Method and apparatus for evaluating a cornering stability of a wheel
First Claim
1. A method of evaluating a cornering stability of a wheel that is mounted to a vehicle and has a tire assembled thereto, when the vehicle is cornering on a road surface, the method comprising:
- a deriving step of deriving an cumulative value of lateral displacement of an outer circumference surface portion of the tire, the cumulative value representing a resultant of an accumulation of the lateral displacement from a contact leading edge to a contact trailing edge of the tire, when the vehicle is cornering, and the cumulative value of displacement being derived continually at every unit of time;
a first calculating step of repeatedly calculating, each time when the cumulative value of displacement is derived, a change amount in the cumulative value of displacement for the unit of time as a change ratio in tire deformation by using the cumulative value of displacement derived present time and the cumulative value of displacement derived last time,;
a second calculating step of calculating, each time when the change ratio is calculated, a rate of change ratio in tire deformation, the rate of change ratio being calculated using the change ratio in tire deformation previously calculated as a reference value and the change ratio calculated present time; and
a determining step of determining, based on the rate of change ratio calculated in the second calculating step, a cornering stability of the wheel that represents a degree of a margin in which the wheel keeps no sliding and beyond which the wheel start sliding.
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Accused Products
Abstract
A method and apparatus derives a change amount in the cumulative value of displacement for the unit of time as a change ratio in tire deformation by using the cumulative value of displacement derived present time and the cumulative value of displacement derived last time, and calculate a rate of change ratio using the change ratio in tire deformation previously calculated as a reference value and the change ratio calculated present time, and determine a cornering stability of the wheel that represents a degree of a margin in which the wheel keeps no sliding and beyond which the wheel start sliding based on the rate of change ratio.
17 Citations
9 Claims
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1. A method of evaluating a cornering stability of a wheel that is mounted to a vehicle and has a tire assembled thereto, when the vehicle is cornering on a road surface, the method comprising:
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a deriving step of deriving an cumulative value of lateral displacement of an outer circumference surface portion of the tire, the cumulative value representing a resultant of an accumulation of the lateral displacement from a contact leading edge to a contact trailing edge of the tire, when the vehicle is cornering, and the cumulative value of displacement being derived continually at every unit of time;
a first calculating step of repeatedly calculating, each time when the cumulative value of displacement is derived, a change amount in the cumulative value of displacement for the unit of time as a change ratio in tire deformation by using the cumulative value of displacement derived present time and the cumulative value of displacement derived last time,;
a second calculating step of calculating, each time when the change ratio is calculated, a rate of change ratio in tire deformation, the rate of change ratio being calculated using the change ratio in tire deformation previously calculated as a reference value and the change ratio calculated present time; and
a determining step of determining, based on the rate of change ratio calculated in the second calculating step, a cornering stability of the wheel that represents a degree of a margin in which the wheel keeps no sliding and beyond which the wheel start sliding. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for evaluating a cornering stability of a wheel that is mounted to a vehicle and has a tire assembled thereto, when the vehicle is cornering on a road surface, the apparatus comprising:
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a memory capable of storing digit information;
a deriving unit that derives and stores in the memory, an cumulative value of lateral displacement of an outer circumference surface portion of the tire, the cumulative value representing a resultant of an accumulation of the lateral displacement from a contact leading edge to a contact trailing edge of the tire, when the vehicle is cornering, and the cumulative value of displacement being derived continually at every unit of time;
a first calculating section that receives the derived cumulative value of displacement each time when the cumulative value of displacement is derived, retrieves the cumulative value of displacement that is derived last time and stored in the memory, and uses the cumulative value of displacement that is derived present time and the cumulative value of displacement that is derived last time so as to repeatedly calculate a change amount in the cumulative value of displacement for a unit of time as a change ratio in tire deformation, a second calculating section that receives the change ratio in tire deformation, each time when the change ratio in tire deformation is derived, uses the change ratio calculated last time as a reference value, and repeatedly calculates a rate of change ratio in tire deformation calculated this time with respect to the reference value, and a determination unit that receives the rate of change ratio in tire deformation calculated in the second calculating section, and based on the rate of change ratio, determines a cornering stability of the wheel that represents a degree of a margin in which the wheel keeps no sliding and beyond which the wheel start sliding. - View Dependent Claims (8, 9)
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Specification