Abstract:
An air spring has a pair of end members which are sealingly connected to ends of a flexible sleeve and form an internal fluid chamber. A rigid annular member is located within the fluid chamber and is spaced from one of the end members and clamps the sleeve against a rigid member located outside of the sleeve and fluid chamber. A vibration isolator, such as an annular elastomeric member, is located between the rigid outer member and the adjacent end member to support the sleeve and reduce its tension in order to isolate sleeve vibration from the end member.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The invention relates to air springs, and in particular to air springs for vehicles which have a vibration absorbing assembly incorporated therein to isolate the air spring sleeve vibrations from the adjacent end member and vehicle. 
     2. Background Information 
     Air springs typically include two end members which are sealingly connected to respective ends of a hollow fabric reinforced elastomeric sleeve. These air springs are used primarily for implementation in motor vehicles for supporting the vehicle body or for use in other types of equipment subject to shock to provide cushioning therefor. The air springs are sealed at the ends to form a pressurized fluid chamber within the sleeve. The air spring will generate a certain load at a given height and pressure, and upon the spring experiencing a road displacement input, the sleeve will begin to compress or extend as the end members move toward and away from each other respectively, to provide predictable dynamic load characteristics. Sudden movement of one end of the air spring will cause vibration of the; elastomeric sleeve which is transmitted from the sleeve to the end members and to the vehicle structure affecting the ride characteristics of the vehicle and suspension system. 
     Various types of vibration isolation have been devised to reduce or prevent the transmission of the sleeve vibrations to the end members and connected vehicle components. Certain of these vibration isolators use various types of elastomeric materials located at the end of the air spring where it is sealed to the end member, such as shown in U.S. Pat. Nos. 4,697,797 and 6,123,325. Other types use bearings and elastomeric materials at the connection of end cap or end members to the supporting vehicle structure, as shown in U.S. Pat. No. 5,690,319. Other types of air spring vibration isolation methods and apparatus use an elastomeric isolator which is mounted on the sleeve in such a manner to require additional sealed connections of the sleeve and vibration isolator, thus creating a potential leak path past the air sleeve from the interior pressure chamber. It is always desirable to reduce to a minimum the number of possible air leak paths from the internal fluid chamber of the air spring to the surrounding atmosphere. 
     Thus it is desirable to provide an air spring with vibration isolation which does not create a potential additional leak path from the internal fluid chamber to the surrounding atmosphere, yet which is usable with existing air spring constructions without increasing the effective height and size of the air spring, and which can be accomplished in a relatively simple and economical manner. 
     BRIEF SUMMARY OF THE INVENTION 
     What the art needs is an air spring assembly which allows for control of the vibrations generated within or transmitted through the air spring sleeve from reaching the end members and vehicle structure without significantly changing the physical size and operating characteristics of the air spring. 
     The air spring of the present invention uses an elastomeric vibration isolator which is clamped to the air spring sleeve at a spaced distance from one of the end members by a rigid annular ring-like member located within the fluid chamber of the air spring sleeve which ring-like member sandwiches and clamps a portion of the sleeve to an outer rigid member. The sleeve is supported by this device, reducing sleeve tension and vibration transmission to the upper end closure by the air spring. This rigid outer member is isolated either from the end member by an elastomeric vibration isolator or from the sleeve with an elastomeric isolator, either of which will attenuate the transmission of the sleeve vibrations to the end member. 
     A further feature of the invention is to provide a mounting arrangement for a vibration isolator on the air spring sleeve without piercing or harming the sleeve and creating a potential air leak path between the internal pressure chamber and surrounding atmosphere. 
     Another aspect of the invention is to enable the vibration isolator to be mounted externally of the air spring and clamped to the sleeve and used in conjunction with a rigid restraining cylinder which extends along the air sleeve to reduce the outward radial expansion of the sleeve, and which protects the sleeve from the surrounding environment. 
     The internal rigid member, which mounts the elastomeric isolator in position, may have an outwardly curved surface to form a convolution in the air spring to assist its movement between compressed and expanded positions and to prevent pinching of the sleeve between the isolator components. 
    
    
     The foregoing advantages, construction and operation of the present invention will become readily apparent from the following description and accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view with portions broken away and in section, showing an air spring mounted between two spaced components containing the vibration isolation feature; 
     FIG. 2 is a view similar to FIG. 1 showing a modified vibration isolator; and 
     FIG. 3 is a view similar to FIGS. 1 and 2 of a further modified vibration isolator. 
    
    
     Similar numerals refer to similar parts through the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A first embodiment of a vehicle air spring assembly according to the present invention, is shown in FIG.  1  and is indicated generally at  1 . Air spring assembly  1  generally includes a top end plate  2  and a bottom end member  3  such as a usual piston, with a flexible bladder or sleeve  5  extending between and connected to end members  2  and  3 . End member  2  and piston  3  attach to two spaced components  7  and  8 , respectively, for providing cushioning therebetween. Members  7  and  8  may be parts of a motor vehicle, such as a vehicle chassis and vehicle axle or any other device where cushioning is desired between two spaced members. 
     Sleeve  5  is sealingly connected with an annular flange  10  of end plate  2  by a usual clamp ring  12  and to piston  3  by a clamp ring  13  and forms a pressurized fluid chamber  15  therein. Sleeve  5  preferably is formed of an elastomeric material and includes fabric reinforcing cords embedded therein to strengthen the sleeve and restrict the inflated diameter as the sleeve is expanded and compressed during operation of air spring assembly  1 . Sleeve  5  can be sealingly attached to end members  2  and  3  by other types of connections, such as having a beaded end and a rolled crimped configuration provided by one or both of the end members without affecting the concept of the invention. Likewise, end members  2  and  3  can have various other configurations than that shown in FIG. 1 without, affecting the concept of the invention. End member  2  preferably will have various openings (not shown) for connection to a fluid supply line which is connected to a remote source of pressurized air, all of which is well known in the air spring art. 
     In accordance with the invention, a vibration isolation assembly indicated generally at  18 , is operatively connected between sleeve  5  and end member  2 . Assembly  18  includes a rigid outer member  20 , a rigid inner member  21 , a swage ring  22 , and an elastomeric isolator  23 . Outer member  20  has a cylindrical portion  25  which has a top inwardly extending end,flange  26  which is rigidly connected by some type of connection, to end member  2 , such as by welding, bonding, press fit, or the like. The opposite end of cylindrical portion  25  terminates in an inwardly tapered flange  27 . 
     Rigid inner member  21  has an annular configuration and is formed with a lower cylindrical portion  30  and an upper outwardly curved portion  31 . As shown in FIG. 1, inner member  21  has generally circular-shaped top and bottom openings  33  and  34 , with top opening  33  having a greater diameter than bottom opening  34 . Swage ring  22  clamps sleeve  5  against inner member  21  at a location  36 . 
     Elastomeric isolator  23  has an irregular shape (and matches) the curvature of curved portion  31  of inner member  21  to form an outwadly extending convolution  24  in sleeve  5 . Isolator  23  also matches cylindrical wall portion  25  and tapered flange  27  of outer member  20 , as well as abut against and matching the outer surface of swage ring  22 . 
     Thus as shown in FIG. 1, elastomeric isolator  23  is in a secured fixed position adjacent clamped sleeve area  36  so that the vibrations developed on sleeve  5  are absorbed by isolator  23 , attenuating their transmission to clamp ring  12  and end member  2  and subsequently to vehicle component  7 . Furthermore, since member  21  is located within pressure chamber  15 , it does not create any possible leak path to the surrounding atmosphere. 
     A second embodiment of an air spring containing a vibration isolation, assembly is indicated generally at  40 , and is shown in FIG.  2 . Air spring  40  is similar to air spring  1  described above, but has a different vibration isolation assembly indicated generally at  41 , mounted thereon. Assembly  41  includes a similar rigid outer member  20  which is rigidly connected to end member  2  and configured elastomeric isolator  23 . In addition to member  20 , assembly  41  includes a second rigid portion  43  which has a cylindrical portion  45  which extends axially along and outside of sleeve  5 . Rigid portion  43  terminates in an annular clamping portion  46  and an upper outwardly curved portion  47 . 
     Cylindrical portion  45  forms a restraining canister to limit the radial outward expansion of sleeve  5  when the air spring moves towards a collapsed or compressed position and protects the sleeve form the surrounding environments, and from puncture and possible damage from road debris and adjacent vehicle components. Rigid outer member  43  is clamped to sleeve, area  36  by an annular inner rigid member or clamp ring  49  which is located within fluid chamber  15 . Member  49  clamps sleeve area  36  against clamping portion  46  of outer member  43  and forces clamping portion  46  of member  43  against elastomeric isolator  23  securing it in a fixed position between cylindrical portion  25  and tapered portion  27  of member  20  and against portions  46  and  47  of member  43 . Thus isolator  41  attenuates the transmission of vibrations of sleeve  5  to end member  2  and subsequently to vehicle component  7  without adding any possible air leakage paths in sleeve  5 . 
     A third embodiment of the air spring of the present invention is indicated generally at  55 , and is shown in FIG.  3 . Air spring  55  has a modified upper end member  56  which includes a fluid access opening  57  in which a connector  58  is inserted for securing a fluid supply line  59  therein. Line  59  will be connected to a remote source of pressurized air, such as a compressor which is usually located within the vehicle for admitting and discharging fluid, which is usually air, into and out of fluid chamber  15 . A modified vibration absorbing assembly  60  is mounted between end member  56  and sleeve  5  and includes a rigid annular outer member  62  which has a cylindrical configuration and terminates in an inwardly curved upper end  63 . Outer member  62  forms a restraining canister similar to cylindrical portion  45  of embodiment  40 , to restrain the outward expansion of sleeve  5 . 
     Outer rigid member  62  is resiliently mounted to end member  56  by an elastomeric vibration isolator  65  which may have an circular cross-sectional configuration as shown in FIG. 3, which is seated within a semi-circular cut-out  67  formed in end member  56 . Isolator  65  is retained after insertion into the assembly by mechanical or adhesive means. A rigid inner member  69  clamps sleeve portion  36  between the outer surface of member  69  and rigid outer member  62 . A dimple  70  may be formed on the outer surface of member  69  which is seated within a complementary shaped recess  71  formed in outer member  62  to help position member  69  within air chamber  15  and to maintain a tight clamping engagement of sleeve  5  between rigid members  62  and  69 . Again, isolator  65  attenuates the vibrations developed in sleeve  5  which heretofore would be transmitted to end member  56 . Again, as in embodiments 1 and 40 described above, rigid inner member  69  which is located within pressure chamber  15 , is spaced axially from the adjacent end member and clamps a portion of sleeve  5  against the annular rigid outer member so that the elastomeric isolator is positioned between a rigid outer member and a rigid end member to which it is connected, to attenuate transmission of the sleeve vibrations to the end member, all without piercing the sleeve or creating another possible leakage path between the sleeve and the outer surrounding atmosphere. 
     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. 
     Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described.