Hydraulic nut is a part specially used for mechanical fastening. Its structure can be classified according to different uses, such as thick and thin, high pressure and ultra-high pressure, top ring locking and bottom ring locking, etc. Generally speaking, a hydraulic nut is mainly composed of a cylinder, a piston and a locking ring, and has an oil port with top-mounted and side-entry designs.
The working principle of a hydraulic nut is very simple. Before using the hydraulic nut, it is first necessary to place it on the central axis of the bolt, and then pressurize it and the joint surface tightly, and make the bolt stretch. While the bolt is stretched, the sealing gasket is also compressed, thereby maintaining the clamped state of the connecting surface. As oil pressure in the hydraulic cylinder gradually increases, so does the load exerted on the bolt, allowing the payload to be retained very precisely. Compared with traditional fastening methods, the hydraulic nut requires a minimum space because the load is directly applied to the bolt, and all the force is used to lengthen the bolt, so it can provide safer and more reliable fastening.
Hydraulic nuts also have many unique features. First of all, due to the ultra-high-pressure hydraulic system, the size of the hydraulic bolt can match the original traditional nut without modifying the bolt pair design. Secondly, the size of the hydraulic nut is more compact, eliminating the need for space for a wrench and a socket, thereby improving assembly efficiency. In addition, the working state of the screw is pure tension, and the screw of the same size can provide 20%-30% more output contribution, making it safer and more reliable. And by hydraulically stretching the bolts, the predetermined load is more accurate and the tightening is more reliable. The hydraulic nut adopts the world's most advanced polyurethane/metal composite sealing overall sealing structure. It has fewer sealing parts and the sealing form takes into account low-pressure, high-pressure and ultra-high-pressure sealing. It is especially suitable for work under ultra-high pressure conditions. In addition, the cylinder has good operating rigidity, works smoothly and reliably, and is easy to operate. When the piston overtravels, the system will automatically relieve pressure, so that the operator's mistakes can be effectively corrected by the system. Finally, all bolts can be tightened at the same time, which can make the flange pressing force more uniform.
To sum up, the hydraulic nut is a very unique fastening part with many advantages. Its features include compact size, high assembly efficiency, safety and reliability, high accuracy, etc. In modern industrial production, hydraulic nuts have been widely used and become an indispensable component of many mechanical equipment.
