Determination of the technical condition of hydraulic vibratory rollers

Abstract: Hydraulic vibratory rollers are widely used in road and bridge engineering construction. The good technical condition of them plays an important role in the quality and progress of the project. This article introduces hydraulic vibratory rollers

The methods for determining the technical conditions of each major system.

The roller is an indispensable compaction equipment in road and bridge engineering construction. The technical condition of the roller will directly affect the quality and progress of the project. A comprehensive understanding of hydraulic rollers that have been in use for a certain period of time and an assessment of their technical conditions are the prerequisites for managing and using them well. The technical condition of a hydraulic vibratory roller can be judged from the following aspects:

The main system for determining the technical condition of a hydraulic vibratory roller

(1) Engine (2) Hydraulic drive system (3) Hydraulic vibration system (4) Hydraulic steering system (5) Vibration wheel (6) Other systems

Among them, the engine, hydraulic drive system, hydraulic vibration system and vibration wheel are the main factors determining the technical condition of the hydraulic vibratory roller. The engine is the power source. The hydraulic drive system determines the driving power performance of the roller. The hydraulic vibration system and the vibration wheel determine the compaction capacity. The above four parts are also often the main cost points for the maintenance of hydraulic vibratory rollers.

2 Engine

The technical condition of an engine mainly depends on its power performance, lubrication performance and heat dissipation performance. The power performance ensures that the engine has sufficient power output. The lubrication performance ensures good lubrication inside the engine and guarantees its normal operation. The heat dissipation performance ensures that the engine's heat is removed in a timely manner, allowing it to operate normally.

2.1 Determination of Engine Power Performance.

The determination of engine power performance can be made by measuring the power output performance of the engine with a dynamometer. However, if most construction enterprises do not have dynamometer instruments, the power performance of the engine can be judged by measuring the compression force of each cylinder of the engine, oil consumption and engine exhaust, etc.

Cylinder compression pressure

Measure the cylinder compression pressure of each cylinder of the engine respectively. If the cylinder compression pressure of each cylinder is within the standard value of the engine, it indicates that the sealing performance of the engine cylinder liner, piston, piston ring and exhaust valve and other sealing components is good, and the engine power performance is good. If the cylinder pressure is too low, it may be due to wear of components such as the piston, cylinder liner, and piston rings, or poor sealing of the intake and exhaust valves, which leads to a decline in the engine's power performance.

(2) Determination of oil burning

Severe oil burning in the engine indicates poor sealing performance of components such as the piston rings, pistons, and cylinder liners. Maintenance is necessary to restore the engine's power performance. Engine oil burning can be determined by observing the engine's exhaust or by measuring the engine's oil consumption (under the premise that there is no oil leakage from the engine). If the engine exhaust is blue or the oil consumption is significantly excessive, it indicates that the engine is burning oil seriously. It is necessary to inspect and repair components such as the piston, piston rings, and cylinder liner.

(3) Engine air leakage

Observe the engine vent. If there is oil dripping from the vent, it indicates that the engine has severe air leakage and needs to be repaired. The problems that may exist in the above three aspects of the engine do not necessarily occur separately. If the sealing mating pairs such as the cylinder liner, piston and piston ring of the engine are worn too much or the piston rings do not match, the problems in the three aspects may occur simultaneously.

(4) Determination of the valve train phase, fuel supply Angle, as well as the fuel supply system and intake system

If the cylinder pressure of the engine is normal, but there is obvious air leakage and oil burning, and its power output is significantly insufficient, it may be caused by an unsmooth intake system, incorrect valve timing, incorrect fuel supply Angle, or poor atomization of the diesel high-pressure fuel pump and fuel injector. Each of the above systems can be inspected respectively.

2.2 Determination of the technical condition of the Engine Lubrication System

The technical condition of the engine lubrication system can be determined by observing the oil pressure value when the engine is hot. If the engine oil pressure is greater than 1.5kg /cm ² when the hot engine is idling and reaches 2 to 4kg/cm ² during high-speed operation, the lubrication system (including the fit between the large and small bearing shells of the crankshaft and the crankshaft, as well as the fit between the eccentric wheel shaft and the eccentric bearing shells) can normally meet the lubrication requirements of the engine. If the engine oil pressure is lower than 1.0kg/cm ², it must be inspected. There may be the following reasons:

(1) The pressure limiting valve of the oil pump is adjusted too low.

(2) Leakage inside the oil pump;

(3) Excessive wear of the large and small bearing shells of the crankshaft and excessive fit clearance cause pressure relief.

(4) The clearance between the eccentric camshaft and the eccentric bearing bush is too large.

2.3 Determination of the technical condition of the Engine Cooling System

The technical condition of the engine's cooling system can be determined by inspecting the engine oil temperature or the water temperature gauge. If the water temperature of a water-cooled engine remains below 100℃ and the oil temperature of an air-cooled engine remains below 130℃, then the engine cooling system is working properly. Otherwise, the engine cooling system is not functioning properly.

The determination of the technical condition of the hydraulic drive system

The technical condition of the hydraulic drive system can be determined by measuring the pressure of the hydraulic drive system. Note that when measuring, the temperature of the hydraulic oil must be between 55℃ and 65℃. If the temperature is too low, due to the excessively high viscosity of the oil, it often leads to inaccurate judgment. Here, taking the CA25 roller as an example, the detection method of the drive system pressure is introduced

Start the roller and vibrate it for a period of time to raise the temperature of the hydraulic oil to 55℃-65℃.

(2) Connect the pressure gauge to the pressure measurement joint of the rear drive motor.

(3) Press the front part of the roller against a fixed object (the fixed object can be a large stone, a wall or other objects), and the fixed object should be able to prevent the roller from moving forward.

(4) Start the roller and place the speed control handle in the forward position. If the roller is blocked by a fixed object and cannot move, the pressure value on the pressure gauge at this time is the maximum driving pressure of the drive system (the designed value is 350kg/cm ²). If the pressure is greater than 300kg/cm ², the drive hydraulic system is in good condition. If the pressure is 100 to 200kg/cm ², there is already leakage in the driving hydraulic system.

(5) When testing the maximum pressure, make sure that neither the front nor the rear wheels spin idly.

(6) The normal working pressure of the drive hydraulic system is 80 to 250kg/cm ², which depends on the magnitude of the resistance encountered by the roller during operation.

Determination of the technical condition of the hydraulic vibration system

The technical condition of the hydraulic vibration system can be determined by measuring the pressure of the vibration system. The following takes CA25 as an example to illustrate the detection of pressure in a vibration system.

(1) Start the roller and let it run for a period of time to raise the temperature of the hydraulic oil to 55℃-65℃.

(2) Connect the pressure gauge to the pressure detection joint of the vibration valve.

(3) Increase the engine speed to 2400r/min;

(4) Start the large vibration and measure the maximum pressure (peak value) at the moment the vibration begins. At this point, the maximum pressure should reach 140kg/cm ². After vibration for 4 to 6 seconds, the vibration pressure value will stabilize at 70 to 110kg/cm ². If the maximum pressure is lower than 70kg/cm ², there is a problem with the vibration system. If the high pressure is around 130kg/cm ², the vibration system is in good condition.

(5) Start the small vibration and measure the maximum pressure at the moment the vibration begins. This pressure should reach 140kg/cm ². After vibration for 4 to 6 seconds, the vibration pressure value will stabilize at 70 to 110kg/cm ². If the maximum pressure is lower than 70kg/cm ², there is a problem with the vibration system. If the peak vibration pressure is around 130kg/cm ², the vibration system is in good condition.

5. Determination of the hydraulic steering system

(1) Start the roller and let it work for a period of time. The hydraulic oil temperature will rise to 55℃ to 65℃.

(2) Make the engine speed reach 1500r/min;

(3) Connect the pressure gauge to the pressure detection joint of the steering pump.

(4) Turn the roller left or right to the maximum position and measure the pressure of the steering system. If the pressure reaches 140kg/cm ² at this time, it indicates that the steering system is in good condition. If the pressure is lower than 120kg/cm ², an inspection is required.

6. Determination of the technical condition of the vibrating wheel

(1) Start the roller and activate the large vibration.

(2) Check and listen for any abnormal sounds inside the vibrating wheel. If there are abnormal sounds, stop the machine immediately for inspection.

(3) Observe or touch the vibrating wheel to see if its amplitude and frequency are close to its design values. If the difference is too large, there may be a problem with the vibrating wheel.

(4) Start the small vibration and observe whether the conversion between large and small vibrations is sensitive and whether the amplitude and frequency of the small vibration are normal.

(5) Vibrate for about 15 minutes (high vibration) and check if there is any oil leakage at both ends of the vibrating wheel.

(6) Vibrate for about 30 minutes and check if the temperature at both ends of the vibrating wheel rises sharply or if there is a significant temperature difference between the left and right ends. If the temperature rises sharply or there is a large temperature difference between the left and right ends, there is very likely a problem with the vibrating wheel.

(7) Pay attention not to vibrate the roller in place.

7 Others

The identification of other systems can be determined by observing, listening to abnormal sounds and other methods to ascertain their technical conditions.

References

"CA25 Vibratory Roller Repair Guide" (Compiled by Xuzhou Construction Machinery Manufacturing Factory)