Abstract: This article divides the technological development history of computer-aided hydraulic integrated block design software and discusses the technical characteristics of each development stage.

In hydraulic system design, the integrated block is the main board that connects the channels or pipelines of various functional valve blocks of the system; it is not only a connection mapping of the hydraulic schematic diagram on the three-dimensional valve block, but also an extension based on the installation conditions of the functional valve block and the manufacturing process of the integrated block; the design of the integrated block is an assembly design from known functional valve bodies, from the bottom up; the design not only considers the installation layout of the functional valve block on a certain surface of the integrated block, but also requires the spatial layout of the channels inside the integrated block; it is necessary to consider not only the connection efficiency of the channels, but also the channel quality and processing process conditions. Therefore, the design of the integrated block is a relatively complex design task in hydraulic system design, which has a certain optimization space and is challenging.

The main board characteristics of the hydraulic integrated block itself determine that it is a complex design work supported by system data and requires designers to design. An optimized design often requires multiple iterations to achieve, and the designer needs to design based on the design data and specific requirements, and objective manufacturing conditions. The advantages and disadvantages of the design often have significant differences in the materials and sizes of the valve blocks used, the cost of design and manufacturing, channel pressure loss, and manufacturing realization. This requires that the tools used by the designer must have strong support capabilities for design, modification, editing, and redesign.

The development of computer-aided design technology has created the basis for the continuous transformation of hydraulic integrated block design tools. The essence of computer-aided design technology is to organically combine people and machines, give full play to the advantages of computers, and provide users with the most intuitive design interface, the most convenient design tools, and the fastest design methods. For the design work of hydraulic integrated blocks, it requires the support of design data, requires a certain amount of calculation, needs to be carried out in three-dimensional space and provide designers with intuitive geometric feedback, and needs to repeatedly correct and quickly and accurately check a large amount of data. These make Computer Aided Design technology an important requirement for hydraulic integrated block design tools. Of course, some research in this field focuses on fully automatic or partially automatic optimization design methods. However, these studies expect AD, that is, Automatic Design, which should have deviated from the basic points of computer-aided design. At present, there is no practical application level, it is only a kind of explorable research.

In general, the main development trajectory of computer-aided design technology in the design of hydraulic integrated blocks is as follows:

Design software based on two-dimensional wireframe technology;

Design software that uses two-dimensional wireframe technology or two-dimensional graphics as the design interface, combined with three-dimensional graphic display;

Design software that designs directly in a three-dimensional design environment.

In the first stage, the application environment of the design is a two-dimensional wireframe drawing environment, and the valve block view and design graphics are composed of wireframes. The software can create a graphic library of valve projections for designers to easily call. Using two-dimensional wireframe graphics to design integrated blocks has high requirements for designers, including spatial graphic imagination; interference between valve bodies and inspection of hole spacing must rely on manual operation. The design graphics are composed of lines and arcs, without the concept and meaning of solid features; there is no substantial improvement in design efficiency and methods compared with the traditional manual method relying on drawings. This stage of design software is actually limited by the level of computer graphics technology, computers, and computer-aided design technology. From the current point of view, it is rarely seen in practical applications.

The second stage of software development is to add the display and browsing of three-dimensional integrated block graphics in the design. Design is carried out on the view of the surface of the integrated block or by defining the valve body layout on the surface, and the channels of the valve are connected through the relationship of engineering views. The difference is that the three-dimensional view of the integrated block can be intuitively browsed by using the three-dimensional graphics environment to display the connecting holes and process holes of the integrated block. Since the design and interaction are carried out through a two-dimensional plane, the technology is still limited to the traditional two-dimensional design method. Designers only perform browsing operations in the three-dimensional model view and need to switch between two-dimensional and three-dimensional. Therefore, this type of application platform has not made any substantial improvements in design efficiency and design environment.

The latest generation of design methods is carried out entirely in a three-dimensional computer-aided design environment. MDTools integrated block design software is a representative example. It makes full use of the computer-aided three-dimensional modeling and human-computer interaction design environment, combined with professional valve block design technology. Designers' operations, design, modification, observation, and other series of work are carried out directly on the three-dimensional model of the integrated block. The design structure tree is defined according to each surface of the integrated block, the valve body installed on the surface, the cavity, the process hole, etc., forming object-oriented operation services and data, better reflecting the professionalism of hydraulic integrated block design.

Its advantages are:

1. Built on commonly used three-dimensional design software, users have a unified and familiar operating environment;

2. Design, browsing, and modification are carried out directly on the three-dimensional model of the integrated block without the need for two-dimensional and three-dimensional switching operations;

3. Design checks are based on three-dimensional solid models and have accurate and convenient features;

4. The design structure tree is defined according to the surface, valve, and hole of the integrated block, which is convenient for operation and modification;

5. Not only design operations, but also design checks and processability checks are based on three-dimensional models, so the model information of the design is the most complete;

6. Engineering drawings and processing drawings are obtained by projecting three-dimensional models and are associated with three-dimensional model parameters, rather than the traditional two-dimensional view-driven three-dimensional browsing graphic mode;

7. The integrated block model composed of three-dimensional cavity features can directly generate the numerical control processing code of the integrated block through the machinable feature recognition technology, reaching the level of drawing-free processing;

8. With the support of the valve body model library, it is convenient to realize the automatic assembly modeling of the integrated block.

In summary, the purpose of applying computer-aided hydraulic integrated block design software is to help designers improve design efficiency, reduce design complexity, avoid design errors, and ultimately reduce the cost of design and manufacturing. In hydraulic system design, computer-aided design of schematic diagrams is generally used, and the integration from schematic diagrams to integrated block design and the integration of integrated block numerical control processing are realized with the support of a unified valve body symbol and model database. The focus of this article is only the technical evolution of computer-aided design of hydraulic integrated blocks.