Previously, Niu Niu introduced the types and marking methods of DME hose fittings. In this issue, Niu Niu will introduce the components of DME hose fittings in detail.
Hydraulic hose assembly uses hydraulic hose fittings to connect hydraulic hoses to transport hydraulic fluid, which is very important to the overall efficiency and safety of the hydraulic system. Among them, the factors to be considered in the selection of hydraulic hose fitting include the style of hose ferrule and the nipple, the sealing mode of nipple, bending degree and thread, etc. Follow Niu Niu to understand.
The material of the hose ferrule is 20 steel, which makes use of good plastic deformation of the material, so that the outer tooth extrusion rubber hose and the nipple seal match. There are many kinds of ferrules, basically be in the light of different nipples, different working environment,different specific working condition, the structural form is different. Usually the inner side of the ferrule is composed of some grooves or teeth, square groove, trapezoid, zigzag and other types, which needs to be used with different forms of nipples.
Commonly used structural types of ferrules are roughly divided into the following three types:
Wave-Shaped Groove Ferrule
The outer surface of the wave-shaped ferrule is mainly a smooth cylinder, the angle between the hypotenuse of the inner teeth and the axis is 25° – 45°, and the radial edge and the hypotenuse are connected by a fillet of 0.2-0.5 mm, which is generally composed of 3-5 inner teeth.
Trapezoidal Groove Ferrule
The outer surface is a smooth cylinder, the inner surface is a groove with a certain number of trapezoidal gullet, the angle between the hypotenuse and the axis is 25° – 45°, and there is a rectangular groove between each sawtooth, the top end of the tooth is a plane with a width of 1-2 mm, and the tax corner is transited with a fillet of 0.2 mm.
Composite Groove Ferrule
The outer surface is a T-shaped groove corresponding to the dislocation of the inner teeth, and the inner surface is a groove with a certain number of bilateral trapezoidal teeth, which is suitable for matching with the interlock nipple.
In addition to the common ferrule types described above, there are some unique structures. As shown in the figure, the ring-shaped ferrule, unlike the traditional ferrule, has different internal teeth machined in the internal test, but has a separate design of "ring structure", which is locked in the ferrule by extrusion, thus reducing the processing cost. The structural design is ingenious and has the same magical effect.
Types of DME hose ferrules are shown in the following figure. Users can choose appropriate hose sleeves according to actual production requirements.
The common materials of nipples are 20, 35 and 45# steel,while the straight nipples are often made of 35 and 45# steel with strong anti-deformation ability. Considering the process of bending nipples, 20 or 35# steel is generally selected. With the popularization of hot bending technology, 35 and 45# steel can also be used for elbow nipple. The structural characteristics of the nipple are closely related to the crimping form of the hose, and the structures designed by each enterprise are also various. According to the regularity of the structure, the types of the nipple can be roughly divided into saw-tooth structure, rectangular structure and interlock structure, etc.
Commonly known as barb-shaped. It is mainly composed of saw-tooth grooves,the angle between bevel and axis is generally not more than 20°,the top of sawtooth is circular or flat,and the flat and short sides of teeth are smooth rounded corners (0.2 - 0.5 mm), so as to prevent damage to the inner layer of rubber hose during assembly and crimping.
It is mainly composed of several rectangular grooves, with 5~7 grooves forming a sealing groove, the groove depth is generally 0.3-0.6 mm, and the transition surface between the groove top and the groove bottom is generally smooth and rounded with a radius of 0.1-0.3 mm, so as to prevent damage to the inner layer of the rubber hose during assembly and crimping.
Also known as anti-pull-out structure. This type of structure is specially designed to prevent the hose from being pulled out of the hose fitting, and sealing is guaranteed by rectangular structure. Therefore,the inter-lock nipple is actually a fusion of the anti-pull-out structure and the rectangular structure.
According to the comparison of hose fittings standards GB/T 9065, SAEJ516-2019, ISO12151 found that GB/ T 9065 and 1SO12151 classification and description are basically the same, the above two standards and SAEJ516-2019 comparison, only Part 6 of SAEJ516-2019 differs from the above two standards, one is a 60°cone ends and the other is dry seal pipe thread hose fittings. (The specific features of DME nipple will be introduced by Niu Niu next time.)
In addition to the above-mentioned types, there are still various types of fittings: 45° cone, 30° cone, 12° cone hose fittings and so on.
In addition to straight hose fittings, fittings also have various elbows: 22.5° elbow, 30° elbow, 45° elbow, 60° elbow, 90° elbow and so on. The company should select the appropriate fitting style and elbow according to the specific conditions of its own production.
We DME&JDE Group provides users with comprehensive and high-quality hoses,fittings and accessories. We constantly optimize production equipment and design schemes to improve product performance. Higher hydraulic system working pressures, faster speed and more compact assembly spaces are the direction of our constant efforts!
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