Planetary gear for a transmission for an aircraft capable of hovering

Planetary gear for a transmission of an aircraft capable of hovering, comprising:

• a sun rotatable around a first axis with a first angular speed;
• a crown angularly fixed with respect to said first axis or rotatable around said first axis with a second angular speed different from said first angular speed;
• at least two satellites meshing, each, with said crown and said sun, which are rotatable around respective second axes, which are in turn rotatable around said first axis;
• a satellite carrier rotatable around said first axis and comprising at least two first pins with respect to which said satellites are rotatable around respective said second axes;
• and
• a plurality of rolling bearings interposed, each, between a respective pin and a respective satellite so as to allow the relative rotation thereof around the respective second axis;
• said bearing each comprising, in turn:
• a first ring angularly integral with said pin and defining a first raceway that is at least partially spherical;
• a second ring angularly integral with the respective said satellite and defining a second raceway;
• and
• a plurality of rolling bodies, radially interposed between said first and second ring, and rolling, in use, on said first and second raceway;
• each said rolling body being in contact with said first raceway at a first curved and convex line on the side of the rolling body;
• said first line comprising first axial ends that are opposite one another and lying on a first straight line;
• each said rolling body being in contact with said second raceway at a second curved and convex line on the side of the rolling body;
• said second curved line comprising second axial ends that are opposite one another and lying on a second straight line;
• wherein said rolling bodies are concave and shaped as a conical hourglass;
• said first and second straight line being tilted between them and converging in first points lying on a third axis of said rolling body and on said second axis;
• said first and second straight line defining a first angle, whose bisector lies on said third axis;
• said rolling bearing comprising a first and a second crown formed respectively by first and second said rolling bodies that are angularly spaced around the respective said second axis;
• said crowns being axially staggered relative to said second axis;
• said first points being arranged on respective sides that are axially opposite one another of said rolling bearing;
• each said rolling body comprising:
• a first axial end;
• and
• a second axial end, which is axially opposite to said first axial end along said third axis of said rolling body;
• said second ring of each rolling bearing comprising:
• a first and a second element adapted to guide a cage for spacing said rolling bodies;
• and
• a shoulder axially interposed between said first and second element and adapted to axially cooperate with said first axial ends that are opposite to said first and second element of respective first and second rolling bodies of respective first and second crowns;
• wherein said cage is arranged in abutment against said first and second cage-guiding element and shoulder of the relative said rolling bearing.

Planetary gear for a transmission of an aircraft capable of hovering, comprising:

• a sun rotatable around a first axis with a first angular speed;
• a crown angularly fixed with respect to said first axis or rotatable around said first axis with a second angular speed different from said first angular speed;
• at least two satellites meshing, each, with said crown and said sun, which are rotatable around respective second axes, which are in turn rotatable around said first axis;
• a satellite carrier rotatable around said first axis and comprising at least two first pins with respect to which said satellites are rotatable around respective said second axes;
• and
• a plurality of rolling bearings interposed, each, between a respective pin and a respective satellite so as to allow the relative rotation thereof around the respective second axis;
• said bearing each comprising, in turn:
• a first ring angularly integral with said pin and defining a first raceway that is at least partially spherical;
• a second ring angularly integral with the respective said satellite and defining a second raceway;
• and
• a plurality of rolling bodies, radially interposed between said first and second ring, and rolling, in use, on said first and second raceway;
• each said rolling body being in contact with said first raceway at a first curved and convex line on the side of the rolling body;
• said first line comprising first axial ends that are opposite one another and lying on a first straight line;
• each said rolling body being in contact with said second raceway at a second curved and convex line on the side of the rolling body;
• said second curved line comprising second axial ends that are opposite one another and lying on a second straight line;
• wherein said rolling bodies are concave and shaped as a conical hourglass;
• said first and second straight line being tilted between them and converging in first points lying on a third axis of said rolling body and on said second axis;
• said first and second straight line defining a first angle, whose bisector lies on said third axis;
• said rolling bearing comprising a first and a second crown formed respectively by first and second said rolling bodies that are angularly spaced around the respective said second axis;
• said crowns being axially staggered relative to said second axis;
• said first points being arranged on respective sides that are axially opposite one another of said rolling bearing;
• each said rolling body comprising:
• a first axial end;
• and
• a second axial end, which is axially opposite to said first axial end along said third axis of said rolling body;
• said second ring of each rolling bearing comprising:
• a first and a second element adapted to guide a cage for spacing said rolling bodies;
• and
• a shoulder axially interposed between said first and second element and adapted to axially cooperate with said first axial ends that are opposite to said first and second element of respective first and second rolling bodies of respective first and second crowns;
• said planetary gear further including a first annular element for collecting a lubricating fluid intended to lubricate said rolling bodies of said bearings of at least two said satellites and arranged on a first side with respect to said rolling bearing;
• and
• means for conveying said lubricating fluid adapted to convey said lubricating fluid in contact with said rolling bodies;
• said first ring, second ring and rolling bodies of each said rolling bearing defining a chamber that can be crossed by said lubricating fluid;
• said chamber being fluidically connected to said first annular element.

Planetary gear for a transmission of an aircraft capable of hovering, comprising:

• a sun rotatable around a first axis with a first angular speed;
• a crown angularly fixed with respect to said first axis or rotatable around said first axis with a second angular speed different from said first angular speed;
• at least two satellites meshing, each, with said crown and said sun, which are rotatable around respective second axes, which are in turn rotatable around said first axis;
• a satellite carrier rotatable around said first axis and comprising at least two first pins with respect to which said satellites are rotatable around respective said second axes;
• and
• a plurality of rolling bearings interposed, each, between a respective pin and a respective satellite so as to allow the relative rotation thereof around the respective second axis;
• said bearing each comprising, in turn:
• a first ring angularly integral with said pin and defining a first raceway that is at least partially spherical;
• a second ring angularly integral with the respective said satellite and defining a second raceway;
• and
• a plurality of rolling bodies, radially interposed between said first and second ring, and rolling, in use, on said first and second raceway;
• each said rolling body being in contact with said first raceway at a first curved and convex line on the side of the rolling body;
• said first line comprising first axial ends that are opposite one another and lying on a first straight line;
• each said rolling body being in contact with said second raceway at a second curved and convex line on the side of the rolling body;
• said second curved line comprising second axial ends that are opposite one another and lying on a second straight line;
• wherein said rolling bodies are concave and shaped as a conical hourglass;
• said first and second straight line being tilted between them and converging in first points lying on a third axis of said rolling body and on said second axis;
• said first and second straight line defining a first angle, whose bisector lies on said third axis;
• said rolling bearing comprising a first and a second crown formed respectively by first and second said rolling bodies that are angularly spaced around the respective said second axis;
• said crowns being axially staggered relative to said second axis;
• said first points being arranged on respective sides that are axially opposite one another of said rolling bearing;
• each said rolling body comprising:
• a first axial end;
• and
• a second axial end, which is axially opposite to said first axial end along said third axis of said rolling body;
• said second ring of each rolling bearing comprising:
• a first and a second element adapted to guide a cage for spacing said rolling bodies;
• and
• a shoulder axially interposed between said first and second element and adapted to axially cooperate with said first axial ends that are opposite to said first and second element of respective first and second rolling bodies of respective first and second crowns;
• wherein each rolling bearing comprises a further annular element, which is unconstrained with respect to said first and second rings and is interposed between said first ring and said second ring radially with respect to said second axis and between said first and second rolling bodies axially with respect to said second axis.

Planetary gear for a transmission of an aircraft capable of hovering, comprising:

• a sun rotatable around a first axis with a first angular speed;
• a crown angularly fixed with respect to said first axis or rotatable around said first axis with a second angular speed different from said first angular speed;
• at least two satellites meshing, each, with said crown and said sun, which are rotatable around respective said second axes, which are in turn rotatable around said first axis;
• a satellite carrier rotatable around said first axis and comprising at least two first pins with respect to which said satellites are rotatable around respective said second axes;
• and
• a plurality of rolling bearings interposed, each, between one first pin of said two first pins and one satellite of said at least two satellites so as to allow the relative rotation thereof around the respective second axis;
• said bearing each comprising, in turn:
• a first ring angularly integral with said pin and defining a first raceway that is at least partially spherical;
• a second ring angularly integral with the respective said satellite and defining a second raceway;
• and
• a plurality of rolling bodies, radially interposed between said first and second ring, and rolling, in use, on said first and second raceway;
• each said rolling body being in contact with said first raceway at a first curved and convex line on the side of the rolling body;
• said first line comprising first axial ends that are opposite one another and lying on a first straight line;
• each said rolling body being in contact with said second raceway at a second curved and convex line on the side of the rolling body;
• said second curved line comprising second axial ends that are opposite one another and lying on a second straight line;
• wherein said rolling bodies are concave and shaped as a conical hourglass;
• said first and second straight line being tilted between them and converging in a first point lying on a third axis of said rolling body and on said second axis;
• said first and second straight line defining a first angle, whose bisector lies on said third axis;
• said planetary gear comprising:
• a first annular element for collecting a lubricating fluid intended to lubricate said rolling bodies of said bearings of at least two said satellites and arranged on a first side with respect to said rolling bearing;
• and
• means for conveying said lubricating fluid adapted to convey said lubricating fluid in contact with said rolling bodies;
• said first ring, second ring and rolling bodies of each said rolling bearing defining a chamber that can be crossed by said lubricating fluid;
• said chamber being fluidically connected to said first annular element;
• said conveying means comprising, for each said satellite, a collecting element housed within the relative pin and in fluidic communication with said first annular element and said chamber;
• said collecting element comprising a plurality of first circumferential and through openings that can be crossed, in use, by said lubricating fluid;
• said pin comprising a plurality of radial first holes arranged at and in fluidic communication with said first openings of said collecting element;
• said first ring comprising a plurality of second radial holes in fluidic communication with said chamber and with said first holes.