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Rigid shaft coupling
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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.
Department of Industrial and
Manufacturing Engineering University of
Malta
Case Study - Rigid Shaft Coupling 24 November 201208:46
10/12/2012 211/12/2012 2
Catalogue
Department of Industrial and
Manufacturing Engineering University of
Malta
Name: Shaft coupling A
Description: Rigid coupler with spline
Number of parts: 2 Bolt tightening torque (Nm): 6
Temperature Range (°C): -40 to 350 Material: Steel
Maximum speed (rpm): 800 Mass (kg): 0.761
Angular misalignment (°): 0.45 Axial misalignment (mm): 1.20
Nom. Torque (Nm): 12 Max. Torque (Nm): 19
Approximate cost (Euros): 23
Comments:
The rigid coupling has internal features
11/12/2012 4
Name: Shaft coupling B
Description: Rigid jaw shaft coupling
Number of parts: 5 Bolt tightening torque (Nm): 12
Temperature Range (°C): - 5 to 250 Material: Stainless Steel and Plastic
Maximum speed (rpm): 1000 Mass (kg): 0.602
Angular misalignment (°): 0.82 Axial misalignment (mm): 1.65
Nom. Torque (Nm): 2 Max. Torque (Nm): 4.1
Approximate cost (Euros): 16
Comments:
11/12/2012 5
Name: Shaft coupling C
Description: One piece rigid shaft coupling (keyed)
Number of parts: 5 Bolt tightening torque (Nm): 10
Temperature Range (°C): -20 to 555 Material: Stainless Steel
Maximum speed (rpm): 10000 Mass (kg): 0.894
Angular misalignment (°): 0.76 Axial misalignment (mm): 0.86
Nom. Torque (Nm): 12 Max. Torque (Nm): 20
Approximate cost (Euros): 29
Comments:
The shaft must have a key
11/12/2012 6
Name: Shaft coupling D
Description: One piece rigid shaft coupling (no-key)
Number of parts: 5 Bolt tightening torque (Nm): 10
Temperature Range (°C): -20 to 555 Material: Stainless Steel
Maximum speed (rpm): 12000 Mass (kg): 0.882
Angular misalignment (°): 0.70 Axial misalignment (mm): 0.81
Nom. Torque (Nm): 15 Max. Torque (Nm): 24
Approximate cost (Euros): 32
Comments:
11/12/2012 7
Name: Shaft coupling E
Description: Two Piece shaft coupling (keyed)
Number of parts: 10 Bolt tightening torque (Nm): 10
Temperature Range (°C): -20 to 555 Material: Stainless Steel
Maximum speed (rpm): 15000 Mass (kg): 0.963
Angular misalignment (°): 0.35 Axial misalignment (mm): 0.27
Nom. Torque (Nm): 18 Max. Torque (Nm): 31
Approximate cost (Euros): 43
Comments:
The shaft must be keyed
11/12/2012 8
Name: Shaft coupling F
Description: Two Piece shaft coupling (no key)
Number of parts: 10 Bolt tightening torque (Nm): 10
Temperature Range (°C): -20 to 555 Material: Stainless Steel
Maximum speed (rpm): 15000 Mass (kg): 0.963
Angular misalignment (°): 0.31 Axial misalignment (mm): 0.34
Nom. Torque (Nm): 16 Max. Torque (Nm): 28.5
Approximate cost (Euros): 38
Comments:
11/12/2012 9
Name: Shaft coupling G
Description: Keyed shaft coupling
Number of parts: 17 Bolt tightening torque (Nm): 15
Temperature Range (°C): -20 to 420 Material: Stainless Steel
Maximum speed (rpm): 11500 Mass (kg): 1.21
Angular misalignment (°): 0.04 Axial misalignment (mm): 0.21
Nom. Torque (Nm): 25 Max. Torque (Nm): 40
Approximate cost (Euros): 62
Comments:
Shaft needs to be keyed
11/12/2012 10
Name: Shaft coupling H
Description: Keyed shaft coupling with external spline
Number of parts: 4 Bolt tightening torque (Nm): 15
Temperature Range (°C): 15 to 80 Material: Plastic and steel
Maximum speed (rpm): 400 Mass (kg): 0.210
Angular misalignment (°): 0.98 Axial misalignment (mm): 0.82
Nom. Torque (Nm): 5 Max. Torque (Nm): 9
Approximate cost (Euros): 8
Comments:
11/12/2012 11
Meeting Notes
Department of Industrial and
Manufacturing Engineering University of
Malta
Spline is very difficult to machine - it is expensive in terms of resources.
Rigid Shaft Coupling A19 November 201219:34
10/12/2012 1311/12/2012 13
The plastic component has a very poor degradation resistance to sea and fresh waterIt has also a relatively low operating temperature.
Allen Keys (x2)
Rigid Shaft Coupling B19 November 201219:43
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Needs to be machined
Rigid Shaft Coupling C
10/12/2012 1511/12/2012 15
We had problems with this shaft due to degradation in sea water
Fasteners are easy to assemble
- additional cost
Has no key …easier to fabricate
4 Allen keys, our current assembly line can easily cope with 4 fasteners per interface
Rigid Shaft Coupling D19 November 201219:47
10/12/2012 1611/12/2012 16
Too many fasteners !
During the meeting the
out that we would need to
Open structure is easy to machine.
Yet on the other hand we
Rigid Shaft Coupling E19 November 201219:30
10/12/2012 1711/12/2012 17
need to machine the key
production engineers pointed
double the assembly lines.
No key = No machining
Rigid Shaft Coupling F19 November 201219:51
10/12/2012 1811/12/2012 18
Very complex assembly
Shaft Key Substantial material to be removed according to our
Rigid Shaft Coupling G19 November 201220:01
10/12/2012 1911/12/2012 19
production engineers
Problems with angular alignment
Only 2 Allen keys required
Rigid Shaft Coupling H19 November 201220:03
10/12/2012 2011/12/2012 20
People
Department of Industrial and
Manufacturing Engineering University of
Malta
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