Systems and methods for controlling rollback in continuously variable transmissions
First Claim
1. A method for controlling tilt angle in a ball planetary continuously variable transmission (CVT) comprising a first carrier comprising a plurality of radially offset slots and a second carrier comprising a plurality of radial slots, the method comprising:
- operating the CVT in a design direction of rotation, wherein operating the CVT in the design direction comprises;
rotating the first carrier in a first direction to a first skew angle associated with a desired tilt angle; and
operating the CVT in a reverse direction of rotation, wherein operating the CVT in the reverse direction comprises;
rotating the first carrier in the CVT in a second direction opposite the first direction to a second skew angle;
monitoring the CVT to determine a change in a tilt angle; and
rotating the first carrier in the first direction to a third skew angle, wherein the third skew angle results in the CVT having the desired tilt angle.
1 Assignment
0 Petitions
Accused Products
Abstract
A continuously variable transmission capable of operating in a forward direction or reverse direction maybe controlled in the reverse direction by providing an initial skew angle in a first skew direction, followed by a set or sequence of skew angle adjustments in an opposite direction to prevent runaway or other unintended consequences. A continuously variable transmission may include a timing plate to maintain all planets at an angle or within a range of an angle in forward and reverse operations.
628 Citations
14 Claims
-
1. A method for controlling tilt angle in a ball planetary continuously variable transmission (CVT) comprising a first carrier comprising a plurality of radially offset slots and a second carrier comprising a plurality of radial slots, the method comprising:
-
operating the CVT in a design direction of rotation, wherein operating the CVT in the design direction comprises; rotating the first carrier in a first direction to a first skew angle associated with a desired tilt angle; and operating the CVT in a reverse direction of rotation, wherein operating the CVT in the reverse direction comprises; rotating the first carrier in the CVT in a second direction opposite the first direction to a second skew angle; monitoring the CVT to determine a change in a tilt angle; and rotating the first carrier in the first direction to a third skew angle, wherein the third skew angle results in the CVT having the desired tilt angle. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A continuously variable transmission (CVT) comprising:
-
a variator, comprising an array of planets orbital about a longitudinal axis, each planet having a planet axle defining a planet axis of rotation, a first ring in contact with the array of planets and orbital about the longitudinal axis, the first ring being on a first side of the array of planets, a second ring in contact with the array of planets and orbital about the longitudinal axis, the second ring being on a second side of the array of planets, a sun located radially inward of and in contact with the array of planets, a first carrier comprising a plurality of radially offset slots oriented in a first carrier direction, each radially offset slot configured for receiving a first end of a planet axle, and a second carrier opposite the first carrier and comprising a plurality of radial slots, each radial slot configured for receiving a second end of the planet axle; an actuator coupled to at least one of the first carrier and the second carrier; and a controller communicatively coupled to the actuator, the controller comprising a processor and a memory storing a set of instructions executable by the processor to perform determining if the variator is operating in a design direction or a reverse direction, wherein when the variator is operating in a design direction, the controller is configured to perform determining a desired tilt angle for the array of planets, and sending a signal to the actuator to rotate the first carrier in a first direction to a first skew angle; and wherein when the variator is operating in a reverse direction, the controller is configured to perform determining the desired tilt angle for the array of planets, sending a first signal to the actuator to rotate the first carrier in a second direction opposite the first direction to a second skew angle, monitoring the CVT to determine a change in the tilt angle, and sending a second signal to rotate the first carrier in the first direction to a third skew angle, wherein the third skew angle adjusts the CVT to the desired tilt angle. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
-
Specification