TheCNC2020 | Analysis model of hydraulic circuit of control slide valve

Analysis model of hydraulic circuit of control slide valve | TheCNC2020 | 

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1- Introduction and symbols of control slide valves

The electro-hydraulic slide valve is an important part in hydraulic automatic control system

force because the quality criteria of the valve directly affect the quality of the control system control. Each type and manufacturer has a different quality, now there are many Famous manufacturers such as Mooc and Parker of the US, Peoto of Germany... Electro-hydraulic valves are divided into the following three main types: - Normally open and closed slide valve (also known as valve-selenoid). This type of valve only does the task of opening or closing or reversing the direction of oil movement (Figure 1.12a) and is usually used in logic control circuits or control switches. - Proportional valve (proportional-valve). This type is capable of infinitely adjusting the position of the slider to supply oil to the actuator according to usage requirements. To control the slider moves along the axis, people use two symmetrically arranged electromagnets (Fig 1.12b). - Servo valve (servo-valve). Similar to proportional valve, servo valve can change sub-position - Stepless performance with high sensitivity. To control the slider one uses a male electromagnet combined with an oil injection system with a symmetrical structure. Thanks to the perfection of the ending structure that this type of valve has the highest control quality today. Symbols of servo valves are shown in Figure 1.12c.
       

a- Symbol of solenoid valve; b- Symbol of proportional valve; c- Symbol of servo valve. P - Shows the pressure supplied to the valve; T - Shows the oil tank pressure (sometimes denoted by R); A and B - Symbol 2 oil lines connected to cylinders or diesel engines.

2- Model of hydraulic circuit analysis of valve
For example, a servo valve has a schematic diagram shown in Figure 1.13a. When the magnet is working The fork will rotate causing the clearance between the fork and the nozzle to change, resulting in the coefficient K changes, pressure PA and PB will also change. The change of PA and P will make the force applied to the unbalanced slider, resulting in the slider moving and controlling being saved flow of oil through the valve. This schematic diagram is modeled as a hydraulic circuit as shown in figure 1.13b. This is a combination circuit between series and parallel - analyzed in Section 1.1. In which, KA and KB are interrelated, when KA increases, KB decrease and vice versa.

Figure 1.14 is another example of a slide valve with 4 control edges.

 

As K increases, KB-T increases and K P-B , K decreases. The diagram of this valve is modeled as a hydraulic circuit as shown in Figure 1.14b.

Hydraulic transmission and control engineering

Calculation model of slider-type pressure reducing valve

Calculation model of slider-type pressure reducing valve

Analysis model of hydraulic circuit of control slide valve

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