Field hydraulic fault analysis is a process that goes from the surface to the core, continuously deepening. After performing surface observations and on-site experiments on hydraulic equipment, the next step is to dismantle and further observe the faulty hydraulic components. The following points should be noted when dismantling hydraulic components: release system pressure before disassembling hydraulic components related to sealed pressure chambers. Prepare oil collection tools to collect the flowing oil. Dismantle and decompose hydraulic components of powder coating equipment in a clean area to prevent dust from mixing during assembly, mainly preventing dust from entering the system through open pipe openings. Both the dismantling and assembly of hydraulic components should avoid excessive force to prevent damage to the hydraulic components. Pay attention to the assembly relationships of internal parts of hydraulic components to avoid assembly and installation errors. Some mating parts (such as plungers and cylinder holes in axial piston pumps) are selected for fitment, ensuring reassembly matches the original assembly relationship. Below, we introduce the content of dismantling, decomposition, and observation tests for various types of hydraulic components.
1. Inspection of pump-type components
(1) Disassembly and observation test of gear pumps: Structure of CB-type gear pumps. By disassembling the sweeper gear pump, you can check the following aspects:
- Wear conditions of the front and rear end covers of the pump.
- Wear conditions of the gear end faces.
- Wear conditions between the tooth tips and the pump housing. These wear areas are related to internal leakage and temperature rise in the pump, as well as decreases in pressure and flow.
- The condition of pump shaft fractures, which relates to oil supply failure.
- The wear condition of bearings, which relates to pressure fluctuations and increased noise.
- The damage condition of seals, which relates to external leakage.
(2) Disassembly and observation test of vane pumps: Structure of YBl-type vane pumps. By disassembling the vane pump, you can check the following aspects:
- Wear conditions of the inner curve of the stator and the distributor plate. These wears are associated with decreased output flow and pressure, increased internal leakage, component heating, and increased pressure fluctuations.
- Correctness of rotor installation direction, which relates to increased noise.
- Wear conditions of the rotor face and the vane slots in the rotor, which relate to increased internal leakage.
- Whether the rotor is fractured, which relates to flow decrease and pulsation, as well as increased noise.
- Whether the vanes are stuck in the vane slots, which relates to flow decrease and pulsation.
- Vane wear conditions, which relate to increased noise.
- Bearing wear conditions, which relate to increased noise.
- Seal wear conditions, which relate to external leakage.
- Whether the shaft is fractured or if there are accumulated wear particles or other contaminants inside the pump.
(3) Disassembly and observation test of axial piston pumps: Structure of SCY-type axial piston pumps. By disassembling the axial piston pump, you can check the following aspects:
- Whether the distributor plate is worn or grooved, and whether the clearance between the plunger and the cylinder hole is too large. These wears are associated with decreased pressure and flow, and increased internal leakage in the drain line.
- Whether the center spring is fatigued or broken, which relates to decreased pressure and flow.
- Whether the plunger damping hole is blocked, which relates to the pump emitting a sharp scream during operation due to dry friction of the shoes.
- Whether the shoes and plunger heads are loose, which relates to increased noise.
- Wear conditions between the shoes and the swashplate, which relate to decreased pump efficiency, heating, and increased noise.
- Whether internal elements have surface damage due to cavitation, and whether there are accumulated wear particles or contaminants inside the pump.