Apparatus and method for predicting fore/aft forces generated by tires

Claim 1

A method of testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising the steps of: (a) rotating the tire under a radial load against a loadwheel and, (b) measuring changes in the instantaneous effective radius of the tire as the tire rotates.

Claim 2

A method of testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising the steps of: (a) rotating the tire under a radial load against a loadwheel and, (b) measuring changes in the instantaneous effective radius of the tire as the tire rotates.

Claim 5

A method of testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising the steps of: (a) rotating the tire under a radial load against a loadwheel and, (b) measuring at least one parameter selected from the group of parameters consisting of, changes in the instantaneous effective radius, (R Eff ) of the tire, the acceleration of the tread surface of the tire, the angular acceleration of the tire and the acceleration of said loadwheel relative to the angular acceleration of the tire.

Claim 6

A method of testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising the steps of: (a) rotating the tire under a radial load against a loadwheel and, (b) measuring at least one parameter selected from the group of parameters consisting of, changes in the instantaneous effective radius, (R Eff ) of the tire, the acceleration of the tread surface of the tire, the angular acceleration of the tire and the acceleration of said loadwheel relative to the angular acceleration of the tire.

Claim 10

A method of testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising the steps of: (a) rotating the tire under a radial load against the circumferential surface of a loadwheel; (b) measuring the instantaneous speed, (V L ) of said circumferential surface of said loadwheel; (c) measuring the instantaneous angular speed (S) of the tire and, (d) calculating the instantaneous effective radius, R Eff of the tire according to the equation: ##EQU19##

Claim 11

A method of testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising the steps of: (a) rotating the tire under a radial load against the circumferential surface of a loadwheel; (b) measuring the instantaneous speed, (V L ) of said circumferential surface of said loadwheel; (c) measuring the instantaneous angular speed (S) of the tire and, (d) calculating the instantaneous effective radius, R Eff of the tire according to the equation: ##EQU19##

Claim 12

A method of determining the fore/aft force generated by a tire as it rotates under load, comprising the steps of: (a) rotating the tire under a radial load against a loadwheel; (b) measuring at least one parameter selected from the group of parameters consisting of, changes in the instantaneous effective radius, (R Eff ) of the tire, the acceleration of the tread surface of the tire, the angular acceleration of the tire and the accelerating of the loadwheel relative to the angular acceleration of the tire; and (c) computing, based on said measured parameter, the fore/aft force generated by the tire.

Claim 13

A method of determining the fore/aft force generated by a tire as it rotates under load, comprising the steps of: (a) rotating the tire under a radial load against a loadwheel; (b) measuring at least one parameter selected from the group of parameters consisting of, changes in the instantaneous effective radius, (R Eff ) of the tire, the acceleration of the tread surface of the tire, the angular acceleration of the tire and the accelerating of the loadwheel relative to the angular acceleration of the tire; and (c) computing, based on said measured parameter, the fore/aft force generated by the tire.

Claim 14

An apparatus for testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising: means for rotating the tire under a radial load against a loadwheel and, means for measuring changes in the instantaneous effective radius of the tire as the tire rotates.

Claim 15

An apparatus for testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising: means for rotating the tire under a radial load against a loadwheel and, means for measuring changes in the instantaneous effective radius of the tire as the tire rotates.

Claim 16

An apparatus for testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising: (a) means for rotating the tire under a radial load against a loadwheel and, (b) means for measuring at least one parameter selected from the group of parameters consisting of changes in the instantaneous effective radius, (R Eff ) of the tire, the acceleration of the tread surface of the tire relative to the angular acceleration of the tire and the acceleration of said loadwheel relative to the angular acceleration of the tire.

Claim 17

An apparatus for testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising: (a) means for rotating the tire under a radial load against a loadwheel and, (b) means for measuring at least one parameter selected from the group of parameters consisting of changes in the instantaneous effective radius, (R Eff ) of the tire, the acceleration of the tread surface of the tire relative to the angular acceleration of the tire and the acceleration of said loadwheel relative to the angular acceleration of the tire.

Claim 19

An apparatus for determing the fore/aft force generated by a tire as it rotates under load, comprising: (a) rotating the tire under a radial load against a loadwheel; (b) measuring at least one parameter selected from the group of parameters consisting of, changes in the instantaneous effective radius, (R Eff ) of the tire, the acceleration of the tread surface of the tire, the angular acceleration of the tire and the acceleration of the loadwheel relative to the angular acceleration of the tire; and (c) computing, based on said measured parameter, the fore/aft force generated by the tire.

Claim 20

An apparatus for determing the fore/aft force generated by a tire as it rotates under load, comprising: (a) rotating the tire under a radial load against a loadwheel; (b) measuring at least one parameter selected from the group of parameters consisting of, changes in the instantaneous effective radius, (R Eff ) of the tire, the acceleration of the tread surface of the tire, the angular acceleration of the tire and the acceleration of the loadwheel relative to the angular acceleration of the tire; and (c) computing, based on said measured parameter, the fore/aft force generated by the tire.

Claim 21

An apparatus for testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising: (a) means for rotating the tire under a radial load against the circumferential surface of a loadwheel; (b) means for measuring the instantaneous speed (V L ) of said circumferential surface of said loadwheel; (c) means for measuring the instantaneous angular speed (S) of the tire and, (d) means for calculating the instantaneous effective radius, (R Eff ) of the tire according to the equation: ##EQU20##

Claim 22

An apparatus for testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising: (a) means for rotating the tire under a radial load against the circumferential surface of a loadwheel; (b) means for measuring the instantaneous speed (V L ) of said circumferential surface of said loadwheel; (c) means for measuring the instantaneous angular speed (S) of the tire and, (d) means for calculating the instantaneous effective radius, (R Eff ) of the tire according to the equation: ##EQU20##

Claim 23

An apparatus for testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising: (a) a loadwheel; (b) a drive for rotating the tire against the circumferential surface of said loadwheel under a radial load; (c) a tire encoder operatively connected to the tire to generate a tire reference pulse and a first predetermined number of substantially equally angularly spaced tire encoder pulses for each complete rotation of the tire; (d) a loadwheel encoder operatively connected to said loadwheel to generate a loadwheel reference pulse and a second predetermined number of substantially equally angularly spaced loadwheel encoder pulses for each complete rotation of said loadwheel; (e) a programmed central processing unit; (f) a first timer operatively connected to said tire encoder and to said central processing unit to cause said central processing unit to determine the time, T T (n T ) of occurrence of each of said tire encoder pulses following one of said tire reference pulses; (g) a second timer synchronized with said first timer and operatively connected to said loadwheel encoder and to said central processing unit to cause said central processing unit to determine the time, T L (n L ) of occurrence of each of said loadwheel encoder pulses following the one of said loadwheel encoder pulses next to occur after the occurrence of said one of said tire reference pulses, said central processing unit being programmed to calculate a parameter correlated to changes in the instantaneous effective radius R Eff of the tire as a measurement of the tendency of the tire to translate fore and aft.

Claim 24

An apparatus for testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising: (a) a loadwheel; (b) a drive for rotating the tire against the circumferential surface of said loadwheel under a radial load; (c) a tire encoder operatively connected to the tire to generate a tire reference pulse and a first predetermined number of substantially equally angularly spaced tire encoder pulses for each complete rotation of the tire; (d) a loadwheel encoder operatively connected to said loadwheel to generate a loadwheel reference pulse and a second predetermined number of substantially equally angularly spaced loadwheel encoder pulses for each complete rotation of said loadwheel; (e) a programmed central processing unit; (f) a first timer operatively connected to said tire encoder and to said central processing unit to cause said central processing unit to determine the time, T T (n T ) of occurrence of each of said tire encoder pulses following one of said tire reference pulses; (g) a second timer synchronized with said first timer and operatively connected to said loadwheel encoder and to said central processing unit to cause said central processing unit to determine the time, T L (n L ) of occurrence of each of said loadwheel encoder pulses following the one of said loadwheel encoder pulses next to occur after the occurrence of said one of said tire reference pulses, said central processing unit being programmed to calculate a parameter correlated to changes in the instantaneous effective radius R Eff of the tire as a measurement of the tendency of the tire to translate fore and aft.

Claim 26

An apparatus for testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising: (a) a loadwheel; (b) a drive for rotating the tire at a substantially constant angular speed against the circumferential surface of said loadwheel under a radial load; (c) a loadwheel encoder operatively connected to said loadwheel to generate a loadwheel reference pulse and a predetermined number of substantially evenly angularly spaced loadwheel encoder pulses for each complete revolution of said loadwheel; (d) a programmed central processing unit; (e) a timer operatively connected to said loadwheel encoder and said central processing unit to cause said central processing unit to determine the time, T L (n L ) of occurrence of each of said loadwheel encoder pulses following one of said loadwheel reference pulses said central processing unit being programmed to calculate a parameter correlated to changes in the effective radius, R Eff of the tire as a measurement of the tendency of the tire to translate fore and aft.

Claim 27

An apparatus for testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising: (a) a loadwheel; (b) a drive for rotating the tire at a substantially constant angular speed against the circumferential surface of said loadwheel under a radial load; (c) a loadwheel encoder operatively connected to said loadwheel to generate a loadwheel reference pulse and a predetermined number of substantially evenly angularly spaced loadwheel encoder pulses for each complete revolution of said loadwheel; (d) a programmed central processing unit; (e) a timer operatively connected to said loadwheel encoder and said central processing unit to cause said central processing unit to determine the time, T L (n L ) of occurrence of each of said loadwheel encoder pulses following one of said loadwheel reference pulses said central processing unit being programmed to calculate a parameter correlated to changes in the effective radius, R Eff of the tire as a measurement of the tendency of the tire to translate fore and aft.

Claim 30

A method of testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising the steps of: (a) rotating the tire under a radial load against the circumferential surface of a loadwheel; (b) measuring the instantaneous speed, (V L ) of said circumferential surface of said loadwheel; (c) measuring the instantaneous angular speed (S) of the tire; (d) calculating the instantaneous effective radius, R Eff of the tire according to the equation: ##EQU21## (e) at least one of, sorting and grading the tire, based upon a value correlated to R Eff , as an indication of the tendency of the tire to generate forces in the fore and aft directions.

Claim 31

A method of testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising the steps of: (a) rotating the tire under a radial load against the circumferential surface of a loadwheel; (b) measuring the instantaneous speed, (V L ) of said circumferential surface of said loadwheel; (c) measuring the instantaneous angular speed (S) of the tire; (d) calculating the instantaneous effective radius, R Eff of the tire according to the equation: ##EQU21## (e) at least one of, sorting and grading the tire, based upon a value correlated to R Eff , as an indication of the tendency of the tire to generate forces in the fore and aft directions.

Claim 32

An apparatus for testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising: (a) means for rotating the tire under a radial load against the circumferential surface of a loadwheel; (b) means for measuring the instantaneous speed (V L ) of said circumferential surface of said loadwheel; (c) means for measuring the instantaneous angular speed (S) of the tire; (d) means for calculating the instantaneous effective radius, (R Eff ) of the tire according to the equation: ##EQU22## (e) means connected to said calculating means for at least one of, sorting and grading the tire based on a value correlated to R Eff as an indication of the tendency of the tire to generate forces in the fore and aft direction.

Claim 33

An apparatus for testing a tire to predict the tendency of the tire to generate forces in the fore and aft directions when the tire is used, comprising: (a) means for rotating the tire under a radial load against the circumferential surface of a loadwheel; (b) means for measuring the instantaneous speed (V L ) of said circumferential surface of said loadwheel; (c) means for measuring the instantaneous angular speed (S) of the tire; (d) means for calculating the instantaneous effective radius, (R Eff ) of the tire according to the equation: ##EQU22## (e) means connected to said calculating means for at least one of, sorting and grading the tire based on a value correlated to R Eff as an indication of the tendency of the tire to generate forces in the fore and aft direction.