Hydraulic impactor and rock drill

Abstract

The utility model discloses a hydraulic impacter and a rock drill, and belongs to the technical field of hydraulic impacters, the hydraulic impacter comprises a piston guide body and a stop piston, the piston guide body is used for supporting and guiding an impact piston; the stop piston is slidably arranged in the mounting cavity, a partition part is arranged on the inner hole wall of the shell, and an annular cavity is formed between the stop piston and the partition part; an adjusting cavity is formed in the position, located at the rear end of the piston guide body, of the inner hole wall of the shell, and a second oil channel is formed in the shell and used for communicating the adjusting cavity with a pressure fluctuation control oil source of the hydraulic impactor. The impact piston is supported and guided through the piston guide body, the annular cavity is formed in cooperation with the stop piston arranged in a sliding mode, meanwhile, the adjusting cavity is formed in the rear side of the piston guide body, cavitation bubbles are discharged through the annular cavity, and the influence of cavitation is reduced.

Description

Technical Field

[0001] This application relates to the field of hydraulic impactor technology, and more particularly, to a hydraulic impactor. Furthermore, this application also relates to a rock drill comprising the aforementioned hydraulic impactor. Background Technology

[0002] The information provided in this section is for the purpose of generally presenting the background of this application. To the extent described in this section, the work of the currently named inventors and aspects of the description that may not constitute prior art at the time of filing are neither explicitly nor implicitly considered to be prior art of this application.

[0003] This invention relates to a piston support and buffer device for use in hydraulic impactors, which buffers the stop piston and supports the impact piston of a rock drill. In a hydraulic rock drill, the impact piston requires guidance and support during its reciprocating motion to prevent piston eccentricity from causing surface damage or jamming.

[0004] In previously known rock drills, the impact piston is generally guided and supported by a guide body installed inside the housing.

[0005] An axial seal is installed at the front end of the guide body to prevent leakage of hydraulic fluid between the impact piston surface and the guide hole during the reciprocating motion of the impact piston. At the same time, it provides a certain degree of support for the impact piston.

[0006] During certain operations, such as the reciprocating motion of the impact piston, the high-speed movement of the impact piston within the working space of the mounting hole generates significant pressure pulsations, causing cavitation within the hydraulic fluid. If these cavitation bubbles reach the piston seal, their collapse poses a risk of damage, leading to leaks and shortening the seal's lifespan. Seal wear can also cause piston eccentricity, resulting in damage to internal components. In previously known rock drills, the area between the piston seal and the piston guide for the impact piston is typically connected to a drainage system to divert hydraulic fluid between the piston guide and the piston, reducing hydraulic pressure and minimizing load on the seal.

[0007] For example, Chinese Patent Publication No. CN104541015A discloses a buffer support system for a rock drill. This patent discloses a device for protecting a piston sealing unit in a hydraulic rock drill. The piston sealing unit seals the cylinder and the piston within the drill's housing. A piston guide is positioned between the piston sealing unit and the working space within the cylinder. An annular, inwardly open chamber is provided between the piston guide and the piston sealing unit, designed to accommodate a volume of hydraulic fluid. This chamber is connected to a hydraulic supply flow channel for supplying the hydraulic fluid. This design incorporates an axial seal between the cylinder and the impact piston within the housing of the hydraulic rock drill. This seal prevents hydraulic fluid leakage between the cylinder and the impact piston. A piston guide is positioned between the sealing device and the internal space of the cylinder to guide and support the piston. A liquid chamber is located between the sealing device and the piston guide and connected to a continuous hydraulic fluid supply channel. By supplying unaffected hydraulic fluid, cavitation bubbles not carried away by the venting chamber are prevented from approaching the seal and causing damage. A venting cavity is also located between the liquid chamber and the piston guide, connected to a return oil channel to carry away hydraulic fluid and cavitation bubbles flowing towards the piston seal between the cylinder and the impact piston. However, while the axial seal between the impact piston and the cylinder provides some support, the reciprocating motion of the piston can cause seal wear. This wear not only leads to hydraulic oil leakage but also causes piston eccentricity, resulting in piston scoring.

[0008] However, it has been noted that this arrangement in the prior art does not satisfactorily reduce cavitation damage to the seals, nor does it reduce the potential impact of seal damage on other parts.

[0009] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0010] In view of at least one of the above technical problems, this application provides a hydraulic impactor that can support and guide the impact piston through a piston guide body, and form an annular cavity with a sliding stop piston. At the same time, an adjustment cavity is opened on the rear side of the piston guide body, and cavitation bubbles are discharged through the annular cavity to reduce the impact of cavitation.

[0011] This application also provides a rock drill including the aforementioned hydraulic impactor.

[0012] According to one aspect of this application, a hydraulic impactor is provided, including a housing of the hydraulic impactor, an impact piston movably disposed in the inner hole of the housing, and a piston support and buffer device of the hydraulic impactor further including a piston guide and a stop piston.

[0013] The piston guide is embedded in the inner wall of the housing. The piston guide is sleeved on the outer ring of the impact piston and located at the front end of the impact piston step of the impact piston. The piston guide is used to support and guide the impact piston.

[0014] The piston guide body has its front end near the impact piston in the forward impact direction as the piston guide body front end. The inner wall of the housing has an installation cavity located outside the piston guide body front end. The stop piston is slidably disposed in the installation cavity. The inner wall of the housing has a partition that separates the piston guide body from the installation cavity. An annular cavity is formed between the stop piston and the partition. A first oil passage is provided inside the housing. The first oil passage is used to connect the annular cavity to the hydraulic inlet line for supply or the hydraulic line for return of the hydraulic impactor. The annular cavity is used to accommodate cavitation bubbles generated between the impact piston and the inner wall of the housing and to discharge the cavitation bubbles through the first oil passage.

[0015] An adjustment chamber is provided on the inner wall of the housing at the rear end of the piston guide body. A second oil passage is provided inside the housing to connect the adjustment chamber with the pressure fluctuation control oil source of the hydraulic shocker.

[0016] In some embodiments of this application, the piston guide body is interference-fitted with a pre-set mounting groove on the inner wall of the housing.

[0017] In some embodiments of this application, the diameter of the inner bore of the piston guide is smaller than the diameter of the impact piston step.

[0018] In some embodiments of this application, there is a horizontal distance between the piston guide and the venting cavity.

[0019] In some embodiments of this application, guide grooves are provided on both sides of the inner wall of the housing located in the adjustment cavity. The guide grooves are used to support and guide the impact piston steps.

[0020] In some embodiments of this application, a venting cavity is provided on the inner wall of the guide body's inner bore of the piston guide body. The venting cavity is used to accommodate cavitation bubbles generated between the impact piston and the inner wall of the housing bore.

[0021] In some embodiments of this application, the venting chamber is connected to the return oil channel of the hydraulic impactor to discharge cavitation bubbles contained in the venting chamber.

[0022] In some embodiments of this application, the piston support and buffer device of the hydraulic impactor further includes a stopper. The end of the stop piston near the impact piston in the forward impact direction is provided as the front end face of the stop piston. The stopper is provided in the mounting cavity of the housing and located at the front end of the front end face of the stop piston. The stopper is used to limit the sliding of the stop piston.

[0023] In some embodiments of this application, the distance between the stop member and the partition is greater than the width of the stop piston, so that the stop piston can slide within the mounting cavity.

[0024] According to another aspect of this application, a rock drill is also provided, which includes the aforementioned hydraulic impactor.

[0025] This application has the following beneficial effects:

[0026] This hydraulic impactor incorporates a piston guide embedded in the inner wall of the housing to support and guide the impact piston. An adjustment chamber is located behind the piston guide on the inner wall of the housing. This chamber is connected to the pressure fluctuation control oil source of the hydraulic impactor via a second oil passage to regulate the oil pressure within the chamber. Simultaneously, a stop piston is movably positioned on the front side of the piston guide, forming an annular cavity between the stop piston and a partition on the inner bore of the housing. This annular cavity is connected to either a hydraulic inlet line for supply or a hydraulic return line via a first oil passage. The annular cavity can accommodate cavitation bubbles generated between the impact piston and the inner wall of the housing, and these bubbles are discharged through the first oil passage, effectively reducing the impact of cavitation.

[0027] The rock drill of this application also has the aforementioned beneficial effects. It also includes effective guidance and support for the impact piston, buffering of the stop piston, and prevention of leakage of hydraulic fluid between the piston guide and the impact piston.

[0028] Of course, any product implementing this application does not necessarily need to achieve all the advantages described above simultaneously. In addition to the purposes, features, and advantages described above, this application also has other purposes, features, and advantages. The application will be further described in detail below with reference to figures. Attached Figure Description

[0029] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0030] Figure 1 This is a schematic diagram of the overall structure of a preferred embodiment of this application;

[0031] Figure 2 This is a schematic diagram of the piston guide body according to a preferred embodiment of this application;

[0032] Legend: 1. Mounting cavity; 2. Housing; 3. Impact piston; 4. Piston guide body; 5. Separator; 6. Annular cavity; 7. First oil passage; 8. Second oil passage; 9. Inner bore of guide body; 10. Stop piston; 11. Discharge cavity; 12. Impact piston step; 13. Adjustment cavity; 14. Front end face of adjustment cavity; 15. Rear end face of stop piston; 16. Front end face of stop piston; 17. Anti-reverse component; 18. Front end face of step; 19. Guide groove. Detailed Implementation

[0033] The embodiments of this application are described in detail below with reference to the accompanying drawings; however, this application may be implemented in a variety of different ways as defined and covered below.

[0034] Figure 1 This is a schematic diagram of the overall structure of a preferred embodiment of this application; Figure 2 This is a schematic diagram of the piston guide body according to a preferred embodiment of this application.

[0035] A hydraulic impactor includes a housing 2, an impact piston 3 movably disposed within the inner hole of the housing 2, and a piston support and buffer device for the hydraulic impactor further including a piston guide 4 and a stop piston 10.

[0036] The piston guide 4 is embedded in the inner wall of the housing 2. The piston guide 4 is sleeved on the outer ring of the impact piston 3 and located at the front end of the impact piston step 12 of the impact piston 3. The piston guide 4 is used to support and guide the impact piston 3.

[0037] The end of the piston guide 4 near the impact piston 3 in the forward impact direction is designated as the front end of the piston guide 4. The inner wall of the housing 2 is provided with an installation cavity 1 located outside the front end of the piston guide 4. The stop piston 10 is slidably disposed in the installation cavity 1. The inner wall of the housing 2 is provided with a partition 5, which separates the piston guide 4 from the installation cavity 1. An annular cavity 6 is formed between the stop piston 10 and the partition 5. A first oil passage 7 is provided inside the housing 2. The first oil passage 7 is used to connect the annular cavity 6 to the hydraulic inlet pipeline for supply or the hydraulic pipeline for return of the hydraulic impactor. The annular cavity 6 is used to accommodate cavitation bubbles generated between the impact piston 3 and the inner wall of the housing 2 and to discharge the cavitation bubbles through the first oil passage 7.

[0038] An adjustment chamber 13 is provided on the inner wall of the housing 2 at the rear end of the piston guide body 4. A second oil passage 8 is provided inside the housing 2. The second oil passage 8 is used to connect the adjustment chamber 13 with the pressure fluctuation control oil source of the hydraulic shocker.

[0039] Here, "piston guide 4" means a structure that is embedded in the inner wall of the inner hole of the housing 2 and sleeved on the outer ring of the impact piston 3 to guide the impact piston 3. In some embodiments, the piston guide 4 is an annular guide sleeve structure.

[0040] In this application, the hydraulic impactor incorporates a piston guide 4 embedded in the inner wall of the housing 2 to support and guide the impact piston 3. An adjustment chamber 13 is provided on the inner wall of the housing 2 behind the piston guide 4. This adjustment chamber 13 is connected to the pressure fluctuation control oil source of the hydraulic impactor via a second oil passage 8 to regulate the oil pressure within it. Simultaneously, a stop piston 10 is movably positioned on the front side of the piston guide 4. An annular cavity 6 is formed between the stop piston 10 and the partition 5 on the inner hole of the housing 2. The annular cavity 6 is connected to a hydraulic inlet line for supply or a hydraulic return line via a first oil passage 7. The annular cavity 6 can accommodate cavitation bubbles generated between the impact piston 3 and the inner wall of the housing 2, and these bubbles are discharged through the first oil passage 7, effectively reducing the impact of cavitation.

[0041] Preferably, the piston guide 4 is interference-fitted with a pre-set mounting groove on the inner wall of the housing 2. Specifically, the diameter of the inner bore 9 of the piston guide 4 is smaller than the diameter of the impact piston step 12.

[0042] Understandably, the diameter of the inner bore 9 of the guide body is smaller than the diameter of the impact piston step 12, meaning that the impact piston step 12 will be limited by the piston guide body 4 to restrict the movement of the impact piston 3. The piston guide body 4 is fixedly installed on the inner wall of the housing 2 by an interference fit, and can provide stable support and guidance for the impact piston 3.

[0043] Preferably, please refer to Figure 1 and 2 As shown, there is a horizontal distance between the piston guide body 4 and the venting cavity 11. In this preferred embodiment, guide grooves 19 are provided on both sides of the inner wall of the housing 2 located in the adjusting cavity 13. The guide grooves 19 are used to support and guide the impact piston step 12.

[0044] It is understandable that a section of the guide groove 19 is located between the piston guide body 4 and the relief cavity 11. That is, the front end face 18 of the step can pass through the adjustment cavity 13 during the movement and is located in front of the front end face 14 of the adjustment cavity. It can seal the adjustment cavity 13 by impacting the piston step 12, which facilitates the adjustment of the internal pressure of the adjustment cavity 13.

[0045] Preferably, please refer to Figure 1 As shown, a venting cavity 11 is provided on the inner wall of the guide body 9 of the piston guide body 4. The venting cavity 11 is used to accommodate cavitation bubbles generated between the impact piston 3 and the inner wall of the housing 2.

[0046] In this preferred embodiment, the venting chamber 11 is connected to the return oil channel of the hydraulic impactor to discharge the cavitation bubbles contained in the venting chamber 11.

[0047] It is understandable that by setting up a relief chamber 11, which can be connected to the return oil channel of the hydraulic impactor, the hydraulic fluid and cavitation bubbles flowing between the working space inside the housing 2 and the impact piston 3 and the piston guide 4 and the impact piston 3 are partially carried away, reducing the cavitation bubbles flowing to the annular cavity 6, which is beneficial to further reduce the impact of cavitation.

[0048] Preferably, please refer to Figure 1 As shown, the piston support and buffer device of the hydraulic impactor also includes a stopper 17. The end of the stop piston 10 near the impact piston 3 in the forward impact direction is provided as the stop piston front end face 16. The stopper 17 is located in the mounting cavity 1 of the housing 2 and at the front end of the stop piston front end face 16. The stopper 17 is used to limit the sliding of the stop piston 10. In this preferred embodiment, the distance between the stopper 17 and the partition 5 is greater than the width of the stop piston 10, so that the stop piston 10 can slide within the mounting cavity 1.

[0049] It is understandable that the anti-reverse component 17 and the partition 5 form an installation cavity 1, which is used for the installation of the stop piston 10 and to enable the stop piston 10 to slide within the installation cavity 1. The stop piston 10 and the partition 5 form an annular cavity 6, which can provide functions such as venting cavitation bubbles, ensuring more stable operation of the impact piston 3 and improving the stability and service life of the hydraulic impactor.

[0050] In summary, this application provides a hydraulic impactor. The device does not have a cylinder structure and does not have an axial sealing device between the cylinder and the impact piston 3. The device serves as support between the impact piston 3 and the piston guide 4, and as a buffer stop for the retraction of the stop piston 10. The stop piston 10 is slidably mounted in the inner hole of the housing 2 according to a displacement axis parallel to the impact axis A of the inner hole of the housing 2. The piston guide 4 is positioned between the stop piston 10 and the working space inside the housing 2. An annular cavity 6 is arranged between the stop piston 10 and the piston guide 4. The annular cavity 6 abuts against the impact piston 3 to contain liquid, and can be connected to a hydraulic inlet line for supply or a hydraulic return line. The annular cavity 6 communicates with the space between the inner hole of the piston guide 4 and the impact piston 3. The annular cavity 6 can also be connected to the return oil pipeline and the space behind the piston guide body 4, so as to carry away the hydraulic fluid and cavitation bubbles flowing between the working space inside the housing 2 and the impact piston 3 and between the piston guide body 4 and the impact piston 3, thereby reducing the impact of cavitation.

[0051] The working principle of this application is as follows:

[0052] An annular cavity 6 is provided between the stop piston 10 and the piston guide body 4. The annular cavity 6 abuts against the impact piston 3 and is located between the hydraulic stop piston 10 and the piston guide body 4. The annular cavity 6 communicates with the space between the inner hole 9 of the piston guide body and the impact piston 3.

[0053] During the process of the impact piston 3 performing an impact action and striking the drill bit, the regulating chamber 13 is connected to the low-pressure oil source. The impact piston 3 moves forward, and its step front end face 18 passes through the front end face 14 of the chamber. At this time, the annular cavity 6 is connected to the low-pressure return oil pipeline through the first oil passage 7 in the housing 2. The stop piston 10 is in a balanced state against the anti-reverse member 17. The hydraulic fluid in the working space inside the housing at the rear end of the piston guide body 4 flows to the annular cavity 6 through the space between the guide body inner hole 9 and the impact piston 3, and flows back to the oil tank through the return oil pipeline.

[0054] After the impact piston 3 strikes the drill bit, it retracts. The drill bit rebounds from the impact of the hard object and strikes the stop element 17. The stop piston 10 abuts against the stop element 17. During the retraction process of the stop piston front end face 16 after being impacted, the annular cavity 6 is connected to the high-pressure oil inlet pipeline to supply a constant flow of hydraulic fluid. The regulating cavity 13 is connected to the high-pressure oil source. A high-pressure buffer cavity is formed between the stop piston rear end face 15 and the piston guide body 4. The high-pressure oil acts on the stop piston 10, and the stop piston 10 is buffered and stopped. Under the action of the high-pressure oil, it moves forward. During the movement, the annular cavity 6 is connected to the return oil pipeline. The stop piston 10 finally abuts against the stop element 17 and stops.

[0055] Due to the reciprocating motion of the impact piston 3, a significant pressure change will occur between the impact piston 3 and the inner wall of the housing 2 under certain operating conditions. If the pressure change is large enough, it will lead to the formation of cavitation bubbles. These cavitation bubbles tend to follow the leaking hydraulic fluid and leak through the space between the inner bore 9 of the guide body and the impact piston 3 into the annular cavity 6 defined between the stop piston 10 and the piston guide body 4, and flow out with the return oil passage, thereby at least reducing the effect of cavitation.

[0056] According to another aspect of this application, a rock drill is also provided, which includes the aforementioned hydraulic impactor.

[0057] The rock drill of this application also has the aforementioned beneficial effects. It also includes effective guidance and support for the impact piston 3, buffering of the stop piston 10, and prevention of leakage of hydraulic fluid between the piston guide 4 and the impact piston 3.

[0058] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0059] This document uses specific examples to illustrate the principles and implementation methods of this application. The examples are merely for the purpose of helping to understand the method and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, and the existence of an infinite number of specific structures, those skilled in the art can make various improvements, modifications, or variations without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, variations, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered as protected by this application.

Claims

1. A hydraulic impactor, comprising a housing (2) of the hydraulic impactor, and an impact piston (3) movably disposed within the inner hole of the housing (2), characterized in that, The piston support and buffer device of the hydraulic impactor also includes a piston guide (4) and a stop piston (10): The piston guide (4) is embedded in the inner wall of the housing (2). The piston guide (4) is sleeved on the outer ring of the impact piston (3) and located at the front end of the impact piston step (12) of the impact piston (3). The piston guide (4) is used to support and guide the impact piston (3). The piston guide (4) is positioned at one end near the impact piston (3) in the forward impact direction as the front end of the piston guide (4). The inner wall of the housing (2) is provided with an installation cavity (1) located outside the front end of the piston guide (4). The stop piston (10) is slidably disposed in the installation cavity (1). The inner wall of the housing (2) is provided with a partition (5). The partition (5) separates the piston guide (4) from the installation cavity (1). An annular cavity (6) is formed between the stop piston (10) and the partition (5). A first oil passage (7) is provided inside the housing (2). The first oil passage (7) is used to connect the annular cavity (6) to the hydraulic inlet pipeline for supply or the hydraulic pipeline for return of the hydraulic impactor. The annular cavity (6) is used to accommodate the cavitation bubbles generated between the impact piston (3) and the inner wall of the housing (2) and to discharge the cavitation bubbles through the first oil passage (7). The inner wall of the housing (2) is provided with an adjustment chamber (13) at the rear end of the piston guide (4). A second oil passage (8) is provided inside the housing (2). The second oil passage (8) is used to connect the adjustment chamber (13) with the pressure fluctuation control oil source of the hydraulic shocker.

2. The hydraulic impactor according to claim 1, characterized in that, The piston guide (4) is interference-fitted with the pre-set mounting groove on the inner wall of the housing (2).

3. A hydraulic impactor according to claim 1, characterized in that, The diameter of the inner bore (9) of the piston guide (4) is smaller than the diameter of the impact piston step (12).

4. A hydraulic impactor according to claim 1, characterized in that, There is a horizontal gap between the piston guide (4) and the adjustment cavity (13).

5. A hydraulic impactor according to claim 1, characterized in that, The inner wall of the housing (2) is provided with guide grooves (19) on both sides of the adjustment cavity (13). The guide grooves (19) are used to support and guide the impact piston step (12).

6. A hydraulic impactor according to claim 1, characterized in that, A venting cavity (11) is provided on the inner wall of the guide body (9) of the piston guide body (4). The venting cavity (11) is used to accommodate cavitation bubbles generated between the impact piston (3) and the inner wall of the housing (2).

7. A hydraulic impactor according to claim 4, characterized in that, The venting chamber (11) is connected to the return oil passage of the hydraulic impactor to discharge the cavitation bubbles contained in the venting chamber (11).

8. A hydraulic impactor according to claim 1, characterized in that, The piston support and buffer device of the hydraulic impactor also includes a stopper (17). The end of the stop piston (10) near the impact piston (3) in the forward impact direction is provided as the front end face (16) of the stop piston. The stopper (17) is located in the mounting cavity (1) of the housing (2) and at the front end of the front end face (16) of the stop piston. The stopper (17) is used to limit the sliding of the stop piston (10).

9. A hydraulic impactor according to claim 6, characterized in that, The distance between the anti-reverse member (17) and the partition (5) is greater than the width of the stop piston (10) so that the stop piston (10) can slide in the mounting cavity (1).

10. A rock drill, characterized in that, Including the hydraulic impactor as described in any one of claims 1-9.

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