A system for providing an automated axial force to a continuously variable transmission (CVT) in a wheelchair. An electronic transmission control receives one or more input signals generated by throttle position or other variables. The microprocessor generates an output signal that adjusts the axial force applied to a CVT thereby automatically adjusting the input to output ratio. The invention also provides a manually controlled variator is designed for use on a wheelchair. The manual shifter hydraulically adjusts an axial force imparted on a variator in communication with a wheelchair wheel and a hand rim. Application of the axial force causes the hand rim input and wheelchair wheel output ratio to change, permitting a wheelchair operator to manually adjust the input to output ratio to more easily operate the wheelchair.
1. A light electric vehicle comprising:
a first wheel;
a drive motor configured to drive the first wheel;
a continuously variable transmission (CVT) disposed between the first wheel and the drive motor, the CVT having a variator shaft, wherein the variator shaft is configured to axially translate and thereby adjust an input to output ratio between the drive motor and the first wheel;
a splined shaft operably coupled to the variator shaft;
an electric servo motor coupled to the splined shaft, the servo motor configured to rotate the splined shaft and thereby axially translate the variator shaft to provide an axial force to the CVT, wherein the axial force is configured to manipulate the CVT between at least a first position and a second position, and wherein the input to output ratio between the drive motor and the first wheel is different when the CVT is in the first position than when the CVT is in the second position; and
a battery, wherein the drive motor and the servo motor are configured to draw power from the battery.
2. The light electric vehicle of claim 1 , further comprising a microprocessor configured to provide a control signal to the servo motor to control the axial force provided to the CVT.
3. The light electric vehicle of claim 2 , further comprising a first sensor configured to sense a characteristic of the drive motor and to provide a first signal to the microprocessor, wherein the first signal is a function of the characteristic of the drive motor.
4. The light electric vehicle of claim 3 , wherein the first sensor comprises a current draw sensor configured to sense the current drawn from the battery by the drive motor.
5. The light electric vehicle of claim 3 , wherein the first sensor comprises a speed sensor configured to sense a speed of the drive motor.
6. The light electric vehicle of claim 3 , further comprising:
a second wheel; and
a second sensor configured to sense a speed of the second wheel and to provide a second signal to the microprocessor, wherein the second signal is a function of the speed of the second wheel.
7. The light electric vehicle of claim 6 , wherein the control signal is a function of at least the first signal and the second signal.
8. The light electric vehicle of claim 1 , further comprising a gearbox disposed between the servo motor and the CVT.
9. The light electric vehicle of claim 1 , wherein the light electric vehicle comprises a wheelchair.
10. The light electric vehicle of claim 1 , further comprising a control board, wherein the control board is disposed between the servo motor and the microprocessor, and wherein the control board is disposed between the servo motor and the battery.