Land vehicles – Wheeled – Running gear
Reexamination Certificate
2002-02-15
2004-05-11
Ilan, Ruth (Department: 3616)
Land vehicles
Wheeled
Running gear
C280S124155, C280S124147, C267S179000
Reexamination Certificate
active
06733023
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims the priority of German Patent Application, Ser. No. 101 06 915.4, filed Feb. 15, 2001, the subject matter of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates, in general, to a suspension for a motor vehicle.
The suspension of the chassis of a motor vehicle is used to couple the vehicle body and the wheel support assembly in an elastic manner. The suspension is intended to insulate the vehicle body from high-frequency vibrations of the wheels and at the same time flexes to absorb the long-wave road surface contour. Various suspension systems are known in the art. Besides the use of leaf springs, which find application mostly in trucks, it is also known to employ torsion bar springs, pneumatic springs as well as silent blocks. Oftentimes, conventional suspension systems employ compression-type coil springs which are able to realize progressive, degressive or linear spring rate through provision of different wire sizes and different configurations. A particular space-saving configuration can be implemented, when using barrel springs which have windings which are nested within one another during compression. In addition to these types of coil springs, called load-carrying springs, auxiliary slave springs have been used to provide a stop in parallel disposition to the load-carrying spring. Typical materials for slave springs are rubber or cellular polyurethane elastomers. The slave spring may also operate as spring buffer to prevent an inadvertent bottoming of the coil spring. Conventionally, the slave springs are arranged outside the load-carrying spring and held in a cup-shaped receptacle.
It is also known to use a spring plate to correctly position the load-carrying spring, and to arrange a spring washer between the load-carrying spring and the spring plate. The spring washer is normally made of rubber, but may also be made of galvanized metal sheet or surface-coated metal sheet, and is used as sacrificial anode to prevent corrosion of the load-carrying spring.
When arranging the slave spring in coaxial relationship to the load-carrying spring, the installation is complex because of the need to place in a tight space three different components, i.e., first, the cup-shaped receptacle with the slave spring for attachment to the spring plate, second, the spring washer arranged between the spring plate and the load-carrying spring, and third, the actual load-carrying spring. While the slave spring and the receptacle may be constructed to form a pre-fabricated unit, the load-carrying spring and the spring washer constitute single parts which only in the spring-loaded installation stage are correctly positioned. Handling of the single parts is difficult during installation, especially when taking into account their considerable weight.
It would therefore be desirable and advantageous to provide an improved suspension which obviates prior art shortcomings and which is easy to handle during installation and allows use of light-weigh materials.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, a suspension includes a load-carrying spring having one end indirectly supported via a first spring washer by a vehicle body component and another end indirectly supported via a second spring washer by a component of the wheel support assembly of a motor vehicle; a cup-shaped receptacle disposed at the one end of the load-carrying spring; an abutment disposed at the other end of the load-carrying spring and having a stop surface; and a slave spring disposed in coaxial relationship to the load-carrying spring and having one end received in the receptacle and another end intended for engagement with the stop surface of the abutment, wherein the receptacle and/or the abutment has a radially outwardly extending support ring for at least partially engaging behind the proximal one of the first and second spring washers at a side distal to the load-carrying spring.
For convenience and sake of simplicity, the following description may on occasion refer only to the area of the receptacle, when in fact the connection of the abutment on the confronting side is substantially a mirror image of the connection and placement of the receptacle about an imaginary horizontal medial plane. Thus, although the suspension may be described with respect to only the area of the receptacle, it will be understood that the same components of the suspension may also be duplicated on the side of the abutment, or vice versa.
The present invention resolves prior art problems by providing the receptacle and/or the abutment with a support ring to engage behind the respectively proximate spring washer on the load-carrying spring distal side, so that the receptacle with the slave spring and the one spring washer and/or the abutment and the other spring washer form a pre-fabricated unitary structure, respectively. The final installation can thus cope with fewer components to thereby significantly facilitate the assembly. Of course, the receptacle as well as the abutment may each be provided with such a support ring.
The suspension according to the present invention is advantageous in particular in those situations, when the load-carrying spring is configured as a barrel spring with reduced winding diameter at the ends. In this case, the support ring can be configured with an outer diameter which is only slightly greater than the winding diameter of the end turn to ensure a secure clamping of the spring washer between the load-carrying spring and the support ring. The use of support rings with comparably smaller outer diameter saves material and thus weight and as a result leads to reduced fuel consumption.
According to another feature of the present invention, the spring washers may each have a collar to bear radially outwards upon the receptacle and/or the abutment, respectively, and points in a direction of the load-carrying spring, for correctly positioning the respective end of the load-carrying spring in a radial direction in cooperation with the receptacle and/or the abutment, respectively. The receptacle thus assumes several functions. The load-carrying spring indirectly rests via the spring washer against the support ring of the receptacle whereby the receptacle at the same time correctly positions the one end of the load-carrying spring in radial direction. The need for central guide pins or the like, as required for barrel springs, is eliminated. The provision of the collar, directed toward the load-carrying spring, prevents wear and noise generation between the load-carrying spring and the receptacle. The collar has a height which corresponds suitably at least to the wire diameter of the end turn of the winding. The abutment assumes the same functions as the receptacle in concert with the other spring washer and also provides a correct disposition of the load-carrying spring.
Apart from the fact that the spring washer at the side of the receptacle and the slave spring may form a prefabricated unitary structure, it is also suitable when this unitary structure is captivated by the load-carrying spring. This can be realized by providing the collar with a radially inwardly pointing undercut for engagement of an end turn of the load-carrying spring. As a consequence of the spring force applied by the load-carrying spring, the end turn is snapped in forced engagement with the undercut. Thence, the collar and thus the spring washer assembly are pressed radially on the outside against the receptacle so that these components can be installed as a whole. The undercut can be so positioned that the spring washer is also pressed in axial direction against the support ring of the receptacle by the load-carrying spring.
In the event, the spring washer is made of rubber or of a highly compliant elastomer, the provision of an undercut of the collar may be insufficient to properly secure load-carrying springs of substantial weight, the receptacle and/or the abutment may have an outer perimeter formed w
Remmert Heiner
Rohde Andreas
Benteler Automobiltechnik GmbH
Feiereisen Henry M.
Ilan Ruth
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