Curvic plate coupling

Our latest new activity is curvic plate coupling. This toothing ensures a very solid and accurate connection between shaft and impeller, for example. Due to the high accuracy, a clearance-free and very strong connection is possible. The teeth can be applied according to the usual standards but also off-standard is not a problem.

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Origin of curvic plate coupling

The principle of the curvic plate coupling is an invention of Mr. Hirth. This engineer has numerous inventions to his name, and later started Hirth AG, a company specialized in camshafts and gears.

A century later, Hirth's inventions are still in use. The curvic plate coupling was a special invention, because 100 years ago there was no other method to meet extreme accuracy and maximum load capacity.

This form-locking, self-centering and easily detachable connecting part, connects shafts, discs, rotors, wheels and cranks with remarkable precision and maximum torque capacity. The design of the curvic plate coupling allows for clearance-free operation and is suitable for alternating loads.

 

Curvic plate couplings today

Regardless of the application, the patent for the curvic plate coupling, developed by Albert Hirth at the beginning of the 20th century, is just as important today. From support during design and layout, to keeping the original balance even after multiple disassemblies, operators benefit from working with GBS Machining Services throughout its lifecycle. At GBS Machining Services we are ready to help you with your curvic plate coupling challenges. We are also able to take care of repair and assembly for you.

 

Spiral curvic plate coupling

The development of curvic plate coupling stems from the spiral bevel gears, which were produced in the same way.

As a rule, three types of curvic plate couplings are distinguished. The fixed curvic plate coupling, a semi-universal curvic plate coupling and a decouple coupling. All these subtypes have the advantage of being clearance-free, can withstand high loads and have excellent precision centering.

 

Fixed curvic plate coupling

The fixed curvic plate coupling is a high precision rigid connection of two elements. You often see the fixed curvic plate coupling in built-up turbine and compressor blades and industrial gas-steam turbines. The curvic plate coupling is used to make the crankshafts from separate and interchangeable parts.

 

Semi-universal curvic plate couplings

The semi-universal curvic plate coupling is - just like the fixed curvic plate coupling - also a precision coupling. The difference is that the semi-universal curvic plate coupling is loosely coupled. This allows 2 degrees of misalignment. The profile of the teeth of one of the parts is often curved, with the result that the load can remain centered and almost 100% uniform movement is transmitted.

 

Curvic plate disconnect coupling

The disconnect couplings are designed to ensure proper tooth contact is maintained when switching on and off. Larger sizes use a helical surface for this purpose, while smaller curvic plate couplings use a specially located tooth bearing.

 

Frequent applications curvic plate coupling

Today, the curvic plate coupling is mainly used in gas turbines and turbo compressors. These are subject to extreme loads, which is why curvic plate couplings are often used here. Curvic plate couplings are used on various applications, for example between gas turbine discs or as a connection between the impeller and pinion shaft. They guarantee high precision in both axial runout and concentricity and reduce bearing loads thanks to their precise, reproducible centering. They also reduce rotating mass compared to press-fit flange connections. Axles and their seals in the drive train of coolant pumps require regular maintenance. In this case, curvic plate coupling offers the option of combining multiple shaft segments into series up to five meters long. Curvic plate couplings guarantee a concentricity of 0.05 mm. In addition, curvic plate couplings keep the original balance, even after being disassembled several times.