A kotrógép hibaellenőrzése forgatás nélkül

Fault of excavator without rotation: It was found that there was no rotation movement, while other movements were normal.

Amikor a működtető fogantyú forgatási helyzetbe kerül, a vezérlőolaj eléri a vezérlőszelepet, és megnyomja a forgószelep rúdját, hogy a hátsó munkaolajszivattyú által biztosított nagynyomású olajat a forgómotorba juttassa; Ezzel egyidejűleg a tartályba történő olajvisszavezetést vezérlő olajkör megszakad, megnövelve a fékkioldó szelep nyomását, annak szelepszárát lenyomva, hogy egy másik segédnyomású olaj juthasson a fékdugattyúba, kinyitva a lengőfék-berendezést, és működésbe hozva a lengőmotort; A forgó motor a sebességváltó kis fogaskerekén keresztül adja le a teljesítményt, amely a forgó fogaskerék gyűrűjével összefogva forgó mozgást hoz létre.

Hibák okainak elemzése és ellenőrzése:

A forgó mechanizmus működési elve alapján a meghibásodásnak három oka van, nevezetesen a fő munkaolajkör, a mechanikus átvitel és a vezérlőolajkör.

(1) A fő munkaolajkör ellenőrzése

Ha a lengő főolajkör nyomása alacsony, nem lehet lengőhatást létrehozni. Mérje meg a fő üzemi olajkör rendszerének nyomását. A hátsó munkaolajszivattyú nyomáskimeneténél van egy belső hatszögletű olajdugó. Távolítsa el, és szereljen be egy nyomásmérőt. A dízelmotor gyorsításához működtesse a forgókart. A mért nyomás eléri a 23,5MPa-t, ami a rendszer normál üzemi nyomása. Ez azt jelzi, hogy a fő munkaolajkörben lévő összes hidraulikus alkatrész rendben van.

(2) A mechanikus erőátviteli rész ellenőrzése

A forgómotor az erőátvitel kis fogaskerekén keresztül adja le a teljesítményt, amely a forgó fogaskerék körül forog. E teljesítményleadási folyamat során, ha az egymásba fogó fogaskerekek elakadnak, akkor nem lesz forgási művelet sem.

Általában a rendellenes sebességváltó-beállás okozhat rendellenes zajt. Jelenleg a járművezető nem hallott rendellenes hangot működés közben, így a mechanikus váltóhiba ideiglenesen kizárható.

(3) A vezérlőolaj-kör ellenőrzése

Mivel a kotrógép minden más művelete normális, ez azt jelzi, hogy a vezérlőolajnyomást biztosító segédolajszivattyú normálisan működik. Három vezérlőolaj-kör van a forgási művelethez, nevezetesen a forgókarszelepet vezérlő olajkör, a fékkioldó szelep és a rögzítőfék dugattyújába kerülő olajkör. A konkrét elemzés a következő.

A forgókar működtetésekor a forgómotor nyomóolajcsövének érintésekor erős olajfolyás jelentkezik, ami azt jelzi, hogy a fő üzemi nyomású olaj elérte a forgómotort, a vezérlőszelep forgókarszárát normálisan ki lehet nyitni, és a vezérlőolaj-kör normálisan működik. Mérje meg az olajnyomást a rögzítőfék dugattyújához. Nyissa ki az olajkör csőcsatlakozását a forgómotorhoz, szerelje fel a háromutas csatlakozót és a nyomásmérőt, és a mért nyomás eléri a 4MPa-t, ami azt jelzi, hogy az olajkör nyomása normális.

Mérje meg az olajnyomást a fékkioldó szelephez. Nyissa ki az olajkör csőcsatlakozását a forgódugattyús motorhoz, szerelje fel a háromutas csatlakozót és a nyomásmérőt, és a mért nyomás 0,4-0,6MPa. Nyilvánvaló, hogy ez a nyomás túl alacsony (a normál üzemi nyomásnak 4MPa-nak kell lennie) a fékkioldó szelep kinyitásához, és a másik körből származó vezérlőolaj nem tud a fékdugattyúba áramlani, nemhogy kinyitni a forgó fékberendezést. Ezért a forgatásban nincs hatás. Két oka van az alacsony nyomásnak ebben az olajkörben. Az egyik az, hogy a vezérlőszelep szivárog, ami miatt a fékkioldószelepbe belépő olajnyomás csökken. (Csatlakoztassa a nyomásmérőt a vezérlőolajcső csőcsatlakozásához a vezérlőszeleptől a fékkioldószelephez, és a mért olajnyomás csak 0,4-0,6MPa, ami azt jelzi, hogy a vezérlőszelep szivárgásának megítélése helyes); A második ok az, hogy a fékkioldószelep az elhasználódás miatt szivárog, ami növeli az illesztési hézagot (szétszerelés és ellenőrzés után a szelepszár és a szelepfurat jól illeszkedik, és nincs elakadási jelenség).

Troubleshooting: An In-Depth Guide to Diagnosing and Resolving Control Valve Malfunctions in Excavators

Excavators are complex pieces of machinery that rely heavily on their hydraulic systems to perform a variety of tasks, from digging and lifting to rotating and moving. One of the critical components in this hydraulic system is the control valve. The control valve regulates the flow and direction of hydraulic fluid, enabling precise control over the excavator’s movements. However, when a malfunction occurs, it can severely impact the performance and efficiency of the machine. This detailed guide delves into the process of troubleshooting a control valve malfunction, including the steps taken to diagnose the issue, the repair process, and the measures to prevent future problems.

Understanding the Role of Control Valves in Excavators

Control valves are essential for directing hydraulic fluid to different parts of the excavator. They are responsible for controlling the flow rate and pressure of the hydraulic fluid, which in turn controls the speed and force of the machine’s movements. The primary functions of control valves in an excavator include:

• Regulating Fluid Flow: Control valves manage the flow of hydraulic fluid to various actuators, such as cylinders and motors, which drive the excavator’s movements.
• Controlling Direction: By adjusting the direction of fluid flow, control valves determine the direction in which the machine’s components move.
• Maintaining Pressure: Control valves help maintain the necessary pressure levels within the hydraulic system to ensure efficient operation.

Given their critical role, any malfunction in the control valve can lead to significant operational issues, such as erratic movements, reduced power, and complete failure of specific functions.

Symptoms of Control Valve Malfunctions

Before diving into the troubleshooting process, it’s essential to recognize the common symptoms of control valve malfunctions. These symptoms can help in early detection and prompt action to prevent further damage to the excavator. Common signs of control valve issues include:

• Erratic Movements: Inconsistent or jerky movements of the excavator’s arm, bucket, or tracks.
• Loss of Power: Reduced force or speed in hydraulic functions, indicating a possible issue with fluid flow or pressure.
• Hydraulic Fluid Leaks: Visible leaks around the control valve area, suggesting seal or component failure.
• Unusual Noises: Hissing, whining, or knocking sounds from the hydraulic system, which could indicate fluid flow disruptions or air ingress.
• Overheating: Excessive heat in the hydraulic system, often caused by restricted fluid flow or pressure imbalances.

Diagnosing the Control Valve Malfunction

The first step in troubleshooting a control valve malfunction is a thorough diagnosis. This involves a systematic approach to identify the root cause of the problem. Here’s a detailed breakdown of the diagnostic process:

1. Visual Inspection

Begin with a visual inspection of the control valve and the surrounding hydraulic components. Look for signs of wear, damage, or leaks. Pay close attention to the following:

• Seals and Gaskets: Check for any visible cracks, tears, or deterioration in seals and gaskets that might cause fluid leaks.
• Connections and Hoses: Inspect the hydraulic hoses and connections for signs of wear, damage, or loose fittings.
• Valve Body: Examine the control valve body for any signs of physical damage, such as cracks or corrosion.

2. Hydraulic Fluid Analysis

The condition of the hydraulic fluid can provide valuable insights into the health of the control valve and the entire hydraulic system. Perform the following checks:

• Fluid Level: Ensure that the hydraulic fluid level is within the recommended range. Low fluid levels can cause air to enter the system, leading to erratic movements and reduced performance.
• Fluid Quality: Check the color, viscosity, and presence of contaminants in the hydraulic fluid. Dark, cloudy, or contaminated fluid indicates the need for a fluid change and potential issues with the control valve.

3. Pressure Testing

Pressure testing the hydraulic system can help identify issues related to fluid flow and pressure regulation. Use a hydraulic pressure gauge to perform the following tests:

• System Pressure: Measure the overall system pressure to ensure it is within the manufacturer’s specifications. Deviations from the recommended pressure levels can indicate valve malfunctions.
• Pressure Drops: Check for any significant pressure drops across the control valve, which can suggest internal leaks or blockages.

4. Functional Testing

Conduct functional tests to observe the performance of the control valve under different operating conditions. These tests can help pinpoint specific issues:

• Actuator Response: Operate the excavator’s functions, such as lifting the arm, rotating the body, or moving the tracks, and observe the response. Slow, weak, or inconsistent movements can indicate control valve problems.
• Directional Control: Test the directional control by moving the actuators in various directions. Difficulty in changing direction or delayed responses can be signs of valve issues.

Identifying the Root Cause: Leakage in the Control Valve

In this case study, the primary symptom observed was erratic rotational movements of the excavator. Upon conducting the above diagnostic steps, it was determined that the main cause of the malfunction was leakage in the control valve. Here’s a detailed analysis of the findings:

1. Visual Inspection

During the visual inspection, hydraulic fluid leaks were detected around the control valve area. The seals and gaskets appeared worn and deteriorated, indicating a potential source of the leakage.

2. Hydraulic Fluid Analysis

The hydraulic fluid analysis revealed contamination with particles and moisture, which can accelerate wear and damage to the control valve components. The fluid’s color and viscosity suggested that it had not been changed according to the recommended maintenance schedule.

3. Pressure Testing

Pressure testing indicated significant pressure drops across the control valve, confirming internal leaks. The system pressure was also lower than the manufacturer’s specifications, further supporting the diagnosis of valve leakage.

4. Functional Testing

Functional testing showed inconsistent and weak rotational movements, which aligned with the symptoms of control valve leakage. The directional control was also affected, with delays and difficulties in changing directions.

Repairing the Control Valve

Given the complexity and critical role of the control valve, repairing it requires careful attention and expertise. Here’s a step-by-step guide to the repair process:

1. Removing the Control Valve

To access and repair the control valve, it is necessary to remove it from the excavator. This involves the following steps:

• Disconnecting Hydraulic Lines: Carefully disconnect the hydraulic lines connected to the control valve, ensuring to cap them to prevent fluid spillage and contamination.
• Disconnecting Electrical Connections: If the control valve has any electrical connections, disconnect them to facilitate removal.
• Removing Mounting Bolts: Remove the bolts or screws securing the control valve to the hydraulic system or frame.

2. Disassembling the Control Valve

Once the control valve is removed, disassemble it to inspect and replace the damaged components. This involves:

• Opening the Valve Housing: Carefully open the control valve housing, taking note of the arrangement and orientation of internal components.
• Inspecting Internal Components: Examine the internal components, such as seals, gaskets, and valve spools, for signs of wear, damage, or contamination.
• Cleaning and Replacing Parts: Clean all components thoroughly and replace any worn or damaged parts with new ones. Ensure that the replacement parts meet the manufacturer’s specifications.

3. Reassembling the Control Valve

After replacing the damaged components, reassemble the control valve with careful attention to detail:

• Reinstalling Internal Components: Reinstall the internal components in the correct order and orientation, ensuring proper alignment and fit.
• Sealing the Valve Housing: Securely close the valve housing, ensuring that all seals and gaskets are correctly positioned to prevent future leaks.

4. Reinstalling the Control Valve

With the control valve repaired and reassembled, reinstall it into the excavator:

• Mounting the Valve: Secure the control valve to the hydraulic system or frame using the mounting bolts or screws.
• Reconnecting Hydraulic Lines: Reconnect the hydraulic lines, ensuring that they are securely fastened and free from leaks.
• Reconnecting Electrical Connections: If applicable, reconnect any electrical connections.

5. Testing the Repaired Control Valve

After reinstalling the control valve, perform comprehensive tests to ensure that the repair was successful:

• Nyomásvizsgálat: Conduct pressure tests to verify that the hydraulic system pressure is within the manufacturer’s specifications and that there are no significant pressure drops across the control valve.
• Funkcionális tesztelés: Operate the excavator’s functions to ensure smooth and consistent movements. Check for any signs of leaks or abnormalities.

Preventing Future Control Valve Malfunctions

To prevent future control valve malfunctions and ensure the longevity of the excavator’s hydraulic system, implement the following maintenance practices:

1. Regular Fluid Checks and Changes

Regularly check the hydraulic fluid level and quality, and change it according to the manufacturer’s recommendations. Using clean, high-quality hydraulic fluid helps prevent contamination and reduces wear on the control valve components.

2. Routine Inspection and Replacement of Seals and Gaskets

Inspect seals and gaskets regularly for signs of wear and deterioration. Replace them as needed to prevent leaks and maintain optimal pressure within the hydraulic system.

3. Regular Maintenance Schedule

Implement a regular maintenance schedule that includes checking the condition of the control valve, hydraulic lines, and other components. Timely maintenance helps identify and address potential issues before they lead to significant malfunctions.

4. Operator Training

Ensure that operators are trained in the correct use and maintenance of the excavator’s hydraulic system. Proper operation and handling can reduce the risk of damage and prolong the lifespan of the control valve and other components.

5. Using Genuine Parts

Always use genuine parts and components that meet the manufacturer’s specifications when repairing or replacing parts of the hydraulic system. This ensures compatibility and reliability, reducing the risk of future malfunctions.