Views: 0 Author: Site Editor Publish Time: 2024-12-12 Origin: Site
In daily excavation operations, tasks such as breaking, demolition, and other heavy-duty work often require the use of a specialized tool. The hydraulic breaker (also known as a hydraulic hammer, rock breaker, or demolition hammer) is the excavator's best "partner" for these tasks, delivering immense destructive power.
A hydraulic breaker is an attachment commonly used with excavators for various applications, including:
Mountain excavation
Road surface breaking
Building demolition
Bridge demolition
Rock breaking in mining operations
The structure of a hydraulic breaker primarily consists of three main sections:
Upper Cylinder (Nitrogen Chamber):
This section stores low-pressure nitrogen, which acts as an energy storage device. During operation, the nitrogen is compressed and expanded to provide additional force for the piston's rapid reciprocating motion.
Middle Cylinder (Oil Cylinder):
This section contains components such as the piston, accumulator, oil seals, and air valve. The piston moves up and down within the oil cylinder, driven by hydraulic oil and the compression/expansion of nitrogen. The accumulator serves as a buffer to reduce impact forces and extend the life of the breaker.
Lower Cylinder:
This section includes components like the chisel (breaker bit), flat pin, cross pin, inner and outer bushings, etc. The chisel is the part that directly contacts the material to be broken, transmitting the impact force from the piston to complete the breaking work.
From the diagram, it can be seen that the main structure of the hydraulic breaker is divided into two parts: the hammer body (core) and the frame. The upper and lower plates protect the core, while the chisel is the component that makes direct contact with the material during breaking operations. The accumulator mainly serves a buffering and protective role, helping to extend the life of the breaker. Generally, small breakers or those with a chisel diameter less than 10 cm do not come equipped with an accumulator.
The working principle of a hydraulic breaker involves the synergistic action of hydraulic oil kinetic energy and the energy stored in the nitrogen chamber. Here’s how it works:
Return Stroke Acceleration Phase:
At the beginning of the return stroke, the piston has just completed a previous impact and is momentarily stationary. The main valve chamber V2 is at low pressure, while chamber V4 is at constant high pressure, so the main valve spool is in its lower limit position. The piston front chamber V1 is connected to the high-pressure oil through the main valve spool, while the piston rear chamber V3 is connected to the return oil chamber, which is at low pressure. Therefore, the piston accelerates upward under the action of high-pressure oil in the front chamber, simultaneously compressing the nitrogen in the nitrogen chamber, causing it to undergo adiabatic compression.
Return Stroke Braking Phase:
As the piston continues to move upward under the action of high-pressure oil, when the middle section of the piston passes below the control port, the high-pressure oil in chamber V1 enters the main valve chamber V2. Since the hydraulic force acting on the main valve spool in chamber V2 is greater than that in chamber V4, the spool begins to shift. As the spool moves, it gradually reduces the flow of high-pressure oil into chamber V1, resulting in a gradual decrease in the return stroke force acting on the piston. Meanwhile, the resistance from the compressed nitrogen increases. The piston then enters the return stroke braking phase. Eventually, the spool will completely cut off the flow of high-pressure oil to chamber V1, and the piston will quickly stop its return stroke.
Impact Stroke Acceleration Phase:
When the piston stops its return stroke, it immediately enters the impact stroke phase. At this point, the main valve spool has already opened the oil path from the piston front chamber V1 to the return oil chamber of the main valve, allowing the oil in the piston front chamber to drain smoothly. Under the action of the adiabatically expanding nitrogen in the nitrogen chamber, the piston begins to move downward rapidly, entering the impact stroke acceleration phase. The spool remains in its upper limit position, ensuring smooth movement of the piston during the impact stroke.
Special State: Impact Pause Phase:
Under the action of the adiabatically expanding nitrogen, the piston moves quasi-acceleratively (with gradually decreasing acceleration). When the middle section of the piston passes above the control port, the main valve chamber V2 is connected to the return oil, becoming a low-pressure chamber. The spool begins to shift downward under the action of high-pressure oil in chamber V4. At this point, the piston, having gained sufficient energy, strikes the chisel, completing the impact action. The spool continues to move downward until it reaches its lower limit position, and the piston is momentarily stationary. After the impact, the piston rebounds, starting the next work cycle.
To ensure the efficient operation and extended lifespan of the hydraulic breaker, operators should follow these guidelines:
Chisel Perpendicular to the Striking Surface:
Reason: Striking at an angle can cause the chisel to break or damage the cylinder body. Failing to press the chisel firmly against the surface can lead to damage when striking empty. Therefore, the chisel should always be perpendicular to the striking surface and pressed firmly.
Warm-Up the Engine:
Reason: Before starting breaking operations, especially in winter, the engine should be warmed up for about 10 minutes. This ensures that the hydraulic system reaches an appropriate temperature, preventing issues caused by cold hydraulic oil, which can be too viscous.
Check Oil Lines and Seals:
Reason: Before breaking operations, visually inspect all oil lines for leaks and address any leaks immediately. Check if the breaker's oil seals are leaking; if they are, replace them promptly. Leaking seals can allow dust to enter the piston, causing wear on the piston.
Avoid Improper Use:
Do Not Use the Breaker to Push Heavy Objects or Large Rocks: This can cause the breaker frame to crack.
Do Not Use the Chisel to Pry or Shake: This can cause the chisel to break.
Do Not Strike the Same Spot for More Than 1 Minute Continuously: Prolonged striking in one spot can lead to excessive wear on the chisel. Change the striking position frequently. For larger, harder rocks, start by striking the edges, as they are easier to break.
Do Not Operate the Breaker in Water or Mud: Water and mud can enter the piston, leading to rust and accelerated wear on the breaker.
Do Not Strike While the Bucket, Arm, or Cylinder is Fully Extended or Retracted: This can cause excessive vibration and damage to the cylinder rod.
Long-Term Storage:
Completely Insert the Chisel into the Breaker: When the breaker is not in use for an extended period, fully insert the chisel to push the piston rod back into the piston, preventing rust due to exposure to air.
Regular Maintenance and Replacement of Components:
Chisel and Chisel Pin: Replace the chisel when it shows excessive wear, and replace the chisel pin at the same time to prevent excessive clearance, which can accelerate chisel wear.
Oil Seals: Replace the oil seals if they leak or every 6 months to prevent contaminants from entering the system, which can damage the piston and hydraulic system.
Through Bolts, Shell Bolts, Hydraulic Lines, Bushings: Regularly inspect these components, and replace them if they show signs of wear to avoid major failures.
Hydraulic Return Filter Element: Replace the return filter element every 250 hours of regular breaker operation.
Hydraulic Oil: Replace the hydraulic oil every 600-1000 hours of regular breaker operation to prevent contamination of the hydraulic system.
A hydraulic breaker operates based on the synergistic action of the hydraulic system and the nitrogen accumulator, generating powerful impact forces suitable for various breaking and demolition tasks. Proper use and maintenance of the breaker not only improve work efficiency but also extend the equipment's lifespan. Operators should strictly adhere to usage guidelines, perform regular inspections, and maintain the breaker to ensure it remains in optimal working condition.