The relationship between the structure and performance of the hydraulic hose joint assembly.
1, rubber hose,
The hydraulic hose consists of an inner rubber layer, a reinforcement layer and an outer rubber layer (as shown in Figure 7). The inner rubber layer is in direct contact with the oil, so it is required that it should not be corroded by the fluid in a long-term working condition and can prevent leakage.Can withstand certain pressure under the action of reinforcement layer.Therefore, it is appropriate to use nitrile rubber, in addition to the rubber, the main factors affecting the performance and the hardness of the inner layer, thickness and permanent deformation.Hardness and permanent deformation have great influence on sealing performance.General hardness, compression after the permanent deformation of small, sealing performance is better.Generally at 70 ~ 85 Shaw hardness, compression permanent deformation of 50% is the best.The thickness of the inner rubber layer should be 1.5 ~ 2.5mm. If it is too thick, the flow momentum will increase during the clamping process, which will cause the excess glue to accumulate in the contact end face of the connector sleeve and the rubber tube, reducing the flow cross section.Too thin and you get frazzled when you pull in pressure.At the same time, the thickness uniformity of the inner adhesive layer is also very important.If the thickness is not uniform, the compression will cause one side of the fracture, one side of the heap of glue.The pitting on the surface of the inner rubber layer is also an important factor affecting the performance and quality.
2) The hydraulic hose mainly relies on the reinforcement layer to bear the pressure.Braided rubber hose is glued tightly by glue paste and internal and external glue layer. Due to the mutual contact between steel wire in the same braided layer, friction between steel wire will affect its durability due to different expansion and contraction under dynamic pressure.The winding pipe is formed by two layers with different winding directions to form a working layer. There is an intermediate glue between the two layers, so there is no intersection point between the two layers of steel wires in the same working layer.Therefore, stress concentration or friction wear will not be formed under the same dynamic pressure as the cross bending of steel wire.Therefore, good durability, can withstand high pressure.
3) The outer adhesive layer of the hydraulic hose is glued on the reinforcing layer for protection, generally using neoprene.Attention should be paid to prevent the aging of the crack and affect the life of the entire hose.
The gusset rubber hose connector is composed of a connector core, a nut and a jacket.
1) Connector core, the main factors affecting the performance of the core rod length, structure shape, wall thickness and material.From the point of view of sealing and preventing pulling out, the longer the core rod is, the better, but too long will waste material and increase the manufacturing cost.In addition, in order to prevent the core end from causing heap glue, the general design requires its length to be slightly longer than the coat.
2) The core rod has a variety of structural shapes, mainly including R groove (Figure 1) and sawtooth groove (Figure 2), which can increase the friction surface and provide rubber flow capacity groove.At present, the steel wire braided tubes are all made of R grooves, while the wound tubes with higher pressure are made of serrated grooves.
3) material: joint core materials generally 20 #, 35 #, 45 # carbon constructional steel, to prevent to withhold the core hole deformation and increase liquid resistance, core wall thickness should be paid attention to the selection, the average of 1.5 ~ 3.5 mm, take big size larger value, core and the cylindrical rubber hose inner hole does not allow excessive interference, can damage the glue, make putting with difficult.Too small inner hole of core will increase liquid resistance and cause pressure drop loss.As the core diameter of the outer circle by the above ****.And the size of the hose itself is large, in order to meet the minimum performance of the joint assembly through the requirements, must be solved by optimizing the amount of the holding.
3.Connector coat.Its shape is shown in Figure 3.The size of the inner hole should be larger than the size of the reinforcement layer, otherwise it can not be loaded, or even cause the reinforcement layer completely scattered.The general clearance is 1 ~ 1.5mm.The groove inside the coat will directly affect the joint quality.At present, there are straight holes without grooves, saw grooves and annular and saw grooves combined.(figure 3)
Cotton thread (fiber) braided rubber hose because of low pressure, small pulling force, the use of slotless structure.The reinforcing layer of steel wire braided rubber hose is easy to produce bending deformation when it is pressed.Generally, the steel wire wound pipe has many layers, and the maximum thickness of the reinforcing layer is up to 3.6mm on one side. In order to make the reinforcing layer form wavy deformation during the clamping process, a combination of annular and sawtooth groove must be adopted for the embedding slot, which is 2/3 wider than the sawtooth groove and has a stronger anti-pulling force.