Patent Application
20060071378
The present novel apparatus broadly relates to the art of fluid suspension systems and, more particularly, to a fluid suspension apparatus adapted for quick connection along an associated damping member and having a frustoconical wall portion on at least one end member that is formed from sheet material.
The present apparatus finds particular application in association with air suspension systems of vehicles, such as passenger cars, pickup trucks and SUVs, for example, and will be described below with particular reference thereto. However, it is to be appreciated that the present apparatus is equally applicable for use in association with other devices, systems and/or environments. For example, the present apparatus can be used in support structures, height adjusting systems and actuators associated with industrial machinery, components thereof and/or other such equipment. Accordingly, the subject apparatus is not intended to be limited to use associated with vehicle suspensions.
Vehicles, such as passenger cars, pickup trucks and SUVs commonly include a damping member and a spring on each corner of the vehicle. The damping member and spring are secured between a wheel supporting structure and the chassis or body of the vehicle. In many cases, the damping member is a strut, and the spring is a coil spring that is disposed around the exterior of the strut. This type of arrangement is now commonly used as the same reduces the envelope or space required for mounting and operation when compared to more traditional (coil or leaf) spring and shock absorber arrangements. When used with a strut, the coil spring is typically supported on and between a housing and damping rod of the strut rather than being secured to the vehicle itself. Oppositely, in a shock absorber and spring arrangement, both components are mounted to and between the two parts of the vehicle, namely, the chassis or body and the wheel supporting structure.
Frequently, an original damping member and coil spring arrangement will be replaced with a damping member and air spring arrangement. This can improve performance and handling of the vehicle, as well as provide height adjusting features not originally found on the vehicle. In some cases, the original suspension components will be replaced by independently selected damping members and air springs that are subsequently assembled together and installed on the vehicle. In other situations, a damping member and air spring assembly can be used to replace the original suspension components. These latter assemblies are designed for synergistic performance and, as such, have benefits over the use of independently selected components. Even so, certain disadvantages exist with these assemblies as well.
One such disadvantage is that the end members for the air spring portion of these assemblies are manufactured from billet aluminum or another suitable metal. This can undesirably increase the weight of the overall assembly. Additionally, these assemblies often include an upper end member that has a frustoconical outer surface. This is primarily done to provide a suitable mounting arrangement to fit within the envelope of the original suspension arrangement and connect it to the vehicle using the original mounting arrangement. However, these assemblies with the machined end members do not provide any significant increase in volume of the air spring.
Another disadvantage is that these assemblies typically capture the resilient bellows or sleeve between opposing end plates, which form the respective end members of the air spring. The end plates are secured together using fasteners to form a fluid-tight seal with the resilient member. Undesirably, leaks can be formed adjacent areas where one or more fasteners become loosened. However, assembly of the air spring using fasteners is maintained due to the construction and material of the machined end members, among other things. As such, these air spring assemblies tend to be expensive to manufacture and assemble, and also include undesirable physical characteristics, such as increased size and weight as well as reduced volume of the air spring, as discussed above.
An air spring according to one embodiment of the present novel concept for use with an associated damping member having an associated housing and an associated damping rod displaceably supported along the associated housing is provided that includes an upper end member, a lower end member and a flexible spring member. The upper end member is supported on the associated damping rod and includes an upper end wall substantially formed from sheet material. The upper end wall includes a frustoconical wall portion. The lower end member is supported on the associated housing and includes a lower end wall substantially formed from sheet material. The lower end wall includes a central wall portion received along the associated housing and removably secured thereto. The flexible spring member is supported between the upper and lower end members.
A suspension assembly according to another embodiment of the present novel concept and adapted for use on an associated vehicle having associated upper and lower vehicle portions is provided that includes a damping member and a fluid suspension device. The damping member is supported between the associated upper and lower vehicle portions and includes a housing and a damping rod movably supported within the housing. The fluid suspension device is supported on the damping member and includes a first end member supported on the damping rod, a second end member supported on the housing in spaced relation to the first end member, and a flexible suspension member supported between the first and second end members. The first end member includes a first wall substantially formed from sheet material. The first wall includes a frustoconical wall portion. The second end member includes a second wall substantially formed from sheet material and also includes an intermediate wall portion.
A method of manufacturing a fluid suspension member according to one embodiment of the present novel concept is provided that includes a step of providing sheet material and a flexible member that includes a side wall extending between opposing open ends. Another step includes forming a first end member from the sheet material. The first end member includes a first end wall having at least a frustoconical wall portion and a first peripheral wall portion formed outwardly from the frustoconical wall portion. Another step includes forming a second end member from the sheet of material. The second end member includes a second end wall having at least a mounting sleeve and a second peripheral wall portion formed outwardly from the mounting sleeve. Another step includes securing the side wall of the flexible member on the first and second peripheral wall portions to form the fluid suspension member.
With reference to
As can be better seen in
With reference to
Damping rod 204 extends from housing 202 and includes a threaded end 214 opposite housing 202 that receives retaining nut 208. A shoulder 216 is formed on the damping rod and first end member 102 is captured between the shoulder and the retaining nut.
First end member 102 includes a first wall 110 having a frustoconical wall portion 112 and an outer peripheral wall portion 114. First end member 102 also includes a mounting ring 116 and a connecting ring 118. The mounting and connecting rings are supported on first wall 110 in a suitable manner, such as by using a flowed-material joint, for example, though it will be appreciated that any suitable connection arrangement can be used. Rings 116 and 118 are shown in
As can be better seen in
Second end member 104 includes a second wall 132 having a substantially cylindrical wall portion 134 and an outer peripheral wall portion 136. Wall portion 134 forms a sleeve that is received along collar 206 and supported on a shoulder 218 formed thereon. Second end member 104 can be secured on collar 206 in any suitable manner. In one preferred embodiment shown in
Collar 206 includes radially inwardly extending grooves 222 that receive suitable sealing members, such as o-rings 224, for example. The sealing members form a substantially fluid-tight seal between collar 206 and cylindrical wall portion 134 of second end member 104.
Flexible suspension member 106 is supported between first and second end members 102 and 104. Flexible suspension member 106 is shown in
It will be appreciated from the drawings that first wall 110 of first end member 102 and second wall 132 of second end member 104 are substantially formed from sheet material. In one preferred embodiment, the sheet material is metal, which can be formed in any typical manner well known by those of skill in the art, including stamping, punching, sheering, breaking, coining and/or any other suitable method of metal forming. Though any suitable thickness can be used, the metal sheet material from about 3/32 of an inch to about 3/16 of an inch in thickness is typically used. Alternatively, the thickness of the metal sheet material can be referred to by gauge size as will be well understood by the skilled artisan. Again, any suitable gauge sheet metal can be used, though material of 9, 10 or 11 gauge, for example, is commonly used. Additionally, the sheet metal can be formed from any suitable material, such as carbon, stainless or alloy steel, for example. Furthermore, the sheet material can include further processing for strength and/or appearance improvements, such as heat treating or plating, for example.
As shown in
One benefit of increasing the volume of the air spring in this manner is that the increased volume is provided without a corresponding increase in the exterior size or envelope of the air spring, especially when compared to other air springs having end members machined from billet material. It is advantageous to increase the volume of an air spring for a number of reasons known by those of skill in the art. One such reason is that increasing the volume of an air spring typically provides an effective reduction in the spring rate of the air spring. This helps to provide a softer, and typically more comfortable, ride in the associated vehicle without a corresponding change in any of the other characteristics of the air spring, such as load capacity or operating height, for example, which could negatively impact the vehicle and/or the performance thereof.
In assembling fluid suspension device 100, peripheral wall portions 114 and 136, respectively of first wall 110 and second wall 132, are deformed or crimped around the associated annular mounting bead. This forms a substantially fluid-tight seal between the end member and the flexible suspension member. As such, a fluid-tight suspension device is formed that permits the ingress and egress of fluid respectively to and from fluid chamber 142 only through the openings in first and second end members 102 and 104. Thereafter, once fluid suspension device 100 has been assembled onto damping member 200, the only operable fluid passage remaining is passage 108 formed in first end member 102. A suitable fluid line connection can then be made to supply and exhaust fluid from chamber 142.
Another benefit of providing an air spring having an increased volume (within the same outer envelope) is that the spring rate can be optimized for different vehicles, such as by slightly reducing the volume of the air spring, for example. One method of accomplishing this that is well known by those of skill in the art includes introducing a quantity of an incompressible fluid, such as water, antifreeze or another compatible liquid, for example, into the fluid chamber of the air spring. Any suitable quantity of liquid can be added, such as from about 5 to about 15 fluid ounces, for example. As an illustration, the spring rate of one group of air springs according to the present novel concept can be optimized for use on one vehicle by filling from about 3 to about 6 ounces of suitable fluid into the spring chambers thereof. The spring rate of another group of the same air springs according to the present novel concept can be optimized for use on a second, different vehicle by filling from about 8 to about 11 ounces of a suitable fluid into the spring chambers thereof. As such, by providing an air spring that has an overall increased volume, the same version of the air spring can be optimized for use on different vehicles due, at least in part, to this increased volume. Additionally, a similar practice can be employed for tailoring a fluid suspension member for use as a machine support where it is desired to isolate a certain vibration frequency, as is well understood by skilled artisans.
In addition to the foregoing, one benefit of fluid suspension members in accordance with the present novel concept is that well established mass production methods and equipment can be used to manufacture these devices at a relatively low cost. Whereas, other known constructions are not adapted to make use of such air spring manufacturing methods and equipment and, as such, do not take full advantage of the efficiencies and cost savings associated with the same. Another benefit of fluid suspension members in accordance with the present novel concept is that the same have improved size, weight and volume characteristics over other constructions. A further benefit is that such fluid suspension members are adapted to quickly and easily attach to an associated damping member. As such, they are well suited for convenient replacement and/or retrofit of OEM parts on vehicles.
While the present novel concept has been described with reference to the foregoing embodiments and considerable emphasis has been placed herein on the structures and structural interrelationships between the component parts of the embodiments disclosed, it will be appreciated that other embodiments of the present novel concept can be made and that many changes can be made in the embodiments illustrated and described without departing from the principles of the present novel concept. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. Accordingly, it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the present novel concept and not as a limitation. As such, it is intended that the present novel concept be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims and the equivalents thereof.
