Basic concepts of hydraulic system

Hydraulic system is a transmission system based on Pascal's principle in fluid mechanics, using liquid as the working medium, and using the internal pressure of the liquid to transmit, convert and control power (or energy). The hydraulic system is the key to controlling mechanical equipment to complete various actions. Its technical level and product performance will directly affect the automation degree and work reliability of mechanical equipment.

The hydraulic system is generally composed of five parts, including power components, control components, executive components, auxiliary components and working medium.

The working principle of the hydraulic system is generally: the prime mover drives the hydraulic pump to work, the hydraulic pump pumps the hydraulic oil into the hydraulic pipeline, and the hydraulic valve adjusts the speed and direction of the reciprocating motion of the hydraulic cylinder by controlling the flow rate and pressure of the hydraulic oil.

Compared with mechanical transmission and electric transmission, the hydraulic system has irreplaceable advantages: (1) Under the same power, the hydraulic system has large capacity, small volume and low mass. For example, with the same output power, the mass of the hydraulic motor is only 10%-20% of the mass of the electric motor, and it can also transmit a large force or torque; (2) It is easy to realize large transmission ratio transmission, and the speed regulation range is large, which can It is convenient to realize stepless speed regulation during operation, and has good low-speed performance; (3) It is easy to realize rotary and reciprocating linear motion, and the system is easy to arrange; (4) The system control and adjustment are relatively simple, and it is easy to realize mechanical automation; (5) Operation Simple, stable work, quick response, small impact, easy to turn and start frequently and quickly; (6) Safe and reliable work, easy to achieve overload protection when the hydraulic system is overloaded; (7) The hydraulic transmission uses oil as the working medium, and the components can be Self-lubricating, easy maintenance.

Based on the above advantages, hydraulic systems are widely used in various host products and technical equipment in various industries, such as construction machinery, mining machinery, port machinery, agricultural machinery, metallurgical machinery, automobile industry, machine tools and other fields.

2. Development trend of hydraulic industry

(1) The trend of import substitution of high-end products appears

Although my country's hydraulic industry has developed rapidly, for a long time, most hydraulic parts manufacturers are small in scale and limited in innovation ability. Hydraulic products are mainly concentrated in low-end products. There is a large amount of excess capacity of ordinary hydraulic parts, and the competition for low-priced and low-level products is fierce. Since the development of high-end hydraulic parts lags behind the downstream equipment manufacturing industry, the high-end hydraulic parts required by domestic host manufacturers have long relied on imports. In recent years, with the development of the industry and the technological innovation of enterprises, domestic hydraulic parts manufacturers have successively made breakthroughs in the technical process and improved product performance. Some high-quality enterprises in the hydraulic industry have gradually eliminated the dependence of domestic OEMs on international brands by virtue of the high cost performance and regional advantages of their products, and continuously expanded their market shares. The outbreak of the new crown epidemic in 2020 has hindered international trade to a certain extent. Domestic host manufacturers are actively looking for domestic enterprises to provide supporting facilities, which has promoted the process of import substitution and provided new opportunities for domestic hydraulic parts manufacturers.

(2) Combination of hydraulic technology and high-tech achievements

In recent years, the integration of hydraulic technology with new technologies such as computer information technology, microelectronic technology, and automatic control technology has promoted the development of hydraulic systems and components. In the short term, the possibility of breakthrough changes in hydraulic technology is low, but hydraulic technology will continue to improve, which is embodied in: miniaturization, light weight and modularization of hydraulic components; green production process; integration and integration of hydraulic systems.

(1) Product miniaturization, light weight and modularization

Miniaturization, light weight and modularization are inevitable trends in the entire hydraulic industry. Miniaturization is achieved by redesigning the component layout and structure, and the miniaturized hydraulic components are beneficial to improve the response speed of the hydraulic system. Lightweight hydraulic components can be achieved through material selection and technology update. Lightweight hydraulic components can reduce the energy consumption of downstream machinery and equipment, prolong the service life, and improve production efficiency. The modularization of hydraulic products refers to the technical means of integrating the functions previously realized by multiple parts into one module, and realizing a single module to replace multiple parts. The modularization of hydraulic products can improve assembly efficiency and improve the sealing performance of hydraulic products.

(2) Green production process

Problems such as process pollution, product vibration and noise, material loss, and medium leakage in the manufacturing process of hydraulic components and parts have always been important challenges faced by my country's hydraulic industry. In the future, green manufacturing technology needs to be applied to the whole life cycle process of product design, process, manufacture, use and recycling. Reduce vibration and noise of hydraulic products and systems through structural optimization technology and active control principles; gradually phase out processing and manufacturing processes that are harmful to the environment, adopt environmentally friendly process manufacturing methods and equipment, and improve resource and energy utilization in the manufacturing process; Materials that reduce friction and reduce the use and loss of hydraulic components to improve material utilization; develop new sealing materials by developing hydraulic pipeline connection technology, optimize sealing structure and finishing process, improve product sealing performance, and reduce media leakage and pollution; develop fluid media recovery Treatment and reuse process, develop special hydraulic components dismantling, recycling and remanufacturing process to improve product recyclability.

(3) Integration and integration of hydraulic system

The integration and integration of the hydraulic system can realize the flexibility and intelligence of the hydraulic system, and give full play to the advantages of large transmission output, small inertia and fast response of the hydraulic system. With the development of new energy technology and equipment intelligence, the terminal application requires the effective combination of hydraulic transmission technology and electronic control technology, changing the traditional control form and improving the system response performance. The industry needs to break through the constraints of tradition, promote the research and development of intelligent and integrated systems, and meet the future demand for hydraulic products in the Chinese market. The integration and integration of the hydraulic system is the future development direction of the hydraulic industry.

3. Opportunities

(1) National industrial policy support

In recent years, the state has attached great importance to the development of the hydraulic industry and has issued a series of policies to encourage development. According to the "Made in China 2025" released by my country in 2015, hydraulic parts belong to the core basic components in the industrial strong foundation project. "Made in China 2025" clearly states that by 2025, 70% of the core basic components and key basic materials will be independently guaranteed, 80 iconic advanced technologies will be promoted and applied, some of them will reach the international leading level, and a relatively complete industrial technology foundation will be built. Service system, and gradually form an industrial innovation pattern of coordinated interaction of the whole machine and basic support. It is proposed in the "14th Five-Year" Development Plan Outline of the Hydraulic, Hydraulic and Pneumatic Sealing Industry that by 2025, more than 80% of the high-end hydraulic and pneumatic sealing products will be independently guaranteed. Therefore, the demand for localization of high-end hydraulic parts is urgent.

Under the guidance of the above-mentioned national policies, some leaders in the mainframe industry have gradually reformed the parts procurement system, allowed domestic high-quality enterprises to enter the list of qualified suppliers, and realized the localization of parts procurement. With the continuous expansion of the global share of my country's main engine manufacturers, some domestic high-quality enterprises can seize the development opportunities of import substitution of key components in the hydraulic industry by virtue of product research and development capabilities, their own scale advantages, and stable product quality. Therefore, the implementation of the import substitution policy will provide a broader development space for leading enterprises with independent research and development capabilities in the industry.

(2) The development of downstream industries provides a broad market space for the hydraulic industry

Hydraulic components are important basic industrial products with a wide range of downstream applications. With the development of my country's national economy, the acceleration of urbanization, industrial upgrading and structural adjustment, in the process of my country's progress from a manufacturing power to a manufacturing power, construction machinery, The automotive industry, heavy machinery, agricultural machinery, marine engineering, high-end equipment and other fields will achieve steady and rapid development, bringing broad market demand for hydraulic products.

4. Challenges

(1) Domestic raw materials and accessories cannot meet the demand

The main raw material required for hydraulic components is steel pipes. On the one hand, domestic steel pipes are mostly standard models, and their technical parameters cannot meet the customized needs of high-end hydraulic parts; In addition to the products, the impurity content and performance indicators of most domestic steel pipes are different from those of imported steel pipes, and the supply of domestic high-end raw materials is insufficient, resulting in the dependence of raw materials for high-end hydraulic parts on imports. Therefore, at present, the performance defects of domestic basic raw materials and accessories and the insufficient supply of domestic high-end raw materials have become the main restricting factors for the quality improvement of high-end hydraulic products.

(2) The international market has insufficient recognition of the domestic hydraulic industry

Due to the early start of the foreign hydraulic industry and the high overall technical level, the high-end market of domestic hydraulic parts is mostly occupied by international giants, and the products of my country's hydraulic industry are concentrated in the middle and low end of the value chain. The general recognition is low, there are obstacles for domestic hydraulic parts manufacturers to enter the supplier system of mainstream international manufacturers, and it is more difficult to participate in international competition.

5. Barriers to entry in the industry

(1) R&D and technical barriers

Since different main engines and even different parts of the same main engine have different requirements for the shape and size of the pipeline, hydraulic parts manufacturers often need to carry out personalized design and production according to the specific needs of customers. In addition, with the continuous improvement of the degree of industrialization and the continuous iteration of technology, downstream customers have higher and higher requirements for the service life, reliability, stability and other performance of hydraulic components.

However, the technical capabilities of R&D, design, production, processing and debugging and testing of the above-mentioned hydraulic products require long-term accumulation of experience to gradually improve and mature. It is difficult for new enterprises in this industry to form stable process control and process control capabilities in a short period of time. Capability and production technology level constitute the barriers to entry in the hydraulic industry.

(2) Barriers to market development

The hydraulic pipeline acts as a transmission device to ensure the operation of the hydraulic main engine, just like the blood circulation system of the main engine. The quality of the hydraulic pipeline directly determines the stability, fluency and life of the main engine. Therefore, the main engine manufacturer will strictly select the hydraulic pipeline supplier, and the products need to undergo strict testing when selecting the supplier. In addition to meeting the audit standards, relevant products also need to pass the actual use evaluation. Therefore, once the cooperative relationship is confirmed, in order to ensure the stability of its own product quality, the host manufacturer will not easily change the supplier, so it has a certain customer stickiness. Generally speaking, hydraulic parts companies that have maintained a good brand reputation for a long time have greater advantages in obtaining customer orders and establishing stable cooperative relations. For new entrants, it is difficult to establish a market reputation and form a brand effect in a short period of time, so there are certain market development barriers in the hydraulic industry.

(3) Capital and scale barriers

The hydraulic industry is a capital-intensive industry, and the production of hydraulic parts requires large-scale investment in fixed assets, mainly including capital investment such as plant construction and equipment purchase. The production efficiency of hydraulic enterprises and the performance, stability, service life and other indicators of products largely depend on the configuration level of production equipment. In the cost structure of hydraulic products, raw materials account for a relatively high proportion. Its production requires the procurement of raw materials such as steel and castings, and production turnover requires a large amount of working capital, which is also an important part of capital investment in the hydraulic industry. In addition, only enterprises with a certain scale can form a scale effect, thereby effectively reducing production costs. Therefore, new entrants must have strong financial strength and scale.

(4) Talent Barriers

With the acceleration of technological innovation in the hydraulic industry, the R&D and production of hydraulic parts involves interdisciplinary technology and manufacturing processes. Enterprises need to have high-level R&D teams and technical personnel, as well as skilled workers who are proficient in production technology and experienced inspections. Personnel to ensure the continuity of research and development, the advancement of manufacturing level and the stability of product quality. At present, there is a lack of professional talents for high-end hydraulic parts in China. To establish a talent team with a reasonable professional structure through the enterprise's own training requires continuous technical accumulation and market precipitation. It is difficult for new entrants to deploy a professional talent team in a short period of time. Therefore, the hydraulic industry has certain talent barriers for new entrants.