Method and apparatus for determining the unbalance of a rotating body

A method of determining an unbalance of a rotational body, comprising the following steps:

• a) mounting said rotational body on a mounting fixture of a dynamometer element;
• b) rotating said rotational body mounted on said fixture about a rotational axis;
• c) transferring all forces and moments originating from said rotational body into and through said dynamometer element, thereby causing at least a portion of said dynamometer element to undergo at least one of translational vibration in a plane of said dynamometer element and pivotal vibration about a pivot axis;
• and
• d) separately detecting a first one of said pivotal vibration and said translational vibration separately from a second other one of said vibrations using only a first sensor that is sensitive to only said first one of said vibrations without being sensitive to said second other one of said vibrations.

An apparatus for determining an unbalance of a rotational body when said rotational body is mounted on said apparatus so as to be rotatable about a rotation axis, said apparatus comprising:

• a mounting plate extending along and defining a plate plane;
• a mounting fixture that is arranged on said mounting plate, and that is adapted to receive the rotational body mounted thereon so as to allow the rotational body to rotate about said rotation axis, wherein said rotation axis is oriented perpendicular to said plate plane;
• an outer frame arranged at least partially outwardly around said mounting plate;
• a plurality of webs respectively connecting said mounting plate to said outer frame, wherein said webs are so configured and arranged so as to support said mounting plate relative to said outer frame, to transmit from said mounting plate to said outer frame forces that are oriented along said rotation axis and that are not induced by the unbalance of the rotational body, to allow said mounting plate to undergo translational vibration relative to said outer frame in said plate plane, wherein said translational vibration is induced in said mounting plate by the unbalance of the rotational body, to define a pivot axis perpendicular to said rotation axis, and to allow said mounting plate to undergo pivotal vibration about said pivot axis;
• and
• a first vibration transducer arrangement that is coupled to said outer frame and to said mounting plate, and that is so arranged and adapted to detect said translational vibration of said mounting plate relative to said outer frame in said plate plane;
• wherein said webs include a first pair of webs that extend along and parallel to said pivot axis respectively on opposite sides of said mounting plate and that define said pivot axis, said webs further include a second pair of webs and a third pair of webs that respectively extend parallel to each other and parallel to said first pair of webs in said plate plane, and said second pair of webs and said third pair of webs are located respectively spaced equidistantly from said pivot axis on opposite sides of said pivot axis.

An apparatus for determining an unbalance of a rotational body when said rotational body is mounted on said apparatus so as to be rotatable about a rotation axis, said apparatus comprising:

• a mounting plate extending along and defining a plate plane;
• a mounting fixture that is arranged on said mounting plate, and that is adapted to receive the rotational body mounted thereon so as to allow the rotational body to rotate about said rotation axis, wherein said rotation axis is oriented perpendicular to said plate plane;
• an outer frame arranged at least partially outwardly around said mounting plate;
• a plurality of webs respectively connecting said mounting plate to said outer frame, wherein said webs entirely support said mounting plate relative to said outer frame, said webs include a first pair of webs that extend axially aligned with one another along a pivot axis perpendicular to said rotation axis on opposite sides of said mounting plate and further webs offset away from said pivot axis, said webs of said first pair are torsionally flexible about said pivot axis to allow said mounting plate to undergo pivotal vibration about said pivot axis and are flexurally stiff with respect to bending perpendicular to said plate plane, and said further webs are flexible with respect to bending perpendicular to said plate plane so as to allow said pivotal vibration of said mounting plate and with respect to bending in said plate plane so as to allow said mounting plate to undergo translational vibration in said plate plane;
• a first vibration transducer arrangement that is coupled to said outer frame and to said mounting plate, and that is so arranged and adapted to detect said translational vibration of said mounting plate relative to said outer frame in said plate plane;
• and
• a second vibration transducer arrangement that is coupled to said outer frame and to said mounting plate, and that is so arranged and adapted to detect said pivotal vibration of said mounting plate relative to said outer frame about said pivot axis.

An apparatus for determining an unbalance of a rotational body when said rotational body is mounted on said apparatus so as to be rotatable about a rotation axis, said apparatus comprising:

• a mounting plate extending along and defining a plate plane;
• a mounting fixture that is arranged on said mounting plate, and that is adapted to receive the rotational body mounted thereon so as to allow the rotational body to rotate about said rotation axis, wherein said rotation axis is oriented perpendicular to said plate plane;
• an outer frame arranged at least partially outwardly around said mounting plate;
• a plurality of webs respectively connecting said mounting plate to said outer frame in an arrangement of said webs that is symmetrical relative to said rotation axis, wherein said webs are so configured and arranged so as to support said mounting plate relative to said outer frame, to transmit from said mounting plate to said outer frame all axially directed forces that are oriented along said rotation axis and that are not induced by the unbalance of the rotational body, and to allow said mounting plate to undergo translational vibration relative to said outer frame in said plate plane, wherein said translational vibration is induced in said mounting plate by the unbalance of the rotational body;
• and
• a first vibration transducer arrangement that is coupled to said outer frame and to said mounting plate, and that is so arranged and adapted to detect said translational vibration of said mounting plate relative to said outer frame in said plate plane;
• wherein said webs are further so configured and arranged so as to define a pivot axis perpendicular to said rotation axis, and so as to allow said mounting plate to undergo pivotal vibration relative to said outer frame about said pivot axis, wherein said pivotal vibration is induced in said mounting plate by the unbalance of the rotational body;
• further comprising a second vibration transducer arrangement that is coupled to said outer frame and to said mounting plate, and that is so arranged and adapted to detect said pivotal vibration of said mounting plate relative to said outer frame about said pivot axis;
• and
• wherein said mounting plate comprises a plate body on which said mounting fixture is arranged and an extension arm protruding outwardly from said plate body, said outer frame comprises a plurality of frame members arranged outwardly around said mounting plate and a frame protrusion that protrudes from at least one of said frame members away from said plate plane and that defines a clearance space therein, a free end of said extension arm extends into said clearance space, and said second vibration transducer arrangement is coupled to said free end of said extension arm and to said frame protrusion in said clearance space.