Hydraulic oil is the hydraulic medium used in the hydraulic system that utilizes the pressure energy of liquid, and plays the roles of energy transfer, wear resistance, system lubrication, corrosion prevention, rust prevention and cooling.
For hydraulic oil, first of all, it is necessary to meet the requirements of hydraulic device for liquid viscosity at working temperature and starting temperature. Because the viscosity change of lubricating oil is directly related to the hydraulic function, transmission efficiency and transmission accuracy, it is also required that the viscosity-temperature performance and shear stability of oil should meet various requirements of different uses.
There are many types of hydraulic oil, and the classification methods are different. For a long time, it is customary to classify hydraulic oil according to its purpose, and some are classified according to its type, chemical composition or flammability. These classification methods only reflect the earned value and injection quantity of oil products, which are not systematic and difficult to understand the relationship and development between oil products.
Extended data:
National standard classification of hydraulic oil:
I. HH type
HH hydraulic oil is a mineral oil without any additives. Although this oil has been classified, it is no longer used in hydraulic systems. Because of its poor stability and easy foaming, this oil has a short service life in hydraulic equipment.
Second, HL type
HL hydraulic oil is made of neutral base oil with high refining depth and antioxidant and antirust additives. According to the kinematic viscosity at 40℃, HL hydraulic oil can be divided into six grades: 15, 22, 32, 46, 68 and 100.
Three. HM type
Anti-wear hydraulic oil (HM hydraulic oil) is developed from anti-rust and anti-oxygen hydraulic oil. It has a series of products, such as alkaline high zinc, alkaline low zinc, neutral high zinc and ashless type. They are all divided into four grades according to the kinematic viscosity of 40'C: 22, 32, 46 and 68.
Four. Human resource type
HR hydraulic oil is used in medium and low pressure hydraulic systems with large environmental temperature changes. The oil has good anti-rust and anti-oxidation properties, and on this basis, viscosity index improver is added to make the oil have better viscosity-temperature characteristics. This kind of oil has not been developed vigorously because of its small dosage, so I won't introduce it in detail here.
Baidu encyclopedia-hydraumatic oil