Truck Telescopic Hydraulic Cylinder
1.Telescopic hydraulic cylinder is also called multi-stage hydraulic cylinder. It is composed of two or multi-stage piston cylinders, mainly composed of cylinder head, cylinder barrel, sleeve, piston and other parts. There are inlet and outlet ports a and B at both ends of the cylinder barrel. When the oil enters port a and oil returns from port B, the first stage piston with larger effective area is pushed, and then the smaller second stage piston moves. Because the flow rate into port a is constant, the piston with large effective area has low velocity and high thrust, otherwise, high velocity and low thrust. If there is oil in port B and oil return in port a, the secondary piston will return to the end point first, and then the first piston will return
2.The characteristics of telescopic hydraulic cylinder are: the working stroke can be very long, and it can be shortened when not working. It is suitable for the occasions where the installation space is limited and the travel requirement is very long, such as the telescopic boom of tipper truck and crane. When the telescopic hydraulic cylinder extends step by step, the effective working area decreases gradually. When the input flow rate is constant, the extension speed gradually increases; when the external load is constant, the working pressure of the hydraulic cylinder increases gradually. The extension of the single acting telescopic hydraulic cylinder depends on the oil pressure, and the contraction depends on the self weight or load. Therefore, it is used in the case of tilting or vertical rotation of cylinder block..
3.a. Connection between cylinder and cylinder
There are many kinds of connection between cylinder and cylinder, such as pull rod connection, flange connection, inner half ring connection, welding connection. Welding connection is selected here. A kind of
b. Connection between piston and piston rod
The connection between piston and piston rod mostly adopts thread connection structure and clamping key connection structure. The structure of thread connection is simple and practical, and it is widely used; the clamping key connection mechanism is suitable for the cylinder with large working pressure and large vibration of working machinery. Therefore, the threaded connection structure is selected from various factors.
c. Safety factor of hydraulic cylinder block
For cylinder block, hydraulic pressure, mechanical force and safety factor all have influence on cylinder block. The failure of hydraulic cylinder due to high pressure and loss of normal working capacity is often manifested in three forms: strength problem, stiffness problem and qualitative problem, and the most important one is strength problem. To ensure the strength of the cylinder block, we must consider the appropriate safety factor