structure.

12. A rock drilling machine (6), comprising: Main body (11); Impact device (8), the impact device (8) includes a reciprocating impact piston (14), the reciprocating impact piston (14) is able to move in a reciprocating motion in the main body (11) in the impact direction (ID) and return direction (RD) under the influence of the alternating pressurized hydraulic fluid in the working pressure chamber of the impact device (8); Piston guide element (20) is used to support the front end of the impact piston (14) to the body (11). Furthermore, the piston guide element (20) includes a sliding bearing section and a braking recess (16) for decelerating the reciprocating impact piston (14). Furthermore, hydraulic fluid is supplied between the sliding bearing section and the brake recess (16); The characteristic feature is that the front end portion of the reciprocating impact piston (14) is supported by the piston guide element (20) comprising two consecutive sliding bearing sections (As1, As2); Hydraulic fluid is supplied between the two adjacent sliding bearing sections (As1, As2); and The piston guide element (20) is the piston guide element according to any one of claims 1-11.

13. The rock drilling machine according to claim 12, characterized in that, The portion between the two adjacent sliding bearing sections (As1, As2) is connected to the impact pressure system of the impact device (8).

14. A method for supporting the front end portion of a reciprocating impact piston (14) of a rock drilling machine (6), wherein the method comprises: The front end of the impact piston (14) is supported to the body (11) of the rock drilling machine (6) by a sleeve-shaped piston guide element (20), the piston guide element (20) including at least two sliding bearing sections and a braking recess (16) for decelerating the reciprocating impact piston (14); and Hydraulic fluid is supplied between the sliding bearing section and the braking recess (16); The method is characterized in that it includes providing at least one bearing sleeve (29) for the piston guide element (20); and The reciprocating impact piston (14) is supported by two sliding bearing sections (As1, As2) and hydraulic fluid is directed to flow between the two sliding bearing sections (As1, As2).

15. The method according to claim 14, characterized in that, The method includes cooling the piston guide element (20) by means of hydraulic fluid supplied between the two sliding bearing sections (As1, As2).

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