The main reasons for the swelling of the cylinder wall of the hydraulic cylinder of a Hydraulic Press are:
The strength and rigidity of the hydraulic cylinder itself is not strong
According to the theory of uniformly distributed load in material mechanics, the strength and stiffness are distributed in a parabolic condition. It is proportional to the uniform distribution pressure of the operating oil pressure and proportional to the 4th power of the uniformly distributed load length. Therefore, the cylinder wall expands the most. It is easy to occur in the slender cylinder, and the swelling direction is often near the midpoint of the highest operating pressure chamber. This requires special attention to check the strength and rigidity of the cylinder when designing.
Abnormal high pressure during operation of hydraulic press
- 1. Pistons with heavy load or high speed have great inertial force. When suddenly intermittently, the pressure in the working chamber increases instantly, and even exceeds the maximum working pressure several times, causing the cylinder bore to expand.
- 2. The hydraulic cylinder is often overloaded. For example, when the packing machine is about to end, the packing is suddenly interrupted, and then the packing is restarted (commonly known as cold packing), which will cause the instantaneous oil pressure to exceed more than 2 times, which will easily cause the cylinder diameter to expand.
- 3. The cushioning equipment is completely inoperative. It is in a fully open situation, so that the working piston cannot decelerate and suddenly hits the cylinder head and may bounce back, causing instantaneous overpressure in the working chamber.
The raw material of the cylinder barrel is defective or the cylinder structure design is unreasonable
The cylinder tube misuses low-strength steel, which reduces the yield point and safety factor. After normal use, the cylinder diameter will inevitably expand. For the cylinder wall of a hydraulic cylinder with a long length, no reinforcement hoop is provided at the center of the outer ring, which causes the load force to be unacceptable.
The expansion of the cylinder wall of the hydraulic cylinder causes leakage and affects the normal operation of the hydraulic press. Therefore, the operator must operate in accordance with the regulations in daily life to strengthen daily maintenance operations; apply a reinforcement structure to the cylinder wall of the hydraulic cylinder; assume that the inner diameter has a large deformation after measurement , The reinforcement method should be adopted first. Regarding the repair of the inner wall, the grinding method is generally used.