Renovation of hydraulic cylinder seal of 200T four-column hydraulic press

The 200T four-column hydraulic press used to install the stator core of the motor often has a problem that the piston rod cannot be lifted up during the work, and the stator core cannot be pressed without adding hydraulic oil. The waste of grinding hydraulic oil and the inefficient work of equipment.

After dismantling and analysis, it was found that the sealing ring was damaged. The hydraulic cylinder and the piston rod of the hydraulic press are sealed with a special sealing ring. The sealing ring is difficult to purchase, strict technical requirements, and easy to wear.

(1) The rubber ring is made of I-4 high-hardness oil-resistant rubber and multi-layer fabric, and the working temperature range is -20 ～ 80 ℃. 

(2) The mechanical and physical properties are: hardness (85 ± 5) HA, tensile strength is not less than 10N, elongation at break is not less than 150%, permanent deformation is not more than 20%, brittle temperature is not higher than -25 ℃, aging the coefficient is not less than 0.8. In the condition of (70 ± 2) ℃ × 24h, the change rate of oil resistance quality of No. 15 engine oil is not more than ± 42%. 

(3) The working surface of the apron should be flat and smooth, and no defects such as bubbles, impurities and uneven cracks are allowed.

After analysis and demonstration, the special I-4 high-hardness oil-resistant rubber and multi-layer fabric seal ring were changed to an O-shaped seal ring and a Yxd seal ring to seal the hole and the shaft in two layers respectively. Figures 1 and 2 show the assembly diagrams before and after the hydraulic cylinder modification. Specifically, the hole seal is sealed by the O-ring seal 3 shown in FIG. 2; the piston rod seal is sealed by the shaft with the seal ring 5; the seal ring 4 (see FIG. 3) is stationary No movement, the anti-wear hydraulic oil enters the oil inlet and return port 7 to push the piston. The piston rod lifts the worktable and presses the stator to work. After the pressing is completed, the piston returns by the weight of the heavy object.

Figure 1 Schematic diagram of hydraulic cylinder assembly before transformation

1. Spare mother 2. Cylinder block 3. 6. Guide bush 4. Special sealing ring 5. Support ring 7. Piston 8. Inlet and return port

Figure 2 Assembly diagram of hydraulic cylinder after transformation

1. Spare mother 2. Cylinder block 3. O-ring seal 4. Seal ring 5. Yxd seal ring for shaft 6. Piston rod 7. Inlet and return port

Figure 3 Sealing ring