Introduction to basic knowledge of hydraulic cylinder
Introduction to very widely used hydraulic rods.
Hydraulic transmission has many outstanding advantages, so it is widely used, such as general industrial plastic processing machinery, pressure machinery, machine tools, etc .; construction machinery, construction machinery, agricultural machinery, automobiles, etc. in walking machinery; steel industry Metallurgical machinery, lifting devices, roll adjustment devices, etc .; flood control gates and dam devices for hydraulic engineering, hydraulic cylinders, river bed lifting devices, bridge operating mechanisms, etc .; power plant turbine speed regulators, nuclear power plants, etc .; decks for ships Heavy machinery (winches), bow doors, bulkhead valves, stern thrusters, etc .; giant antenna control devices for special technologies, measuring buoys, lifting and rotating stages; artillery controls for military industries, ship stabilizers, aircraft Simulation, retractable device of aircraft landing gear and rudder control device.
The hydraulic cylinder is an actuator that converts the pressure energy output from the hydraulic pump into mechanical energy. It is mainly used to output linear motion (including swing motion).
1. Classification of hydraulic cylinders According to their structural forms, hydraulic cylinders can be divided into three types: piston cylinder, plunger cylinder and swing cylinder. The piston cylinder and plunger cylinder realize reciprocating motion, output thrust and speed, and the swing cylinder can achieve reciprocating swing less than 360 degrees, outputting torque and angular velocity. In addition to the single use of hydraulic cylinders, several hydraulic cylinders can also be combined or combined with other mechanisms to complete special functions.
Analysis and treatment of hydraulic cylinder creep failure:
1. The sealing ring is pressed too tightly. Treatment method: Adjust the sealing ring so that it is not loose or tight, and ensure that the piston rod can be pulled back and forth by hand.
2. Negative pressure is formed somewhere in the cylinder. Treatment method: find out where the hydraulic cylinder forms a negative pressure and seal it; and exhaust it.
3. There is air in the cylinder or pipeline. Treatment method: set exhaust device; if there is no exhaust device, the hydraulic system can be operated to reciprocate several times with the maximum stroke to force the air to be removed; seal the system and pipeline.
4. The piston and the piston rod have different axes, and the processing method: Install the two together and place them on a V-shaped block for correction so that the same-degree error is within 0.04mm; replace the piston with a new one.
5. The piston rod is not straight (with bending), processing method: Place it on the V-shaped block alone or with the piston, use a press to control the straight and use a dial indicator to correct the straightening.
The hydraulic cylinder is composed of a cylinder bottom, a cylinder barrel, a cylinder head, a piston and a piston rod. One end of the cylinder barrel is welded with the cylinder bottom as a whole, and the other end is connected with the guide sleeve and the cylinder barrel through a snap key, and oil ports A and B are provided at both ends. The piston is fixed to the piston rod by a key, a key cap and a retaining ring. The support ring on the piston supports the piston. The seal between the two chambers in the cylinder is ensured by the inner bore of the piston and the O-ring seal on the piston end, and two Y-shaped seal rings and retaining rings installed on the outer edge of the piston in opposite directions. In order to prevent oil from leaking, the outer edge of the guide sleeve is provided with an O-shaped seal ring, and the inner hole is sealed with a Y-shaped seal ring and a retaining ring. The role of the dust ring is to scrape off the dust sticking to the exposed part of the piston rod. On the connecting earrings at the bottom of the cylinder and the top of the piston rod, there are pin holes for installation or connection with working machinery. The pin holes must ensure that the center of the hydraulic cylinder is under pressure. The pin hole is supplied with lubricating oil by a grease nipple. In addition, in order to reduce the impact of the piston on the cylinder bottom or the cylinder head at the end of the stroke, there are gap throttling buffer devices at both ends. When the piston quickly moves near the cylinder bottom, the buffer plunger at the end of the piston rod will block the oil return port. This forces the remaining oil to squeeze out only through the gap in the plunger, creating hydraulic resistance, which slows down the speed of the hydraulic cylinder to achieve cushioning. The reverse stroke is also buffered in the same principle.