An impact mechanism for a hydraulic rock drill

Abstract

The application relates to the technical field of percussion mechanisms of rock drills, in particular to a percussion mechanism of a hydraulic rock drill, which comprises a body part, a containing groove being formed in the body part along the axial direction, a percussion piston being slidably arranged in the containing groove, a high-pressure flow channel and a low-pressure flow channel being arranged on the body part, and a reversing valve, which comprises a valve body, an inner flow channel being formed in the valve body, and the cross section of the inner flow channel being at least partially in the shape of a circular truncated cone; wherein the inner part of the body part is provided with a first pressure space and a second pressure space, the reversing valve is slidably arranged in the second pressure space, and the sliding of the reversing valve is used for making the second pressure space communicate with the high-pressure flow channel and / or the low-pressure flow channel; the percussion piston is used for making the first pressure space communicate with the high-pressure flow channel or making the fluid in the first pressure space enter the low-pressure flow channel; and a dynamic gap is always present between the percussion piston and the inner wall of the reversing valve.

Description

Technical Field

[0001] This utility model relates to the technical field of impact mechanisms for rock drills, and in particular to an impact mechanism for a hydraulic rock drill. Background Technology

[0002] In impact mechanisms driven by pressurized fluids (such as hydraulic oil or compressed air), such as hydraulic breakers and pneumatic rock drills, the impact piston, as a core functional component, needs to perform efficient reciprocating linear impact motion. Precise control of this motion, especially the reliable switching between its working stroke (impact) and return stroke (reset), is crucial to the impact energy, working efficiency, and reliability of the mechanism.

[0003] The core component for controlling the reciprocating motion of the impact piston is the directional valve. The directional valve is responsible for precisely guiding the pressurized fluid to a specific pressure surface (such as the front or rear chamber) of the impact piston according to the working state of the mechanism, thereby driving the piston forward to complete the impact or backward to reset.

[0004] Chinese Patent No. 2007800477076 discloses an impact device comprising a body and an impact piston movable within the body, pressure fluid spaces located at the rear and front ends of the impact piston, and pressure fluid channels for supplying pressure fluid to the impact device. At the rear end of the impact piston, there is an annular surface facing a control valve; correspondingly, on the inner surface of the control valve, there is an annular surface facing the impact piston, such that when the two annular surfaces are aligned, they substantially block the pressure fluid flow between the impact piston and the control valve. This causes a rapid increase in pressure in the rear chamber, providing a damping buffer for the impact piston and also providing additional thrust to the control valve, assisting in its switching. However, during the retraction of the impact piston, when the two annular surfaces face each other, the pressure in the second pressure fluid space rapidly increases, which increases pressure pulses. These pressure pulses act on the guide sleeve and seals, affecting their service life. Utility Model Content

[0005] In view of the shortcomings or problems existing in the prior art, this disclosure provides an impact mechanism for a hydraulic rock drill. The impact mechanism is reasonably designed and can effectively avoid the generation of large pressure pulses during the piston's retraction process.

[0006] The technical solution adopted by this disclosure to solve the above-mentioned technical problem is: an impact mechanism for a hydraulic rock drill.

[0007] include:

[0008] The main body has a receiving groove along its axial direction;

[0009] The impact piston is slidably disposed in the receiving groove;

[0010] High-pressure flow channels and low-pressure flow channels are provided on the main body;

[0011] A reversing valve includes a valve body, the interior of which forms an internal flow channel, the cross-section of which is at least partially frustum-shaped;

[0012] The main body is provided with a first pressure space and a second pressure space. The reversing valve is slidably disposed in the second pressure space. The sliding of the reversing valve is used to connect the second pressure space with the high-pressure flow channel and / or the low-pressure flow channel respectively.

[0013] The impact piston slides in the receiving groove to connect the first pressure space with the high-pressure flow channel or to allow the fluid in the first pressure space to enter the low-pressure flow channel.

[0014] There is always a dynamic gap between the impact piston and the inner wall of the reversing valve.

[0015] In a preferred embodiment, a first opening and a second opening are respectively provided at both axial ends of the valve body. The first opening and the second opening are connected through an internal flow channel, and the diameter of the first opening is larger than the diameter of the second opening.

[0016] In a preferred embodiment, the inner flow channel includes an axially connected tapered flow channel and at least one straight flow channel, wherein the straight flow channel is located at the end of the inner flow channel, and the connection between the tapered flow channel and the straight flow channel is a smooth transition.

[0017] In a preferred embodiment, the DC channel includes a first channel and a second channel, the tapering channel is disposed between the first channel and the second channel, a first opening is disposed at the end of the first channel, and a second opening is disposed at the end of the second channel.

[0018] In a preferred embodiment, the axial length of the first flow channel is L1, the axial length of the second flow channel is L2, and the axial length of the tapered flow channel is L3; L3≥2L1; L3≥2L2.

[0019] In a preferred embodiment, the valve body has a cylindrical structure, and the outer peripheral wall of the valve body is provided with a first annular protrusion, a second annular protrusion and a third annular protrusion in sequence along the axial direction. The first annular protrusion is located near the first opening, and the third annular protrusion is located near the second opening. The radial height of the first annular protrusion is H1, the radial height of the second annular protrusion is H2, and the radial height of the third annular protrusion is H3, where H2 > H1 > H3.

[0020] In a preferred embodiment, the high-pressure flow channel includes a first high-pressure channel and a second high-pressure channel, and the low-pressure flow channel includes a first low-pressure channel and a second low-pressure channel; the first pressure space is connected to the first high-pressure channel or the fluid in the first pressure space is allowed to enter the first low-pressure channel by sliding the impact piston; the second pressure space is connected to the second high-pressure channel and / or the second low-pressure channel by sliding the reversing valve.

[0021] In a preferred embodiment, the impact piston is provided with a first annular segment, and a first gap is provided between the first annular segment and the body portion, through which fluid in the first pressure space enters the first low-pressure channel.

[0022] In a preferred embodiment, a pressure fluid supply assembly is also included, wherein the first high-pressure channel and the second high-pressure channel are respectively connected to the pressure fluid supply assembly.

[0023] In a preferred embodiment, the main body is provided with a first annular groove and a second annular groove along its axial direction, a first guide sleeve is provided in the first annular groove, and a second guide sleeve is provided in the second annular groove. The second guide sleeve is located on the side of the second pressure space.

[0024] Compared with the prior art, the beneficial effects of this utility model are as follows: the cross-section of the inner flow channel is at least partially set as a frustum shape, and the cross-section of the inner flow channel forms a continuously decreasing flow section, so that the cross-sectional area of ​​the flow channel in the flow section continuously and uniformly decreases along the fluid flow direction. This setting can not only improve energy transfer efficiency, but also effectively reduce pressure fluctuations in the chamber where the directional valve is located, thereby suppressing the generation of pressure pulses, thus effectively improving the working environment of the hydraulic system, improving system stability and extending the service life of related components; since there is always a dynamic gap between the impact piston and the inner wall of the directional valve, when the impact piston moves backward, it ensures that the pressure fluid in the second pressure space can flow out continuously, and forms a gradually increasing pressure and a large pressure action surface in the second pressure space to assist the directional valve in switching, while no pressure pulse is generated in this process. Attached Figure Description

[0025] Figure 1 This is one of the cross-sectional views of the impact mechanism of a hydraulic rock drill disclosed herein;

[0026] Figure 2 This is a second cross-sectional view of the impact mechanism of a hydraulic rock drill disclosed herein;

[0027] Figure 3 This is the third cross-sectional view of the impact mechanism of a hydraulic rock drill disclosed herein;

[0028] Figure 4 This is one of the structural schematic diagrams of the directional valve disclosed in this publication;

[0029] Figure 5 This is a public announcement Figure 4 Cross-sectional view of the directional control valve;

[0030] Figure 6 This is the second schematic diagram of the reversing valve disclosed in this publication;

[0031] Figure 7 This is a public announcement Figure 6 A cross-sectional view of the directional valve.

[0032] In the diagram: 1. Valve body; 3. Inner flow channel; 4. First flow channel; 5. Gradually narrowing flow channel; 6. Second flow channel; 7. First annular protrusion; 8. Second annular protrusion; 9. Third annular protrusion; 10. Pressure fluid supply assembly; 11. First opening; 12. Second opening; 13. First pressure space; 14. Second pressure space; 15. Body; 16. Impact piston; 17. Fourth annular protrusion; 18. First gap; 19. First high-pressure channel; 20. Second high-pressure channel; 21. First low-pressure channel; 22. Second low-pressure channel; 23. Signal channel; 24. First guide sleeve; 25. Second guide sleeve; 26. Sealing sleeve. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0034] Please refer to Figures 1-3As shown, an impact mechanism of a hydraulic rock drill includes a reversing valve, a body 15, and an impact piston 16. The body 15 has a receiving groove along its axial direction. The impact piston 16 is slidably disposed in the receiving groove and reciprocates within the receiving groove. The body 15 is provided with a high-pressure flow channel and a low-pressure flow channel. The body 15 has a first pressure space 13 and a second pressure space 14 inside. The reversing valve is slidably disposed in the second pressure space 14. The sliding of the reversing valve allows the second pressure space 14 to communicate with the high-pressure flow channel and / or the low-pressure flow channel, respectively. The sliding of the impact piston 16 allows the first pressure space 13 to communicate with the high-pressure flow channel or allows the fluid in the first pressure space 13 to enter the low-pressure flow channel. The impact piston 16 is provided with a fourth annular protrusion 17. There is always a dynamic gap between the fourth annular protrusion 17 and the inner wall of the reversing valve. Assuming that the impact piston 16 moves to the left as forward and moves to the right as backward, it can be understood that when the impact piston 16 retracts to face the end of the fourth annular protrusion 17 and the inner flow channel 3, the dynamic gap between the fourth annular protrusion 17 and the inner wall of the reversing valve is the smallest. During this process, the dynamic gap can be regarded as a dynamic throttling orifice, which makes the pressure in the second pressure space 14 rise slowly and pushes the reversing valve to move quickly.

[0035] Please refer to the following: Figures 4-7 As shown, specifically, the directional control valve includes a valve body 1, with an internal flow channel 3 formed inside the valve body 1. A first opening 11 and a second opening 12 are respectively provided at both axial ends of the valve body 1, and the first opening 11 and the second opening 12 are connected through the internal flow channel 3. The diameter of the first opening 11 is larger than the diameter of the second opening 12. The first opening 11 of the directional control valve is closer to the first pressure space 13 than the second opening 12. The cross-section of the internal flow channel 3 is at least partially frustum-shaped. By setting the cross-section of the internal flow channel 3 to at least partially frustum-shaped, and forming a continuously decreasing flow section in the cross-section of the internal flow channel 3, the cross-sectional area of ​​the flow channel 3 in this flow section continuously and uniformly decreases along the fluid flow direction. This arrangement not only improves energy transfer efficiency but also effectively reduces pressure fluctuations in the chamber where the directional control valve is located, thereby suppressing the generation of pressure pulses. This effectively improves the working environment of the hydraulic system, enhances system stability, and extends the service life of related components.

[0036] It is understandable that, since the cross-section of the inner flow channel 3 is at least partially frustum-shaped, the gap between the fourth annular protrusion 17 and the inner wall of the valve body 1 during the reciprocating motion of the impact piston 16 can be considered to be constantly changing, that is, the gap is not a constant distance gap, hence it is called the dynamic gap. The first opening 11 of the reversing valve is closer to the first pressure space 13 than the second opening 12. When the impact piston 16 moves to the right (retracts), the dynamic gap can be approximated as gradually decreasing. When the impact piston 16 moves to the rightmost end, that is, when the fourth annular protrusion 17 is closest to the second opening 12 of the reversing valve, the dynamic gap is at its minimum.

[0037] like Figure 6 and Figure 7 As shown, in some embodiments, the inner diameter of the inner flow channel 3 gradually decreases from the first opening 11 to the second opening 12. This arrangement ensures that when the impact piston 16 moves toward the second pressure space 14, the pressure in the second pressure space 14 increases gradually, avoiding a sudden pressure surge that could lead to a pressure pulse.

[0038] like Figure 4 and Figure 5 As shown, in some embodiments, the inner flow channel 3 includes an axially connected tapered flow channel 5 and at least one direct flow channel. The direct flow channel is located at the end of the inner flow channel 3, and the connection between the tapered flow channel 5 and the direct flow channel is a smooth transition. The tapered flow channel 5 converts the kinetic energy of the fluid into pressure energy, providing a stable driving force for the reversing valve. The smooth transition between the tapered flow channel 5 and the direct flow channel can eliminate the flow field separation phenomenon of traditional stepped diameter change. Specifically, the direct flow channel includes a first flow channel 4 and a second flow channel 6. The tapered flow channel 5 is located between the first flow channel 4 and the second flow channel 6. The first opening 11 is located at the end of the first flow channel 4, and the second opening 12 is located at the end of the second flow channel 6. The cross-sectional area of ​​the tapered flow channel 5 decreases continuously and uniformly along the fluid flow direction, thereby effectively reducing pressure fluctuations in the chamber (second pressure space 14) where the reversing valve is located and suppressing the generation of pressure pulses. The second flow channel 6 is set as a direct flow channel, which can store the kinetic energy converted by the tapered flow channel 5 and quickly release energy during the reversing stage of the impact piston 16.

[0039] Specifically, the axial length of the first flow channel 4 is L1, the axial length of the second flow channel 6 is L2, and the axial length of the tapered flow channel 5 is L3; L3 ≥ 2L1; L3 ≥ 2L2. This arrangement aims to lengthen the tapered flow channel 5, making the fluid velocity gradient change more gradual and avoiding turbulence and pressure pulsations caused by abrupt changes in cross-section. Simultaneously, the shorter lengths of the first and second flow channels reduce the ineffective residence time of the fluid within the direct flow channels (first and second flow channels 6), lowering the risk of local vortices.

[0040] The valve body 1 has a cylindrical structure. The outer peripheral wall of the valve body 1 is provided with a first annular protrusion 7, a second annular protrusion 8 and a third annular protrusion 9 in sequence along the axial direction. The first annular protrusion 7 is located near the first opening 11 and the third annular protrusion 9 is located near the second opening 12. The radial height of the first annular protrusion 7 is H1, the radial height of the second annular protrusion 8 is H2 and the radial height of the third annular protrusion 9 is H3, where H2 > H1 > H3.

[0041] Furthermore, the high-pressure flow channel includes a first high-pressure channel 19 and a second high-pressure channel 20, and the low-pressure flow channel includes a first low-pressure channel 21 and a second low-pressure channel 22; the sliding of the impact piston 16 allows the first pressure space 13 to connect with the first high-pressure channel 19 or allows the fluid in the first pressure space 13 to enter the first low-pressure channel 21; the sliding of the reversing valve allows the second pressure space 14 to connect with the second high-pressure channel 20 and / or the second low-pressure channel 22 respectively.

[0042] The impact piston 16 is provided with a first annular segment, and a first gap 18 is provided between the first annular segment and the body part 15. The fluid in the first pressure space 13 enters the first low pressure channel 21 through the first gap 18.

[0043] The impact mechanism also includes a pressure fluid supply assembly 10, with a first high-pressure channel 19 and a second high-pressure channel 20 respectively connected to the pressure fluid supply assembly 10. A first low-pressure channel 21 and a second low-pressure channel 22 are also connected to the pressure fluid supply assembly 10, and the fluid discharged from the first low-pressure channel 21 and the second low-pressure channel 22 enters the pressure fluid supply assembly 10. The pressure fluid in this application is hydraulic oil.

[0044] The main body 15 is also provided with a signal channel 23, and the first pressure space 13 is connected to the second pressure space 14 through the first gap 18 and the signal channel 23.

[0045] The main body 15 has a first annular groove and a second annular groove along its axial direction. A first guide sleeve 24 is disposed in the first annular groove, and a second guide sleeve 25 is disposed in the second annular groove. The second guide sleeve 25 is located on the side of the second pressure space 14. The first guide sleeve 24 and the second guide sleeve 25 serve to limit movement, preventing the impact piston 16 from shifting, bending, or swaying due to uneven force. In addition, the first guide sleeve 24 and the second guide sleeve 25 also serve to support the impact piston 16, acting as a "central fulcrum" to reduce its suspended length and enhance the stability of the overall structure. A sealing sleeve 26 is also provided at the end of the main body 15 to strengthen the sealing effect inside the impact mechanism. To further enhance the sealing effect, a sealing ring is also provided in the sealing sleeve 26.

[0046] like Figure 1In the impact mechanism shown, it is assumed that the reversing valve is located at the rear end of the impact piston 16, and the other end is the front end of the impact piston 16. The first pressure space 13 is connected to the signal channel 23 through the first gap 18. The fluid in the first pressure space 13 is connected to the signal channel 23 through the first gap 18. The fluid in the signal channel 23 acts on the side of the first annular protrusion 7, giving the side a rightward thrust F1, causing the reversing valve to move to the right until it reaches the rightmost end. At this time, the second pressure space 14 is connected to the second low-pressure channel 22 through the dynamic gap. The rear end of the impact piston 16 loses the high pressure effect, and the front end of the impact piston 16 begins to accelerate to the right under the push of the high-pressure fluid (the retraction of the impact piston 16).

[0047] like Figure 2 As shown, as the impact piston 16 moves to the right, the signal channel 23 connects to the first low-pressure channel 21 through the first gap 18, and the force F1 exerted by the fluid in the signal channel 23 on the side of the first annular protrusion 7 weakens. Due to the rightward movement of the impact piston 16, the second pressure space 14 is compressed, and the fluid in the second pressure space 14 is discharged to the second low-pressure channel 22 through the dynamic gap, thereby generating a throttling pressure P. The throttling pressure P acts on the right end face of the reversing valve, causing the reversing valve to receive a leftward thrust F2. Furthermore, the fluid in the first high-pressure channel 19 exerts a leftward thrust F3 on the side of the third annular protrusion 9 throughout the process, and the sum of F2 and F3 is greater than F1. Under the combined action of F2 and F3, the reversing valve accelerates its reversing (moves to the left). At this time, due to the existence of the dynamic gap, the pressure in the second pressure space 14 slowly increases.

[0048] like Figure 3 As shown, after the reversing valve is reversed, it is on the left side. At this time, the second pressure space 14 is connected to the second high pressure channel 20. The fluid in the pressure fluid supply assembly 10 enters the second pressure space 14 through the second high pressure channel 20 and generates a leftward thrust on the side of the fourth annular protrusion 17 (impact piston 16), causing the impact piston 16, which was originally accelerating to the right, to decelerate and move to the right until it stops at the rightmost end.

[0049] The present application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present application. The descriptions of the embodiments above are only for the purpose of helping to understand the present application and its core ideas. It should be noted that those skilled in the art can make several improvements and modifications to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. An impact mechanism for a hydraulic rock drill, characterized in that, include: The main body (15) has a receiving groove along its axial direction; The impact piston (16) is slidably disposed in the receiving groove; High-pressure flow channels and low-pressure flow channels are provided on the main body (15); A reversing valve includes a valve body (1), the interior of which is formed an internal flow channel (3), the cross-section of which is at least partially frustum-shaped; The body part (15) is provided with a first pressure space (13) and a second pressure space (14). The reversing valve is slidably disposed in the second pressure space (14). The sliding of the reversing valve is used to connect the second pressure space (14) with the high pressure channel and / or the low pressure channel respectively. The impact piston (16) slides in the receiving groove to connect the first pressure space (13) with the high pressure channel or to allow the fluid in the first pressure space (13) to enter the low pressure channel. There is always a dynamic gap between the impact piston (16) and the inner wall of the reversing valve.

2. The impact mechanism of the hydraulic rock drill according to claim 1, characterized in that, The valve body (1) has a first opening (11) and a second opening (12) at its two axial ends respectively. The first opening (11) and the second opening (12) are connected through an inner flow channel (3). The diameter of the first opening (11) is larger than the diameter of the second opening (12).

3. The impact mechanism of the hydraulic rock drill according to claim 2, characterized in that, The inner flow channel (3) includes an axially connected tapered flow channel (5) and at least one direct flow channel, wherein the direct flow channel is located at the end of the inner flow channel (3), and the connection between the tapered flow channel (5) and the direct flow channel is a smooth transition.

4. The impact mechanism of the hydraulic rock drill according to claim 3, characterized in that, The direct current channel includes a first flow channel (4) and a second flow channel (6). The tapered flow channel (5) is located between the first flow channel (4) and the second flow channel (6). The first opening (11) is located at the end of the first flow channel (4), and the second opening (12) is located at the end of the second flow channel (6).

5. The impact mechanism of the hydraulic rock drill according to claim 4, characterized in that, The axial length of the first flow channel (4) is L1, the axial length of the second flow channel (6) is L2, and the axial length of the tapered flow channel (5) is L3; L3≥2L1; L3≥2L2.

6. The impact mechanism of the hydraulic rock drill according to claim 2, characterized in that, The valve body (1) is a cylindrical structure. The outer peripheral wall of the valve body (1) is provided with a first annular protrusion (7), a second annular protrusion (8) and a third annular protrusion (9) in sequence along the axial direction. The first annular protrusion (7) is located near the first opening (11), and the third annular protrusion (9) is located near the second opening (12). The radial height of the first annular protrusion (7) is H1, the radial height of the second annular protrusion (8) is H2, and the radial height of the third annular protrusion (9) is H3, where H2 > H1 > H3.

7. The impact mechanism of the hydraulic rock drill according to claim 1, characterized in that, The high-pressure flow channel includes a first high-pressure channel (19) and a second high-pressure channel (20), and the low-pressure flow channel includes a first low-pressure channel (21) and a second low-pressure channel (22); the first pressure space (13) is connected to the first high-pressure channel (19) by sliding the impact piston (16), or the fluid in the first pressure space (13) is allowed to enter the first low-pressure channel (21); the second pressure space (14) is connected to the second high-pressure channel (20) and / or the second low-pressure channel (22) by sliding the reversing valve.

8. The impact mechanism of the hydraulic rock drill according to claim 7, characterized in that, The impact piston (16) is provided with a first annular segment, and a first gap (18) is provided between the first annular segment and the body part (15). The fluid in the first pressure space (13) enters the first low pressure channel (21) through the first gap (18).

9. The impact mechanism of the hydraulic rock drill according to claim 7, characterized in that, It also includes a pressure fluid supply assembly (10), wherein the first high-pressure channel (19) and the second high-pressure channel (20) are respectively connected to the pressure fluid supply assembly (10).

10. The impact mechanism of the hydraulic rock drill according to claim 1, characterized in that, The main body (15) is provided with a first annular groove and a second annular groove along its axial direction. A first guide sleeve (24) is provided in the first annular groove, and a second guide sleeve (25) is provided in the second annular groove. The second guide sleeve (25) is located on the side of the second pressure space (14).

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