U.S. patent application number 11/921932 was filed with the patent office on 2009-09-03 for highly elastic leaf spring.
Invention is credited to Volker Gedenk.
Application Number | 20090218740 11/921932 |
Document ID | / |
Family ID | 36646222 |
Filed Date | 2009-09-03 |
United States Patent
Application |
20090218740 |
Kind Code |
A1 |
Gedenk; Volker |
September 3, 2009 |
Highly elastic leaf spring
Abstract
The invention relates to a multilayered spring, especially for
rail vehicles, having an inner and an outer connecting part and at
least two spring layers that are located therebetween and are made
alternately of an elastomeric layer and a sheet-metal layer. The
elastomeric layers are vulcanized together with the connecting
parts and the sheet-metal layers and the elastomeric layers of the
spring layer have different thicknesses with respect to each other.
Each elastomeric layer is made of the same material. The
multilayered spring has a substantially conically contoured support
plate which is arranged above the thickest spring layer in the
direction in which load is applied. The inner portion of the
softest layer initially rests on the support plate when the spring
is loaded while the outer portions of the softest layer, followed
by the other spring-layers, rest on the support plate in a
continually increasing manner as the load increases. The contour of
the support plate influences the characteristic line of the
spring.
Inventors: |
Gedenk; Volker; (Hemmingen,
DE) |
Correspondence
Address: |
WALTER OTTESEN
PO BOX 4026
GAITHERSBURG
MD
20885-4026
US
|
Family ID: |
36646222 |
Appl. No.: |
11/921932 |
Filed: |
May 10, 2006 |
PCT Filed: |
May 10, 2006 |
PCT NO: |
PCT/EP2006/004364 |
371 Date: |
December 11, 2007 |
Current U.S.
Class: |
267/294 |
Current CPC
Class: |
F16F 1/3935 20130101;
B61F 5/305 20130101; F16F 1/371 20130101 |
Class at
Publication: |
267/294 |
International
Class: |
B61F 5/30 20060101
B61F005/30 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 21, 2005 |
DE |
10 2005 028 565.5 |
Claims
1. (canceled)
2. A multilayered spring for a vehicle, including a rail vehicle,
the multilayered spring being subjectable to a load in a
predetermined direction and comprising: an inner connecting part;
an outer connecting part; a plurality of spring layers disposed
between said connecting parts; said spring layers including a
plurality of sheet-metal layers and a plurality of elastomer layers
alternating with corresponding ones of said sheet-metal layers;
said elastomer layers being vulcanized to corresponding ones of
said connecting parts and said sheet-metal layers; said elastomer
layers having different thicknesses and one of said elastomer
layers having a thickness greater than the remainder of said
elastomer layers; a conically-shaped contoured support plate
mounted above said one elastomer layer in said load direction; said
one layer having an outer portion and being softer than said
remainder of said elastomer layers; and, said support plate
corresponding to said elastomer layers to cause first said one
layer to be supported against said support plate in response to
said load and, with said load increasing, to cause said outer
portion of said one layer and said remainder of said elastomer
layers to become continuously and increasingly supported against
said support plate.
3. The multilayered spring of claim 2, wherein all of said
elastomer layers are made of the same material.
4. The multilayered spring of claim 3, wherein said one layer is
thicker than the elastomer layers of said remainder of said
elastomer layers by a factor of three.
Description
[0001] The invention relates to a multilayered spring, in
particular for rail vehicles, having an inner connecting part and
an outer connecting part and having at least two spring layers
which are located between the connecting parts. The spring layers
include alternately an elastomer layer and a sheet-metal layer and
the elastomer layers are each vulcanized together with the
connecting parts and the sheet-metal layers. The elastomer layers
of the spring layers have different thicknesses from one another
with each elastomer layer being manufactured from the same
material.
[0002] Such multilayered springs are also referred to as primary
springs because they frequently form the primary spring stage, that
is, the spring stage between the wheel and the swivel truck in rail
vehicles. The multilayered springs can have different shapes. For
example, the individual spring layers can be arranged
concentrically with respect to one another in a cylindrical or
conical fashion. However, multilayered springs made of differently
arranged horizontal or vertical spring layers are also possible.
The shape, position and number of the spring layers are adapted to
the particular application.
[0003] Individual multilayered springs are usually manufactured for
each application and a specific spring characteristic line has to
be achieved. Given low loading, which is particularly critical for
protection against derailing during the travel operation, the
spring must be made very soft. In contrast, when the loading is
high, the spring should be hard so that the vehicle remains within
the free space profile.
[0004] DE 85 20 180 U1 discloses a multilayered spring which has an
additional rubber layer with a Shore hardness which is lower than
that of the other layers in order to achieve a specific spring
characteristic. However, this multilayered spring requires a
limiting stop in order to limit the spring compression of this
additional layer. The spring characteristic line is therefore
composed of two line segments, a soft, flat segment up to the time
when the spring abuts against the limiting stop and a hard, steep
segment. The characteristic line therefore has an unevenness which
has an unfavorable effect on the suspension behavior.
[0005] In order to obtain an optimal characteristic line of the
multilayered spring, it is known to manufacture the elastomer
layers of the spring layers from different materials. Such a
multilayered spring is shown in DE 28 19 306 A1 or DE 103 01 756
B4.
[0006] However, the use of different materials requires
considerable complexity with respect to manufacture, especially
when there are different materials within one layer.
[0007] The invention is based on the object of providing a
multilayered spring of the type described above which has an
improved, constant spring characteristic line while avoiding the
above-mentioned disadvantages.
[0008] This object is achieved by virtue of the fact that the
multilayered spring has a support plate which is contoured
substantially in the shape of a cone, is arranged above the
thickest spring layer in the loading direction and corresponds to
the spring layers of different thicknesses in such a way that
initially the inner part of the softest layer is supported on the
support plate and, as the loading increases, the outer parts of the
softest layer and the further spring layers are supported in a
constantly increasing fashion on the support plate.
[0009] The support plate produces a continuous spring
characteristic line since, as a result of this configuration, only
the inner, soft spring layer of the multilayered spring experiences
spring compression under relatively low loads and the further
spring layers increasingly participate in the spring compression
under higher loads. Because of the support plate, the thickest,
softest spring layer is not overloaded. The characteristic line can
be adapted to the application, for example, as a continuously
progressive characteristic line depending on the contour of the
support plate.
[0010] According to one embodiment of the invention, the elastomer
layer of the inner spring layer is thicker than the elastomer
layers of the other spring layers by a factor of three.
[0011] As a result, the inner spring layer is considerably softer
than the other spring layers. The hardness of such a spring layer
is determined both by the hardness of the material and by the
geometry of the layer, with the influence of the geometry being
determined by the form factor F. The form factor F describes the
ratio of free elastomer area to bound elastomer area of an
elastomer layer. If the free surface of an elastomer layer becomes
larger while the fixedly vulcanized, that is, bound area remains
the same, the form factor increases. High values of F describe a
soft spring property, while low values of F describe a hard spring
property.
[0012] Such a multilayered spring can be adapted in the inventive
fashion to various applications with a constant characteristic line
and does not require complex production methods since, for example,
the omission of one or more sheet-metal layers allows the freely
deformable elastomer area of the resulting, relatively thick
elastomer layer to be easily enlarged. There is no need to use
different materials.
[0013] An exemplary embodiment of the invention will be explained
in more detail below with reference to the drawing.
[0014] The single FIGURE shows a multilayered spring 1 in a
longitudinal section in the installed position without loading with
an inner connecting part 2 directed upwardly with a connecting lug
3 and bearing a load (not shown here).
[0015] Furthermore, the multilayered spring 1 has an outer
connecting part 4 and a plurality of conical,
concentrically-arranged sheet-metal intermediate layers (5, 6, 7,
8) with average diameters which become larger toward the outside.
Conical elastomer layers (9, 10, 11, 12) are arranged between each
two sheet-metal intermediate layers 5 to 8. The conical elastomer
layers (9, 10, 11, 12) are fixedly vulcanized with their respective
surfaces to corresponding surfaces of the inner connecting part 2,
the sheet-metal intermediate layers 5 to 8 and the outer connecting
part 4. These surfaces of the elastomer layers face toward the main
axis 13 of the multilayered spring 1 or face away from the main
axis 13.
[0016] The sheet-metal intermediate layers 5 to 8 and the elastomer
layers 9 to 12 are arranged with respect to one another in such a
way that the multilayered spring 1 has an upwardly tapering
truncated cone-like shape.
[0017] A support plate 14, which has a conical shape on its
underside 15 facing toward the inner-lying elastomer layer 9, is
fixedly mounted on the connecting lug 3 concentrically with respect
to the inner connecting part 2.
[0018] The inner-lying elastomer layer 9 has a significantly larger
radial thickness than the other elastomer layers 10 to 12. The
increased thickness gives rise to a form factor F which is
increased compared to the other elastomer layers 10 to 12. The
inner elastomer layer 9 is therefore significantly softer than the
other elastomer layers 10 to 12.
[0019] Under load, the inner connecting part 2 moves downwardly
toward the outer connecting part 4 and the multilayered spring 1 is
compressed. In the process, at first only the inner-lying elastomer
layer 9 experiences spring compression owing to the softer spring
characteristic line. The elastomer layer 9 is supported against the
support plate 14. The configuration of the underside 15 of the
support plate 14 thereby contributes to the determination of the
spring characteristic line of the inner-lying elastomer layer 9.
The thickness of the inner-lying elastomer layer 9 and the shape of
the underside 15 of the support plate 14 are matched to one another
in such a manner that, when the inner-lying elastomer layer 9
experiences complete spring compression, the support plate 14 comes
to rest on the inner sheet-metal intermediate layer 5 and the other
elastomer layers 10 to 12 are increasingly involved in the further
spring compression. This results in a continuously progressive
spring characteristic line for the entire multilayered spring
1.
List Of Reference Numerals
[0020] (part of the description) 1 Multilayered spring 2 Inner
connecting part
3 Connecting lug
[0021] 4 Outer connecting part 5 Sheet-metal intermediate layer 6
Sheet-metal intermediate layer 7 Sheet-metal intermediate layer 8
Sheet-metal intermediate layer 9 Inner-lying elastomer layer 10
Elastomer layer 11 Elastomer layer 12 Elastomer layer 13 Main axis
of the multilayered spring 1 14 Support plate 15 Underside of the
support plate
* * * * *