Maintenance and repair of shovels (1979)

The excavator loads the soil into the dump truck.

Grabbing the soil with a bucket.

The excavator digs a pit.

The excavator digs a trench for laying pipes.

The power plant of the excavator is a diesel engine.

The excavator's fuel tank is designed to work several shifts.

The most important part of the hydraulic drive of the machine is the hydraulic distributor of the working fluid flow.

The placement of hydraulic equipment for different sizes of machines may be different.

Placement of hydraulic equipment at the excavator EO4121A.

Cartoon explaining the device of the excavator EO4121A.

More powerful hydraulic excavators are equipped with a crawler.

Each caterpillar is driven by its own hydraulic motor through a gear reducer.

Hydraulic cylinder that provides tension of the track belt.

Less powerful excavators are equipped with pneumatic wheels.

The driving wheels are driven by a hydraulic motor.

The steerable wheels are articulated with the front axle using universal joints.

The rotation of the wheels is provided by a hydraulic cylinder.

Braking is carried out by means of pneumatic chambers.

An important node of the machine is a running trolley with a central collector.

A cartoon explaining the device of a running trolley.

The rotary platform rotates from a low torque axial piston hydraulic motor or from a high torque hydraulic motor.

A cartoon explaining the operation of a high-torque hydraulic motor.

The front steerable axle has a balancing suspension.

Thanks to it, the rotary platform always maintains a horizontal position.

Hydraulic supports increase the stability of the excavator and release the wheels from the load.

The cabin provides a good overview and comfortable working conditions.

The management of work operations is extremely simplified and is carried out with only two handles.

Demonstration of the excavator operation.

Control devices.

The working equipment of the excavator consists of an arrow, a handle and a bucket.

The boom can be single-link or double-link.

The elements of the working equipment and hydraulic cylinders are pivotally connected to each other.

The hydraulic cylinder of the working body can be located above or below the handle.

The hydraulic drive is capable of creating large forces on the working organ.

The reverse shovel is used to develop soils below the parking level.

The bucket is equipped with loosening teeth.

The use of a straight shovel.

A special pressure grab can be installed on the EO5122 excavator for the development of particularly deep wells and trenches.

A hydraulic hammer is used to develop hard soils, concrete asphalt pavements.

A bucket with an additional tooth for gripping can be used for loading bulk piece items.

With the help of ramming, excellent soil compaction is achieved in cramped conditions, especially in the sinuses.

The hook suspension allows the excavator to be used as a crane.

Decoding of the abbreviation in the designation of the excavator.

Alternating frames with different models of excavators.

Simplified hydraulic scheme of the excavator.

Image of axial piston pumps of a hydraulic motor.

A cartoon explaining the operation of an axial piston pump with an inclined block.

A swinging block with a set of pistons.

The image of the excavator drive is above the third dimension group with twin pumps.

A cartoon explaining the operation of such a drive.

In addition to axial-piston, there are radial-piston designs of hydraulic motors.

A cartoon explaining the operation of a radial piston hydraulic motor.

The excavators use double-acting piston hydraulic cylinders.

Hydraulic cylinder in the section.

Rubber seals of the rod and piston.

A cartoon explaining the design of flexible high-pressure hoses used for movable joints.

Cartoon explaining the connection of flexible hoses with fittings.

Working fluids are checked in the laboratory.

Checking the viscosity of the working fluid.

The temperature range at which the working fluids are used.

Brands of oils that are used in a wide temperature range.

The capacity of the working fluid tank is designed for pump performance for 2-3 minutes, i.e. for 20-30 exchanges per hour.

Heat exchangers cool the working fluid in hydraulic systems and protect against overheating.

The main condition for long-term operation of machines is the purity of the working fluid.

Filters with replaceable filter elements are used to purify the liquid.

Filter assembly.

The distribution hydraulic equipment changes the direction of movement and ensures that the working bodies stop.

Samples of manual and pedal control units.

The operation of the control unit is shown on a sample with an internal cross section.

Hydraulic valves can be monoblock and sectional, allowing you to assemble complex distribution schemes and easily replace worn sections during repair.

A cartoon explaining the various schemes of hydraulic valves.

Combining work operations reduces the working cycle of the machine and increases its productivity.

Special care is required when installing intermediate steel plates and rubber rings.

Properly assembled seals eliminate leakage between sections.

Maintenance of machines.

Installation of cotter pin connections.

The tightening of the screws securing the fingers of the working equipment is checked.

Checking the fastenings of the twin pump.

According to a special card, the driver lubricates the excavator assembly units.

The fuel level in the tank is checked.

The radiator is filled with water.

The oil level in the engine crankcase is monitored.

The battery is inspected and the voltage at its terminals is measured.

The tension of the compressor and fan belts is regulated.

Upon arrival of the car at the facility, it is subjected to a run-in.

First of all, the operation of the engine is checked, then the operation of the hydraulic drive without load.

Then the operation of the machine under load is checked.

The accuracy of the safety valve operation is checked at the highest external load.

During the run-in, the heating of the working fluid is checked.

Work at temperatures above 70 degrees is not allowed.

The filling of the working fluid is carried out using special machines that are equipped with cleaning devices.

When the filter becomes dirty, its resistance increases and the pressure in the drain line increases.

Therefore, it is necessary to ensure that the pressure on the filter does not exceed three atmospheres.

The liquid level in the tank.

Every shift maintenance begins with an inspection of the machine.

With daily maintenance, many control operations performed during rollback are repeated.

In the field, the car is fueled by a fuel-oil tanker.

After starting the engine, the driver checks the oil pressure and temperature in the diesel engine.

The control of the bucket tilt mechanism is checked on the excavator planner.

The daily maintenance includes the control of the pneumatic wheel.

The braking distance is checked.

Every shift maintenance ends with testing the machine at full load.

The car, fully prepared for work, goes to the facility.

For maintenance No. 1, the frequency of 80 engine hours is set.

It includes all the mandatory operations performed during the daily maintenance.

Maintenance No. 1 also includes the lubrication of bearings in accordance with the lubrication chart.

The condition of the surface of the rods is checked.

Loosened bolted connections are tightened.

Check the setting of the safety valves, adjust if necessary.

Check the pressure in the pneumatic wheels.

The battery terminals are being lubricated again.

Cleaning the car.

Areas with corrosion should be covered with grease.

It is necessary to check the operation of the working equipment.

For maintenance No. 2, a frequency of 120 engine hours is set.

In addition to those operations that are provided for by maintenance No. 1, more complex operations are performed.

It is necessary to rinse the filter elements with a degreasing solution, the remains of the solution are removed with compressed air.

Top up the batteries with distilled water, if necessary with electrolyte.

When the receiver is filled, check the tightness of the pneumatic system.

If necessary, adjust the setting of the valve block springs and safety valves of the hydraulic distributor.

Check the fastening of the steering rods.

If there is a backlash in the steering, it must be eliminated.

The condition of the rear wheel tires is checked.

For uniform wear of the wheels, the paired wheels must be swapped.

In conclusion, the braking of the turntable is checked.

For maintenance No. 3, a frequency of 720 engine hours is set.

It includes the operations of previous technical services.

Additionally, the fuel tank is cleaned, washed with diesel fuel and refueled.

The oil in the engine crankcase is being replaced.

The filter elements are replaced with new ones.

If necessary, sections of flexible pipelines are replaced.

At the same time, it is necessary to check the control levers.

Finally, the hydraulic systems of excavators completely replace the working fluid.

Before that, the tanks are thoroughly washed.

After 1500 hours of work, the excavator is being repaired.

Replacement of hydraulic cylinder seals.

The parts are carefully removed, washed with a degreasing solution in special sinks.

After washing, the parts must be protected from dust.

Replace the sealing gaskets of the pump covers.

New rubber cuffs and locking rings are placed on the pump shaft necks.

It is necessary to check the quality of the fasteners.

The overhaul almost completely renews the excavator.

It is carried out after 4000 hours.

Before entering the workshop, the machine is washed with hot water.

Hydraulic units are marked.

Strict requirements are imposed on the pump body, at the slightest cracks they are sent to scrap metal.

When creating modern machines, the aggregate-node method of layout is used.

A characteristic feature of the modern overhaul is the replacement of the entire hydraulic drive units and units.

Before starting the repair of pumps and hydraulic motors, they are washed in washing machines.

Especially contaminated hydraulic equipment units are washed with hot degreasing solutions under pressure in closed chambers.

The most critical parts and components of hydraulic equipment are undergoing major repairs, the wear of which can significantly disrupt the operation of the excavator.

All sealing parts, gaskets and rubber rings must be replaced.

If a malfunction is suspected, bearings, inner rings and gears are replaced.

Hydraulic motors and pumps that have undergone major repairs are tested under pressure on special stands.

Overhaul of other parts.

High torque hydraulic motors are installed on a rotary platform on special control pins.

When repairing hydraulic valves, the accuracy of surface treatment is of great importance.

Processing on a grinding machine.

The hydraulic valves assembled after repair are tested on special stands.

During major repairs, the hydraulic cylinders are completely disassembled.

The technical condition of all parts is checked.

If necessary, the inner surface of the hydraulic cylinder is rolled out.

Cylinder rods are carefully ground or rolled.

Parts that cannot be restored are made anew.

All cylinders are subjected to mandatory hydraulic tests after repair.

Replacement of pipelines.

Repaired and painted excavators are sent to construction sites by rail.

Excavators are delivered by road to nearby objects.

Alternating frames with different excavators.