The function symbol of the hydraulic element only represents the element () () and ().
In the hydraulic transmission system, the hydraulic component is allowed to be represented by a schematic diagram if it cannot be expressed in a graphical symbol. The graphic symbol of the hydraulic element shall be expressed in the static or zero position of the element. Exceptions can be made when the action of the constituent system is otherwise specified. 3. The name of the element, model and parameters (such as pressure, flow rate, power and pipe diameter, etc.) should be in commonly system diagram of the components in the table indicate that mark beside the element symbols when necessary. 4. Element symbols said only element of the function and connection path of the system, and does not represent components of concrete structure and parameters, nor the location of the piping system and the installation position of the element. The size of the symbol of the symbol is based on the principle of clarity and beauty, which should be measured in terms of the size of the drawing, but should guarantee the proportion of the symbol itself.
A graphic symbol that is not specified in the standard can be derived based on the principle of the standard and the regularity of the chart example. When cannot reference and derived directly, or it is necessary to specify one of the important components in the system structure and principle of action, all permits the local structure diagram. 7. Graphic symbol in the transmission system arrangement of components, in addition to have directional element symbols (tank and instrument, etc.), can be horizontal or vertical drawing according to the concrete situation. Summary of questions: The function symbol of hydraulic element only indicates the element (name) (model) and (parameter). The actual position and element of the element (the parameters) and the connection port are not represented. And it is expressed in the system as a symbol.
There are two types of graphic symbols in the hydraulic system. One is a semi-structure diagram, as in figure 1 minus 2 in the textbook. In this diagram, each hydraulic element only represents its internal structure principle, and the external shape is not represented, so it is called a semi-structure diagram. The advantage of this diagram is that it is intuitive and easy to understand when the hydraulic system fails. The disadvantages: the graphics are more complex, especially when the system elements are more difficult to draw, and the area is larger. The other is the functional symbol diagram (text I). In this figure, each hydraulic component is represented by a graphical symbol (GB/t7861-93) set by the state. These symbols said only the functions of the corresponding element (role), the connection path of the system, and does not represent components of concrete structure and parameters, and each symbol represents is the corresponding components of stationary position or zero position (the initial position). This kind of graph is characterized by the simplicity of the drawing, the oil road is clear, the analysis of the system and the design are very convenient. Therefore, there are more and more countries in the world today. A semi-structure can be used if some of the non-standard hydraulic parts designed by themselves cannot be represented by functional symbols.
