SYSTEMS AND METHODS FOR CONTROLLING ROLLBACK IN CONTINUOUSLY VARIABLE TRANSMISSIONS
First Claim
1. A method for controlling rollback in a continuously variable transmission (CVT) capable of operating in a design direction of rotation and a reverse direction of rotation, wherein when the CVT is operating in a reverse direction, the method comprises:
- rotating, a carrier in the CVT in a first direction to a first skew angle;
monitoring the CVT to determine a change in a tilt angle; and
rotating the carrier in an opposite direction to a second skew angle, wherein the second skew angle results in the CVT having a zero tilt angle.
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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.
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Citations
20 Claims
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1. A method for controlling rollback in a continuously variable transmission (CVT) capable of operating in a design direction of rotation and a reverse direction of rotation, wherein when the CVT is operating in a reverse direction, the method comprises:
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rotating, a carrier in the CVT in a first direction to a first skew angle; monitoring the CVT to determine a change in a tilt angle; and rotating the carrier in an opposite direction to a second skew angle, wherein the second skew angle results in the CVT having a zero tilt angle. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A variator, comprising:
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an array of planets orbital about a longitudinal axis, each planet having an axle; a first ring in contact with the army 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 army of planets and orbital about the longitudinal axis, the second ring being on a second side of the array of planets; a first carrier having a plurality of carrier slots oriented in a first direction, each carrier slot configured for receiving a first end of a planet axle of the array of planets; a second carrier opposite the first carrier and having a plurality of carrier slots oriented in the first direction, each carrier slot configured for receiving a second end of the planet axle of the array of planets; 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 the variator is operating in a reverse direction; initiating a first rotation to cause the variator to operate based on the reverse direction, wherein the array of planets are biased to tilt towards reduction; and changing a skew angle to change a tilt angle of the array of planets. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A drivetrain comprising:
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a power source; a variator coupled to the power source, the variator comprising; an array of planets orbital about a longitudinal axis; 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 power load; an actuator coupled to at least one of a first carrier and a 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; initiating a first rotation to cause the variator to operate in a reverse direction, wherein the variator is biased to rotate to a maximum reduction; and changing the skew angle to offset the bias of the variator to rotate. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification