We all know that the human body can replace the kidney, the heart and other organs. The complexity of this super large operation is difficult to imagine. The replacement of engine and hydraulic pump for the excavator, loader and other engineering machinery is also a super operation for the machine. We will explain the structure and installation of the excavator hydraulic pump in this period. We hope you can criticize and correct this matter.
The previous "Three Big Things of the Excavator: Those Things about the Hydraulic Pump" has told you the basic knowledge of the hydraulic pump of the excavator. The engine, the hydraulic pump, the distribution valve are three big parts that people often say, the engine drives the hydraulic pump to rotate, and the high pressure hydraulic oil is driven by hydraulic motor, hydraulic cylinder and other hydraulic actuators.
The engine provides power for the hydraulic pump, hydraulic pump, hydraulic oil pipeline, hydraulic motor, hydraulic cylinder and other hydraulic transmission, distribution valve for hydraulic control.
First, the structure of excavator hydraulic pump and several hydraulic circuits.
As we all know, in general, the larger excavator is controlled by a double pump plus a pilot pump. Taking Kawasaki hydraulic pump as an example, Kawasaki hydraulic pump is generally used in Shenyang Steel, 31, Sumitomo (- 5 series) and other brands of excavators.
The next picture is a schematic diagram of the Kawasaki K3V series hydraulic pump. Basically, there are several parts, such as the front pump, the middle pump body, the rear pump, the pilot pump, the regulator and so on. The pump is made up of two plunger pumps and a pilot gear pump connected in series. The pump is equipped with a pilot safety valve, a plunger pump displacement: 110mL/r x 2, a pilot pump displacement: 10mL/r.
From the hydraulic circuit diagram of the lower Kato (KATO) excavator, we can see that the hydraulic oil in the oil return line is low pressure oil, the variable plunger pump in series is installed on the engine, the low pressure hydraulic oil enters the oil suction chamber of the hydraulic pump, the high pressure oil is discharged from the hydraulic pump, into the combination valve, and the high-pressure oil is carried out in the combination valve. Distribution.
In case of great strength, the hydraulic fluid supplied by the hydraulic pump is also large, usually combined with two pumps. The front pump and the rear pump control the left and right side of the excavator to walk in one walk to supply oil for the walking motor; the big arm cylinder is a double pump confluent, the middle arm and the middle arm (the bucket cylinder) are the two pump confluence, and the bucket and rotation are one of the pumps in the front and back pumps to supply oil.
The pilot pump is to provide control pressure for the combined valve. Oil from the main pump to the control valve (multichannel valve, distribution valve), and then through the control of the control valve spool switch control (may be the pilot oil control, mechanical pull rod control, electromagnetic control, etc.), the pressure oil into the large arm or small arm cylinder of the different cavity, to push the cylinder piston movement, thus promoting the movement of the arms.
Hydraulic circuit is composed of hydraulic pump circuit, walking circuit, rotary circuit, dynamic breakthrough circuit, bucket bar circuit, bucket loop.
The regulator and solenoid valve of the excavator have been described in "the regulator and proportional solenoid valve on the excavator hydraulic pump", and you can click the link to view it.
Two. Notice on the installation of hydraulic pump for excavator
(1) ensure that the hydraulic oil is very clean
Hydraulic oil directly into the hydraulic pump, if there are impurities in the hydraulic oil, it will wear the plunger, disks and other structures, causing damage to the hydraulic pump, even the hydraulic pump is scrapped! So the hydraulic oil filter must be genuine filter element, the larger the density of the general filter screen, the better the quality of the filter element.
(2) after the installation of the new pump, there is no hydraulic oil, the strict direct start, the return oil pipe injection hydraulic oil, the oil pipe can not be blocked, otherwise the hydraulic pump back oil pressure is too large, will make the hydraulic damage!
(3) notice the discovery of abnormal phenomena at any time
The abnormal sound, vibration or abnormal signal of monitoring system must have its reasons. When there are abnormal phenomena, it is necessary to find the circuit diagram immediately, and to observe whether the abnormal phenomenon is caused by the error of the moment. No parking is required for the assessment. Pressure, load, temperature, time, starting time and stopping all contain the possible causes of abnormal phenomena. In peacetime, it is necessary to analyze and discuss item by item.
(4) do not add to the load immediately after the hydraulic pump is started
The hydraulic pump must be carried out for a period of time without load (about 10 minutes ~30 minutes). Especially when the temperature is very low, the hydraulic pump must be heated through the process, so that the circulation of the hydraulic circuit is normally added to the load, and the operation condition is confirmed.
(5) observe the change of oil temperature
Check the maximum and minimum oil temperature changes, and find out the relationship between the oil temperature and the ambient temperature, so as to know whether the capacity of the cooler, the capacity of the tank with the conditions and the conditions of use, and the failure of the cooling system can be ruled out.
(6) pay attention to the noise of the hydraulic pump
The new hydraulic pump early wear less, easy to be affected by bubbles and dust, high temperature bad lubrication or use condition overload, all will cause adverse consequences, making the hydraulic pump out of the abnormal effect.
(7) pay attention to the display value of the check meter class
Observe the display value of the pressure meter, the signal of the pressure switch and other vibration and stability of the hydraulic circuit at any time, so as to find out whether the hydraulic circuit function is normal as soon as possible.
(8) observe the action of the machine (for refitted pump).
The improper design of the hydraulic circuit or the poor manufacturing of the components is not easy to find in the initial stage of use, so special attention should be paid to the state of action displayed under various conditions of use.
(9) pay attention to the adjustment of the valves
Fully understand the use of pressure control valves, flow control valves and direction control valves, special attention to the range and limit of adjustment, otherwise adjustment errors not only damage the machinery, but also pose a threat to safety.
(10) check the state of the filter
The filter in the loop should be cleaned regularly, and the state of the filter and the adsorbed contaminants on the net are checked, and the quality, quantity and size should be analyzed, so that the pollution level in the loop can be observed, and the source of the pollution is inferred.
(11) check the change of hydraulic oil regularly
Check and analyze the deterioration, discoloration and pollution of hydraulic oil every other month or two to ensure the normal hydraulic transmission medium.
(12) pay attention to the leakage of the piping part
If the piping of the hydraulic device is good, it can be seen after a period of operation whether the oil leakage is detected and whether the piping is loose.
(13) attention should be paid to the operation of the new machine within three months.
During the operation of the new machine, the operation condition should be checked, such as the maintenance of the machine parts, the loosening of the screw, the abnormal rise of the temperature of the oil, the rapid deterioration of the hydraulic oil, and the inspection of the use conditions.
