Overview of hydraulic press

Update:19 Oct 2021

The hydraulic press is a machine that uses liquid as th […]

The hydraulic press is a machine that uses liquid as the working medium and is made according to Pascal's principle to transfer energy to realize various processes. Hydraulic presses are generally composed of the machine (host), power system and hydraulic control system. Hydraulic presses (also known as hydraulic presses) are made by Pascal's law and are driven by hydraulic pressure. There are many types of hydraulic presses. Of course, the use is also diverse according to needs. For example, according to the type of liquid that transmits pressure, there are two categories: hydraulic press and hydraulic press. The total pressure generated by the hydraulic press is relatively large, and it is often used for forging and stamping. Forging hydraulic press is divided into die forging hydraulic press and free forging hydraulic press. The die forging hydraulic press uses molds, while the free forging hydraulic press does not use molds. The first 10,000-ton hydraulic press manufactured in China is a free forging hydraulic press. A hydraulic press is a machine that uses liquid as a working medium to transfer energy to realize various processes. In addition to being used for forging and forming, hydraulic presses can also be used for straightening, pressing, packing, briquetting and pressing.

Hydraulic presses include hydraulic presses and hydraulic presses. Water-based liquids are called hydraulic presses, and oils are called hydraulic presses. The specifications of hydraulic presses are generally expressed in terms of nominal working force (kN) or nominal tonnage (tons). Most hydraulic presses for forging are hydraulic presses with relatively high tonnage. In order to reduce the size of the equipment, large forging hydraulic presses usually use higher pressures (about 35 MPa), and sometimes use ultra-high pressures of more than 100 MPa. Hydraulic presses for other purposes generally use a working pressure of 6 to 25 MPa. The tonnage of a hydraulic press is lower than that of a hydraulic press. The working principle of a hydraulic press. The areas of the large and small plungers are S2 and S1 respectively, and the hydraulic pressure on the plunger is F2 and F1 respectively. According to Pascal's principle, the liquid pressure is equal everywhere. It represents the gain effect of hydraulic pressure. Like mechanical gain, the force increases, but the work does not gain. Therefore, the movement distance of the large plunger is S1/S 2 times the movement distance of the small plunger.

The function of the working medium used in the hydraulic press is not only to transmit the pressure, but also to ensure that the working parts of the machine are sensitive, reliable, long-lived and less leaking.

The basic requirements of hydraulic press for working medium are:

<1>, suitable fluidity and low compressibility to improve transmission efficiency;

<2>, can prevent corrosion;

<3>, have good lubricating performance;

<4>, easy to seal;

<5>, stable performance, long-term work without deterioration.

According to the structure type, the hydraulic press has two-column, four-column, eight-column, welded frame and multi-layer steel belt winding frame, etc., and medium and small vertical hydraulic presses also use C-frame type. In the vertical four-column free forging hydraulic press with upper transmission, the oil cylinder is fixed in the upper beam, the plunger is rigidly connected with the movable beam, and the movable beam is guided by the column and moves up and down under the pressure of the working fluid. There is a workbench that can move back and forth on the beam. The upper anvil and the lower anvil are respectively installed under the movable beam and on the work surface. The working force is borne by the frame composed of upper and lower beams and columns. Large and medium free forging hydraulic presses driven by pump-accumulators often use three working cylinders to obtain three levels of working force. A balance cylinder and a return cylinder that exert upward force are also arranged outside the working cylinder.