The main function of the hydraulic tank of the excavator is to store the hydraulic oil of the hydraulic system, distribute the heat in the hydraulic oil, and separate the gas and sediment in the hydraulic oil. The hydraulic oil tank is equipped with a partition to prevent excessive fluctuation of hydraulic oil, increase the circulation distance of hydraulic oil, so that the hydraulic oil has enough time to separate bubbles, precipitate impurities, and dissipate heat. The hydraulic oil tank is equipped with an Oil Suction Filter and an Oil Return Filter, which are used to prevent foreign objects such as metal chips generated by hydraulic components from flowing back to the hydraulic system.
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1. Oil suction filter structure
The hydraulic oil tank suction filter of medium and large hydraulic excavator is connected with the oil suction port of the main pump, the bottom of which is connected with the flange seat at the bottom of the hydraulic oil tank box, and the top of which is connected with the flange sleeve at the top of the box. The oil suction filter is used to prevent foreign matter in the oil tank from mixing into the main pump and other hydraulic components, and plays a protective role in the main pump and the entire hydraulic system. The oil suction filter is mainly composed of spring 1, large nut 2, connecting rod 3, small nut 4, oil suction filter element 5, etc., as shown in Figure 1.
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With the increase of the working time of the excavator, the foreign matter on the oil suction filter element 5 will gradually increase, which can cause the oil absorption resistance to increase. In order to prevent the oil absorbing resistance of the Oil Absorbing Filter element 5 from being too large and to maintain sufficient flow capacity, it is necessary to clean or replace it regularly. Therefore, considering from the structure of the tank box, the oil suction filter element 5 should be convenient to disassemble.
2. Existing problems
There are the following three problems in the installation method of the oil suction filter of the hydraulic tank of the medium and large hydraulic excavator: First, the connecting rod of the oil suction filter is long, and it is difficult to align the installation seat during installation, which is easy to install the phenomenon of not being in place, resulting in the oil suction filter not working normally, and it brings trouble to cleaning and replacing the oil suction filter; Second, there is more oil in the hydraulic oil tank, and the hydraulic oil in the oil tank will shake violently when the excavator is working, which is easy to fall off the oil suction filter and the filter element is broken, resulting in hydraulic oil pollution; Third, due to the large volume of the hydraulic oil tank and the thin steel plate for making the oil tank, the hydraulic oil tank is prone to sucking and bulging after the oil suction filter is blocked.
3. Improvement measures
In view of the above problems of oil suction filter, we designed a new structure of oil suction filter which is easy to fix for the hydraulic tank of medium and large hydraulic excavator.
(1) Technical solutions
The improved hydraulic oil tank is composed of flange cover 1, partition board 2, fixing plate 3, oil suction filter 4, cleaning hole flange 5, mounting seat 6, connecting rod 7 and box, etc., as shown in Figure 2. The partition board 2 and the fixed plate 3 are welded to the inside of the box; The flange cover 1 is welded with a sleeve, and the fixing plate 3 is welded with a guide seat; The center of the mounting seat 6, flange cover 1 and guide seat at the bottom of the tank is a vertical center line. A cleaning hole is made on the oil tank box at the corresponding part of the oil suction filter 4, and a cleaning hole flange 5 is installed on the cleaning hole.
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(2) Installation method
The oil suction filter 4 is fixed by the sleeve on the mounting seat 6, the fixing plate 3 and the flange cover 1. The installation method is as follows: First, put the oil suction filter 4 with connecting rod 7 into the hydraulic oil tank from the flange cover 1, and place it on the mounting seat through the guide seat on the fixing plate 3; Secondly, the position of the oil absorption filter 4 is corrected, and the oil absorption filter 4 is positioned on the mounting seat 6; Finally, observe the oil suction filter 4 at the cleaning hole flange 5, install the flange cover 1, and fix the oil suction filter 4 through the sleeve and connecting rod 7 on the flange cover 1. The 3D view inside the hydraulic tank with the Oil Filter installed is shown in Figure 3.
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Step 4: Features
The improved hydraulic oil tank has the following four characteristics: First, the diaphragm and the fixed plate divide the hydraulic oil tank into three smaller cavities, and the volume of each cavity is smaller, which reduces the shaking of hydraulic oil in the box, reduces the impact of hydraulic oil on the oil suction filter, and increases the structural strength of the hydraulic oil tank box; Second, the fixed plate and the mounting seat fix the oil filter in the box to effectively prevent the oil filter from falling off; Third, the guide seat on the fixed plate plays a guiding role in the installation of the oil suction filter, which is easy to install the oil suction filter; Fourth, the cleaning hole flange 5 is added to facilitate the cleaning and replacement of the oil filter element.
