Home > Industry knowledge > Content

Application principle of hydraulic nut on elevator


In the past, traditional nuts could no longer meet the tightening requirements of many heavy machinery fields. At this time, a new type of powerful fastening element hydraulic nut appeared abroad. Gradually in China, hydraulic nuts have also become power generation, aviation and hydraulic lifting machinery. Fastening elements widely used in many heavy machinery fields. People use it reasonably and let it play the role of strong fastening and strong anti-loosening.

The hydraulic nut is an advanced bolt fastening system. It works on the same principle as the hydraulic tensioner. It is mainly used for the fastening of fastener devices in narrow spaces and heavy load sensation machinery. It reforms the traditional tightening method, using a hydraulic system to make the tightened bolts through pure axial stretching to accurately reach the predetermined load, then mechanically lock on the fastener, and then complete the tightening operation. Since the screw is only subjected to pure tensile force, the pretension of the bolt pair can be increased by 20%-30%.

The hydraulic cylinder is located on the central axis of the bolt, and is used to axially stretch the bolt to complete the required amount of bolt stretching. It is this amount of bolt tension that determines the clamping force required for bolt tightening. When the hydraulic nut is pressurized, the bolt is stretched, and the hydraulic nut and the joint surface are tightly attached. Then the axial deformation of the bolt is locked, that is, the load of the remaining bolt is locked in the nut. There are seals between many connecting surfaces. The gasket only works when the connection surface is compressed, so it is particularly important that the connection surface always remains clamped. The load applied to the bolt is in direct proportion to the hydraulic pressure in the hydraulic cylinder. Such a plan can retain the useful load very accurately. Since the load is directly applied to the bolt, and all the forces are used to lengthen the bolt, the space required for load generation can be small.

The characteristics of the hydraulic nut are: 1. Due to the selection of the ultra-high pressure hydraulic system, the size of the hydraulic bolt matches the original traditional nut, and there is no need to modify the original bolt pair planning. 2. The space of the wrench and sleeve is not required, and the size of the bolt pair is more compact; 3. Screw operation and pure tension, the same scale screw can provide 20%-30% more contribution, the bolt pair is safer; 4. Through hydraulic tension bolts, the booking load is more accurate and the fastening is more reliable; 5. Selection At present, the overall sealing structure of polyurethane/metal composite seals in the world has few sealing parts, and the sealing form takes into account low-pressure, high-pressure and ultra-high pressure seals, and is particularly suitable for operation under ultra-high pressure; 6. The oil cylinder has good working rigidity, stable and reliable operation, and operation Convenient; 7. The system actively relieves pressure when the piston overtravels, and the operator's mistakes can be effectively corrected by the system; 8. All bolts can be tightened together to greatly improve the power of the device, and the pressing force of the flange is more uniform.