Rotatable trunnions for variable pitch blades
Rotatable trunnions for variable pitch blades are disclosed herein. An variable pitch blade assembly comprises a trunnion defining a pitch axis, the trunnion including: a first sleeve defining a face of the trunnion; and a second sleeve within the first sleeve, the second sleeve including a pedestal and a column extending from the pedestal; a first spar for a fan blade, the first spar having a base portion and a mounting portion, the mounting portion protruding from the face of the trunnion, the base portion including an inner surface defining a bore, wherein the column of the second sleeve is disposed within the bore of the base portion, wherein the first sleeve, the second sleeve, and the first spar are coaxial with the pitch axis; and a second spar extending from the face of the trunnion, the second spar laterally offset relative to the first spar.
1 . A variable pitch blade assembly, the variable pitch blade assembly comprising:
a trunnion defining a pitch axis, the trunnion including:
a first sleeve defining a face of the trunnion; and
a second sleeve within the first sleeve, the second sleeve including a pedestal and a column extending from the pedestal;
a first spar for a fan blade, the first spar having a base portion and a mounting portion, the mounting portion protruding from the face of the trunnion, the base portion including a first inner surface defining a bore, wherein the column of the second sleeve is disposed within the bore of the base portion, wherein the first sleeve, the second sleeve, and the first spar are coaxial with the pitch axis; and
a second spar extending from the face of the trunnion, the second spar laterally offset relative to the first spar.
2 . The variable pitch blade assembly of claim 1 , wherein the second spar implements a splitter blade.
3 . The variable pitch blade assembly of claim 1 , wherein the second spar is integrally formed with the first sleeve.
4 . The variable pitch blade assembly of claim 1 , further including a splitter blade coupled to the second spar.
5 . The variable pitch blade assembly of claim 1 , further including a third spar, the first spar positioned between the second spar and the third spar.
6 . The variable pitch blade assembly of claim 5 , wherein the third spar is larger than the second spar.
7 . The variable pitch blade assembly of claim 5 , wherein the second spar and the third spar are asymmetrically located with respect to the first spar.
8 . The variable pitch blade assembly of claim 1 , wherein the trunnion further includes a third sleeve, the third sleeve disposed between the first sleeve and the base portion of the first spar.
9 . The variable pitch blade assembly of claim 1 , wherein a second inner surface of the mounting portion of the first spar has a first cross-sectional profile, and wherein the column of the second sleeve has an outer surface having a second cross-sectional profile, the outer surface of the column abutting the second inner surface of the mounting portion of the first spar such that the second cross-sectional profile is aligned with the first cross-sectional profile.
10 . A fan for a turbine engine, the fan comprising:
a trunnion including:
an outer sleeve having a first inner surface defining an interior and first transverse surface defining a face of the trunnion; and
an inner sleeve having a column portion housed within the outer sleeve;
a first spar for holding a fan blade, the first spar including a first base portion within the trunnion and a first mounting portion protruding from the face of the trunnion, the first base portion having a second inner surface defining a bore and a pitch axis, wherein the column portion of the inner sleeve is disposed within the bore; and
a second spar extending from the face of the trunnion.
11 . The fan of claim 10 , wherein the second spar includes a second base portion and a second mounting portion, the second base portion abutting the first base portion of the first spar, and further including a spacer disposed between the first spar and the second spar to separate the first mounting portion and the second mounting portion.
12 . The fan of claim 10 , wherein the first spar has a first outer surface, the first outer surface spaced apart from the second inner surface of the first base portion to define a thickness of the first base portion.
13 . The fan of claim 12 , wherein the first outer surface of the first spar abuts the first inner surface of the outer sleeve of the trunnion.
14 . The fan of claim 12 , wherein the trunnion further includes an intermediate sleeve disposed between the outer sleeve and the first spar, the intermediate sleeve having a third inner surface that abuts the first outer surface of the first spar, the intermediate sleeve having a second outer surface that abuts the first inner surface of the outer sleeve.
15 . The fan of claim 14 , wherein the second spar includes a second base portion and a second mounting portion, the second mounting portion extending from the face of the trunnion, the second base portion disposed between the outer sleeve of the trunnion and the intermediate sleeve of the trunnion to secure the second mounting portion relative to the trunnion.
16 . The fan of claim 14 , wherein the trunnion includes a fastener disposed between the intermediate sleeve and the outer sleeve, the fastener to couple the intermediate sleeve to the outer sleeve.
17 . The fan of claim 10 , wherein the outer sleeve of the trunnion further includes a second surface opposite the first inner surface, a third annular surface extending between the first inner surface and the second surface, and a fourth annular surface opposite the third annular surface, the second surface defining a base of the trunnion, and wherein the first base portion of the first spar diverges outward relative to the pitch axis to form a lip, the lip closer to the base of the trunnion than the face of the trunnion.