Patent Application
20100270766
1. Technical Field
The invention relates generally to an improved vehicle suspension system for vehicles, such as trailers and trucks. More particularly, the invention relates to an air spring suspension system with a single piece trailing beam for land vehicles. Specifically, the invention relates to a trailing beam air suspension system which provides the advantages of independent wheel suspension with integrated components and a more compact arrangement.
2. Background Information
Torsion axles have been known for many years, such as shown in U.S. Pat. No. 2,998,981. Torsion axles have proven to be extremely popular because if one wheel hits a bump or rut, it can react independently of the other wheel, which may not hit a bump or rut at the same time. This torsion axle concept operates to keep a trailer moving as straight as possible behind a towing vehicle and absorbs some of the shock of the road over which it is passing with an independent suspension. This is contrasted with a straight axle where if one wheel drops into a rut or is slowed down for any reason while the other wheel of the trailer does not have the same experience at the same time, the trailer would tend to turn somewhat to allow the wheel that is on the flat part of the road to move forward while the wheel that is in the rut is restrained, therefore causing the axle not to be perpendicular with the direction of towing of the vehicle itself.
Most torsion axles are constructed of a square axle in cross section with elongated rubber members disposed in-between the square axle and a larger outer tube. U.S. Pat. Nos. 5,161,814 and 5,820,156 discloses such a construction. One common torsion axle is a TorFlex® rubber torsion suspension system distributed by Dexter Axle. This type of torsion axle has independent and separate stub axles or stub shafts on each end which are part of spaced suspension assemblies mounting each of the wheels on the trailer frame to enhance the independent aspect of such an axle.
Torsion axles can also be constructed as in U.S. Pat. No. 5,163,701 which uses a plurality of elongated bars which can twist and bend but return to their original position after such bending. It is also known to use air bags, commonly referred to as air springs, for straight, non-torsion axles, such as shown in U.S. Pat. Nos. 3,784,221 and 5,427,404. While it is true that both the torsion axle technology and the air spring technology has been quite successful independently in making a smoother ride and enhanced the handling performances of vehicles having such suspension systems, these suspension systems still have their shortcomings and there is a need for improvement thereto.
The vehicle suspension system of U.S. Pat. No. 6,340,165 combines the advantage of both the torsion axle and air spring into a single suspension assembly and has provided a more efficient and better performing suspension system than that believed provided by the systems using only a torsion axle or only an air spring.
The suspension assembly of the present invention improves on the prior art by providing a more rugged, compact, lighter weight suspension by providing a completely independent trailing arm style suspension that still provides superior lateral stability. This also allows the traditional torsion axle to be completely removed and enable lower design heights to be achieved. This also requires only a single integrated moving part at each wheel to provide a superior ride quality.
Therefore, a need exists for a trailing arm suspension which is a fully independent wheel suspension and incorporates air springs to improve ride quality.
The suspension system of the present invention broadly comprises a suspension system for use with a vehicle comprising a control arm having an upper rear arm and a spring mounting plate integrally formed as a single member, a spindle extending outwardly from the upper rear arm, an air spring adapted to be mounted intermediate the spring plate and the vehicle, and a pivot assembly for pivotally mounting the control arm to the vehicle whereby the pivot assembly has a fist axis of rotation.
The preferred embodiments of the invention, illustrative of the best modes in which Applicant has contemplated applying the principles of the invention, are set forth in the following description and are shown in the drawings.
At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention. While the present invention is described with respect to what is presently considered to be the preferred embodiment, it is to be understood that the invention as claimed is not limited to the disclosed aspects.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described.
The vehicle suspension system of the present invention is indicated generally at 12, as is particularly shown in
Referring to
In accordance with one of the main features of the present invention, control arm 38 is generally arcuate in shape and includes a central body 40 with a cavity 42 extending through the front portion of the central body. The control arm also includes an upper rear portion 43 with a spindle 44 protruding from an outer surface 46 and arranged to support tire-wheel assembly 22. A rear surface 47, proximate and below upper rear portion 43, is preferably concave in shape with the bowl-shaped opening directed rearward. The generally concave shape of rear surface 47 is partially defined at the top by upper rear portion 43 and at the bottom by bottom rear portion 57 (described infra). Cavity 42 receives and supports a complimentary shaped cross tube assembly 48. Control arm 38 pivots at cavity 42 due to spindle 44 and cavity 42 being offset from one another.
In particular, cross tube assembly 48 has a first end 50 and a second end 52 with an overall length of approximately 19.75 inches in a preferred embodiment. First end 50 is fully inserted within cavity 42 such that the outer portion of first end 50 is generally flush with outer surface 46. A plug 54 is inserted at least partially into first end 50 and protects the inner diameter of cross tube assembly 48 as well the bearings and connections between control arm 38 and cross tube assembly 48.
Control arm 38 also includes a lower spring support 56 extending from a bottom rear portion 57 of the control arm. The lower spring support is preferably welded to the control arm at bottom rear portion 57. However, the lower spring support may also be arranged to be bolted to the control arm without departing from the spirit and scope of the invention. Lower spring support 56 has a spring mounting surface 58 proximate spindle 44. Advantageously, an air spring 60 is located on an axis similar to spindle 44 and permits full functional use of the air spring. In particular, the distance between the center of control arm cavity 42 and the center axis of air spring 60 is approximately 10 inches in a preferred embodiment, while the distance between the center of control arm cavity 42 and the center axis of spindle 44 is approximately 7.36 inches. Thus, the control arm is a compact component that locates the spindle axis very close to the air spring axis to provide superior dampening by using virtually the full range of motion of air spring 60.
An axle tube 62 extends from the driver side to the passenger side and is preferably a hollow tube that includes a first end 64 with a bearing surface 66. Axle tube 62 is intermediate the pair of cross tube assemblies 48 and arranged to accept second end 52 of the cross tube assembly. Cross tube 48 is coupled to axle tube 62 by welding 69 through weld windows 68 after the cross tube is fully seated within the axle tube, as particularly seen in
While axle tube 62 is described as connecting the driver side and passenger side suspensions, the axle tube need not connect the driver side and passenger side suspensions. In particular, each suspension can be connected to a separate axle tube, which is in turn connected to the frame or other structurally sound component. While only one end of axle tube 62 has been described in detail, the second end is identical to first end 64 with respect to suspension system 20 of the passenger side, as should be apparent to one of ordinary skill in the art.
Averting to
Air spring 60 is located between the bottom side of frame mounting bracket 24 and spring mounting surface 58 of control arm 38. Preferably, the bottom of air spring 60 is bolted to mounting surface 58 with bolts 59 and the top of air spring 60 is bolted to plate 61 with another set of bolts 59. A plate 61 may be integral to frame mounting bracket 24, welded to bracket 24, or be secured with additional fasteners at slots 63 (
In accordance with another main feature of the present invention and referring to
A retainer assembly 80 includes an insert 82 which is welded to a first end 81 of inner member 72 indicated at 83. Next, an inner axle retainer 88 is slid onto the outer surface of the insert and located proximate first end 81. The inner axle retainer includes clearances 85 and 87. Clearance 85 is provided to allow room for weld 83, while clearance 87 is provided to allow rotation of inner member 72 and insert 82. After the inner axle retainer is located on insert 82, a stop 84 is slid onto the outer surface of the insert. The stop is then welded to the outer surface of the insert at 86 and prevents movement of the axle in the direction associated with arrow A. Insert 82 preferably has an outside diameter of approximately 3″, but may be any appropriate size to slide within the inside diameter of inner member 72 and is arranged to assist in preventing axial movement of the inner member relative to cross tube 62.
Inner axle retainer 88 is then welded into place through weld window 68 at weld 69. Inner axle retainer 88 is thus axially and rotationally secured after being welded and thereby prevents axial or rotational movement of retainer assembly 80 due to the welding of the inner member and insert 82. Accordingly, retainer assembly 80 prevents axial movement of inner member 72 and control arm 38 in the directions indicated by arrows A and B while still permitting free rotational movement at bushings 74 and 76.
Axle tube 62 is axially spaced apart from control arm 38 by a washer 90 and connected to the control arm at a weld 89. Washer 90 is preferably a heavy-duty washer with an inside diameter slightly larger than the outside diameter of inner member 72 and an outside diameter approximately equal to the outside diameter of axle tube 62. Advantageously, washer 90 properly spaces axle tube 62 and outer bushing 76 axially apart from control arm 38 to allow inner member 72 and control arm 38 to spin freely with little resistance. While the preferred embodiment is described with an axle tube, it is within the spirit and scope of the present invention to provide a pair of control arms 38 spaced apart from and parallel to one another and mounted to frame rail 18.
Having described the structure of the present invention, a preferred method of operation will be described in detail and should be read in light of
Averting to
In summary, suspension system 12 provides a trailing beam style suspension with fully independent wheel action and all the advantages known in the art, while still providing a suspension that is light weight and compact. Each suspension assembly 20 operates such that as tire-wheel assemblies 22 move into and out of a ground engaging position, control arm 38 pivots independently from the opposing control arm. Thus, the need for a heavy torque arm, u-bolt frame connections, rubber strips, and rubber bushings, which add significant weight and unwanted compliance, have been eliminated, as well as the associated variations in tow and camber. Further, since suspension assembly 20 is a one-piece structure and bearings or bushings are located at the pivot points, hysteresis is virtually eliminated and allows frame rails 18 to be located closer to the ground while dramatically improving ride quality.
Accordingly, the suspension system is an effective, safe, inexpensive, and efficient device that achieves all the enumerated objectives of the invention, provides for eliminating difficulties encountered with prior art devices, systems, and methods, and solves problems and obtains new results in the art.
In the foregoing description, certain terms have been used for brevity, clearness, and understanding; but 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 by way of example, and the scope of the invention is not limited to the exact details shown or described.
Having now described the features, discoveries, and principles of the invention, the manner in which the suspension system is constructed and used, the characteristics of the construction, and the advantageous new and useful results obtained; the new and useful structures, devices, elements, arrangement, parts, and combinations are set forth in the appended claims.
This application claims priority from U.S. Provisional Patent Application Ser. No. 61/171,637 filed Apr. 22, 2009; the disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61171637 | Apr 2009 | US |
