What are the components of the hydraulic hose joint assembly?
Hydraulic hose joint assembly
The hydraulic hose joint assembly is composed of two parts: a hose and a metal joint. It is mainly classified according to the operating pressure scale and the connection method of the hose and the joint.
1. Classified by scale of work pressure
The operating pressure is below 3mpa, and the most important thing is the hydraulic hose woven with cotton thread. It is mainly used to control oil circuit, car brake pipeline and some hydraulic machine tools.
The operating pressure is between 3～10mpa, the most important is the ⅰ, ⅱ type large diameter hydraulic hose made of steel wire. Mainly used for medium and low pressure oil circuit and return oil circuit.
The operating pressure is between 10～31.5mpa, and the first is steel wire weaving type ⅰ, ⅱ, ⅲ and steel wire wound pipes below 25. Mainly used in high-pressure systems.
The operating pressure is above 31.5mpa, and the most important thing is to weave the steel wire wound pipe with the diameter below 31.5. With the development of ultra-high-pressure and high-power hydraulic machinery, the demand for it is increasing.
2. According to the connection method of the hose and the joint, there are: detachable type and withholding type
1) Withholding hose joint assembly, after the hose is pre-matched with the connection, external force is used to force the connector jacket to shrink inward to a certain degree in the cold state, so that the hose and the joint can be connected firmly.
2) Detachable assembly, the joint and hose are passed through a core with an outer cone to shrink the inner rubber layer of the hose, making it close to the inner cone of the joint sleeve. That is, the inverted tapered gap formed between the core and the joint sleeve is connected by squeezing the outer and inner rubber layers of the rubber tube together. But the connection quality is unstable. Therefore, domestic professional manufacturers generally choose the withholding type.
The connection between the structure and function of the hydraulic hose joint assembly
1) The hydraulic hose is composed of an inner rubber layer, a reinforcement layer and an outer rubber layer. The inner rubber layer directly touches the oil. Therefore, it is required that it should not be corroded by fluids and be leak-proof under long-term operating conditions. Under the effect of the enhanced layer, it can accept certain pressure. Therefore, nitrile rubber should be used. In addition to the rubber material, the primary factors affecting the function are the hardness, thickness and deformation of the inner rubber layer. The hardness and deformation have a great influence on the sealing function. Generally, with high hardness and small deformation after shrinkage, the sealing function is better. Generally, the hardness is 70-80 Shore hardness, and the shrinkage deformation is 50%. The thickness of the inner rubber layer is 1.5～2.5mm. If it is too thick, its flow will be added during crimping, and the remaining glue will accumulate in the touch end surface of the joint core sleeve and the hose, reducing the flow cross-section; too thin will be compressed during crimping crack. At the same time, the uniformity of the wall thickness of the inner rubber layer is also very important. If the thickness is uneven, one side will be cracked and the other side will be piled up after shrinking. The pits on the surface of the inner rubber layer are also an important factor affecting the functional quality.
2) The hydraulic hose mainly relies on the reinforcement layer to receive pressure. The woven hose is glued to the surface and the inner layer of glue. Because the steel wires in the same woven layer touch each other, when they receive dynamic pressure, they will form friction between the steel wires and affect its durability. . The winding pipe is composed of two layers with different winding directions to form a working layer, and there is a center glue between the two layers, so there is no interpenetrating point between the two steel wires of the same working layer. Therefore, it will not be the same as the interspersed twists and turns between the steel wires when receiving dynamic pressure, which will cause stress concentration or conflict wear. Therefore, it has good durability and can withstand high pressure.
3) The outer rubber layer of the hydraulic hose is adhered to the reinforcement layer for maintenance effect, and neoprene is generally used. Attention should be paid to avoid aging and cracking which will affect the life of the entire hose.