Continuously variable planetary gear set
First Claim
Patent Images
1. A power transfer assembly comprising:
- a plurality of balls distributed radially about a longitudinal axis of the power transfer assembly, each ball having a tiltable axis about which it rotates;
an input disc in contact with the balls;
an output disc in contact with the balls;
an idler coaxial and rotatable about the longitudinal axis and in contact with the balls;
a bearing disc mounted along the longitudinal axis and operationally coupled to the input disc;
a fluid pressure drive device adapted to vary the contact force between the bearing disc and the input disc;
a limiting member configured to limiting the axial displacement of the bearing disc;
wherein the limiting member produces an elastic resistance against a direction of the displacement when there is no fluid pressure from the pressure drive device and the bearing disc receives an input torque; and
an axial force generator adapted to generate a contact force between the input disc, the output disc, the balls and the idler,wherein the axial force generator comprises;
a thrust washer coaxial with the idler, the washer having a first side facing the input disc and having a set of thrust ramps formed on the first side;
a set of thrust-receiving ramps formed on the input disc facing the thrust washer; and
a plurality of thrust elements in contact with the thrust ramps and the thrust-receiving ramps.
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Abstract
A continuously variable planetary gear set is described having a generally tubular idler, a plurality of balls distributed radially about the idler, each ball having a tiltable axis about which it rotates, a rotatable input disc positioned adjacent to the balls and in contact with each of the balls, a rotatable output disc positioned adjacent to the balls opposite the input disc and in contact with each of the balls such that each of the balls makes three-point contact with the input disc, the output disc and the idler, and a rotatable cage adapted to maintain the axial and radial position of each of the balls, wherein the axes of the balls are oriented by the axial position of the idler.
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Citations
20 Claims
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1. A power transfer assembly comprising:
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a plurality of balls distributed radially about a longitudinal axis of the power transfer assembly, each ball having a tiltable axis about which it rotates; an input disc in contact with the balls; an output disc in contact with the balls; an idler coaxial and rotatable about the longitudinal axis and in contact with the balls; a bearing disc mounted along the longitudinal axis and operationally coupled to the input disc; a fluid pressure drive device adapted to vary the contact force between the bearing disc and the input disc; a limiting member configured to limiting the axial displacement of the bearing disc; wherein the limiting member produces an elastic resistance against a direction of the displacement when there is no fluid pressure from the pressure drive device and the bearing disc receives an input torque; and an axial force generator adapted to generate a contact force between the input disc, the output disc, the balls and the idler, wherein the axial force generator comprises; a thrust washer coaxial with the idler, the washer having a first side facing the input disc and having a set of thrust ramps formed on the first side; a set of thrust-receiving ramps formed on the input disc facing the thrust washer; and a plurality of thrust elements in contact with the thrust ramps and the thrust-receiving ramps. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of manufacturing a power transfer assembly, the method comprising:
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arranging a plurality of balls radially about a longitudinal axis of the power transfer assembly, each ball having a tihable axis about which it rotates; providing an input disc adapted to contact the balls; providing an output disc adapted to contact the balls; mounting an idler coaxially with the longitudinal axis, wherein the idler is adapted to contact the balls; mounting a bearing disc along the longitudinal axis; operationally coupling the bearing disc to the input disc; providing a fluid pressure drive device adapted to vary the contact force between the bearing disc and the input disc; providing a ring-shaped wave spring for limiting the axial displacement of the bearing disc, the wave spring operationally coupled to the pressure drive device; wherein the wave spring produces an elastic resistance against a direction of the displacement when there is no fluid pressure from the pressure drive device and the bearing disc receives an input torque; providing an axial force generator adapted to generate a contact force between the input disc, the output disc, the balls and the idler; and wherein the axial force generator comprises; a thrust washer coaxial with the idler, the washer having a first side facing the input disc and having a set of thrust ramps formed on the first side; a set of thrust-receiving ramps formed on the input disc facing the thrust washer; and a plurality of thrust elements in contact with the thrust ramps and the thrust-receiving ramps. - View Dependent Claims (18, 19, 20)
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Specification