Patent Application
20050006868
Known shock absorber installations have a similar motion ratio for both roll and vertical wheel movements. Typically, these installations include at least one shock absorber having one end attached to the chassis of the vehicle and the other end attached to the axle of the vehicle.
Examples of known shock absorber installations can be found in for example, U.S. Pat. No. 2,941,817 which provides for a vehicle axle and air suspension assembly. A first end of a shock absorber is attached to an inside portion of a chassis. The second end of the shock absorber is attached to an inside portion of a non-steerable axle.
U.S. Pat. No. 4,262,929 teaches a vehicle suspension for connecting an axle to the frame. The suspension includes both a spring and a shock absorber. The upper end of the shock absorber is mounted to a vehicle frame beam. The lower end of the shock absorber is mounted to the axle.
U.S. Pat. No. 4,802,690 provides for a suspension assembly for a steering axle. The assembly uses a shock absorber attached to both the chassis side rail and a portion of the axle adjacent the air spring.
U.S. Pat. No. 6,073,946 teaches a suspension system for a steerable axle assembly. The system has a shock absorber attached at a first end to the frame of the vehicle and a second end to a plate. The plate is attached to the axle of the vehicle.
U.S. Pat. No. 6,135,470 provides for a wheel axle suspension system having a shock absorber. The shock absorber is attached to the chassis frame member and to an axle seat directly above the axle.
The transient roll dampening characteristics of these known installations need to be improved while not exhibiting overly harsh vertical wheel movements. It has been found in the present invention that by locating at least one dampening structure having an inboard end pivotally mounted to a vehicle frame and an outboard end pivotally mounted to a king pin, that the transient roll dampening characteristics are improved.
This invention fulfills the above-described needs in the art by providing a control rod suspension with at least one dampening structure having an outboard end and an inboard end. The inboard end is pivotally mounted to the vehicle frame. The outboard end is pivotally mounted to a king pin. A king pin rotatably connects the knuckle with a beam axle. The dampening structure improves the transient roll dampening characteristics of the vehicle.
The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description when considered in the light of the accompanying drawings in which:
It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless the claims expressly state otherwise.
The front axle beam 12 has a first end portion 16 and a second end portion 18. Both the first 16 and the second end portions 18 are located outboard from the chassis frame rails 10. End portion 16 has a first 20 cylindrical portion integrally formed therewith. End portion 18 has a second 22 cylindrical portion integrally formed therewith.
A first 24 and a second knuckle 26 are each rotatably mounted to the first 20 and second 22 cylindrical portions, respectively, of the front steer axle beam 12. Preferably, the first knuckle 24 is mounted by locating a first king pin 28 through both the knuckle 24 and the first 20 cylindrical portion of the front steer beam axle. A second king pin 30 similarly mounts the second knuckle 26 to the second 22 cylindrical portion of the front steer axle beam. The knuckles 24, 26 may be such as for example a Dana® Spicer® steer knuckle from the E-1200 W series made by Dana Corporation of Toledo, Ohio, however, the present invention can be used with any knuckle.
The following description, for clarity, will describe the remaining portions of the suspension with reference to a first side 32 of the suspension. Unless specified otherwise, a substantially identical complimentary structure is present on a second side 34 of the suspension.
Additionally, this description and the accompanying figures depict a Watts link type suspension 36. It should be understood, however, that the present invention can be used with many types of suspensions including, by way of example only and without limitation, an link air leaf suspension, a trailing arm suspension and a parallelogram rod suspension.
As best seen in
In a preferred embodiment depicted in
A lower king pin bracket 58 is located adjacent a lower portion 60 of the knuckle 24 in a manner similar to that described for the upper king pin bracket 38. The lower king pin bracket 58 preferably has an attachment portion 62 for a front suspension linkage 64 and an attachment portion 66 for a steering tie rod 68.
A knuckle steer arm 70 is preferably located below the upper king pin bracket 38 and above the steer axle beam 12. Additionally, the knuckle 24 extends in an outboard direction and has a knuckle spindle 72 for receiving a vehicle wheel (not shown), as known by those skilled in the art.
Still referring now to
The dampening structure 52 may be any device that mechanically connects the chassis and an end portion, 16 or 18, and that dampens a compressive and/or de-compressive force between the chassis and an end portion 16 or 18.
In a preferred embodiment, the dampening structure 52 is a shock absorber as known to those skilled in the art. The shock absorber may be for example, a Monroe Shock absorber manufactured by Tenneco Automotive Company of Monroe, Mich. Those skilled in the art understand that any type of shock absorber may be used depending upon the desired ride and desired vehicle dynamic roll rate. Additionally, those skilled in the art will appreciate that any viscoelastic member and/or any mechanical member such as, without limitation, air shocks/bags and/or struts and/or shocks and/or springs, can be used as the dampening structure.
Preferably, the dampening structure 52 is angled so that a longitudinal centerline 82 of the dampening structure 52 is at an acute angle 84 (i.e., less than ninety degrees) from the vertical 86, as depicted in
In a preferred embodiment, the selected angle maximizes the perpendicular distance 88 from the centerline 82 of the dampening structure 52 to a vehicle suspension roll center point 90. The vehicle suspension roll center point 90 is the point about which the vehicle chassis rotates in response to a roll input. The suspension roll center point 90 is alternately defined as the point in the transverse axle plane at which lateral forces may be applied to the chassis without producing suspension roll. Maximizing this distance reduces the vehicle dynamic roll and provides shock absorption in the vertical direction. It is also well within the scope of the present invention to connect the dampening structure 52 to the chassis rail 10 and the portion of the beam axle 16 without concern for maximizing the distance to provide a degree of vehicle dynamic roll reduction and shock absorption.
In a preferred embodiment, a dampening structure 52 having what is characterized by those skilled in the art as a high dampening coefficient is used. The acute installation angle 84 of the dampening structure 52 reduces the effectiveness of the dampening structure 52 in vertical motion, however, the installation angle allows the dampening structure 52 to be effective in roll. Other dampening structures 52, such as for example, air springs can be used to supplement the effectiveness of the suspension in the vertical direction.
In an alternative embodiment depicted in
A bracket 94, having an aperture 96 for the torsion tube 92, is attached to a steer beam axle spring pad 98. The bracket 94 may be located anywhere on the steer axle beam 12. In a preferred embodiment, the bracket 94 is located under an air spring 14. The aperture 96 accommodates the torsion tube 92 which extends from one end of the steer axle beam 12 to the other end of the steer axle beam 12 where it is received by a substantially identical bracket (not shown).
In yet another embodiment of the present invention depicted in
In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiments. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.
