EP0083501A2 — Variable speed belt driven transmission system an…

Claim 1

Independent Claim 251 words

In a variable speed belt drive system of the type with a driver pulley having axially separable pulley halves; a driven pulley having axially separable pulley halves responsively operable to axial forces variable with rotational torque for closing the driven pulley halves together; a V-belt entrained by the driver and driven pulleys, the driven pulley axial forces and driver pulley cooperatively causing variable belt tensions for transmitting predetermined power loads between the driver and driven pulleys from (1) a maximum (speed down) ratio where the driver pulley halves are axially separated to a full open position and the driven pulley halves are axially together to a full closed position to (2) a minimum (speed up) ratio where the driver pulley halves are axially together to a full closed position and the driven pulley halves are axially separated to a full open position; and a family of required driven pulley axial force lines for transmitting torques at corresponding percentages of a maximum input peak torque from the driver pulley, the force lines generally decreasing from the driven pulley full closed position to the full open position, the improvement comprising: a means for closing the driven pulley halves while generating a family of axial closing forces that generally follow the decreasing force lines of the required driven pulley axial forces and wherein the maximum generated axial force to close the driven pulley at 100 percent peak torque is from about 100 to about 120 percent of the maximum required driven pulley axial force.

Claim 2

Dependent Claim 251 words

In a variable speed belt drive system of the type with a driver pulley having axially separable pulley halves; a driven pulley having axially separable pulley halves responsively operable to axial forces variable with rotational torque for closing the driven pulley halves together; a V-belt entrained by the driver and driven pulleys, the driven pulley axial forces and driver pulley cooperatively causing variable belt tensions for transmitting predetermined power loads between the driver and driven pulleys from (1) a maximum (speed down) ratio where the driver pulley halves are axially separated to a full open position and the driven pulley halves are axially together to a full closed position to (2) a minimum (speed up) ratio where the driver pulley halves are axially together to a full closed position and the driven pulley halves are axially separated to a full open position; and a family of required driven pulley axial force lines for transmitting torques at corresponding percentages of a maximum input peak torque from the driver pulley, the force lines generally decreasing from the driven pulley full closed position to the full open position, the improvement comprising: a means for closing the driven pulley halves while generating a family of axial closing forces that generally follow the decreasing force lines of the required driven pulley axial forces and wherein the maximum generated axial force to close the driven pulley at 100 percent peak torque is from about 100 to about 120 percent of the maximum required driven pulley axial force.

Claim 3

Dependent Claim 45 words

The variable speed belt drive system as claimed in Claim 1 wherein the driven pulley closing means includes a biasing means that contributes no more than about 25 percent of the maximum force generated by the driven pulley closing means at 100 percent peak torque.

Claim 4

Dependent Claim 21 words

The variable speed drive system as claimed in Claim 2 wherein the biasing means is a spring having a negative rate.

Claim 5

Dependent Claim 37 words

The variable speed drive system as claimed in Claim 1 wherein the maximum generated axial force to close the driven pulley is from about 100 to about 115 percent of the maximum required driven pulley axial force.

Claim 6

Dependent Claim 73 words

The variable speed drive system as claimed in Claim 1 wherein the family of generated driven pulley axial forces have profiles spaced at 20 percent increments, and the family of required driven pulley axial forces have corresponding profiles spaced at 20 percent increments, the generated forces at any 20 percent increment profile exceeding a corresponding required force 20 percent increment profile by less than two successive 20 percent increment levels of required force.

Claim 7

Dependent Claim 41 words

The variable speed drive system as claimed in Claim 5 wherein the generated axial forces at any 20 percent increment profile exceed a corresponding required 20 percent increment profile from about zero to about one successive increment level of required force.

Claim 8

Dependent Claim 186 words

The variable speed belt drive system as claimed in Claim 1 wherein the means for closing the driven pulley halves together comprises: a rotatable shaft; one driven pulley half defining a fixed pulley half that is coaxially and fixedly attached to rotate with said shaft; one driven pulley half defining a movable pulley half that is coaxially and free to rotate and axially move in relation to said shaft; a plurality of substantially parallel circumjacent links having first and second end portions radially spaced from the shaft; a first means for attaching the first end portions of the links to the movable pulley half; an axially spaced second means for attaching the second end portions of the links to the shaft, the first attachment means, second attachment means and links positioned so that a rotation of the movable pulley half and first attachment means, relative to the shaft, shortens the axial space between the first and second attaching means so the movable pulley half is axially displaced toward the fixed pulley half; and a means for biasing the movable pulley half toward the fixed pulley half.

Claim 9

Dependent Claim 20 words

The variable speed belt drive system as claimed in Claim 7 wherein the biasing means has a negative spring rate.

Claim 10

Dependent Claim 20 words

The variable speed belt drive system as claimed in Claim 7 wherein the links are in the form of cords.

Claim 11

Dependent Claim 16 words

The variable speed belt drive system as claimed in Claim 7 wherein the links are rods.

Claim 12

Dependent Claim 167 words

A variable speed pulley comprising: a rotatable shaft; a fixed pulley half that is coaxial and fixedly attached to rotate with said shaft; a movable pulley half that is coaxial and free to rotate and axially move in relation to said shaft; a plurality of substantially parallel, circumjacent links having first and second end portions radially spaced from the shaft; a first means for attaching the first end portions of the links to the movable pulley half; an axially spaced, second means for attaching the second end portions of the links to the shaft, the first attachment means, second attachment means and links positioned so that a rotation of the movable pulley half and first attachment means, relative to the shaft, shortens the axial space between the first and second attaching means so the movable pulley half is axially displaced toward the fixed pulley half; and a means for biasing the movable half toward the fixed pulley half, the biasing means having a negative spring rate portion.

Claim 13

Dependent Claim 167 words

A variable speed pulley comprising: a rotatable shaft; a fixed pulley half that is coaxial and fixedly attached to rotate with said shaft; a movable pulley half that is coaxial and free to rotate and axially move in relation to said shaft; a plurality of substantially parallel, circumjacent links having first and second end portions radially spaced from the shaft; a first means for attaching the first end portions of the links to the movable pulley half; an axially spaced, second means for attaching the second end portions of the links to the shaft, the first attachment means, second attachment means and links positioned so that a rotation of the movable pulley half and first attachment means, relative to the shaft, shortens the axial space between the first and second attaching means so the movable pulley half is axially displaced toward the fixed pulley half; and a means for biasing the movable half toward the fixed pulley half, the biasing means having a negative spring rate portion.

Claim 14

Dependent Claim 26 words

The variable speed pulley as claimed in Claim 11 wherein the movable pulley half is pre-rotated with the links from about 30 to about 70 degrees.

Claim 15

Dependent Claim 18 words

The variable speed pulley as claimed in Claim 11 wherein the links are in the form of cords.

Claim 16

Dependent Claim 18 words

The variable speed pulley as claimed in Claim 11 wherein the links are in the form of rods.

Claim 17

Independent Claim 409 words

A method for minimizing belt tension in a variable speed belt drive system of the type with a driver pulley having axially separable pulley halves; a driven pulley having axially separable pulley halves responsively operable to axial forces variable with rotational torque for closing the driven pulley halves together; a V-belt entrained by the driver and driven pulleys; the driven pulley axial forces and driver pulley cooperatively causing variable belt tensions for transmitting predetermined power loads between the driver and driven pulleys from (1) a maximum (speed down) ratio where the driver pulley halves are axially separated to a full open position and the driven pulley halves are positioned axially together by means of an actuator to a full closed position to (2) a minimum (speed up) ratio where the driver pulley halves are axially together to a full closed position and the driven pulley halves are axially separated to a full open position; the belt making a total arc of contact with the driven pulley, the total arc having a seating arc portion wherein the rate of belt tension increase with arc of contact is substantially zero; and the driven pulley halves are axially separated by means of the actuator to a full open position; comprising the steps of: determining the maximum input peak torque at the driver pulley; establishing a driver and driven pulley diameter and belt size and center distance between pulleys for a desired range of speed ratios; determining a family of driven pulley torques based on maximum input torque at the driver pulley and speed ratio; determining an ideal axial force line for the family of driven pulley torques at a traction ratio from about 0.65 to about 0.85 between maximum speed ratio and about 1.0 speed ratio, and a seating arc from about 10 degrees to about 20 degrees for speed ratios from about 1.0 to the minimum ratio; interpolating a family of axial force lines for the driven pulley from 0 to 100 percent of the line established for maximum axial force; whereby the family of ideal force lines is generally decreasing from the driveN pulley full closed position to the driveN pulley full open position; shaping the actuator axial closing forces to define a family of closing forces that generally follow the ideal decreasing force lines so that the actuator force line for peak torque is from about 100 to about 120 percent of the ideal axial force for peak torque.

Claim 18

Independent Claim 409 words

A method for minimizing belt tension in a variable speed belt drive system of the type with a driver pulley having axially separable pulley halves; a driven pulley having axially separable pulley halves responsively operable to axial forces variable with rotational torque for closing the driven pulley halves together; a V-belt entrained by the driver and driven pulleys; the driven pulley axial forces and driver pulley cooperatively causing variable belt tensions for transmitting predetermined power loads between the driver and driven pulleys from (1) a maximum (speed down) ratio where the driver pulley halves are axially separated to a full open position and the driven pulley halves are positioned axially together by means of an actuator to a full closed position to (2) a minimum (speed up) ratio where the driver pulley halves are axially together to a full closed position and the driven pulley halves are axially separated to a full open position; the belt making a total arc of contact with the driven pulley, the total arc having a seating arc portion wherein the rate of belt tension increase with arc of contact is substantially zero; and the driven pulley halves are axially separated by means of the actuator to a full open position; comprising the steps of: determining the maximum input peak torque at the driver pulley; establishing a driver and driven pulley diameter and belt size and center distance between pulleys for a desired range of speed ratios; determining a family of driven pulley torques based on maximum input torque at the driver pulley and speed ratio; determining an ideal axial force line for the family of driven pulley torques at a traction ratio from about 0.65 to about 0.85 between maximum speed ratio and about 1.0 speed ratio, and a seating arc from about 10 degrees to about 20 degrees for speed ratios from about 1.0 to the minimum ratio; interpolating a family of axial force lines for the driven pulley from 0 to 100 percent of the line established for maximum axial force; whereby the family of ideal force lines is generally decreasing from the driveN pulley full closed position to the driveN pulley full open position; shaping the actuator axial closing forces to define a family of closing forces that generally follow the ideal decreasing force lines so that the actuator force line for peak torque is from about 100 to about 120 percent of the ideal axial force for peak torque.

Claim 19

Dependent Claim 37 words

The method as claimed in Claim 10 comprising the additional step of determining a zero torque biasing axial force to close the driven pulley halves prior to the step of interpolating the family of axial force lines.

Claim 20

Dependent Claim 360 words

In a variable speed belt drive transmission for a vehicle, having vehicle inertia powered by an engine, having engine inertia, the transmission of the type with a driver pulley having axially separable pulley halves; a driven pulley having axially separable pulley halves operated with an actuator that is responsively operable to axial forces variable with rotational torque for closing the driven pulley halves together, the actuator of the type with a torque ramp and closing spring; a V-belt entrained by the driver and driven pulleys, the driven pulley axial forces and driver pulley cooperatively causing variable belt tensions for transmitting predetermined power loads between the driver and driven pulleys from (1) a maximum (speed down) ratio where the driver pulley halves are axially separated to a full open position and the driven pulley halves are axially together to a full closed position to (2) a minimum (speed up) ratio where the driver pulley halves are axially together to a full closed position and the driven pulley halves are axially separated to a full open position; and a family of required driven pulley axial force lines for transmitting torques at corresponding percentages of a maximum input peak torque from the driver pulley, the force lines generally decreasing from the driven pulley full closed position to the full open position, the improvement comprising: a means for closing the driven pulley halves including a first force means for generating a tapered axial force that generally decreases from the driven pulley full closed position to the driven pulley full open position and a second force means for generating a second axial force component that biases the movable pulley half toward the driven pulley full closed position, the second force component being less than the first force component at the driven pulley full open position and wherein the driver pulley is coupled to a first inertia reflective of the engine inertia and the driven pulley is coupled to a second inertia reflective of the vehicle inertia, the ratio of the second inertia to the first inertia being greater than 1 to 1 whereby responsiveness of the driven pulley is stable between the maximum speed ratios.

Claim 21

Dependent Claim 360 words

In a variable speed belt drive transmission for a vehicle, having vehicle inertia powered by an engine, having engine inertia, the transmission of the type with a driver pulley having axially separable pulley halves; a driven pulley having axially separable pulley halves operated with an actuator that is responsively operable to axial forces variable with rotational torque for closing the driven pulley halves together, the actuator of the type with a torque ramp and closing spring; a V-belt entrained by the driver and driven pulleys, the driven pulley axial forces and driver pulley cooperatively causing variable belt tensions for transmitting predetermined power loads between the driver and driven pulleys from (1) a maximum (speed down) ratio where the driver pulley halves are axially separated to a full open position and the driven pulley halves are axially together to a full closed position to (2) a minimum (speed up) ratio where the driver pulley halves are axially together to a full closed position and the driven pulley halves are axially separated to a full open position; and a family of required driven pulley axial force lines for transmitting torques at corresponding percentages of a maximum input peak torque from the driver pulley, the force lines generally decreasing from the driven pulley full closed position to the full open position, the improvement comprising: a means for closing the driven pulley halves including a first force means for generating a tapered axial force that generally decreases from the driven pulley full closed position to the driven pulley full open position and a second force means for generating a second axial force component that biases the movable pulley half toward the driven pulley full closed position, the second force component being less than the first force component at the driven pulley full open position and wherein the driver pulley is coupled to a first inertia reflective of the engine inertia and the driven pulley is coupled to a second inertia reflective of the vehicle inertia, the ratio of the second inertia to the first inertia being greater than 1 to 1 whereby responsiveness of the driven pulley is stable between the maximum speed ratios.

Claim 22

Dependent Claim 21 words

The variable speed belt drive transmission as claimed in Claim 17 wherein the ratio is at least about 11 to 1.

Claim 23

Dependent Claim 32 words

The variable speed belt drive transmission as claimed in Claim 17 wherein the second force is less than 50 percent of the required axial force at the driven pulley full open position.

Claim 24

Dependent Claim 187 words

The variable speed belt drive system as claimed in Claim 17 wherein the means for closing the driven pulley halves together comprises: a rotatable shaft; . one driven pulley half defining a fixed pulley half that is coaxially and fixedly attached to rotate with said shaft; one driven pulley half defining a movable pulley half that is coaxially and free to rotate and axially move in relation to said shaft; a plurality of substantially parallel circumjacent links having first and second end portions radially spaced from the shaft; a first means for attaching the first end portions of the links to the movable pulley half; an axially spaced second means for attaching the second end portions of the cords to the shaft, the first attachment means, second attachment means and cords positioned so that a rotation of the movable pulley half and first attachment means, relative to the shaft, shortens the axial space between the first and second attaching means so the movable pulley half is axially displaced toward the fixed pulley half; and a means for biasing the movable pulley half toward the fixed pulley half.

Variable speed belt driven transmission system and method

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