Tire profile design method
AssigneeSumitomo Rubber Industries, Ltd.
InventorsMasatoshi Tanaka, Takuya Yamamoto
Life of this patent
Estimating the term…
Abstract
First of all, size data (MD), (BD), (BH) and (MW) of a tire are input. Next, a ratio (b/a) of a major axis radius (b) to a minor axis radius (a) of an ellipse (18) is input. Then, constants (S), (a) and (b) of an involute function are calculated. Based on the involute function having these constants, a profile function (22) from a central position in a lateral direction to a maximum width position is determined over an X-Y plane. Subsequently, the profile curve (22) is divided into a large number of segments. Next, each of the segments is caused to approximate to a circular arc. In the approximation, a radius of curvature is determined in such a manner that the adjacent circular arcs are tangent to each other. Thus, a profile is designed.
Claims5
A method for designing a tire profile, comprising the steps of:
- inputting tire size data;
- determining a ratio (b/a) of a second axis radius “b” to a first axis radius “a” in an ellipse in which one of ends of a first axis is placed on a tire equator plane and a direction of the first axis is coincident with an axial direction of a tire;
- determining a constant of an involute function based on the tire size data in such a manner that an involute curve based on the ellipse having the ratio of (b/a) passes through a maximum width position of the tire and a central position in a lateral direction;
- and
- determining a profile curve reaching the maximum width position from the central position in the lateral direction based on the involute function having the constant;
- wherein
- the involute function is expressed in the following equations (I) and (II):
- x
-
- (
- θ
- )
- =
- a
-
- (
- 1
- +
- cos
-
-
- θ
- )
- +
- b
-
-
- sin
-
-
- θ
-
- 1
- /
- (
- a
- 2
-
- cos
- 2
-
- θ
- +
- b
- 2
-
- sin
- 2
-
- θ
- )
-
- [
- S
- -
- ∫
- π
- π
- -
- θ
-
- (
- a
- 2
-
- cos
- 2
-
- θ
- +
- b
- 2
-
- sin
- 2
-
- θ
- )
-
- ⅆ
- θ
- ]
- (
- I
- )
- and
- y
-
- (
- θ
- )
- =
- b
-
-
- sin
-
-
- θ
- +
- a
-
-
- cos
-
-
- θ
-
- 1
- /
- (
- a
- 2
-
- cos
- 2
-
- θ
- +
- b
- 2
-
- sin
- 2
-
- θ
- )
-
- [
- S
- -
- ∫
- π
- π
- -
- θ
-
- (
- a
- 2
-
- cos
- 2
-
- θ
- +
- b
- 2
-
- sin
- 2
-
- θ
- )
-
- ⅆ
- θ
- ]
- (
- II
- )
- (In the Equations (I) and (II), “a” represents the first axis radius of the ellipse, “b” represents the second axis radius of the ellipse and “S” represents a length of a thread wound upon the ellipse. θ is π/2 to π).
A tire profile design system comprising:
- input means for inputting a ratio (b/a) of a second axis radius “b” to a first axis radius “a” in an ellipse in which one of ends of a first axis is placed on a tire equator plane and a direction of the first axis is coincident with an axial direction of a tire and tire size data;
- and
- calculating means for determining a constant of an involute function based on the tire size data in such a manner that an involute curve based on the ellipse having the ratio (b/a) passes through a maximum width position of the tire and a central position in a lateral direction and determining a profile curve reaching the maximum width position from the central position in the lateral direction based on the involute function having the constant;
- wherein
- the involute function is expressed in the following equations (I) and (II):
- x
-
- (
- θ
- )
- =
- a
-
- (
- 1
- +
- cos
-
-
- θ
- )
- +
- b
-
-
- sin
-
-
- θ
-
- 1
- /
- (
- a
- 2
-
- cos
- 2
-
- θ
- +
- b
- 2
-
- sin
- 2
-
- θ
- )
-
- [
- S
- -
- ∫
- π
- π
- -
- θ
-
- (
- a
- 2
-
- cos
- 2
-
- θ
- +
- b
- 2
-
- sin
- 2
-
- θ
- )
-
- ⅆ
- θ
- ]
- (
- I
- )
- and
- y
-
- (
- θ
- )
- =
- b
-
-
- sin
-
-
- θ
- +
- a
-
-
- cos
-
-
- θ
-
- 1
- /
- (
- a
- 2
-
- cos
- 2
-
- θ
- +
- b
- 2
-
- sin
- 2
-
- θ
- )
-
- [
- S
- -
- ∫
- π
- π
- -
- θ
-
- (
- a
- 2
-
- cos
- 2
-
- θ
- +
- b
- 2
-
- sin
- 2
-
- θ
- )
-
- ⅆ
- θ
- ]
- (
- II
- )
- (In the Equations (I) and (II), “a” represents the first axis radius of the ellipse, “b” represents the second axis radius of the ellipse and “S” represents a length of a thread wound upon the ellipse. θ is π/2 to π).
A computer program, carried on a computer-readable medium, for designing a tire profile, the program, when executed, carrying out the steps of:
- inputting tire size data;
- determining a ratio (b/a) of a second axis radius “b” to a first axis radius “a” in an ellipse in which one of ends of a first axis is placed on a tire equator plane and a direction of the first axis is coincident with an axial direction of a tire;
- determining a constant of an involute function based on the tire size data in such a manner that an involute curve based on the ellipse having the ratio (b/a) passes through a maximum width position of the tire and a central position in a lateral direction;
- and
- determining a profile curve reaching the maximum width position from the central position in the lateral direction based on the involute function having the constant;
- wherein
- the involute function is expressed in the following equations (I) and (II):
- x
-
- (
- θ
- )
- =
- a
-
- (
- 1
- +
- cos
-
-
- θ
- )
- +
- b
-
-
- sin
-
-
- θ
-
- 1
- /
- (
- a
- 2
-
- cos
- 2
-
- θ
- +
- b
- 2
-
- sin
- 2
-
- θ
- )
-
- [
- S
- -
- ∫
- π
- π
- -
- θ
-
- (
- a
- 2
-
- cos
- 2
-
- θ
- +
- b
- 2
-
- sin
- 2
-
- θ
- )
-
- ⅆ
- θ
- ]
- (
- I
- )
- and
- y
-
- (
- θ
- )
- =
- b
-
-
- sin
-
-
- θ
- +
- a
-
-
- cos
-
-
- θ
-
- 1
- /
- (
- a
- 2
-
- cos
- 2
-
- θ
- +
- b
- 2
-
- sin
- 2
-
- θ
- )
-
- [
- S
- -
- ∫
- π
- π
- -
- θ
-
- (
- a
- 2
-
- cos
- 2
-
- θ
- +
- b
- 2
-
- sin
- 2
-
- θ
- )
-
- ⅆ
- θ
- ]
- (
- II
- )
- (In the Equations (I) and (II), “a” represents the first axis radius of the ellipse, “b” represents the second axis radius of the ellipse and “S” represents a length of a thread wound upon the ellipse. θis π/2 to π).
Dependencies are inferred from the claim text.