Exhaust case for a turbomachine with a flexible hub
View Patent ↗An exhaust case for a turbomachine includes, from outside towards inside, yokes, a collar and a hub, which are annular and coaxial. The hub is connected to the collar by radial arms and extends between an annular flange and an inner collar capable of guiding a gas flow. In the hub each arm includes a rib in a shape of a triangle which ends with the flange. The inner collar is extended into the hub by a plate capable of transferring forces between the flange and the yokes. The plate can be advantageously inclined with respect to a radial plane. Two portions, which enclose a cut-out formed in a minimum-stress region along the plate, are coupled with pre-set plays. The case is capable of absorbing compression and traction at a thermal gradient.
1. An exhaust case for a turbomachine, comprising, from an outside towards an inside:
yokes, an outer collar and a hub, which are coaxial, the hub being connected to the outer collar by radial arms and extending between an inner collar, for guiding a gas flow, and an annular flange;
wherein in the hub, the inner collar is extended by at least one annular plate for connection between the annular flange and the inner collar to transfer forces between the annular flange and the yokes; and
wherein each radial arm is extended by a radial rib comprising two opposed portions enclosing a cut-out formed in a central minimum-stress region of the rib, the portions being intercoupled with pre-set plays.
2. An exhaust case according to claim 1 , wherein the portions are joined by welding.
3. An exhaust case according to claim 1 , wherein the portions are formed by two rods including complementary heads which are capable of forming a closure, clearances between opposed heads defining the pre-set plays.
4. An exhaust case according to claim 1 , wherein the at least one annular plate extends annularly through the hub between the inner collar and the annular flange.
5. An exhaust case according to claim 4 , wherein the at least one annular plate is inclined between 0 and 45° with reference to a radial plane, or between 10 to 30°.
6. An exhaust case according to claim 1 , wherein the at least one annular plate is substantially conical.
7. An exhaust case according to claim 1 , wherein each radial rib has a generally triangular shape.
8. An exhaust case according to claim 7 , wherein each radial rib extends substantially between regions corresponding to leading edges and trailing edges of the arm at the inner collar and the annular flange.
9. An exhaust case according to claim 8 , wherein each radial rib has a leading edge in an extension of the leading edge of a corresponding arm, the leading edge of each radial rib being extended by the annular flange.