Control valves and impact devices

Abstract

The present invention relates to a control valve, an impact device for rock breaking equipment, and a method. The control valve (26) is an elongated part having a central axis and outer and inner diameter surfaces (Ros, Ris). The control valve comprises a plurality of axially spaced control surfaces for controlling hydraulic fluid flow (Hff) in response to an axial control movement (M). One or more radial surfaces of the control valve comprise one or more inclined surfaces (SS), the longitudinal direction of which is obliquely oriented with respect to the central axis (Ca) of the control valve. As a result, hydraulic flow acting on the inclined surfaces causes the control valve to rotate or change direction during an operating cycle.

Description

[Background technology]

[0001] The present invention relates to a control valve for a hydraulic percussion device of a rock breaking tool.

[0002] The invention further relates to an impact device and a method for generating impacts in a hydraulic impact device of a rock breaking tool.

[0003] The field of the invention is more particularly defined in the preambles of the independent claims.

[0004] In rock drills and other rock breaking equipment, various types of hydraulic impact devices are used, which are provided with a reciprocating striking piston, the working cycle of which is controlled by means of a control valve, however, these known solutions can present drawbacks with regard to the durability of the control valve. Summary of the Invention

[0005] SUMMARY OF THE INVENTION It is an object of the present invention to provide a new and improved control valve, impact device, and method for generating impact in a hydraulic impact device for rock breaking equipment.

[0006] The control valve according to the invention is characterized by the characterizing features of the first independent claim of the device.

[0007] The percussion device according to the invention is characterized by the characterizing features of the second independent tool claim.

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

[0009] The disclosed solution concept is that the control valve of the hydraulic impact device of the rock breaking equipment is an elongated element having a central axis and an outer and inner diameter surface, and further comprises a plurality of control surfaces axially spaced from one another to control hydraulic fluid flow in response to axial control movement. Furthermore, at least one radial surface of the valve comprises at least one inclined surface, the longitudinal direction of which is obliquely oriented relative to the central axis of the valve. In other words, the control valve comprises one or more inclined surfaces in one or more surface areas, and the one or more inclined surfaces are acted upon by fluid flow during the impact device's operating cycle. The fluid flow thereby generates torque on the inclined surfaces around the central axis of the control valve, causing the control valve to rotate or at least change orientation relative to the central axis. The control valve is a control sleeve with a central axial opening configured to serve as a fluid passage. In other words, the control sleeve can surround a striking piston that can be disposed in the central axial opening.

[0010] An advantage of the disclosed solution is that the control valve changes position relative to the central axis automatically and without any external actuator or external force, which makes it possible to increase the durability of the control valve. The control valve may be subject to cavitation, which can reduce cavitation damage to the control valve. A further advantage is that the manufacturing of the inclined surface is easy and cheap. The use of the disclosed solution requires only minor changes to the basic structure of the impact device.

[0011] According to one embodiment, the control valve has no lateral openings passing laterally through it, in other words, the control valve is a laterally closed-faced, apertureless element.

[0012] According to one embodiment, the inclined surface has an axial dimension and extends axially a limited distance onto the face of the control valve.

[0013] According to one embodiment, the inclined surface has an inclination of at least 10° relative to the central axis of the control valve, for example, the inclination may be 8 to 15°.

[0014] According to one embodiment, the inclined surface has a limited dimension in the axial direction of the control valve, i.e. the inclined surface does not extend across the control valve.

[0015] According to one embodiment, the ramped surface extends across the control valve.

[0016] According to one embodiment, the angled surface of the control valve is formed by a chip-removal machining process, such as milling.

[0017] According to one embodiment, the control valve is manufactured using additive manufacturing (AM).

[0018] According to one embodiment, the rock breaking tool is a jackhammer.

[0019] According to one embodiment, the rock breaking tool is alternatively a breaking hammer.

[0020] According to one embodiment, the outer diameter surface is provided with a plurality of inclined surfaces, in other words, the rotational torque generated can be increased by increasing the number of inclined surfaces.

[0021] According to one embodiment, the number of inclined surfaces in one cross section may be 2-20.

[0022] According to one embodiment, the inner diameter surface is provided with a plurality of inclined surfaces.

[0023] According to one embodiment, the inclined surface has a linearly oriented shape on the radial surface of the control valve, in other words, the shape of the inclined surface is straight and therefore deviates from a curved or spiral surface. The advantage of this solution is that linearly oriented inclined surfaces can be manufactured more easily.

[0024] According to one embodiment, the ramp has a helical shape in the longitudinal direction of the ramp.

[0025] According to one embodiment, the inclined surface has a uniform radial dimension in at least one longitudinal portion of the inclined surface.

[0026] According to one embodiment, the inclined surface has a continuously varying radial dimension in at least one longitudinal portion of the inclined surface.

[0027] According to one embodiment, the control valve has a first end surface and an opposite second end surface, and a plurality of angled surfaces extend to at least one of the first end surface and the second end surface.

[0028] According to one embodiment, the control valve has at least one control protrusion on at least one of the inner and outer diameter surfaces, the at least one control protrusion having a plurality of inclined surfaces.

[0029] According to one embodiment, the inclined surface has a groove-like shape, in other words, the groove has an angled surface portion or wall that opposes hydraulic fluid flow through the surface of the control valve during operation, thereby generating a torque on that surface.

[0030] According to one embodiment, the groove has a constant cross section from end to end.

[0031] According to one embodiment, the cross-sectional shape of the groove varies along the length of the groove.

[0032] According to one embodiment, the groove has a sloped bottom, the slope angle of which may be 10 to 20°, for example about 15°.

[0033] According to one embodiment, the inclined surface has a protrusion-like shape. In other words, the control valve may include one or more longitudinally inclined protrusions, such as ridges, bulges, bumps, or spirals. As a result, there is an angled surface portion or wall that opposes hydraulic fluid flow through the face of the control valve during operation, thereby generating a torque on that face.

[0034] According to one embodiment, the control valve has a first set of a plurality of first inclined surfaces and a second set of a plurality of second inclined surfaces axially spaced from the first set. The first and second inclined surfaces have opposite oblique orientations. In other words, the control valve can control fluid flows having opposite flow directions. That is, the first set is acted upon by a first fluid flow having a first flow direction, and the second set is acted upon by a second fluid flow having a second flow direction. The first and second sets are configured to rotate the control valve in the same rotational direction when acted upon by the first and second fluid flows.

[0035] According to one embodiment, the disclosed solution relates to an impact device of a rock breaking equipment, comprising: a body; a striking piston movable in an impact direction towards the front end of the impact device and in a reverse direction towards the rear end of the impact device; a working pressure space to which hydraulic fluid is supplied to move the striking piston in the reverse direction; and a control pressure space at the rear end of the valve cylinder, provided with a control valve, the control valve for controlling the hydraulic pressure acting on the control pressure space and thereby controlling the reciprocating movement of the striking piston, the control valve being configured to rotate hydraulically during operation of the impact device. Furthermore, the control valve comprises a plurality of inclined surfaces on at least one radial surface of the control valve for generating a torque realizing the hydraulic rotation. The control valve is in accordance with the embodiments and features disclosed herein.

[0036] The above disclosed embodiments can be combined to form a suitable solution having the required above feature embodiments.

[0037] Some of the embodiments are shown in more detail in the accompanying drawings. [Brief explanation of the drawings]

[0038] [Figure 1] FIG. 1 is a schematic side view of a rock drilling unit provided with a hydraulic rock drill. [Figure 2] 1 is a schematic side view of an excavator equipped with a hydraulic demolition hammer; [Figure 3] 1 is a schematic cross-sectional side view of a rock drill equipped with a hydraulic impact device. [Figure 4] FIG. 1 is a schematic side view of an impact device controlled using a spool valve. [Figure 5] 1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 6] 1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 7] 1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 8] 1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 9] 1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 10] 1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 11] 1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 12] 1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 13]1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 14] 1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 15] 1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 16] 1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 17] 1 is a schematic diagram of a portion of a sleeve-shaped control valve provided with ramps that cause desired rotation during the control valve's operating cycle. [Figure 18] 1 is a schematic diagram of a portion of a shaft-like control valve for a spool valve, provided with an inclined surface to produce a desired rotation during the operating cycle of the control valve. FIG. [Figure 19] 1 is a schematic diagram of a portion of a shaft-like control valve for a spool valve, provided with an inclined surface to produce a desired rotation during the operating cycle of the control valve. FIG. [Figure 20] 1 is a schematic diagram of a portion of a shaft-like control valve for a spool valve, provided with an inclined surface to produce a desired rotation during the operating cycle of the control valve. FIG. [Figure 21] 1 is a schematic diagram of a portion of a shaft-like control valve for a spool valve, provided with an inclined surface to produce a desired rotation during the operating cycle of the control valve. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0039] For clarity, the drawings show some embodiments of the disclosed solution in a simplified manner, and in the figures, like reference numerals indicate like elements.

[0040] FIG. 1 shows a rock drilling unit 1 adapted to drill holes in a rock face. The rock drilling unit 1 is typically mounted on a drilling boom 2 of a rock drilling rig. The rock drilling unit 1 is provided with a feed beam 3 and a rock drill 4 supported on the feed beam. A drilling tool 5 is connectable to the drill 4. The rock drill 4 may be provided with a shank adapter 6 at its front end for connecting the tool 5. The opposite end of the tool 5 carries a drill bit 7. The rock drill 4 is provided with an impact device 8 for applying rock-breaking impact pulses to the drilling tool 5, and a rotation device 9 for rotating the drilling tool 5 about its longitudinal axis. The rock drill 4 further comprises a base 10 for mounting the impact device 8, the rotation device 9, and, if necessary, other devices and elements. The rock drill 4 can be moved on the feed beam 3 by means of a feed device 11 in a drilling or feed direction A and a return direction B. The rock drill 4 is hydraulically operated, so that the impact device 8 and the rotation device 9 are connected to a hydraulic system HS. Furthermore, the impact device 8 may be according to the solutions disclosed in this document and may consequently be equipped with the disclosed rotation control valve.

[0041] 2 discloses a hydraulic breaking hammer 12 mounted on a boom 13 of an excavation vehicle 14 and connected to the hydraulic system HS of the excavation vehicle 14. The breaking hammer 12 comprises a hydraulic impact device 8 which generates impact pulses towards a breaking tool 15 which is connectable to the breaking hammer 12. The breaking tool 15 is movable in an impact direction A and a return direction B during rock breaking. The impact device 8 may be according to the solutions disclosed in this document and may consequently comprise a rotary control valve as disclosed.

[0042] In Figures 1 and 2, rock breaking equipment such as a rock drill 4 and a hydraulic breaking hammer 12 is designated by the reference Rba.

[0043] 3 discloses a rock drill 4 comprising a body 10, an impact device 8, a rotation device 9, a flushing housing 16, an open space 17 for receiving a shank adapter, and a gear housing 18. The flushing housing 16 and the gear housing 18 are located at the front end Fe of the body 10, and the impact device 8 is located at the rear end Re. The shank adapter can be mounted in the open space 17, and the rear end of the shank adapter can be connected to a rotation element at the gear housing 18, so that the shank adapter and a drilling tool connectable to the shank adapter can be rotated using the rotation device 9. Flushing fluid can be supplied via the flushing housing 16 to a flushing channel on the axis of the shank adapter and further to the drilling tool.

[0044] The impact device 8 includes a striking piston 19 configured to move in a reciprocating manner in an impact direction A and a return direction B. The front end of the striking piston 19 includes an impact surface 20 configured to strike the shank adapter. The impact device 8 may include a striking cartridge 21 axially disposed inside a rear portion Re2 of the central space 22 of the body 10. The striking cartridge 21 may include a valve cylinder 23 through which the striking piston 19 passes. The impact device 8 includes an operating pressure space 24 to which hydraulic fluid is supplied to move the striking piston 19 in the reverse direction B. A control pressure space 25 is located at the rear end Re2 of the valve cylinder 23. The control pressure space 25 includes a sleeve-shaped control valve 26 for controlling the hydraulic pressure acting on the control pressure space 25 and thereby controlling the reciprocating motion of the striking piston 19. The pressure in the control valve space 25 moves the striking piston 19 in the impact direction. This is because the working pressure area of the striking piston in the impact direction A in the control valve space is larger compared to the working pressure area or striking piston in the working pressure space 24, which acts in the return direction B. In the working pressure space 24, a high pressure can always prevail during operation, while in the control pressure space 25, the magnitude of the pressure can be varied by means of a control valve 26 to cause the striking piston 19 to reciprocate. Furthermore, the valve cylinder 23 is provided with a pilot pressure space 27 which generates pressure pulses in response to the movement of the striking piston 19 in the impact direction A. The valve cylinder 23 is further provided with a plurality of axial fluid channels 28 connecting the pilot pressure space 27 and the control pressure space 25. The pressure pulses generated in the pilot pressure space 27 act on the control surface of the control valve 26, causing the control valve to change its control position.

[0045] The control valve 26 is an elongated component having a central axis and an outer and inner diameter surface, and includes a plurality of axially spaced control surfaces for controlling hydraulic fluid flow in response to axial control movement. Additionally, one or more radial, i.e., inner or outer, surfaces of the control valve 26 include one or more inclined surfaces, the longitudinal direction of which is obliquely oriented relative to the central axis of the control valve. Possible configurations of the inclined surfaces are disclosed in Figures 5-17.

[0046] The impact device 8 disclosed in Figure 3 can also be used in a rock breaking hammer, in which case there is no rotation device, gearing housing, flushing housing and shank adapter. The striking piston can be configured to strike the impact surface of the breaking tool.

[0047] FIG. 4 shows a simplified diagram of another type of impact device 8 and a valve system for controlling the reciprocating movement of the striking piston 19. The valve system includes a spool valve 29 with an elongated shaft-like control valve 26 axially movably disposed within a valve housing 30. The control valve 26 includes a plurality of axially spaced control surfaces 31a-31d for controlling hydraulic fluid flow in response to an axial control movement M. The control valve 26 thereby opens and closes connections between a tank 32, a hydraulic pump 33, a first working pressure space 34 of the impact device 8, and a second working pressure space 35 of the impact device 8, thereby controlling the movement of the striking piston 19 in the impact direction A and the return direction B. Hydraulic pressure acts on the working pressure surfaces 36 and 37, causing the axial movement. Furthermore, one or more outer diameter surfaces of the control valve 26 include one or more inclined surfaces, the longitudinal direction of which is oblique to the central axis of the control valve 26. Possible shapes of the inclined surface of the control valve 26 are disclosed in Figures 18-21.

[0048] In FIG. 4, the control valve 26 alternates the pressure occupying the working pressure spaces 34 and 35, but in the alternative, the pressure may be varied in only one working pressure space if the working pressure area is sized accordingly.

[0049] 5 and 6 disclose the control valve 26, which is a control sleeve 38 having a central axis Ca and a central axial opening 39 configured to serve as a fluid passageway. The control sleeve 38 has an outer diameter surface Ros and an inner diameter surface Ris. The control valve 26 has a control protrusion 40 on the outer diameter surface Ros. The control protrusion 40 is provided with a plurality of inclined surfaces SS. The inclined surfaces SS have a groove-like shape. When hydraulic fluid flow is directed onto these inclined surfaces SS, a torque T is generated, causing the control sleeve 38 to rotate. The direction of hydraulic fluid flow Hff is indicated by arrows. FIG. 6 shows that the inclined surfaces 40 have a continuously varying radial dimension. This can be seen in the inclined surfaces 40 having a wider left edge 41 that narrows toward a right edge 42.

[0050] 7 and 8 show a control valve 26 having a control sleeve 38 with an inclined surface SS on the inner diameter surface Ris of the control sleeve. The inclined surface SS is a groove having a helical shape in the longitudinal direction of the inclined surface SS. When a hydraulic fluid flow Hff is directed to these inclined surfaces SS, a torque T is generated, causing the control sleeve 38 to rotate.

[0051] 9 and 10 disclose a control sleeve 38 which differs from that shown in FIGS. 7 and 8 in that the number of inclined surfaces SS, i.e., the number of spiral grooves, on the inner diameter surface is increased.

[0052] Furthermore, the control sleeve 38 has a first end face 43 and an opposite second end face 44, and the spiral groove extends from end to end in FIGS. 7-10. In this case, the surface area of the inclined surface SS is increased, allowing a large and effective torque T to be generated. The groove forming the inclined surface SS may have a constant depth, as shown in FIGS. 7-11.

[0053] 11 to 13 show a control sleeve 38 in which the inner diameter surface Ris at the second end face 44 is provided with a plurality of inclined surfaces SS.

[0054] 14 and 15 show a control sleeve 38 having a plurality of inclined surfaces SS on the inner diameter surface Ris at the first end face 44. As can be seen, the shape of the grooved inclined surfaces SS varies continuously along the length of the grooved inclined surfaces. In other words, the width and depth of the grooves decrease toward the second end 43.

[0055] 16 and 17 disclose a control sleeve 38 in which the inner control projection 45 is provided with a plurality of inclined surfaces SS.

[0056] Furthermore, various combinations of the solutions disclosed in Figures 4 to 17 can also be implemented. Thus, it may be possible to arrange inclined surfaces on both the inner and outer diameter surfaces. Also, a combination of protruding inclined surfaces and grooved inclined surfaces is possible.

[0057] 18 and 19 show a spool valve shaft-like control valve 26. The outer diameter surface Ros of the control valve 26 has two sections with inclined surfaces SS. The inclined surfaces SS can be grooves whose cross section varies along their length. The inclined surfaces SS are located in the section where hydraulic fluid flow Hff occurs, and the hydraulic fluid flow rotates the control valve 26 due to the contribution of the inclined surfaces SS.

[0058] 20 and 21 also disclose a spool valve shaft-like control valve 26. The control valve 26 differs from that shown in FIGS. 18 and 19 in that it includes a first set 46 of multiple first inclined surfaces SS-1 and a second set 47 of multiple second inclined surfaces SS-2 axially spaced apart from the first set SS-1. The first inclined surfaces SS-1 and the second inclined surfaces SS-2 have opposite oblique orientations O1 and O2. In other words, the control valve 26 can control fluid flows having opposite flow directions Hff1 and Hff2. That is, the first set 46 is acted upon by a first fluid flow Hff1 having a first flow direction, and the second set 47 is acted upon by a second fluid flow Hff2 having a second flow direction. The first and second sets 46, 47 are configured to rotate P the control valve 26 in the same rotational direction when acted upon by the first and second fluid flows Hff1, Hff2.

[0059] 20 and 21 further illustrate that the control valve 26 may include inclined surfaces SS-1 and SS-2 having different shapes and dimensions.

[0060] The drawings and the associated description merely illustrate the concept of the invention, in details of which the invention may vary within the scope of the claims.

Claims

1. A control valve (26) for a hydraulic impact device (8) of a rock breaking tool (Rba), comprising: an elongated part having a central axis and outer and inner diameter surfaces (Ros, Ris); a plurality of control surfaces (31) spaced axially from one another about said outer diameter surface for controlling hydraulic fluid flow (Hff) in response to axial control movement (M); In the control valve, During operation of the hydraulic impact device (8), the hydraulic impact device (8) is configured to rotate about the central axis hydraulically; There is no opening radially through the control valve (26); At least one of the outer and inner diameter surfaces (Ros, Ris) of the control valve (26) has at least one inclined surface (SS) for generating a torque (T) for realizing hydraulic rotation, and the longitudinal direction of the at least one inclined surface is obliquely oriented with respect to the central axis of the control valve (26); A control valve, characterized in that the control valve (26) is a control sleeve having a central axial opening (39) configured to serve as a fluid passageway.

2. A plurality of inclined surfaces (SS) are provided on the outer diameter surface (Ros).

2. The control valve according to claim 1 , characterized in that:

3. The inner diameter surface (Ris) is provided with a plurality of inclined surfaces (SS).

2. The control valve according to claim 1 , characterized in that:

4. The inclined surface (SS) is linearly directed toward at least one of the outer and inner diameter surfaces (Ros, Ris) of the control valve (26).

2. The control valve according to claim 1 , characterized in that:

5. The inclined surface (SS) has a spiral shape in the longitudinal direction of the inclined surface.

2. The control valve according to claim 1 , characterized in that:

6. The inclined surface (SS) has a uniform radial dimension in at least one longitudinal portion of the inclined surface.

2. The control valve according to claim 1 , characterized in that:

7. The inclined surface (SS) has a continuously varying radial dimension in at least one longitudinal portion of the inclined surface.

2. The control valve according to claim 1 , characterized in that:

8. having a first end surface (43) and an opposite second end surface (44); A plurality of inclined surfaces (SS) extend to at least one of the first end surface (43) and the second end surface (44).

2. The control valve according to claim 1 , characterized in that:

9. At least one of the inner diameter surface (Ris) and the outer diameter surface (Ros) has at least one control protrusion (40, 45); The at least one control protrusion (40, 45) is provided with a plurality of inclined surfaces (SS).

2. The control valve according to claim 1 , characterized in that:

10. The inclined surface (SS) has a groove shape.

2. The control valve according to claim 1 , characterized in that:

11. The inclined surface (SS) has a protruding shape.

2. The control valve according to claim 1 , characterized in that:

12. a first set (46) of a plurality of first inclined surfaces (SS-1) and a second set (47) of a plurality of second inclined surfaces (SS-2) axially spaced from said first set (46); The first inclined surface (SS-1) and the second inclined surface (SS-2) have mutually opposite oblique directions (O1, O2).

2. The control valve according to claim 1 , characterized in that:

13. A percussion device (8) of a rock breaking tool (Rba), A main body (10); a striking piston (19) movable in an impact direction (A) toward the front end (Fe) of the body (10) and in a reverse direction (B) toward the rear end (Re) of the body (10), the striking piston (19) passing through a valve cylinder (23) arranged in a rear part (Re2) of a central space (22) inside the body (10) in the moving direction of the striking piston (19); a working pressure space to which hydraulic fluid is supplied to move the striking piston (19) in the reverse direction (B); a control pressure space located at the rear end of the valve cylinder (23) and provided with a control valve (26), the control valve controlling the hydraulic pressure acting on the control pressure space and thereby controlling the reciprocating movement of the striking piston (19); Equipped with The control valve (26) is configured to rotate hydraulically during operation of the impact device (8), the control valve (26) comprises at least one inclined surface (SS) on at least one radial surface (Ros, Ris) of the control valve (26) for generating a torque (T) for realizing the hydraulic rotation; The control valve (26) according to any one of claims 1 to 12 An impact device characterized by:

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