Continuously variable transmission
First Claim
1. A shift cam disc for facilitating a ratio shift of a continuously variable transmission (“
- CVT”
), the CVT having a longitudinal axis and a ball-leg assembly, wherein the ball-leg assembly is provided with a ball coupled to a set of legs, each leg coupled to a cam wheel, the shift cam disc comprising;
a surface following the x and y values of the datum curve according to a set of parametric equations of the form;
theta=2*gamma_max*t−
gamma_max
x=LEG*sin(theta)−
0.5*ball_dia*RSF*theta*pi/180+0.5*ARM*cos(theta)
y=LEG*cos(theta)−
0.5*ARM*sin(theta)wherein theta is a variable representing a tilt angle of the ball-leg assembly, gamma_max is a variable representing a maximum tilt angle of the ball-leg assembly, t is a parametric range variable, x and y are variables representing a center point with respect to an x-y coordinate system of the cam wheel, wherein an x-axis is substantially parallel to the longitudinal axis, LEG is a variable representing a perpendicular distance between a centerline of the ball and a centerline of the cam wheels, ball_dia is a variable representing a dimension of the ball, RSF is a variable representing a roll-slide factor, and ARM is a variable representing a distance between the cam wheels.
9 Assignments
0 Petitions
Accused Products
Abstract
A continuously variable transmission (CVT) having a number of tiltable ball-leg assemblies configured angularly about a longitudinal axis. Each ball-leg assembly is in contact with, and guided through a tilting motion by an axially translating shift cam having a convex shape. The convex shape of the shift cam can have a profile defined by a set of parametric equations. In one embodiment, the profile of the shift cam vary according to the location of the contact point between an idler and the ball-leg assembly as well as the amount of relative axial motion between the ball-leg assembly and the idler. In some embodiments, the profile of the shift cam can be configured to control the axial translation of the idler relative to the change in tilt angle of the ball-leg assembly. In other embodiments, a roll-slide factor can be used to characterize the axial translation of the idler relative to the tilt angle of the ball-leg assembly.
373 Citations
21 Claims
-
1. A shift cam disc for facilitating a ratio shift of a continuously variable transmission (“
- CVT”
), the CVT having a longitudinal axis and a ball-leg assembly, wherein the ball-leg assembly is provided with a ball coupled to a set of legs, each leg coupled to a cam wheel, the shift cam disc comprising;a surface following the x and y values of the datum curve according to a set of parametric equations of the form;
theta=2*gamma_max*t−
gamma_max
x=LEG*sin(theta)−
0.5*ball_dia*RSF*theta*pi/180+0.5*ARM*cos(theta)
y=LEG*cos(theta)−
0.5*ARM*sin(theta)wherein theta is a variable representing a tilt angle of the ball-leg assembly, gamma_max is a variable representing a maximum tilt angle of the ball-leg assembly, t is a parametric range variable, x and y are variables representing a center point with respect to an x-y coordinate system of the cam wheel, wherein an x-axis is substantially parallel to the longitudinal axis, LEG is a variable representing a perpendicular distance between a centerline of the ball and a centerline of the cam wheels, ball_dia is a variable representing a dimension of the ball, RSF is a variable representing a roll-slide factor, and ARM is a variable representing a distance between the cam wheels. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- CVT”
-
8. A method of manufacturing a shift cam disc for facilitating a ratio shift of a continuously variable transmission (“
- CVT”
), the CVT having a longitudinal axis and a ball-leg assembly, wherein the ball-leg assembly is provided with a ball coupled to a set of legs, each leg coupled to a cam wheel, the method comprising;generating a datum curve according to a set of parametric equations of the form;
theta=2*gamma_max*t−
gamma_max
x=LEG*sin(theta)−
0.5*ball_dia*RSF*theta*pi/180+0.5*ARM*cos(theta)
y=LEG*cos(theta)−
0.5*ARM*sin(theta)wherein theta is a variable representing a tilt angle of the ball-leg assembly, gamma_max is a variable representing a maximum tilt angle of the ball-leg assembly, t is a parametric range variable, x and y are variables representing a center point with respect to an x-y coordinate system of the cam wheel, wherein an x-axis is substantially parallel to the longitudinal axis, LEG is a variable representing a perpendicular distance between a centerline of the ball and a centerline of the cam wheels, ball_dia is a variable representing a dimension of the ball, RSF is a variable representing a roll-slide factor, and ARM is a variable representing a distance between the cam wheels, and forming a shift cam disc surface according to the x and y values of the datum curve. - View Dependent Claims (9, 10, 11, 12, 13, 14)
- CVT”
-
15. A method for generating cam profiles for facilitating a ratio shift of a continuously variable transmission (“
- CVT”
), the CVT having a longitudinal axis and a ball-leg assembly, wherein the ball-leg assembly is provided with a ball coupled to a set of legs, each leg coupled to a cam wheel, the method comprising;determining a desired shift force in comparison to a shifter displacement; and generating a datum curve that corresponds to the desired shift force in comparison to the shifter displacement according to a set of parametric equations of the form;
theta=2*gamma_max*t−
gamma_max
x=LEG*sin(theta)−
0.5*ball_dia*RSF*theta*pi/180+0.5*ARM*cos(theta)
y=LEG*cos(theta)−
0.5*ARM*sin(theta)wherein theta is a variable representing a tilt angle of the ball-leg assembly, gamma_max is a variable representing a maximum tilt angle of the ball-leg assembly, t is a parametric range variable, x and y are variables representing a center point with respect to an x-y coordinate system of the cam wheel, wherein an x-axis is substantially parallel to the longitudinal axis, LEG is a variable representing a perpendicular distance between a centerline of the ball and a centerline of the cam wheels, ball_dia is a variable representing a dimension of the ball, RSF is a variable representing a roll-slide factor, and ARM is a variable representing a distance between the cam wheels. - View Dependent Claims (16, 17, 18, 19, 20, 21)
- CVT”
Specification