Rigid Shaft Coupling

Case Study: Rigid Shaft Couplings

Design Brief This coupling is required to provide torque from an engine to a variety of propellers. There are three different sources which could provide the required torque. All the specifications of the concepts fulfil the design constraints.

University of Malta

Department of Industrial and Manufacturing Engineering

Case Study - Rigid Shaft Coupling 24 November 2012 08:46

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Catalogue

University of Malta

Department of Industrial and Manufacturing Engineering

Name: Shaft coupling A Description: Rigid coupler with spline

Number of parts: 2 Temperature Range (째C): -40 to 350 Maximum speed (rpm): 800 Angular misalignment (째): 0.45 Nom. Torque (Nm): 12 Approximate cost (Euros): 23 Comments: The rigid coupling has internal features

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Bolt tightening torque (Nm): 6 Material: Steel Mass (kg): 0.761 Axial misalignment (mm): 1.20 Max. Torque (Nm): 19

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Name: Shaft coupling B Description: Rigid jaw shaft coupling

Number of parts: 5 Temperature Range (째C): - 5 to 250 Maximum speed (rpm): 1000 Angular misalignment (째): 0.82 Nom. Torque (Nm): 2 Approximate cost (Euros): 16 Comments:

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Bolt tightening torque (Nm): 12 Material: Stainless Steel and Plastic Mass (kg): 0.602 Axial misalignment (mm): 1.65 Max. Torque (Nm): 4.1

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Name: Shaft coupling C Description: One piece rigid shaft coupling (keyed)

Number of parts: 5 Temperature Range (째C): -20 to 555 Maximum speed (rpm): 10000 Angular misalignment (째): 0.76 Nom. Torque (Nm): 12 Approximate cost (Euros): 29 Comments: The shaft must have a key

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Bolt tightening torque (Nm): 10 Material: Stainless Steel Mass (kg): 0.894 Axial misalignment (mm): 0.86 Max. Torque (Nm): 20

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Name: Shaft coupling D Description: One piece rigid shaft coupling (no-key)

Number of parts: 5 Temperature Range (째C): -20 to 555 Maximum speed (rpm): 12000 Angular misalignment (째): 0.70 Nom. Torque (Nm): 15 Approximate cost (Euros): 32 Comments:

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Bolt tightening torque (Nm): 10 Material: Stainless Steel Mass (kg): 0.882 Axial misalignment (mm): 0.81 Max. Torque (Nm): 24

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Name: Shaft coupling E Description: Two Piece shaft coupling (keyed)

Number of parts: 10 Temperature Range (째C): -20 to 555 Maximum speed (rpm): 15000 Angular misalignment (째): 0.35 Nom. Torque (Nm): 18 Approximate cost (Euros): 43 Comments: The shaft must be keyed

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Bolt tightening torque (Nm): 10 Material: Stainless Steel Mass (kg): 0.963 Axial misalignment (mm): 0.27 Max. Torque (Nm): 31

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Name: Shaft coupling F Description: Two Piece shaft coupling (no key)

Number of parts: 10 Temperature Range (째C): -20 to 555 Maximum speed (rpm): 15000 Angular misalignment (째): 0.31 Nom. Torque (Nm): 16 Approximate cost (Euros): 38 Comments:

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Bolt tightening torque (Nm): 10 Material: Stainless Steel Mass (kg): 0.963 Axial misalignment (mm): 0.34 Max. Torque (Nm): 28.5

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Name: Shaft coupling G Description: Keyed shaft coupling

Number of parts: 17 Temperature Range (째C): -20 to 420 Maximum speed (rpm): 11500 Angular misalignment (째): 0.04 Nom. Torque (Nm): 25 Approximate cost (Euros): 62 Comments: Shaft needs to be keyed

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Bolt tightening torque (Nm): 15 Material: Stainless Steel Mass (kg): 1.21 Axial misalignment (mm): 0.21 Max. Torque (Nm): 40

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Name: Shaft coupling H Description: Keyed shaft coupling with external spline

Number of parts: 4 Temperature Range (째C): 15 to 80 Maximum speed (rpm): 400 Angular misalignment (째): 0.98 Nom. Torque (Nm): 5 Approximate cost (Euros): 8 Comments:

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Bolt tightening torque (Nm): 15 Material: Plastic and steel Mass (kg): 0.210 Axial misalignment (mm): 0.82 Max. Torque (Nm): 9

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Meeting Notes

University of Malta

Department of Industrial and Manufacturing Engineering

Rigid Shaft Coupling A 19 November 2012 19:34

Spline is very difficult to machine - it is expensive in terms of resources.

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Rigid Shaft Coupling B 19 November 2012 19:43

Allen Keys (x2)

The plastic component has a very poor degradation resistance to sea and fresh water It has also a relatively low operating temperature.

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Rigid Shaft Coupling C

We had problems with this shaft due to degradation in sea water Fasteners are easy to assemble

Needs to be machined - additional cost

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Rigid Shaft Coupling D 19 November 2012 19:47

Has no key ‌easier to fabricate

4 Allen keys, our current assembly line can easily cope with 4 fasteners per interface

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Rigid Shaft Coupling E 19 November 2012 19:30

Open structure is easy to machine.

Yet on the other hand we need to machine the key

Too many fasteners !

During the meeting the production engineers pointed out that we would need to double the assembly lines.

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Rigid Shaft Coupling F 19 November 2012 19:51

No key = No machining

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Rigid Shaft Coupling G 19 November 2012 20:01

Shaft Key Very complex assembly

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Substantial material to be removed according to our production engineers

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Rigid Shaft Coupling H 19 November 2012 20:03

Only 2 Allen keys required

Problems with angular alignment

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People

University of Malta

Department of Industrial and Manufacturing Engineering

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