The working medium used by the hydraulic machine of the hydraulic pneumatic fluid equipment not only transmits the pressure, but also ensures that the working parts of the machine are sensitive, reliable, long in life and low in leakage. The basic requirements of the hydraulic press for the working medium are: ① suitable fluidity and low compressibility to improve the efficiency of the transmission; ② can prevent corrosion; ③ has good lubrication performance; ④ easy to seal; ⑤ stable performance, long-term work And not degenerate. The hydraulic press uses water as the working medium. In the future, it will be replaced with an emulsion made by adding a small amount of emulsified oil to the water to increase lubricity and reduce rust. In the late 19th century, hydraulic presses with mineral oil as the working medium appeared. The oil has good lubricity, corrosion resistance and moderate viscosity, which is helpful to improve the performance of the hydraulic machine. A new type of water-based emulsion appeared in the second half of the 20th century. Its emulsified form was "water-in-oil" instead of the original "oil-in-water". The external phase of the "water-in-oil" emulsion is oil, and its lubricity and corrosion resistance are close to oil, and its oil content is very small, and it is not easy to burn. But water-based emulsions are more expensive, which limits their promotion.
According to the direction of the force, there are two types of hydraulic machines: vertical and horizontal. Most hydraulic presses are vertical, hydraulic presses for extrusion, double-column hydraulic presses. This series of products are suitable for press fitting, bending and shaping, embossing, flanging, punching and shallow drawing of various parts; metal powder. Processing technology such as product molding. It adopts electric control, equipped with jog and semi-automatic cycle, can maintain pressure delay, and has good slider guidance, easy operation, easy maintenance, economical and durable. Functions such as thermal instrumentation, ejection cylinder, stroke digital display, and counting can be added according to the needs of users.
Hydroforming is also known as "internal high-pressure forming". Its basic principle is to use the tube as a blank, and at the same time, apply an axial thrust to the two ends of the tube to feed it while applying ultra-high pressure liquid inside the tube. Under the combined action of two external forces, the tube blank material is plastically deformed and adhered to the inner wall of the mold cavity to obtain a hollow part whose shape and accuracy meet the technical requirements.
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