Five advantages of hydraulic coupling over traditional coupling

2022-08-03 15:42

Traditional couplings mainly rely on various key connections to transmit torque. For equipment with relatively large torque transmission, the keyway on the shaft will seriously weaken the strength, stiffness and load-bearing capacity of the shaft. Blindly increasing the radius of the shaft, on the one hand, will increase the size of the entire equipment, making the equipment large and heavy, and will also increase the production cost; on the other hand, simply increasing the radial size of the shaft cannot get the desired effect.

In addition, large couplings are required to be able to operate stably for a long time during the working process. In order to ensure the concentricity of the connected two shafts and avoid vibration, generally large couplings and shafts are fitted with transition fit or interference fit. This type of coupling is difficult to install and remove. Smaller size couplings can be assembled with the shaft by mechanical beating or pressing, but the inner wall of the coupling sleeve and the shaft are often strained during the assembly process, while large couplings The device simply cannot be assembled by mechanical beating.

In order to avoid strain and assembly difficulties, large couplings are generally assembled by hot-loading or temperature difference method during the installation process. First, the coupling sleeve is heated or the shaft is cooled, and then the coupling and shaft are quickly assembled together. After the temperature is restored, the coupling sleeve and the shaft will be tightly held. The maintenance and disassembly of the coupling is more difficult than the installation. Forcible disassembly often damages the coupling and shaft. At the same time, the disassembly process takes a long time, which seriously affects the normal operation of the equipment and brings significant damage. Economic losses.

The emergence of hydraulic coupling solves these problems. By injecting a little hydraulic medium into a sleeve with a sandwich, the pressure can be distributed and evenly transmitted to the contact surface of the shaft and the hub through a screw/piston or an external working pump. The sleeve with a sandwich surrounds the surrounding The hub expands evenly, resulting in an even contact pressure. Compared with the general traditional keyed coupling, the hydraulic coupling has a more compact structure, faster installation and disassembly, easier positioning, no damage to the joint surface, and easier disassembly and assembly. 

 

Compared with traditional rigid couplings for shafting, hydraulic couplings have five major advantages 

(1) The integrity of the drive shaft structure is protected. High-strength shafting is usually made of alloy steel material, and stress concentration is prone to occur in the part where the size of the shaft section changes abruptly. The hydraulic coupling is a keyless connection, and there is no need for a keyway on the shaft, so the sudden change of the section of the transmission shaft is avoided, the stress concentration is reduced, and the high-strength performance of the shafting is ensured.

(2) The space occupancy rate is low. The power range transmitted by the hydraulic coupling is wide, so in the case of transmitting the same torque, the wall thickness is smaller and the radial space is not required. It is very suitable for the occasions where the volume saturation of the installation chamber is large and the radial dimension of the coupling is small. 

(3) The hydraulic coupling is easy to assemble and disassemble and has high safety. The hydraulic coupling consists of a hardened steel elastic annular sandwich and flange. The elastic annular interlayer is filled with hydraulic medium, and the pressure regulating screw and piston are installed in the flange to change and maintain the hydrostatic pressure in the annular interlayer, or to provide pressure from an external working pump, relying on the friction force between the mating surfaces. It transmits torque and releases oil pressure to elastically restore and deform the inner jacket and becomes a clearance fit, which is quick and easy to install. 

(4) The hydraulic coupling meets the requirements of transmitting large torque. The hydraulic coupling and the shaft realize a keyless interference fit, and rely on the friction between the mating surfaces to transmit a large torque, which is suitable for high-strength and high-torque occasions. 

(5) It has better economy. The hydraulic coupling has stable performance, reliable operation, simple management, and can achieve rapid and multiple non-destructive disassembly and assembly. 

Because of the above advantages, the use of hydraulic couplings is becoming more and more popular. Especially when it is used in the occasion of heavy-duty transmission shafting.

 

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