Thermoplastic jounce bumpers
AssigneeE. I. Du Pont de Nemours and Company
InventorsPeter Laszlo Szekely, Damien Van Der Zyppe
Life of this patent
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Abstract
The invention provides vehicle suspension systems, and more particularly jounce bumpers made of elastomeric thermoplastic material, having improved design to maximize energy absorption.
Claims14
A jounce bumper made of elastomeric thermoplastic material, comprising:
- a hollow elongated tubular body having a wall, the tubular body having at least two bellows, each bellow being defined by a peak and a trough, the peak having a fillet radius of rs, the trough having a fillet radius of rc and a maximum wall thickness in the trough of Tmax;
- wherein rc is greater than rs, and wherein the ratio of Tmax, the maximum thickness of the wall in a trough to Tm, the thickness of the wall at intermediate points between peaks and troughs, is greater than or equal to 1.5, wherein the trough is defined by a wall arc having end points at said intermediate points where the wall thickness is Tm;
- wherein each of said intermediate points is a point of tangency between a circle of radius rc and a circle of radius rs, or if rs and rc are not tangent, Tm is the wall thickness wherein each of said intermediate points is a midpoint of a line drawn tangent to circles rs and rc;
- and
- wherein the force required to compress said jounce bumper to 50 percent relative deformation is at least 14 percent greater than the force required to compress a jounce bumper to 50 percent relative deformation which does not have a ratio of Tmax to Tm of greater than or equal to 1.5.
A method for the manufacture of a jounce bumper, comprising the step of:
- shaping elastomeric thermoplastic material into a hollow elongated tubular body having a wall, the tubular body having at least two bellows, each bellow being defined by a peak and a trough, the peak having a fillet radius of rs, the trough having a fillet radius of rc and a maximum wall thickness at the trough of Tmax;
- wherein rc is greater than rs, and wherein the ratio of Tmax, the maximum thickness of the wall at a trough, to Tm, the thickness of the wall at intermediate points between peaks and troughs, is greater than or equal to 1.5, wherein the trough is defined by a wall arc having end points at said intermediate points where the wall thickness is Tm;
- wherein each of said intermediate points is a point of tangency between a circle of radius rc and a circle of radius rs, or if rs and rc are not tangent, Tm is the wall thickness wherein each of said intermediate points is a midpoint of a line drawn tangent to circles rs and rc;
- and
- wherein the force required to compress said jounce bumper to 50 percent relative deformation is at least 14 percent greater than the force required to compress a jounce bumper to 50 percent relative deformation which does not have a ratio of Tmax to Tm of greater than or equal to 1.5.
A method for absorbing shocks in an automobile suspension comprising using a jounce bumper to absorb energy from displacement of the suspension, wherein the jounce bumper is made of elastomeric thermoplastic material and comprises a hollow elongated tubular body having a wall, the tubular body having at least two bellows, each bellow being defined by a peak and a trough, the peak having a fillet radius of rs, the trough having a fillet radius of rc and a maximum wall thickness at the trough of Tmax;
- wherein rc is greater than rs, wherein the ratio of Tmax the thickness of the wall at a trough, to Tm, the thickness of the wall at intermediate points between peaks and troughs, is greater than or equal to 1.5
- wherein the trough is defined by a wall arc having end points at said intermediate points where the wall thickness is Tm;
- wherein each of said intermediate points is a point of tangency between a circle of radius rc and a circle of radius rs, or if rs and rc are not tangent, Tm is the wall thickness wherein each of said intermediate points is a midpoint of a line drawn tangent to circles rs and rc;
- and
- wherein the force required to compress said jounce bumper to 50 percent relative deformation is at least 14 percent greater than the force required to compress a jounce bumper to 50 percent relative deformation which does not have a ratio of Tmax to Tm of greater than or equal to 1.5.
Dependencies are inferred from the claim text.