Propulsion unit with propeller and electric motor comprising an adapted primary structure, and aircraft having at least one such propulsion unit
A propulsion unit, and an aircraft, with a propeller and electric motor, including at least one intermediate element interposed between the electric motor and the propeller and configured to transmit at least thrust loads generated by the propeller, a primary structure supporting the propulsion unit, at least one interface having: a first load path, configured to transmit loads perpendicular to the axis of rotation of the propeller, linking the at least one intermediate element to a support linked rigidly to or incorporated in the primary structure, a second load path, configured to transmit loads that are parallel to the axis of rotation of the propeller, linking the at least one intermediate element to a support linked rigidly to or incorporated in the primary structure.
1. A propulsion unit comprising:
at least one electric motor,
a propeller exhibiting an axis of rotation,
at least one intermediate element interposed between the motor and the propeller and configured to transmit at least thrust loads generated by the propeller, and
a primary structure supporting the propulsion unit,
wherein the propulsion unit comprises at least one interface comprising:
a first load path, configured to transmit loads that act mainly perpendicular to the axis of rotation of the propeller, linking the intermediate element or one of the intermediate elements to a support linked rigidly to or incorporated in the primary structure, and
a second load path, configured to transmit loads that act mainly parallel to the axis of rotation of the propeller, linking the intermediate element or one of the intermediate elements to the support linked rigidly to or incorporated in the primary structure,
wherein the second load path comprises at least two connecting rods which converge toward the axis of rotation of the propeller and each of which forms an angle of between 20° and 70° with the axis of rotation of the propeller.
2. The propulsion unit as claimed in claim 1 , wherein the at least two connecting rods are positioned symmetrically with respect to a vertical plane passing through the axis of rotation of the propeller.
3. The propulsion unit as claimed in claim 1 , wherein the first path comprises multiple attachments each having a pivoting connection exhibiting a pivot axis oriented parallel to the axis of rotation of the propeller.
4. The propulsion unit as claimed in claim 3 , wherein each one of the multiple attachments comprises:
a clevis integral with a first element, where the first element is the support or the intermediate element,
a cylindrical rod supported by the clevis and oriented parallel to the axis of rotation of the propeller,
a body integral with a second element, where the second element is the other of the support or the intermediate element, having a cylindrical recess which exhibits a diameter greater than that of the cylindrical rod and an axis parallel to the axis of rotation of the propeller,
a sleeve made of elastic material interposed between the recess in the body and the cylindrical rod supported by the clevis.
5. The propulsion unit as claimed in claim 3 , wherein the multiple attachments are positioned symmetrically with respect to a vertical plane passing through the axis of rotation of the propeller.
6. The propulsion unit as claimed in claim 5 , wherein each attachment is positioned in the same longitudinal plane as a connecting rod.
7. The propulsion unit as claimed in claim 1 , wherein the interface comprises:
a first support positioned in a first transverse plane,
multiple attachments linking the first support and the intermediate element and positioned approximately in the first transverse plane or close to the first transverse plane,
a second support positioned in a second transverse plane and offset toward the rear with respect to the first transverse plane, and
an extension integral with the intermediate element extending in a direction approximately parallel to the axis of rotation of the propeller toward the rear with respect to the intermediate element, said extension being linked to the second support by a connection.
8. The propulsion unit as claimed in claim 7 , wherein the connection linking the second support and the extension has a finger integral with the extension and oriented in a direction parallel to the axis of rotation of the propeller, and also a recess integral with the second support and configured to receive the finger, the recess and the finger having approximately the same diameter.
9. The propulsion unit as claimed in claim 1 , wherein the interface comprises:
a support,
at least three flexible attachments which link the support and the intermediate element and are positioned in a first transverse plane perpendicular to the axis of rotation of the propeller, and
at least three connecting rods having a first end linked to the support by a first connection and a second end linked to the intermediate element by a second connection positioned in a second transverse plane perpendicular to the axis of rotation of the propeller, spaced apart from the first transverse plane and offset toward the front with respect to this first transverse plane.
10. The propulsion unit as claimed in claim 9 , wherein each first or second connection is a pivoting connection exhibiting a pivot axis positioned in a transverse plane that is perpendicular to the axis of rotation of the propeller, the pivot axes of the first and second connections of each connecting rod being parallel to one another.
11. The propulsion unit as claimed in claim 1 , wherein the interface comprises:
a first support positioned in a first transverse plane,
multiple attachments which link the first support and the intermediate element and are positioned approximately in the first transverse plane or close to the first transverse plane,
a second support positioned in a second transverse plane, and
multiple connecting rods, each having a first end linked to the second support by a first connection and a second end linked to the intermediate element by a second connection positioned in a third transverse plane, spaced apart from the second transverse plane and offset toward the front with respect to this second transverse plane.
12. The propulsion unit as claimed in claim 1 , wherein the first load path comprises an extension, integral with the intermediate element, extending in a direction approximately parallel to the axis of rotation of the propeller toward the rear with respect to the intermediate element, said extension being linked by a connection to the support to which the connecting rods are linked.
13. The propulsion unit as claimed in claim 12 , wherein the connection linking the support and the extension has a finger integral with the extension and oriented in a direction parallel to the axis of rotation of the propeller, and a recess integral with the support and configured to receive the finger, the recess and the finger having approximately the same diameter.
14. An aircraft comprising at least one propulsion unit as claimed in claim 1 .
15. The propulsion unit as claimed in claim 1 , wherein the second load path comprises four rods positioned around the axis of rotation of the propeller, symmetrically with respect to a vertical plane passing through the axis of rotation of the propeller.
16. The propulsion unit as claimed in claim 1 , wherein the intermediate element is one of:
a gearbox linking the motor and the propeller; or
a guiding system for guiding a first shaft linking a gearbox and the propeller.