Hydraulic coupling

Hydraulic coupling

• Introduce

The working principle is using the same cone between the inner and outer sleeve, inject the radial and axial hydraulic oil into outer sleeve at the same time, making it moving the design value of the position; then lifted the radial and axial oil, to make the outer sleeve shrinks and compressed onto the inner sleeve, the inner sleeve compressed tightly onto the shaft, through the produced friction between each other to transfer torque.

Hydraulic coupling installation location in ship shafting:

• Between the intermediate shaft and gear box;
• Between the intermediate shaft and intermediate shaft;
• Between the intermediate shaft and stern shaft;
• The stern shaft(or intermediate/reduction gear box output shaft) and between the propeller shaft;

The hydraulic coupling mainly has the following type:

We can design and custom-made hydraulic coupling with special requirements.

Hydraulic coupling is an important and key part of the ship’s main thrust shafting. Through it, the gear box, the intermediate shaft and the propeller shaft are connected, and the power of the main engine is transmitted to the propeller to push the ship sailing. In shafting, sleeve hydraulic coupling is generally used for connection between shaft and shaft, and flange coupling is often used for connection between shaft and gearbox output flange or intermediate shaft flange.

Comparison and analysis of key-less and key coupling:

• The axle diameter of key-less coupling is 10~15% smaller than that of key-less coupling, then the stern shaft seal, stern tube bearing and stern tube are at least 2 grades smaller, reducing the total construction cost of the whole shaft system.
• Machining key way on propeller shaft, due to high precision, difficulty and high scrap rate, will increase the processing cost;
• For removable flange coupling, in addition to machine the key way, but also need to match grind, the hydraulic coupling does not need this process.
• Because of its conical connection with the shaft, key coupling can not compensate for the error caused by the deformation of hull structure. Therefore, it is necessary to set a short shift to compensate for the adjustment, and then add a set of connecting bolts. The hydraulic coupling connected with the shaft by cylindrical hole, it can be installed in the shaft within a certain range of arbitrary positioning, also can economize the adjustment shaft and connecting bolts.
• Shaft with key way will produce too much concentrated stress, result in crack and lose power when operation,  but if use hydraulic coupling, key less joint can effectively avoid the accident. Greatly improve the safety factor.

Advantage:

• The inner sleeve of the hydraulic coupling adopts special surface treatment of independent intellectual property rights.
• The film has good lubricity and plasticity, which can prevent surface pulling damage and biting, so that the coupling can be installed and disassembled for so many times.
• After surface treatment, the diameter of inner sleeve has no deformation and the surface hardness is improved.
• Increase the friction coefficient of inner sleeve surface to 0.3~0.5.

Produce diagram: