DUAL COMPOUND ELASTOMER BUSHING FOR VEHICLE SUSPENSION COMPONENT

A dual compound bushing includes a tube having a first end, a second end, and an intermediate portion extending therebetween. A first elastomeric member having a first durometer value is arranged on the intermediate portion. A second elastomeric member having a second durometer value that is distinct from the first durometer value is arranged at the first end. A ferrule is mounted to the tube at the first end. The second elastomeric member being arranged between the ferrule and the first elastomeric member.

INTRODUCTION

The subject disclosure relates to the art of vehicles and, more particularly, to a dual compound elastomer bushing for a vehicle suspension component.

Vehicles include a number of suspension components that operate to dampen vibrations, and other forces, that may transmit from road surfaces into occupant spaces. Suspension components may include coil springs, hydraulic pistons such as shock absorbers and struts, and leaf springs. Leaf springs are typically secured to a vehicle frame through a shackle. The shackle is supported at the leaf spring through elastomeric bushings. The elastomeric bushings serve to dampen forces and reduce wear at contact points between the leaf spring and the vehicle frame. Current bushings are typically a two part construction. That is, two metal sleeves sandwich an elastomeric material to form the bushing.

While effective at dampening and reducing wear, current bushings possess various limitations including the ability to provide both axial and conical stiffness. As such, materials that may be used to form suspension components, such as leaf springs, are limited. That is, if the bushings cannot provide a selected stiffness, suspension components, such as leaf springs, formed from certain lighter weight materials may not meet desired lateral stiffness requirements. Accordingly, it is desirable to provide a bushing with selected axial and conical stiffness so as to open the door to new materials that may be used in forming vehicle suspension components.

SUMMARY

In one exemplary embodiment, a dual compound bushing including a tube having a first end, a second end, and an intermediate portion extending therebetween. A first elastomeric member having a first durometer value is arranged on the intermediate portion. A second elastomeric member having a second durometer value that is distinct from the first durometer value is arranged at the first end. A ferrule is mounted to the tube at the first end. The second elastomeric member being arranged between the ferrule and the first elastomeric member.

In addition to one or more of the features described above or below, or as an alternative, further embodiments could include a third elastomeric member arranged at the second end of the tube, the third elastomeric member including the second durometer value.

In addition to one or more of the features described above or below, or as an alternative, further embodiments could include another ferrule mounted to the tube at the second end, the third elastomeric member being arranged between the another ferrule and the first elastomeric member.

In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the first elastomeric member is mold bonded to the tube.

In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the ferrule is press-fit to the first end of the tube.

In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the first elastomeric member is integrally bonded with the second elastomeric member.

In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the second elastomeric member is formed from a self-lubricating elastomer.

In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the first durometer value is about 55 durometer and the second durometer value is about 75 durometer.

In accordance with another aspect of an exemplary embodiment, a method of forming a dual compound bushing includes mounting a first elastomeric member having a first durometer value about an intermediate portion of a tube, positioning a second elastomeric member having a second durometer value distinct from the first durometer value at a first end of the tube, and securing the second elastomeric member to the tube with a ferrule.

In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein securing the second elastomeric member to the tube includes press-fitting the ferrule to the tube.

In addition to one or more of the features described above or below, or as an alternative, further embodiments could include positioning a third elastomeric member having the second durometer value distinct from the first durometer value at a first end of the tube, and securing the third elastomeric member to the tube with another ferrule.

In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein securing the third elastomeric member to the tube includes applying a compression force to the first elastomeric member with the ferrule and the another ferrule.

In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein mounting the first elastomeric member to the tube includes mold bonding the first elastomeric member to the tube.

In addition to one or more of the features described above or below, or as an alternative, further embodiments could include bonding the second elastomeric member to the first elastomeric member.

DETAILED DESCRIPTION

A vehicle, in accordance with an exemplary embodiment, is indicated generally at10inFIG. 1, vehicle10includes a frame12that supports a suspension component14. Suspension component14supports an axle (not shown) which, in turn, supports a wheel (also not shown). Suspension component14is coupled to frame12through a shackle18having a first shackle component22and a second shackle component23.

In an embodiment, suspension component14takes the form of a leaf spring28including a bushing receiver30. A first mechanical fastener34secures shackle18to frame12. A second mechanical fastener36secures leaf spring28to shackle18. In an embodiment, a dual compound bushing40is arranged in bushing receiver30and supports leaf spring28to shackle18.

Referring toFIGS. 2 and 3, and with continued reference toFIG. 1, dual compound bushing40, in accordance with an exemplary embodiment, includes a tube44. Tube44may be formed from steel, an Aluminum extrusion or other materials depending upon vehicle requirements. Further, tube44may possess various cross-sectional geometries including circular or oval cross-sections depending on application or vehicle requirements. Tube44includes a first end46, a second end47, and an intermediate portion48. Tube44also includes an outer surface50that extends between first end46and second end47. In an embodiment, tube44supports a first elastomeric member54. More specifically, first elastomeric member54may be mold bonded to intermediate portion48of tube44. First elastomeric member54is formed from a first material having a first durometer value. In an embodiment, the first durometer value is about 55 durometer.

In further accordance with exemplary embodiments, a second elastomeric member61is arranged at first end46of tube44and a third elastomeric member63is arranged at second end47of tube44. In an embodiment, second elastomeric member61is formed from a second material having a second durometer value. In accordance with an exemplary aspect, the second durometer value greater than the first durometer value. For example, the second durometer value may be about 75 durometer. Thus, second elastomeric member61is stiffer than first elastomeric member54. Third elastomeric member63is formed from a third material having a third durometer value. In accordance with an exemplary aspect, third elastomeric member is formed from the second material. As such, the third durometer value is the same as the second durometer value. It should be understood that the particular durometer values may vary and could depend upon application and/or vehicle requirements. In another aspect, second and third elastomeric members may be formed from a self-lubricating elastomer.

In an embodiment, second elastomeric member61includes an inner surface66and an outer surface67. Inner surface61may be spaced from first elastomeric member54at first end46of tube44. In an embodiment, inner surface61may abut first elastomeric member54. In another embodiment, inner surface61may be bonded to and/or integrally formed with first elastomeric member54. Similarly, third elastomeric member63includes an inner surface70and an outer surface71. Inner surface70may be spaced from first elastomeric member54at second end47of tube44. In another embodiment, inner surface70may be bonded to and/or integrally formed with first elastomeric member54. In yet another embodiment, first elastomeric member54, second elastomeric member61and third elastomeric member63may be co-molded into tube44.

In an embodiment, inner surface70may abut first elastomeric member54. In another embodiment, inner surface70may be bonded to and/or integrally formed with first elastomeric member54. For example, second and third elastomeric members61and63may be vulcanized to first elastomeric member54. In another example, first, second, and third elastomeric members may be molded together using multiple injection nozzles that deliver different materials.

In further accordance with an exemplary aspect, a first ferrule79is arranged at first end46of tube44and a second ferrule82is arranged at second end47of tube44. First ferrule79may be press-fit onto tube44at first end46. Second ferrule82may be press-fit onto second end47of tube44. In accordance with an exemplary aspect, first and second ferrules79and82may be mounted to tube44such that a compressive force is applied to second elastomeric member61and third elastomeric member63. In an embodiment, the compressive force may provide a pre-load on second elastomeric member61and third elastomeric member63. The pre-load may cause first and second ferrules79and82to compress corresponding ones of second elastomeric member61and third elastomeric member63about 0.5 mm. Dual compound bushing40may be installed into bushing receiver30using a variety of techniques. For example, first elastomeric member54may be mechanically bonded to leaf spring28at bushing receiver30.

At this point, it should be appreciated that the exemplary embodiments describe a dual compound bushing that is formed from materials that are specifically selected to achieve selected axial and conical stiffness values. The ability to tune both the axial and conical stiffness values will open up a wide array of materials that may be used for suspension components. For example, dual compound bushing may be formed to provide selected axial and conical stiffness values that allow the use of various composite materials that will result in a significant weight savings.

The terms “about” and “substantially” are intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” and “substantially” can include a range of ±8% or 5%, or 2% of a given value.