line reciprocating movement or rotational movement.
    Control components (that is, the various hydraulic valves) in the hydraulic system to control
and regulate the pressure of liquid, flow rate and direction. According to the different control
functions, hydraulic pressure control valve can be pided into valves, flow control valves and
directional control valve. Pressure control valves are pided into benefits flow valve (safety
valve), pressure relief valve, sequence valve, pressure relays, etc.; flow control valves including
throttle, adjusting the valves, flow persion valve sets, etc.; directional control valve includes a
one-way valve , one-way fluid control valve, shuttle valve, valve and so on. Under the control
of different ways, can be pided into the hydraulic valve control switch valve, control valve
and set the value of the ratio control valve.  
    Auxiliary components, including fuel tanks, oil filters, tubing and pipe joints, seals, pressure
gauge, oil level, such as oil dollars.  
    Hydraulic oil in the hydraulic system is the work of the energy transfer medium, there are a
variety of mineral oil, emulsion oil hydraulic molding Hop categories.
    The role of the hydraulic system is to help humanity work. Mainly by the implementation of
components to rotate or pressure into a reciprocating motion.  
     Hydraulic system and hydraulic power control signal is composed of two parts, the signal
control of some parts of the hydraulic power used to drive the control valve movement.  
   Part of the hydraulic power means that the circuit diagram used to show the different
functions of the interrelationship between components. Containing the source of hydraulic
pump, hydraulic motor and auxiliary components; hydraulic control part contains a variety of
control valves, used to control the flow of oil, pressure and direction; operative or hydraulic
cylinder with hydraulic motors, according to the actual requirements of their choice. In the analysis and design of the actual task, the general block diagram shows the actual
operation of equi - pment. Hollow arrow indicates the signal flow, while the solid arrows that
energy flow.  
    Basic hydraulic circuit of the action sequence - Control components (two four-way valve)
and the spring to reset for the implementation of components (double-acting hydraulic cylinder),
as well as the extending and retracting the relief valve opened and closed . For the
implementation of components and control components, presentations are based on the
corresponding circuit diagram symbols, it also introduced ready made circuit diagram symbols.
    Working principle of the system, you can turn on all circuits to code. If the first
implementation of components numbered 0, the control components associated with the
identifier is 1. Out with the implementation of components corresponding to the identifier for
the even components, then retracting and implementation of components corresponding to the
identifier for the odd components. Hydraulic circuit carried out not only to deal with numbers,
but also to deal with the actual device ID, in order to detect system failures.
DIN ISO1219-2 standard definition of the number of component composition, which
includes the following four parts: device ID, circuit ID, component ID and component ID. The
entire system if only one device, device number may be omitted.  
    Practice, another way is to code all of the hydraulic system components for numbers at this
time, components and component code should be consistent with the list of numbers. This
method is particularly applicable to complex hydraulic control system, each control loop are the 液压系统英文文献和中文翻译(2):http://www.youerw.com/fanyi/lunwen_17592.html