Method of controlling a variator

#The invention generally relates to a method of controlling a variator, such as continuously variable transmission, that requires a clamping pressure between a first component and a second component to transfer torque between the first component and the second component.

#A variator is a mechanical device that changes operating parameters, or changes operating parameters of another device. An example of a variator is a Continuously Variable Transmission (CVT), which is a mechanical power transmission device for transmitting torque from an engine to an output, such as a wheel. The CVT is capable of continuously changing between an infinite number of gear ratios. Often, the variator includes a first component, such as a belt, that is compressed by a second component, such as between two sheaves of a variable width pulley, to transfer torque therebetween.

#A clamping force may be applied to at least one of the components of the variator, e.g., the variable width pulley, to compress the belt between sheaves of the variable width pulley and generate friction therebetween. Setting the clamping force too low may allow slippage between the components of the variator, e.g., between the belt and the sheaves of the variable width pulley. Setting the clamping force too high may reduce the efficiency of the variator.

#FIG. 1 is a schematic plan cross sectional view of a variator, shown as a continuously variable transmission.

#FIG. 2 is a flowchart showing a method of controlling a variator.

#Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” “top,” “bottom,” etc., are used descriptively for the figures, and do not represent limitations on the scope of the invention, as defined by the appended claims. Furthermore, the invention may be described herein in terms of functional and/or logical block components and/or various processing steps. It should be realized that such block components may be comprised of any number of hardware, software, and/or firmware components configured to perform the specified functions.

#Referring to the Figures, wherein like numerals indicate like parts throughout the several views, a variator is generally shown at 20 in FIG. 1. The variator 20 is a mechanical device that changes operating parameters, or changes operating parameters of another device. The variator 20 may include any device that includes a first component and a second component, and requires a clamping pressure between the first component and the second component to transfer torque between the first component and the second component. Referring to FIG. 1, the variator 20 is shown embodied as a continuously variable transmission. In general, a continuously variable transmission is a transmission that can change steplessly through an infinite number of effective gear ratios between a maximum gear ratio and a minimum gear ratio.

#Referring to FIG. 1, the continuously variable transmission includes a primary pulley 22, a secondary pulley 24, and a belt 26 rotating continuously about the primary pulley 22 and the secondary pulley 24. The first component may be defined as one of the primary pulley 22 or the secondary pulley 24, and the second component may be defined as the belt 26.