What are Hydraulic Locknuts?
They are very special nuts that allow bolts with large diameters to be easily tensioned to facilitate high and accurate preloads. The internal jacking system gets activated; therefore, the effort needed to tighten a large-size bolt is reduced. Hydraulic locknuts also reduce the time to mount or dismount bearings during installation and removal, which helps bearing to last longer. Since a manual hydraulic pump performs heavy-duty assembly and disassembly, it takes lesser time than regular methods using tools like a spanner and hammer.
The nut depends on hydraulic forces to execute proper bearing seating into the shaft. First, the bearing is hydraulically pressed into the shaft at a specified pressure (PSI), and after that, a dial indicator and additional hydraulic pressure are used to measure the seating.
Working Principle of Hydraulic Nuts
A hydraulic locknut follows the principle that once hydraulic oil is put into the nut using a high-pressure oil pump, it generates enough force to push the piston making installation and disassembly of the bearing easy. Using high-pressure oil, the hydraulic nut creates enough thrust on the shaft and tension on the shaft sleeve to facilitate the shaft and sleeve connection.
The hydraulic locknut is a very efficient bolt assembly that is ideal for cramped spaces and fastening heavy-duty loads under mechanical vibration. The hydraulic nut takes help from a hydraulic cylinder to create an external force to enable the bolt to elongate within its elastic range. Once the bolt is elongated, the lock ring is tightened to secure the bolt while the ring is locked in the elongated position.
The hydraulic cylinder is situated at the bolt’s central axis and facilitates a suitable axial stretching of the bolt. The tension in the bolt determines the clamping force needed for bolt tightening. The bolt gets stretched through pressure on the hydraulic nut, which allows the hydraulic nut to reach close to the joint surface. Eventually, the axial deformation in the bolt is locked, allowing the remaining bolt load to be locked in the nut. Since the bolt is already bearing the load, the entire force is used for the bolt elongation. Therefore, you can easily reduce the space required for load generation.
Application of HMV Hydraulic Locknuts
HMV Hydraulic locknuts are perfect for bolts that require regular assembly and disassembly. Besides, they also help pre-tighten large bolts and lock huge components. You can also use them like hydraulic interference to connect disassembly tools. Installing and removing bearings on tapered shafts or adapter sleeves are complicated and time-consuming, but HMV Hydraulic locknuts can solve such problems.
Hydraulic locknuts have a lot of applications in metallurgy, copper, aluminium, and paper industry. Besides, they are also used for hydraulic locking on slitting machines, installing and removing propellers and rudder shoes and disassembling high-pressure connection surfaces like train wheels, couplings, flywheels and gears.
Features of Hydraulic Locknuts
- It makes mounting and dismounting of bearings on tapered shafts and sleeves convenient.
- It facilitates accurate and reliable adjustments in bearing clearance.
- It helps in pushing out the piston after being properly lubricated by oil.
- It contains quick connection coupling for fitting hydraulic pumps.
- It is suitable for shaft diameters of 50 mm to 1000 mm.
- It makes mounting and dismounting of bearings quick.
- It has a unique design of Back & Forth.
- It comes in both metric and inch threads.
Benefits of using HMV hydraulic locknuts
- It’s ideal for a place experiencing different types of vibration, fast rotation, high-power equipment and cramped spaces;
- It’s accurate, lightweight, efficient and economical;
- You can provide them with a manual hydraulic pump, pneumatic, hydraulic pump and electric hydraulic pump;
- You can use several hydraulic nuts simultaneously;
- The measuring ring in the design can help you to find the axial distance required by the bearing accurately;
- You can use a withdrawal sleeve and hydraulic nut of the same specification during installation and disassembly, which is missing in patented Hydraulic locknuts.
- You get an extra screw in the measuring ring to replace the damaged O-ring, which saves time and money;
- You can conveniently install sealed bearings without measuring the internal clearance of the bearing.
Spare parts and accessories of hydraulic locknuts
You get a maintenance kit and a spare set of piston seals as standard accessories. There is also a lubricant tube, nuts of size HMV(C) 54E and more for easy nut threading, and two Tommy bars and four mating holes on their front face. You get following spare parts and accessories:
- Ball Plug
- Quick Connection Nipple
- Maintenance Set – Threaded Pins, Hexagonal Keys
- Hydraulic Pumps
- Dial indicators
- Hose pressure pipe
- Special threads and sizes available on request
How to handle leakage from the nut?
If oil from the hydraulic nut leaks, it may be due to a torn or damaged seal, which should be immediately replaced. You can easily push the piston out of the ring using threaded pins. After removing the O-rings and cleaning the grooves, the new O-rings should be fixed from the spare set of O-rings supplied with the nut.