HK1160910A - Gas suspension member and method - Google Patents

Description

Gas suspension member and method

Technical Field

The subject matter of the present disclosure relates generally to the field of suspension systems, and more particularly to a gas suspension member adapted for interconnection with a gas transmission line and a method of forming such a gas suspension member.

Background

The subject matter of the present disclosure finds particular application in connection with gas suspension members for use on vehicle suspension systems, and is discussed herein with particular reference thereto. However, it should be appreciated that the subject gas suspension member and method may be equally suitable for use in other applications and environments, and is not intended to be limited in any way for use in the applications discussed herein, which are merely exemplary.

Gas suspension members having an inlet for connection to a gas transmission line are generally well known. One example of such a gas suspension member is disclosed in U.S. patent US6,145,894 to Myers, which is hereby incorporated by reference in its entirety.

Gas suspension members have generally been used in a wide variety of applications, such as in vehicle suspension systems, with great success. Gas suspension members for vehicle suspension systems may be used in a wide variety of types, styles and configurations, including those having rigid end members and designs having flexible end walls. While there are many advantages associated with the use of gas suspension members in vehicle suspension systems, there are areas where improvement is needed, such as reduced maintenance or increased ease of installation.

An improved opportunity exists for a gas suspension member having a flexible end wall. Vehicle suspension systems are designed to allow dynamic motion between various parts and components of the vehicle, depending on their particular attributes. As such, repeated bending or stressing is common to the portions associated with vehicle suspension systems. Gas suspension members are one example of such components, and those having flexible end walls are generally well suited to such bending action.

For example, the connection of these fluid suspension members to a fluid supply is typically accomplished by fittings that fit on the end walls of the fluid suspension members, as shown in Myers' 894 patent. Fittings, typically made of metal, are mounted on the flexible end walls to form a fluid-tight seal therewith. However, repeated flexing of the end walls may in some cases cause the flexible material surrounding the fitting to separate from the connector fitting. This typically compromises the seal around the connector fitting, resulting in a loss of compressed gas, which, among other problems, reduces the performance and/or efficiency of the suspension system.

One important source of separation is caused by stresses induced by expansion along the flexible wall to which the fitting is mounted. That is, the opposite end walls of the gas suspension member are slightly bulged or dome-shaped due to the pressure inside the gas suspension member. The nature of the deflection and the general positioning of the fitting on the end wall may cause any forces that would otherwise act to overcome the sealing of the fitting. This may undesirably result in a loss of integrity of the seal forming the fluid seal around the fitting.

Various arrangements have been employed to improve the interconnection between the connector fitting and the flexible end wall. One method is to mold the connector fitting into the component during the manufacture of the flexible wall. Unfortunately, it has been found that the mechanical properties of the wall material alone are not sufficient to consistently withstand the separation stresses discussed above. As such, this joining method has not been successful on a consistent basis even with the residual compressive stresses created by the overmolding process. Another method that has been used to improve the interconnection between the connector fitting and the surrounding flexible material includes the use of adhesives. While this arrangement significantly enhances the interconnection between the connector fitting and the flexible wall, the adhesive and the process of applying the adhesive, among other drawbacks, results in an undesirable increase in production costs.

Another example of a gas suspension member that has been successful in improving the interconnection between the connector fitting and the flexible end wall is disclosed in united states patent US 7,270,317 to Leonard, which is hereby incorporated by reference in its entirety. Broadly, the' 317 patent discloses an arrangement in which a groove is formed along a flexible end wall of the gas suspension member and adjacent a portion of the end wall that sealingly engages the connector fitting. This arrangement allows the end wall to flex while minimizing or at least reducing the transmission of forces resulting from separation to the end wall portion that sealingly engages the connector fitting.

Despite the success of the arrangement in the' 317 patent and other known devices, there remains a desire to continue to develop gas suspension members and methods of making gas suspension members that will further contribute to the prior art of gas spring devices.

Disclosure of Invention

A gas suspension assembly according to the subject matter of the present disclosure is provided that includes a first suspension device having opposing first and second ends and a first longitudinally extending axis extending therebetween. The first suspension arrangement comprises a spring element extending helically around the first axis such that a plurality of windings are formed between the first end portion and the second end portion. The plurality of windings at least partially define an interior of the first suspension. The second suspension device is disposed within the interior of the first suspension device. The second suspension device includes a first end wall formed of a first polymeric material having a first value for a preselected material property and an opening extending through the first end wall. The second end wall is spaced from the first end wall such that a second longitudinally extending axis extends therebetween. The second axis is arranged in general alignment with the first axis of the first suspension device. The sidewall is formed of a first polymeric material having substantially a first value for a preselected material property. The sidewall extends between the first and second end walls and at least partially defines a gas chamber therebetween. The third end wall extends across the opening in the first end wall and is secured to the first end wall in a substantially fluid tight manner. The third end wall is formed of a second polymer material having a second value for the preselected material property that is different from the first value of the first material. A connector fitting is received within the third end wall such that a substantially fluid tight seal is formed therethrough. The connector fitting includes a passage extending therethrough and in fluid communication with the gas chamber, and the passage has an open end adapted to receive and retain an associated gas delivery line.

A gas suspension assembly according to the preceding paragraph may include a preselected material property that is a hardness property, wherein a first value of hardness is in a range of about 70 Shore a to about 90 Shore a, and a second value of hardness is in a range of about 40 Shore D to about 70 Shore D (Shore D).

A gas suspension assembly according to either of the preceding two paragraphs may comprise a first polymer material and a second polymer material from the same family of materials.

The gas suspension assembly according to the previous paragraph may be selected from the same family of materials including the group of polyolefins, polyurethanes and polypropylenes.

A gas suspension assembly according to any of the preceding four paragraphs can include a second end wall formed of a first polymeric material having approximately a first value of a preselected material property.

The gas suspension assembly of any of the preceding five paragraphs may include a first suspension device comprising a steel compression spring.

A gas suspension member according to the subject matter of the present disclosure is provided that includes a first end wall having an opening formed therethrough. The second end wall is spaced from the first end wall such that a longitudinally extending axis extends therebetween. The side wall extends between the first end wall and the second end wall and at least partially defines a gas chamber therebetween. The third end wall is attached to the first end wall across the opening of the first end wall. The connector fitting is at least partially embedded within the third end wall to form a substantially fluid-tight seal along an interface between the connector fitting and the third end wall. The connector fitting includes a passage extending therethrough at opposite first and second open ends. The first open end is disposed outside of the gas chamber and is adapted to receive an associated gas transfer line. The first end wall has a first bending stiffness and the third end wall has a second bending stiffness, the second bending stiffness being greater than the first bending stiffness, such that the first end wall is more bendable than the third end wall. This allows for greater deflection of the first end wall relative to the third end wall and reduces the transmission of stresses caused by separation from the first end wall to the interface between the connector fitting and the third end wall.

A method of forming a gas suspension frame according to the subject matter of the present disclosure is provided that includes forming a first section of a gas suspension member from a first polymeric material having a first value for a preselected material property thereof. The first segment has a first longitudinally extending axis and includes a first end wall extending generally transverse to the first axis and a first side wall extending from the first end wall generally along the first axis. The first end wall and the first side wall each include an inner surface at least partially bounding an interior cavity of the first segment. The first end wall includes an opening formed therethrough. The method also includes forming a second section of the gas suspension member from a first polymeric material having a first value for a preselected material property thereof. The second section includes a second end wall. The method also includes providing a connector fitting for receiving and retaining the gas delivery line. The connector fitting includes a fluid passage extending therethrough. The method also includes forming the cap wall from a second polymeric material for a second value having its preselected material properties. The method also includes embedding the connector fitting within the cap wall such that the fluid passage extends through the cap wall. The method also includes disposing a cover wall from within the interior chamber of the first section along an inner surface of the first end wall of the first section, and securing the cover wall along the inner surface of the first end wall through the opening such that the passage of the connector fitting is in communication between the opening and the interior chamber. The method also includes attaching the first segment and the second segment together to form a substantially fluid-tight joint therebetween.

Drawings

Fig. 1 is a side cross-sectional view of one embodiment of a gas suspension member, shown in use on a vehicle suspension system, according to the subject matter of the present disclosure.

Fig. 2 is an enlarged side view of the connector fitting shown in fig. 1.

Fig. 3 is a side cross-sectional view of the gas suspension member of fig. 1 prior to assembly.

Fig. 4 is an enlarged view of a detail 4 of the gas suspension member shown in fig. 1.

Fig. 5 is a view of the end wall and connector fitting of fig. 4 shown undergoing deflection caused by expansion.

Fig. 6 is a view of the end wall and connector fitting of fig. 4 shown undergoing deflection caused by an external load.

Fig. 7 is an illustration of an exemplary method of forming a gas suspension member according to the subject matter of the present disclosure.

Detailed Description

Turning now to the drawings, wherein the showings are for the purpose of illustrating preferred embodiments of the presently disclosed subject matter only and not for the purpose of limiting the same in any way, FIG. 1 illustrates a gas suspension assembly 100 including first and second suspension elements or devices supported between opposing structural members, such as a first structural component FSC and a second structural component SSC of an associated vehicle (not shown). In the exemplary arrangement shown in FIG. 1, the gas suspension assembly 100 includes a conventional compression spring 102 made of a spring element (e.g., a length of wire or rod) having a plurality of coils 104 extending circumferentially about a longitudinally extending axis AX. An inner region (not numbered) is disposed within the plurality of windings, such as may be defined within the inner dimension ID 1.

Gas suspension assembly 100 further includes a gas suspension member 106 sized to be received within the interior region of compression spring 102 in accordance with the subject matter of the present disclosure. Gas suspension member 106 also has a longitudinally extending axis AX and includes a first or upper segment 108 and a second or lower segment 110. The upper section 108 includes: a first or upper end wall 112 extending in a generally transverse (e.g., perpendicular) direction relative to the axis AX; and a first or upper sidewall 114 extending from the upper endwall in a generally longitudinal direction (e.g., approximately aligned) along the axis AX. The lower section 110 is shown in fig. 1 as including: a second or lower end wall 116 that extends in a generally transverse (e.g., perpendicular) direction relative to the axis AX. The lower segment 110 optionally includes one or more additional structures, such as a second or lower sidewall 118 extending from the lower end wall in a generally longitudinal direction (e.g., approximately aligned direction) along the axis AX. In the exemplary arrangement shown, sections 108 and 110 are generally circular in cross-section. However, it should be appreciated that any other shape and/or arrangement may alternatively be used.

Upper end wall 112 and upper side wall 114 at least partially define a gas chamber 120 within gas suspension member 106 that is capable of maintaining a volume of compressed gas at a gas pressure greater than that of the surrounding ambient atmosphere ATM. In the exemplary arrangement shown, a gas chamber 120 is formed, for example, between the upper and lower end walls 112, 116 and the upper and lower sidewalls 114, 118 by the upper and lower sections acting together. In the exemplary arrangement shown, the upper and lower sections of gas suspension member 106 are secured to each other to form gas suspension member 106. This may be achieved in any suitable way. As one example, the first and second sections 108 and 110 may include radially outwardly extending annular flanges 122 and 124, respectively, formed along the sidewalls 114 and 118 thereof. In the exemplary embodiment shown, flanges 122 and 124 are disposed generally opposite end walls 112 and 116. The sections 108 and 110 are shown in FIG. 1 as being joined along flanges 122 and 124 at a joint 126 and together define a gas chamber 120. It will be appreciated that the sections may be secured together by any suitable means, for example, by hot plate welding, rotary fusion welding, ultrasonic welding and/or the use of adhesives.

Gas suspension member 106 includes a gas delivery connection, generally indicated at 128, disposed along upper end wall 112. The gas delivery connection 128 is shown in fig. 1-6 as including a push-pull connector, generally indicated by reference numeral 130. It will be recognized that the general structure and principle of operation of such push-pull connectors are well known. Further, it should be appreciated that any other suitable type, kind, configuration and/or construction of connector fitting or device may alternatively be used. Any such connector fitting would preferably be adapted to receive and retain an associated gas delivery line, such as gas delivery line 132 in fig. 1. The inlet to the gas delivery connection 128 may be provided in any suitable manner, for example, through an opening OPN in the first structural component FSC, as shown in fig. 1.

In one preferred arrangement, any type and/or kind of connector fitting provided (e.g., connector fitting 130) is received on or at least partially embedded within the cover wall 134, which may also be referred to herein as the third end wall. In one preferred arrangement, the cover wall is formed separately from the upper end wall and is secured to the upper end wall 112 or otherwise attached to the upper end wall 112 such that a substantially fluid-tight joint 136 is formed therebetween. As will be discussed in more detail below, the first end wall 112 and the lid wall 134 will preferably have two different bending stiffnesses, such that the first end wall is more bendable than the lid wall. This may be achieved in any suitable manner, for example by forming the two walls from two different polymeric materials (or two different grades of a common polymeric material). As another example, the two walls may have different geometric characteristics (e.g., thickness) that will produce the desired change in bending stiffness.

Turning now to fig. 2, the connector fitting 130 includes a connector body 138, an inner support member 140, a sealing member (e.g., O-ring 142), and a retaining member 144, which are collectively disposed generally coaxially about an axis AX 1. Connector body 138 includes a generally cylindrical body wall 146 that extends between an end wall 148 and a frustoconical support wall 150. A flange 152 extends radially outwardly from body wall 146 adjacent support wall 150 and has opposed annular faces 154 and 156. A plurality of retention structures, such as annular barbs 158, are provided along the body wall 146 for interengagement with the material of the cap wall 134 at the substantially fluid-tight interface therebetween.

Internal support member 140 includes a bottom wall 160 and a frustoconical support wall 162 extending radially outwardly from bottom wall 160 and terminating at an opposite end wall 164. An inner support wall 166 extends from the base wall 160 and is spaced radially inwardly from the frustoconical support wall 162, forming an axially extending annular groove 168 between the support walls 162 and 166. A fluid passage 170 is at least partially defined by the inner support wall 166 and extends through the bottom wall 160. The frustoconical wall 162 of the internal support member 140 abuttingly engages the support wall 150 of the connector body 138. The end wall 164 of the inner support member serves as a shoulder to support the O-ring 142.

An annular projection 172 extends radially inwardly from the body wall 146 of the connector body 138 and cooperates with the retaining member 144, as will be discussed below. The retaining member 144 includes a generally cylindrical wall 174 having a passage 176 formed therethrough that communicates with the fluid passage 170 to form a fluid path (not identified) through the connector fitting 130. A flange 178 extends radially outwardly from wall 174 adjacent end wall 148 of connector body 138. A plurality of fingers 180 are separated by slots (not identified) and extend from the wall 174 opposite the lip 178. Barbs 182 are provided on each finger along the passage 176 for engaging the exterior of a length of tubing (not identified), such as the gas delivery line 132 in fig. 1. Opposite the barbs 182 on the outer surface of each finger 180 is a shoulder 184 operable to engage the projection 172 and move the fingers radially inward so that the barbs 182 engage the exterior of the tube (not shown) to grip and retain the tube within the connector.

Fig. 3 illustrates the components of gas suspension member 106 prior to assembly. The first or upper section 108 and the second or lower section 110 are provided independently of each other. In addition, the cover wall 134 and the connector fitting 130 are also shown in fig. 3 as being provided separately. However, it should be appreciated that in other cases, the cover wall and connector fitting may alternatively be provided in an assembled configuration. For example, the cover wall may be formed by casting a quantity of the second polymeric material around a portion of the connector fitting (e.g., overmolding the fitting body or housing with the second polymeric material).

First segment 108 includes an interior surface 186 and an opposing exterior surface 188 extending along at least a portion of first end wall 112 and first side wall 114. The first end wall 112 also includes an inner wall portion 190 that at least partially defines an opening 192 formed through the first end wall 112. The outer wall portion of the first end wall 112 is disposed radially outward of the inner wall portion 190 and extends circumferentially around the inner wall portion 190. The outer wall portion is generally identified by reference numeral 194 in fig. 3-6. The inner wall portion 190 projects axially inwardly relative to the outer wall portion 194 and includes a first engagement surface 196 disposed along an axial distal end region (extension) or end 198 of the inner wall portion 190.

As discussed above, the lid wall 134 is separately disposed from the first segment 108 and is shown in fig. 1 and 3-6 as including a first or bottom wall portion 200 that at least partially defines a peripheral wall 202 and a second engagement surface 204 formed therealong. The cover wall 134 also includes a second or inner wall portion 206 that at least partially defines a channel 208 extending through the cover wall. Shoulder wall portion 210 optionally extends radially inwardly therefrom along inner sidewall portion 206 to at least partially define an annular wall or connector engagement portion 212 adapted to receive and retain connector fitting 130 at an interface (not identified) therebetween in a substantially fluid-tight manner.

As can be seen more clearly in fig. 4, an opening 192 (fig. 3) at least partially defined by the inner wall portion 190 of the first end wall 112 has a nominal cross-sectional dimension, such as an inner diameter, for example, generally identified by reference dimension D1. Bottom wall portion 200 is also shown in fig. 4 as having a nominal cross-sectional dimension, such as an outside diameter, generally identified by reference dimension D2, for example. In a preferred arrangement, the peripheral area of the lid wall 134 (e.g., the cross-sectional dimension of the peripheral wall 202) will be sufficiently larger than the peripheral area of the opening 192 (e.g., the diameter identified by dimension D1) to allow the bottom wall portion 200 to overlap the inner wall portion 190, which in turn allows the joint 136 to be formed therebetween. Further, the inner sidewall portion 206 of the cap wall 134 has a nominal cross-sectional dimension, such as an outer diameter, generally identified by reference dimension D3, for example. In one preferred arrangement, the outer peripheral area of the inner sidewall portion 206 (e.g., the outer diameter identified by dimension D3) will be sufficiently smaller than the outer peripheral area of the opening 192 (e.g., the diameter identified by dimension D1) so as to form the channel 214 therebetween.

The lid wall 134 and the inner wall portion 190 are shown here as extending generally circumferentially about the longitudinally extending axis AX, whereby they may be disposed in generally coaxial relationship with other structures of the gas suspension member (e.g., the sidewalls 114 and 118). However, it should be appreciated that any other shape, configuration, and/or arrangement may alternatively be used. For example, the gas-delivery connection 128 may be offset relative to the axis AX, or otherwise disposed in spaced relation to the axis AX. Furthermore, the geometry and/or characteristics of the walls and wall portions of the first segment 108, the second segment 110, and/or the cover wall 134 may vary from structural component to structural component depending on the desired performance and/or operational characteristics of the resulting gas suspension member, as will be discussed below in connection with fig. 5 and 6. For example, the first end wall 112 may have a first nominal wall thickness along the inner wall portion 190 and/or the outer wall portion 194, as identified by reference dimension D4 in fig. 4, e.g., the thickness thereof may be selected depending on the desired bending stiffness of the first end wall. The lid wall 134 may have a second nominal wall thickness, as identified in fig. 4 with reference to dimension D5, along the bottom wall portion 200 and/or the inner sidewall portion 206, which thickness may be selected depending on the desired bending stiffness of the lid wall, for example.

Furthermore, the materials (or material properties and/or characteristics) forming the walls and wall portions of the first section 108, the second section 110, and/or the cover wall 134 may also or alternatively differ depending on the desired performance and/or operational characteristics of the resulting gas suspension member, as will be discussed below in connection with fig. 5 and 6. That is, for example, the first and second sections 108, 110 may be formed, for example, from a first polymeric material having a first value for a preselected material property, such as tensile strength, elastic modulus, or hardness. The cover wall 134 can be formed of a second polymeric material having a second value for the preselected material property that is different from (e.g., greater than or less than) the first value for the preselected material property. These first and second polymeric materials may be selected from different families of materials. Alternatively, these first and second polymeric materials may be selected from different grades of the same family of materials. One exemplary group of materials from which different polymeric materials may be selected may include polyolefins, polyurethanes, polyethylenes, polypropylenes, and polyvinyl chlorides.

In a preferred embodiment, the preselected material property is hardness, and the change in bending stiffness of the first and second polymeric materials (or multiple grades of the same family of polymeric materials) is at least partially related to, or otherwise associated with or attributable to, different hardness values thereof. An exemplary range of hardness values for the first polymeric material is from about 70 shore a to about 90 shore a, although it is recognized that any suitable value or range of values may be used for the preselected material properties. A corresponding exemplary range for the second polymer material is from about 40 shore D to about 70 shore D. However, as noted above, the use of a hardness value for use as the pre-selected material property, as preferred in one embodiment, is merely exemplary, and any other suitable material property or combination of material properties may alternatively be used.

Turning now to fig. 5 and 6, the first end wall 112 is shown in two different deflected states. The deflection shown in fig. 5 may be caused by expansion of a gas suspension member (e.g., gas suspension member 106) having a flexible end wall (e.g., first end wall 112), e.g., to deflect into an extended state in which, e.g., contact with first structural component FSC is reduced. In fig. 5, the deflection of the first end wall 112 is shown to be due at least in part to the pressure of the bulk gas held within the gas chamber of the gas suspension member, as indicated by arrow GPR. Gas pressure acts on only one side of the first end wall 112, i.e. along the inner surface 186, while ambient atmospheric pressure ATM acts along the outer surface 188 of the first end wall. It is of course better understood that the gas pressure acts uniformly on or along the surface of all other wall surfaces of the gas chamber that also form the gas suspension member. Typically, however, since the gas pressure GPR is significantly greater than the ambient atmospheric pressure ATM, in fig. 5 the pressure difference is shown as acting to deflect the first end wall outwardly into a bulging or dome shape, in particular along its outer wall portion 194. This expansion-induced deflection produces corresponding expansion-induced stresses along the walls of the gas suspension member, including the first end wall 112. These expansion-induced stresses typically include tensile stresses acting at least along the exterior surface of the first end wall.

In the known suspension member and in certain conditions, such as high working pressures, stresses in the material of the first end wall around the connector fitting may reach high levels. In these conditions, suitably, there is a high strain in these regions, which results in the material adjacent the connector fitting being separated from the connector fitting. This may undesirably result in at least a partial loss of integrity of the seal around and along the connector fitting. The presently disclosed subject matter allows the material around and along the connector fitting (e.g., the cover wall 134) to have a stiffness greater than that of the first end wall material. This acts to reduce the amount of strain in the area adjacent the connector fitting at the same high stress level. Such strain reduction helps to minimize or at least reduce the aforementioned separation at or along the connector fitting. This arrangement also allows the first end wall to retain its functionality by using a material having a lower relative stiffness than the material of the cover wall.

As shown in fig. 5, the action of the gas pressure GPR creates expansion-induced stresses that deflect the outer wall portion 194 of the first end wall 112 axially outward. As noted above, the cover wall 134 will preferably have a greater bending stiffness than the bending stiffness of the first end wall 112. Likewise, it is contemplated that the deflection of the cover wall 134 is reduced relative to the deflection of the first end wall as a result of the gas pressure GPR. In the exemplary embodiment shown in fig. 5, an area or end (not identified) of the inner wall portion 190 is integrally formed with the outer wall portion 194. An opposite region or end of the inner wall portion, identified herein as an axial distal region 198, is fixedly attached to a bottom wall portion 200 of the cover wall 134. Likewise, the inner wall portion 190 is shown to undergo a significant deflection that forms a transition between the relatively undeflected lid wall and the significantly deflected outer wall portion of the first end wall. Deflection of inner wall portion 190 results in a corresponding deformation of groove 214, such as by expansion or outward opening of the groove (e.g., as identified by angle AG 1). Due at least in part to this difference in bending stiffness, compressive stresses in the material of the connector engagement portion 212 extending around the connector body 138 of the connector fitting 132 maintain a substantially fluid-tight seal along the interface therebetween.

Further, the groove 214 and the inner wall portion 190 may serve as a stress relief means for externally applied loads acting on the connector, such as unintentional tightening from a gas transmission line or pipe (not shown). In fig. 6, gas delivery connection 128 is shown in a deflected state due to the load applied to the connector fitting as indicated by arrow LD. The groove 214, the inner wall portion 190, and the outer wall portion 194 allow the cover wall 134 and the connector fitting 132 to deflect in any direction or combination of directions, including a transverse direction as identified by dimension D6, a vertical direction as identified by dimension D7, or a twist as identified by angular dimension AG2, without adversely affecting the substantially fluid-tight interface between the materials of the connector fitting and the cover wall 134.

It should be appreciated that the illustrations in fig. 5 and 6 are merely examples of typical loads and end wall deflections, and of the responses of such loads and deflections that are desired for an end wall of a gas suspension member according to the subject matter of the present disclosure. Furthermore, it is recognized that some combination of these loads and deflections shown in each of fig. 5 and 6 are likely to be present during use of the subject gas suspension member. Moreover, those skilled in the art will appreciate that the various wall thicknesses and other dimensions shown and described herein, particularly the wall thicknesses and other dimensions of the first end wall 112 and the cover wall 134, may be varied or modified to provide the desired deflection and stress relief depending on numerous other factors, such as the expected loads, environmental conditions, and mechanical properties of the materials.

Fig. 7 illustrates an exemplary method 300 of assembling a gas suspension member according to the subject matter of the present disclosure. Method 300 includes forming or otherwise disposing a first section of a gas suspension member (e.g., first section 108 of gas suspension member 106), as shown at block 302 in fig. 7. In a preferred arrangement, the first section includes a first end wall (e.g., first end wall 112) having at least a first bending stiffness, for example, due to a preselected material property (e.g., tensile strength or stiffness) and/or due to a given geometry (e.g., wall thickness) of the first end wall. The method 300 also includes forming or otherwise disposing a second section of the gas suspension member (e.g., the second section 110), as shown in block 304. In a preferred embodiment, the second section will be formed of the same or substantially similar material as the first section as described above.

The method 300 also includes providing a connector fitting (e.g., the connector fitting 132) of any suitable type, kind, configuration, and/or construction, as shown in block 306. The method also includes forming the cap wall with a second bending stiffness, as shown at block 308 in fig. 7, which may be due, for example, to having different values for preselected material properties (e.g., tensile strength or stiffness) and/or due to having a different geometric configuration than the first end wall.

The method 300 also includes embedding the connector fitting within the cover wall, as shown in block 310. It will be appreciated that this may be achieved in any suitable way. AS one example, such action may include press-fitting the connector 132 into the channel 208 of the lid wall 134, such AS generally illustrated by arrow AS1 in fig. 3. In a preferred embodiment, the connector fitting 132 may be positioned such that the retaining member 144 extends through the cap wall 134 and the face 154 of the flange 152 engages the shoulder wall portion 210 of the cap wall 134. By being pressed into abutting engagement with shoulder wall portion 210, flange 152 prevents the connector from being pulled through and out of channel 208 by loads applied to the gas delivery line or pipe (not shown). Alternatively, the connector body 138 may be pressed into the channel 208 without other elements of the connector fitting 132. Once assembled, these other components may then be inserted from the exterior of the fluid suspension member in a later step.

With further reference to the previous example, the connector fitting 132 may be pressed into the channel 208 such that the barbs 158 on the connector body 138 embed into the annular wall 212, thereby retaining the connector on the annular wall. Preferably, the diameter of the channel 208 is less than the diameter of the body wall 146 of the connector body 138. Thus, as the connector body is pressed into the channel during assembly, the material holding the annular wall 212 is stressed around the connector body and forms a fluid-tight compression seal. Thus, it is possible to avoid the use of other sealing techniques, such as the use of adhesives.

As another example of embedding the connector fitting within the cover wall, the connector fitting 132 or a portion thereof (e.g., the connector body 138) may be inserted into a suitable injection mold, and the cover wall 134 may be overmolded or otherwise formed around the connector fitting or a component thereof. In this example, operations 308 and 310 may be performed substantially simultaneously in one operation. However, if only the connector body (or a lesser number of components than a complete connector fitting) is overmolded, then some assembly of additional parts and/or components may optionally be performed.

The method 300 further includes positioning a cover wall on or along the first end wall, such AS the through opening 192 formed in the first end wall AS indicated by arrow AS2 in fig. 3, AS indicated by block 312 in fig. 7. In one preferred arrangement, such manipulation includes orienting the cover wall such that a portion thereof (e.g., bottom wall portion 200) is disposed along an inner surface of the first end wall (e.g., engagement surface 196 of inner wall portion 190). It will be appreciated that this operation may be performed by accessing the inner surface from the open end of the first section. The method 300 further includes securing the cover wall to the first end wall such that a substantially fluid-tight joint (e.g., joint 136) is formed between the cover wall and the first end wall, as shown at block 314. Such a bond may be formed by any suitable means, such as by ultrasonic welding, hot plate welding, spin welding, and/or the use of an adhesive. Also, it should be appreciated that operations 312 and 314 occur before or after operation 310 of embedding the connector fitting within the cover wall. That is, as discussed with reference to operations 312 and 314, the cover wall may be formed in operation 308 and then positioned and secured to the first end wall. Thereafter, an operation 310 of embedding the connector fitting in the cover wall may be performed.

Since the connector fitting 132 is shown installed from the interior of the first segment 108, the method 300 further includes positioning the first and second segments (e.g., the first segment 108 and the second segment 110) together such that the second segment extends across or otherwise closes off the open end of the first segment, AS generally shown by arrow AS3 in fig. 3. The method 300 further includes securing or otherwise attaching the first and second segments together, as shown at block 316 in fig. 7, such as by forming a substantially fluid-tight joint 126 between the first and second segments. The joint 126 may be formed by any suitable means, such as by welding, using an adhesive, or one or more mechanical fasteners. In one exemplary embodiment, the first and second sections 108 and 110 may be molded from a polymeric material, such as polyurethane, and the joint 126 is formed by welding the flanges 122 and 124 together using a suitable welding method known to those skilled in the art. Examples of such welding methods include ultrasonic welding, hot plate welding, and spin welding. However, it will be appreciated that any suitable material or materials may also be used and that any suitable method of joining the materials may also be used.

It should be clearly understood that, more specifically, the geometry, configuration and arrangement of the gas delivery connection structure 128 (generally, the groove 214, the inner wall portion 190 and the lid wall 134) is merely an exemplary embodiment of a suitable geometry, and that any other suitable geometry may be used without departing from the principles of the present novel concept. For example, the present embodiments show and describe a generally cylindrical fluid suspension member having a central axis with a channel extending substantially coaxially with a connector mounted along an end wall in general alignment with the central axis. However, in other applications, the connector may be secured to the end wall in a spaced apart (i.e., offset) relationship from the central axis. Preferably, the groove and the inner wall portion of the end wall will remain substantially arranged around the connector. Furthermore, the trenches may have any suitable aspect ratio and may take any suitable form or shape.

As used herein, reference to certain elements, components and/or structures (e.g., "first side wall" and "second side wall"), a numerical designation merely indicates a different one of the components and means any order or sequence unless explicitly defined by the language of the claims. Further, the term "gas" as used herein refers broadly to any gaseous or vaporous fluid. Most often, air is used as the working medium for the suspension system and its components, such as those described herein. However, it should be understood that any suitable gaseous fluid may alternatively be used.

While the novel concepts of the present subject matter have been described with reference to the foregoing embodiments, and considerable emphasis has been placed herein on the structures of the embodiments disclosed and the structural interrelationships between the component parts, it will be appreciated that other embodiments can be made and that many changes can be made in the embodiments illustrated and described without departing from the principles of the novel concepts of the present subject matter. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is to be clearly understood, therefore, 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 novel concepts of the present subject matter be interpreted as including all such alterations and modifications as fall within the scope of the appended claims and any equivalents thereof.

Claims (16)

1. A gas suspension member, comprising:

a first end wall including an opening formed therethrough;

a second end wall spaced from the first end wall such that a longitudinally extending axis extends therebetween;

a sidewall extending between the first and second end walls and at least partially defining a gas chamber therebetween;

a third end wall attached to said first end wall across said opening of said first end wall; and

a connector fitting at least partially embedded within the third end wall such that a substantially fluid-tight seal is formed along an interface between the connector fitting and the third end wall, the connector fitting including a passage extending therethrough between opposing first and second open ends, the first open end disposed outside of the gas chamber and adapted to receive an associated gas delivery line;

the first end wall has a first bending stiffness and the third end wall has a second bending stiffness greater than the first bending stiffness such that the first end wall is more bendable than the third end wall, thereby allowing greater deflection of the first end wall relative to the third end wall and reducing the transmission of stress from the first end wall to separation of the interface between the connector fitting and the third end wall.

2. A gas suspension member according to claim 1, wherein said first end wall is formed of a first polymeric material having a first durometer and said third end wall is formed of a second polymeric material that is different from said first polymeric material and has a second durometer that is greater than said first durometer of said first polymeric material.

3. A gas suspension member according to claim 2, wherein said first hardness is in the range of from about 70 shore a to about 90 shore a, and said second hardness is in the range of from about 40 shore D to about 70 shore D.

4. A gas suspension member according to claim 2 or 3, wherein said first and second polymeric materials comprise different grades of polymeric materials from the same family of polymeric materials.

5. A gas suspension member according to claim 4, wherein said polymeric material of the same family is selected from the group consisting of polyolefins, polyurethanes and polypropylenes.

6. A gas suspension member as recited in claim 1, wherein the first end wall has a first nominal thickness and the third end wall has a second nominal thickness that is greater than the first nominal thickness, the first bending stiffness being associated with the first nominal thickness and the second bending stiffness being associated with the second nominal thickness such that a greater value of the second nominal thickness relative to the first nominal thickness of the first end wall contributes to a greater bending stiffness of the third end wall.

7. A gas suspension member according to claim 1, wherein said first end wall includes an inner surface at least partially defining said gas chamber and an outer surface disposed outwardly of said gas chamber, said third end wall extending along said inner surface of said first end wall, pressurized gas within said gas chamber urging said third end wall against said inner surface of said first end wall.

8. A gas suspension member according to claim 7, wherein the first end wall includes an inner wall portion at least partially defining the opening in the first end wall and an outer wall portion disposed radially outward of the inner wall portion, the inner wall portion extending axially inward relative to the outer wall portion forming an axial distal region of the inner wall portion of the first end wall, the third end wall being secured along the axial distal region of the inner wall portion of the first end wall.

9. A gas suspension member according to claim 8, wherein said third end wall includes a bottom wall portion and a connector engagement portion, and said bottom wall portion abuttingly engages and is attached to said axial distal end region of said inner wall portion of said first end wall.

10. A gas suspension member according to claim 9, wherein said connector engagement portion extends axially outwardly from said bottom wall portion such that a groove is formed between said inner wall portion of said first end wall and said connector engagement portion of said third end wall.

11. A gas suspension assembly, comprising:

a first suspension arrangement having opposite first and second ends and a longitudinally extending first axis extending therebetween, the first suspension arrangement including a spring element extending helically about the first axis such that a plurality of windings are formed between the first and second ends, the plurality of windings at least partially defining an interior of the first suspension arrangement; and

a second suspension arrangement disposed inside the first suspension arrangement, the second suspension arrangement comprising a gas suspension member as claimed in any one of claims 1-3 or 6-10.

12. A method of forming a gas suspension member, the method comprising:

a) forming a first section of a gas suspension member from a first polymeric material having a first value for a preselected material property thereof, the first section having a first longitudinally extending axis and comprising a first end wall extending generally transverse to the first axis and a first side wall extending generally longitudinally from the first end wall along the first axis, the first end wall and the first side wall each comprising an inner surface at least partially defining an interior chamber of the first section, and the first end wall comprising an opening formed therethrough;

b) forming a second section of the gas suspension member from the first polymeric material having a first value for a preselected material property thereof, the second section including a second end wall;

c) providing a connector fitting for receiving and retaining a gas delivery line, the connector fitting including a fluid passage extending therethrough;

d) forming a cover wall from a second polymeric material having a second value for the preselected material property thereof;

e) embedding the connector fitting within the cap wall such that the fluid passage extends through the cap wall;

f) positioning said cover wall from within said interior chamber of said first section along said inner surface of a first end wall of said first section and securing said cover wall along said inner surface of said first end wall across said opening such that said passage of said connector fitting is in communication between said opening and said interior chamber; and

g) attaching the first and second sections together to form a substantially fluid tight joint therebetween.

13. The method of claim 12, wherein securing the cover wall in step f) includes forming a substantially fluid-tight engagement between the inner surface of the first end wall and the cover wall.

14. The method of claim 12 or 13, wherein forming the first section in step a) includes forming a first end wall including an outer wall portion and an inner wall portion projecting axially inwardly along the outer wall portion, and securing the cover wall in step f) includes securing the cover wall to the inner wall portion such that a substantially fluid-tight joint is formed therebetween.

15. The method of claim 14, wherein forming the cover wall in step d) includes forming a cover wall including a base portion and an annular portion projecting axially outward from the base portion, and embedding the connector fitting in step e) includes embedding the connector fitting at least partially within the annular portion of the cover wall.

16. The method of claim 15, wherein positioning the cap wall in step f) includes orienting the cap wall such that the annular portion extends into the opening in the first end wall to form a radially outwardly extending groove between the annular portion and the inner wall portion of the first end wall.