Use of Hydraulic Components
Nowadays, people have placed many different expectations on hydraulic components because they are widely used. For example, we hope hydraulic components can adapt to different working environments, such as severe cold and heat; some should be corrosion resistant, and some should be explosion-proof. Components apply into mobile hydraulics are expected to have the merit of small size and light weight. And the hydraulic components which used in hospitals and offices require no leakage, low noise, etc.
(1) Excellent control and adjustment characteristics
High stability and repeatability. It can be subtly adjusted, especially for valves.
(2) Pressure resistance performance
The working pressure of modern hydraulic technology is high. And there are often moments of extremely high pressure peak, which require hydraulic components to withstand.
The pump is the component with the highest working pressure and the longest continuous working time in the entire system. Therefore, we have set the highest standards for the pressure resistance of the pump.
(3) Working durability
What is particularly valuable for a hydraulic component is its good working durability under high pressure and extreme pressure changes.
There are many factors that affect the durability of work. Among them, the most important factor is the lubrication condition and the material heterogeneity of the raw material -impurities, gas content, etc.
The rapid progress of new materials and new processes helps to improve the durability of hydraulic components.
(4) Stable manufacturing quality
In other words, it is the consistency of manufacturing.
We often use Six Sigma and PPM to measure, Among the 1 million possible unqualified places in the seized finished products, several unqualified places appeared. This is particularly important for large-scale production OEMs, such as automobiles, excavators, loaders, etc.
Reliability refers to the ability to complete the specified function within the specified time under specified conditions.
High reliability means:
1) To be able to meet the requirements. As we all known, hydraulic components wear out during work, so their performance can meet the requirements not only at the beginning, but also after long-term work.
2) There are always deviations in mechanical manufacturing. Therefore, it is hoped that there are very few components that cannot meet the requirements. For example, there are less than ten or even less than one in an average of one million.
For hydraulic components, in fact, it is a comprehensive manifestation of excellent design performance and stable manufacturing quality. The failure of any component in the hydraulic system due to malfunction will affect the normal operation of the entire system. Replacing failed components not only means we should pay for replacement parts and repairs, but also often means that the entire equipment must be suspended. The loss often exceeds the cost of replacement parts and repairs. Therefore, in many occasions, users would rather pay a higher fee to purchase components that are less likely to fail.
Now the international community has begun to use the “mean time to dangerous failure MTTFd” (or “mean time to failure MTTF”) to measure the reliability of hydraulic components. This is an indicator obtained by a durability test based on sampling and simulating actual working conditions. After working continuously for one year, if the probability of dangerous failure is less than 3.3%. It can be said that MTTFd>30 years. Only when the probability of dangerous failure <0.6% can it be said that MTTFd>150 years. Most of the world’s advanced hydraulic products have reached this level.
The above requirements for hydraulic components are the benchmark to measure the level of hydraulic components, and they also divide the grade of hydraulic components.
The market for hydraulic components can be divided into a pre-market and a post-market, both of which have different demands.
- Pre-market: To provide components for mainengine plants, often referred to as “OEM”. Generally, the order quantity of each batch is relatively large, but the requirements for performance consistency, service life (shelf life at least one year), and payment terms are also relatively strong, especially for those first-class manufacturers.
2) Post-market: Provide replacement parts. Although the requirements for performance consistency, service life and shelf life of more than three months) are lower, the requirements for small batches and low prices are often strong.
Of course, customers’ ability to bear the price is also different. Cost performance is a very sensitive indicator and also plays an extremely important role in the development of technology.
—from <HYDRAULICS FOR EVERYONE>