Valveless hydraulic hammer capable of being operated in air or nitrogen

Abstract

The application discloses a valve-free and air-blastable hybrid or nitrogen-explosion hydraulic hammer, which comprises a piston and a cylinder body, the piston reciprocates in the cylinder body, a buffer section is arranged at one end of a middle rear section of the piston close to a tail section, when the buffer section enters a buffer cavity, a rear cavity is communicated with oil return through a reversing valve, due to the fact that a front cavity is communicated with high-pressure oil P, hydraulic pressure of the high-pressure oil P acting on a stepped surface formed by the middle front section and the head overcomes nitrogen resistance in a nitrogen chamber, the piston is pushed out of the buffer cavity, and continuous work is realized. The application avoids repeatedly pressing materials during the working process of the hybrid or nitrogen-explosion hydraulic hammer, and the phenomenon of low crushing efficiency is avoided.

Description

Technical Field

[0001] This invention relates to an engineering machinery attachment, and more particularly to a valveless, dry-firing hybrid or nitrogen-explosion type hydraulic hammer. Background Technology

[0002] Hydraulic hammers are often mounted on various machine tools (such as excavators, demolition robots, and skid steer loaders) to break materials such as rocks and concrete.

[0003] A hydraulic hammer is an impact tool that converts hydraulic energy into mechanical energy. It has two basic moving elements—a piston and a directional valve—which are controlled by feedback. The reciprocating motion of the valve core controls the piston's direction, and at the beginning and end of each stroke, the piston, through the opening or closing of the directional valve's control oil circuit, reverses the valve core's direction, thus creating a cyclical operation. The basic working principle of a hydraulic hammer is: through the feedback control of the piston and valve core, the piston achieves rapid reciprocating motion, striking the chisel to perform work and complete the crushing task.

[0004] Existing hybrid or nitrogen-explosive hydraulic hammer cores ( Figure 1 , Figure 2 , Figure 3 The main components include: 1. Nitrogen chamber; 2. Piston rings; 3. Piston; 4. Cylinder block; 5. Chisel holder; 6. Inner sleeve; 7. Outer sleeve; 8. Chisel; 9. Reversing valve; 10. Accumulator. The return stroke begins... Figure 1High-pressure oil P enters the front chamber 12 through oil port a4 and acts on the lower end of the valve core of the reversing valve 9, so that the valve core is stably in the state shown in Figure (1). At this time, the front chamber 12 is connected to high-pressure oil P, and the rear chamber 13 is connected to return oil T through oil port a1. Under the drive of high-pressure oil P in the front chamber 12, the piston 3 accelerates its return stroke and compresses the nitrogen in the nitrogen chamber 1 to store energy. The accumulator 10 stores oil. When the piston 3 returns to the front chamber 12 and the control oil port a3, the high-pressure oil P reaches the upper end of the valve core. At this time, the upper and lower ends of the valve core are connected to the high-pressure oil. Since the effective area of ​​the upper end of the valve core is larger than the effective area of ​​the lower end in the design, the valve core is reversed to the state shown in Figure (2) under the action of high-pressure oil. At this time, the front and rear chambers are connected to high-pressure oil P. The piston 3 accelerates its stroke under the action of nitrogen pressure or nitrogen pressure and oil pressure (when the diameters of the head 15 and the tail 17 are the same, only nitrogen does work during the stroke process, which is a nitrogen explosion type hydraulic hammer; when the diameter of the tail 17 is smaller than the diameter of the head 15, nitrogen and hydraulic oil do work together during the stroke process, which is a hybrid type hydraulic hammer), and strikes the chisel 8, outputting impact energy. When piston 3 passes the impact point, control ports a2 and a3 are connected and connected to the return oil T. The upper end of the valve core of the reversing valve 9 is depressurized. Under the action of the lower oil pressure, the valve core quickly reverses to the state shown in Figure (1) and returns to the initial state. Piston 3 begins to return and enters the next impact cycle, and so on. In the drill rod seat 5, there is a drill rod 8 for crushing operations, an inner sleeve 6 and an outer sleeve 7 that serve as guides. At the same time, the inner sleeve 6 and the outer sleeve 7 have the function of protecting the drill rod seat 5 from wear.

[0005] Problems with existing technology: When the middle front section 18 of piston 3 enters the buffer chamber 14 ( Figure 3 Because the stepped surface formed by the front section 18 and head 15 of piston 3 lacks high-pressure oil P, and the nitrogen chamber 1 is filled with high-pressure nitrogen (nitrogen pressure: 1.5MPa-3.5MPa, depending on the size of the hydraulic hammer), the high-pressure nitrogen acts on the end face of the tail 17 of piston 3, preventing the hydraulic hammer from working. Before starting the hydraulic hammer, the host machine (e.g., excavator) needs to press down on the hydraulic hammer and use the chisel 8 to push the piston 3 out of the buffer chamber 14. Due to the effect of high-pressure nitrogen, pressing down is difficult. Furthermore, during the operation of the hydraulic hammer, the chisel 8 needs to be in a compressed state to prevent piston 3 from entering the buffer chamber 14, so that the hydraulic hammer can work continuously.

[0006] Due to the aforementioned technical issues, hybrid or nitrogen-explosive hydraulic hammers have difficulty meeting the following working conditions.

[0007] (1) For secondary crushing of materials, since the materials have undergone primary crushing (e.g., blasting), they are light in weight and small in volume, and are prone to displacement during the process of clamping with a hydraulic hammer. If the chisel 8 cannot clamp the materials, the piston 3 cannot be pushed out of the buffer chamber 14, and the hydraulic hammer cannot work properly. During operation, it is necessary to repeatedly try to clamp the materials, resulting in low crushing efficiency.

[0008] (2) In some working conditions, when breaking the surface attachments, the internal structure cannot be damaged (e.g., the steel ladle lining cannot be damaged during the process of removing steel slag). If the hydraulic hammer needs to be pressed to work, it is difficult to stop the machine in time after the surface attachments are broken, which will damage the inner structure.

[0009] Chinese invention patent CN113700074B / Chinese utility model patent CN215715667U discloses a hydraulic hammer that can operate without clamping the chisel. The technical solution is as follows: a blow-off valve is installed between the buffer chamber and the high-pressure oil in the system. When the piston enters the buffer chamber, the blow-off valve opens, allowing high-pressure oil to enter and push the piston out; when the piston leaves the buffer chamber, the blow-off valve closes. The blow-off valve consists of a valve core and a valve sleeve, with the valve core sliding along the axial direction within the valve sleeve. Problems include: 1. Due to the high operating frequency of the hydraulic hammer (500-1200 times / minute), the high-speed and frequent sliding and reversing of the valve core within the valve sleeve easily leads to wear and scoring. 2. The structure is complex, and the manufacturing process is cumbersome, requiring turning, quenching, and grinding. The grinding process requires high precision and is labor-intensive. It involves grinding the holes that mate with the cylinder body and the air-operated valve sleeve, the outer / inner circle / end face of the air-operated valve sleeve, and the outer / end face of the air-operated valve core. Dimensional accuracy, positional accuracy, surface roughness, and fit clearance must be ensured, making the machining difficult. 3. If the air-operated valve core jams (e.g., due to oil contamination), the buffer chamber 14 loses its buffering function, leading to damage to the hydraulic hammer.

[0010] Chinese utility model patent CN218148613U discloses a hydraulic breaker that achieves dry-firing function based on the hydraulic hammer effect and damping orifice. The technical solution is as follows: a floating valve is installed between the buffer chamber and the system high-pressure oil P. The floating valve includes a valve body, a floating valve core, and a plug. The two ends of the floating valve core have equal areas; one end near the plug is connected to the buffer chamber, and the other end is connected to the system high-pressure oil P. A damping orifice is installed inside the floating valve core. When hydraulic oil flows through the damping orifice, it passes through the damping orifice structure whose axes are perpendicularly connected. The floating valve controls the connection or disconnection between the buffer chamber 14 and the system high-pressure oil P, thereby buffering the piston 3 or pushing the piston 3 out of the buffer chamber 14. Problems include: 1. The floating valve core slides and reverses at high frequency, making it prone to wear and scoring. 2. The structure is complex, and the manufacturing process is cumbersome, requiring turning, quenching, grinding, and other processes.

[0011] Chinese invention patent CN114908833B discloses a dry-firing hydraulic breaker based on a Tesla valve. The technical solution involves installing a Tesla valve between the buffer chamber and the high-pressure oil P in the system. Utilizing the Tesla valve's unique geometric circuit, it provides a higher pressure drop in one direction than the other, allowing fluid to flow smoothly in one direction (forward) and with difficulty in the other (reverse), thus buffering the piston 3 or pushing it out of the buffer chamber 14. Problems include: 1. The Tesla valve cannot completely block reverse flow, leading to an increased length of the buffer chamber 14. 2. The impact of the piston 3 on the hydraulic oil in the buffer chamber 14 generates extremely high pressure instantaneously, potentially damaging the Tesla valve's seals. 3. Sufficient flat surface is required to mount the Tesla valve. Summary of the Invention

[0012] The technical problem to be solved by this invention and the ideas behind it are as follows.

[0013] 1. Because the nitrogen chamber is filled with high-pressure nitrogen, the chisel rod must be pressed tightly during the operation of the hybrid or nitrogen explosion type hydraulic hammer, which makes it difficult for the main unit to press down and results in low crushing efficiency.

[0014] 2. Existing technologies require the installation of valves (air-operated valves, floating valves, Tesla valves) between the high-pressure oil P and the buffer chamber, all of which have technical defects.

[0015] 3. If the piston can be pushed out of the buffer chamber without using a valve to overcome the nitrogen resistance in the nitrogen chamber, all the problems will be solved.

[0016] Based on the above problems and ideas, this invention provides a valveless, dry-firing hybrid or nitrogen-explosion type hydraulic hammer. Figure 4 , Figure 5 The system includes: piston, cylinder, drill rod holder, inner sleeve, outer sleeve, and drill rod. The piston reciprocates within the cylinder, striking the drill rod. The drill rod holder houses the drill rod for crushing operations, as well as the inner and outer sleeves, which also protect the drill rod holder from wear. A buffer section is located at the rear end of the piston, near the tail. When the buffer section enters the buffer chamber (the piston rapidly decelerates), the rear chamber is connected to the return oil via a reversing valve. Since the front chamber is connected to high-pressure oil P, the hydraulic pressure exerted by high-pressure oil P on the stepped surface formed by the front section and the head overcomes the nitrogen resistance in the nitrogen chamber, pushing the piston out of the buffer chamber, thus enabling continuous operation.

[0017] Beneficial effects: Compared with the existing technology that uses an air-operating valve, a floating valve, or a Tesla valve to push the piston out of the buffer chamber and achieve operation without pressing the hydraulic hammer, this invention can achieve this function without any valve. Attached Figure Description

[0018] Figure 1 Schematic diagrams of existing hybrid or nitrogen-explosion type hydraulic hammers.

[0019] Figure 2 Schematic diagrams of existing hybrid or nitrogen-explosion type hydraulic hammers.

[0020] Figure 3 A schematic diagram of the piston entering the buffer chamber of an existing hybrid or nitrogen-explosion type hydraulic hammer.

[0021] Figure 4 Schematic diagram of the hybrid or nitrogen-explosion type hydraulic hammer of this invention.

[0022] Figure 5 The piston structure diagram of the hybrid or nitrogen explosion type hydraulic hammer of the present invention.

[0023] Figure reference numerals: 1. Nitrogen chamber; 2. Piston ring; 3. Piston; 4. Cylinder block; 5. Pyropod seat; 6. Inner sleeve; 7. Outer sleeve; 8. Pyropod; 9. Reversing valve; 10. Accumulator; 11. Main seal; 12. Front chamber; 13. Rear chamber; 14. Buffer chamber; 15. Head; 16. Middle section; 17. Tail section; 18. Front-middle section; 19. Rear-middle section; 20. Buffer section Detailed Implementation

[0024] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Figure 4 , Figure 5 ).

[0025] This invention provides a valveless, dry-firing hybrid or nitrogen-explosion type hydraulic hammer, comprising: a piston 3, a cylinder 4, a chisel holder 5, an inner sleeve 6, an outer sleeve 7, and a chisel 8. The piston 3 reciprocates within the cylinder 4, striking the chisel 8. The chisel holder 5 houses the chisel 8 for crushing operations, the inner sleeve 6, and the outer sleeve 7, which also serve to guide the chisel holder 5 and protect it from wear. A buffer section 20 is provided at the rear section 19 of the piston 3 near the tail 17. When the buffer section 20 enters the buffer chamber 14 (the piston 3 decelerates rapidly), the rear chamber 13 is connected to the return oil via the reversing valve 9. Since the front chamber 12 is connected to the high-pressure oil P, the hydraulic pressure of the high-pressure oil P acting on the stepped surface formed by the front section 18 and the head 15 overcomes the nitrogen resistance in the nitrogen chamber 1, pushing the piston 3 out of the buffer chamber 14, thus achieving continuous operation.

Claims

1. A valveless, dry-firing hybrid or nitrogen-explosion type hydraulic hammer, comprising: Piston (3) and cylinder (4) are used to reciprocate within the cylinder (4). The piston (3) is characterized by the following: a buffer section (20) is provided at the end of the middle and rear section (19) of the piston (3) near the tail (17). When the buffer section (20) enters the buffer chamber (14), the rear chamber (13) is connected to the return oil via the reversing valve (9), and the front chamber (12) is connected to the high-pressure oil P. The hydraulic pressure of the high-pressure oil P acting on the stepped surface formed by the middle and front section (18) and the head (15) overcomes the nitrogen resistance in the nitrogen chamber (1) and pushes the piston (3) out of the buffer chamber (14) to achieve continuous operation.

Images