What types of hydraulic oil are there in hydraulic power steering racks?
Hydraulic Power Steering (HPS) is a common steering assist system in modern cars. It relies on hydraulic oil to transmit power and help the driver easily control the steering wheel. The hydraulic power steering system generates pressure through a hydraulic pump to deliver hydraulic oil to the steering rack to provide the necessary steering assistance. The role of hydraulic oil in the system is crucial. It is not only a medium for transmitting power, but also needs to meet multiple functions such as lubrication, cooling, corrosion prevention, and sealing.
As one of the core components of the system, the type, performance, and quality of hydraulic oil in the hydraulic power steering rack directly affect the stability and efficiency of the steering system. Therefore, understanding the different types of hydraulic oil in the hydraulic power steering system and how to choose the right hydraulic oil has become an important issue of concern to every car owner and maintenance personnel.
This article will discuss in detail the types of hydraulic oil in the hydraulic power steering rack, the selection criteria, and its impact on the performance of the steering system.
What performance does hydraulic power steering oil need to have?
Hydraulic oil has multiple functions in the hydraulic power steering system, including power transmission, lubrication, cooling, rust prevention, corrosion prevention, and sealing. According to these requirements, hydraulic oil not only needs to have appropriate viscosity, fluidity and lubricity, but also has excellent oxidation resistance, corrosion resistance, foam resistance and wear resistance. In addition, hydraulic oil also needs to have good temperature adaptability and be able to work normally in high and low temperature environments.
Specifically, the basic requirements of hydraulic power steering oil are as follows:
● Viscosity requirements: The viscosity of hydraulic oil is its ability to flow at different temperatures. The viscosity of hydraulic oil should be selected according to the vehicle's operating environment and temperature conditions. Viscosity that is too high or too low will affect the performance of the hydraulic system. Too high viscosity may cause power loss, while too low viscosity may cause insufficient lubrication.
● Antioxidation: Hydraulic oil needs to maintain good performance at high temperatures. Hydraulic oil with strong oxidation resistance can avoid oil aging due to high temperature, thereby avoiding deposits in the system and ensuring long-term stable operation of the hydraulic system.
● Corrosion resistance: Hydraulic oil must have anti-corrosion ability to avoid rust caused by metal parts of the system contacting hydraulic oil, especially when moisture, air pollution or water invades the system.
● Anti-foaming property: The anti-foaming property of hydraulic oil can ensure that the hydraulic oil will not produce too much foam during the pumping process. Excessive foaming will cause system cavitation, thereby reducing system efficiency and performance.
● Temperature adaptability: Hydraulic oil needs to adapt to different temperature environments. Too high working temperature may cause the viscosity of hydraulic oil to decrease, affecting the transmission force, while too low temperature will make the hydraulic oil have poor fluidity and affect the response speed of the hydraulic system.
What types of hydraulic oil are there in hydraulic power steering racks?
The hydraulic oil used in hydraulic power steering systems can be divided into several types according to different formulations and functional requirements. The following are common types of hydraulic power steering oil:
Mineral oil hydraulic oil
Mineral oil hydraulic oil is the most common type of hydraulic oil, which is mainly processed from oil-based oil products extracted from crude oil. They usually contain additives to enhance the anti-oxidation, anti-corrosion, anti-foaming and other properties of hydraulic oil. Mineral oil hydraulic oil is suitable for most ordinary hydraulic power steering systems, especially those vehicles that do not require high-performance hydraulic oil.
The advantages of mineral oil hydraulic oil include:
● Low cost, suitable for most mid- and low-end vehicles.
● With good lubricity, it can effectively reduce friction and extend the service life of the steering system.
However, the disadvantage of mineral oil hydraulic oil is that it has poor stability in high temperature environment and is prone to produce oxides after long-term use, which in turn affects the working performance of the hydraulic system.
Synthetic hydraulic oil
Synthetic hydraulic oil is a hydraulic oil produced by artificial synthesis process, which usually has better high temperature stability, low temperature fluidity and longer service life than mineral oil. The base oil used in synthetic hydraulic oil is usually chemical substances such as olefins, esters or synthetic ethers.
The advantages of synthetic hydraulic oil are:
● Provide better oxidation resistance and corrosion resistance.
● Able to maintain stable performance at extreme temperatures.
● Suitable for vehicles with high performance requirements, especially high-end cars and sports vehicles.
However, the disadvantage of synthetic hydraulic oil is that it is more expensive. It is suitable for occasions that require higher performance hydraulic systems. Excessively expensive synthetic hydraulic oil may not be suitable for all types of cars.
Vegetable oil hydraulic oil
Vegetable oil hydraulic oil is an environmentally friendly hydraulic oil obtained by refining vegetable oil as the base oil through a special process. This type of hydraulic oil has good biodegradability and can reduce environmental pollution, so it is gradually favored by some environmentally friendly vehicles and industrial equipment.
The advantages of vegetable oil hydraulic oil include:
● Good biodegradability and environmentally friendly.
● Excellent antioxidant properties, which can extend the service life of the hydraulic system.
However, vegetable oil hydraulic oil also has some disadvantages, mainly including its poor low-temperature fluidity, high price and unsuitability for some hydraulic systems with high performance requirements.
Water-based hydraulic oil
Water-based hydraulic oil is a hydraulic oil formed by adding appropriate amounts of additives and mixtures based on water. This type of hydraulic oil is not common in automotive steering systems, but in some special hydraulic systems, especially in systems that require higher cooling performance, water-based hydraulic oil has irreplaceable advantages.
Advantages of water-based hydraulic oil:
● Extremely high cooling efficiency, able to maintain the normal operation of the hydraulic system at high temperatures.
● Low cost, water itself is a cheap and readily available resource.
However, the disadvantages of water-based hydraulic oil are also obvious: due to the chemical properties of water, it is easy to cause corrosion and damage to metal parts.
During use, great attention must be paid to preventing water evaporation and freezing of water-based liquids.
How to choose hydraulic oil for hydraulic power steering system?
Choosing the right hydraulic oil is the key to ensure the normal operation of hydraulic power steering system. When choosing hydraulic oil, car owners and maintenance personnel should make comprehensive considerations based on the following factors:
● Vehicle type and use environment: Different types of vehicles and different use environments have different requirements for hydraulic oil. For example, sports vehicles may require high-performance synthetic hydraulic oil, while economical cars may only need mineral oil hydraulic oil.
● Temperature range: Different types of hydraulic oil have different operating temperature ranges, and car owners should choose hydraulic oil according to the climatic conditions of the area. For example, vehicles in cold areas may require hydraulic oil with good low-temperature fluidity.
● System requirements: The hydraulic systems of some high-end cars or special-purpose vehicles may have higher performance requirements and require the use of hydraulic oil with excellent anti-oxidation, anti-corrosion and anti-foaming properties.
● Manufacturer recommendation: The most important point is that car owners should refer to the car manufacturer's recommendation on the type of hydraulic oil. Car manufacturers usually recommend the use of a certain type of hydraulic oil based on the characteristics of the car model and steering system.
Maintenance and replacement of hydraulic oil
Hydraulic oil is the "blood" of the hydraulic power steering system, and its quality and state directly affect the normal operation of the steering system. It is very important to regularly check the quality, level and leakage of hydraulic oil.
● Regularly check the hydraulic oil level: If the hydraulic oil level is too low, the system will not be able to provide sufficient power, which will affect the steering operation.
● Replace the hydraulic oil: According to the vehicle's manual or the manufacturer's recommendations, replace the hydraulic oil regularly to maintain the stability and performance of the hydraulic system.
● Pay attention to oil contamination: Hydraulic oil may be contaminated by moisture or impurities in the air. Regular inspection and replacement of oil filters is the key to avoiding oil contamination.
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