The hydraulic cylinder is one of the main components of a four-column hydraulic press. Its function is to convert the pressure energy of the liquid into mechanical work. According to its structure, it can be divided into plunger type, piston type, and double-head plunger type. In this article, we mainly introduce the hydraulic press cylinder, load efficiency, and assembly precautions for the four-column hydraulic press.
1. Introduction to the hydraulic cylinder of a four-column hydraulic press:
1) The hydraulic cylinder is one of the main components of a four-column hydraulic press. Its function is to convert the pressure energy of the liquid into mechanical work. That is, under the action of high-pressure liquid, the piston (or plunger) is pushed to move the movable crossbeam downward, and the four-column liquid pressure is transmitted to the workpiece through the movable crossbeam of the hydraulic press so that the workpiece produces the required deformation.
2) The hydraulic cylinders used in four-column hydraulic presses are basically high-pressure cylinders. According to their different structures, they can be divided into plunger type, piston type, and double-head plunger type. What kind of structure is used in actual use should be determined comprehensively based on the overall structure of the four-column hydraulic press, the total pressure and stroke size of the cylinder, the working conditions of the four-column hydraulic press, and the manufacturing capacity of the manufacturer.
2. Load efficiency of hydraulic cylinder of the four-column hydraulic press:
1) When the four-column hydraulic press is tested for load efficiency, the dynamometer is first installed on the piston rod. Gradually increase the hydraulic pressure and output force simultaneously. Then increase the pressure value p and the corresponding hydraulic cylinder output force w value, record, and draw a graph. According to the requirements, the load efficiency of the hydraulic cylinder of the four-column hydraulic press should be higher than 90%.
2) The efficiency of the hydraulic cylinder of the four-column hydraulic press is different at all stages of the movement process. At startup, the hydraulic cylinder of the four-column hydraulic press must overcome the static friction of the sealing device, so the efficiency is low, and the sealing friction is small at high speed, and the efficiency is high. However, since the startup time of the hydraulic cylinder of the four-column hydraulic press is very short, it can usually be ignored.
3. When assembling hydraulic press cylinder, matters needing attention:
1) The hydraulic press cylinder buffer plunger will form friction iron powder or iron filings when the fit clearance of the buffer device is very small. When the lateral load on the piston rod is very large, it may cause sintering. These friction iron powders or metal fragments that have fallen off due to sintering will remain in the cylinder.
2) Scars on the inner surface of the hydraulic cylinder wall. The piston’s high sliding surface pressure causes sintering, which squeezes and cracks the inner surface of the hydraulic cylinder body. The squeezed metal falls off and remains in the hydraulic cylinder, causing scars.
3) When assembling the hydraulic press cylinder, the piston, cylinder head, and other parts have large mass, size, and inertia. Even if lifting equipment assists in the installation, friction will occur anyway because the prescribed fit clearance is small. Therefore, when the end of the hydraulic piston or the cylinder head boss hits the inner surface of the cylinder wall, it is very easy to cause scars.
4) Scars caused by foreign objects mixed in during assembly. Before the hydraulic cylinder is assembled, all parts must be fully deburred and cleaned. When installing parts with burrs or dirt, due to the “extra force” and the weight of the parts, foreign matter can easily embed into the surface of the cylinder wall, causing scratches.
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Post time: Apr-15-2025
