Shrink-fit stress coupling for a shaft of differing materials
AssigneeHamilton Sundstrand Corporation
InventorJun Shi
Life of this patent
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Abstract
A shrink-fit coupling includes a discontinuous ring between a ceramic stub shaft of a turbine rotor and an inner diameter r2 of a metallic shaft which typically supports a compressor rotor. If the materials for the ceramic stub shaft and the discontinuous ring are pre-determined and the radius of the ceramic stub shaft is also given, then the inner radius r2 of the shaft should be chosen by the equation: r2=(CTE1−CTE2)/(CTE3−CTE2) r1.
Claims9
A gas turbine rotor assembly comprising:
- a stub shaft of a turbine rotor manufactured of a ceramic material, said stub shaft defining an outer radius of r1;
- an outer rotor shaft manufactured of a metallic material said outer rotor shaft defining an inner radius of r2;
- and
- a discontinuous ring between said stub shaft and said outer rotor shaft,
- where r2 is defined by the equation:
- r2=(CTE1−CTE2)/(CTE3−CTE2) r1 where:
- CTE1 is a coefficent of thermal expansion for the stub shaft;
- CTE2 is a coefficent of thermal expansion for the discontinous ring;
- CTE3 is a coefficent of thermal expansion for the outer shaft.
A method of mounting an inner shaft to an outer rotor shaft, the outer rotor shaft having inner radius r2 which receives the inner shaft having an outer radius of r1 and a discontinuous ring having an inner radius of r1 and outer radius of r2, the discontinuous ring mounted between the inner shaft and the outer rotor shaft, said method comprising the steps of:
- (1) determining r2 by the equation:
- r2=(CTE1−CTE2)/(CTE3−CTE2) r1 where:
- CTE1 is a coefficent of thermal expansion for the inner shaft;
- CTE2 is a coefficent of thermal expansion for the discontinuous ring;
- and CTE3 is a coefficent of thermal expansion for the outer rotor shaft;
- and
- (2) shrink fitting the outer rotor shaft and the discontinuous ring to the inner shaft.
A gas turbine rotor assembly comprising:
- a stub shaft of a turbine rotor manufactured of a ceramic material, said stub shaft defining an outer radius of r1;
- a tubular outer rotor shaft manufactured of a metallic material, said outer rotor shaft defining an inner radius of r2;
- a compressor rotor mountable to said outer rotor shaft;
- and
- a discontinuous ring between said stub shaft and said outer rotor shaft,
- where r2 is defined by the equation:
- r2=(CTE1−CTE2)/(CTE3−CTE2) r1 where:
- CTE1 is a coefficent of thermal expansion for the stub shaft;
- CTE2 is a coefficent of thermal expansion for the discontinous ring;
- CTE3 is a coefficent of thermal expansion for the outer shaft.
Dependencies are inferred from the claim text.