Spring element

The invention relates to a spring element (1) used for elastically supporting large loads. The spring element comprises an elastic rubber block having uniformly distributed spherical cavities (2) which are intersected by clindrical or prismatic channels (3) also formed in the rubber material. The channels (3) form groups of channels defining areas stacked on top of each other in the direction of the vector of a load to be supported, which areas neither intersect nor touch each other. These areas may be three-dimensionally-shaped areas, for example envelopes of a cone or corrugated areas, as well as mutually parallel planes oriented obliquely to the direction of the load vector. When projected onto a horizontal plane, the groups of channels (3) are either radially extending and uniformly angularly spaced if the areas are envelopes of a cone, or are mutually parallel if the areas are obliquely arranged planes. In no way, the channels (3) intersect or touch each other. Alternatively, an axial channel (6), which is at least open at one side, is arranged centrally in the direction of the load vector wherein none of the channels (3) or the spherical cavities (2) contact or intersect this central axial channel (6).

TECHNICAL FIELD 
The present invention relates to a spring element for elastically 
supporting one port relative to another port and, more specifically, to an 
elastic support buffer for cushioning a vehicle engine. 
BACKGROUND ART 
When elastically supporting relatively large masses it is difficult to 
attain spring characteristics which are as soft as possible, i.e., 
comprising a flat spring characteristic curve, while at the same time 
achieving good durability of the spring elements. Another problem which 
has to be taken into account when constructing spring elements is that the 
acoustically insulating behaviour between the two parts to be elastically 
connected has to be as good as possible. Therefore, elastic support 
buffers are used frequently in engineering fields and, especially, in 
vehicle construction for cushioning engines. Nowadays, spring elements 
consisting of a relatively rigid elastomer material which are interspersed 
by channels to attain soft spring characteristics and to decrease the 
local loads inside the material are used instead of solid elastomer blocks 
according to the prior art which comprised a relatively fast fatigue 
material. When the elastomer blocks are compressed by a load, the volume 
of the channels is decreased by the displaced material, which means the 
channels are used as a deformation zone, such that the deformation of the 
outer shape of the blocks and the high local loads caused by the 
nonhomogeneous load concentration can be reduced. 
An example of a buffer of the above type is disclosed in German application 
DE 35 35 897 A1, wherein an elastomer block is interspersed with channels 
intersecting cavities uniformly distributed inside the elastomer material. 
The channels form groups of channels extending equidistantly spaced and 
parallel to each other wherein these groups of channels are arranged in 
planes stacked on top of each other with respect to the direction of the 
vector of the load and wherein the planes defined by the groups of 
channels are orientated horizontally and parallel to each other, which 
means that the channels neither intersect nor contact each other. Each 
plane is rotated for a certain constant angle with respect to the plane 
below whereat the direction of the rotation remains unchanged such that 
the channels are helically distributed in space. For example, when having 
a rotation angle of 90.degree., an alternating arrangement of the channels 
is provided wherein the channels cross each other without intersecting or 
touching each other such that the cavities form a packed cubic lattice. 
Rubber springs of this kind comprise exceptionally good acoustically 
damping characteristics, a flat spring characteristic curve and a high 
mechanical rigidity, but they are limited in their range of application by 
the horizontal orientation of the groups of channels. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a spring element for 
use in complex structures, for example when loads are acting upon the 
spring element from different directions, and for complex functions, such 
as when the spring element has to stabilize itself with respect to 
transversal loads. 
To attain this object, a spring element according to the present invention 
comprises a rubber block interspersed by uniformly distributed cavities. 
A plurality of these cavities are connected by one channel each. The 
cylindrical or prismatic channels are dimensioned such that their 
cross-sectional area is at least 25% of the largest cross-sectional area 
of the nearest cavity intersected by the respective channel. The channels, 
which are at least open at one side, are arranged in groups which, 
according to a first embodiment of the invention, each define a 
three-dimensionally-shaped area, for example an envelope of a cone or a 
corrugated area. These three-dimensionally-shaped areas are stacked on top 
of each other with respect to the direction of the vector of the load to 
be supported and neither intersect nor touch each other. Projected onto a 
horizontal plane, the channels of each envelope of a cone are preferably 
radially extending and uniformly angularly spaced without intersecting or 
touching each other in the center. 
By the interlacing arrangement of the sections of the block stacked on top 
of each other, each section being defined by two adjacent 
three-dimensionally-shaped areas which may be shaped like the envelope of 
a cone or corrugated area, the spring element is stabilized with respect 
to lateral displacement of the elastomer block or the sections of the 
block, respectively. In contrast to the above prior art spring element, 
the form stability of the rubber block loaded in the direction of the 
central axis of the cone is improved and the load acting on the block is 
distributed more uniformly. 
According to a further embodiment of the spring element of the present 
invention, a central channel extending axially in the direction of the 
load vector to be supported is provided inside the spring element. This 
centrally-arranged axial channel which may be open at one side or at both 
sides, respectively, is arranged such that none of the cavities or 
channels leads into that axial channel. With the axial channel, which may 
be receive a stabilizing or guide rod, an additional stabilizing effect 
may be achieved which counteracts lateral displacement of the respective 
sections of the elastomer block defined each by two groups of channels. 
It is astonishing and surprising even to a person skilled in the art that 
neither the spring characteristics nor the acoustic damping 
characteristics of the spring element are decreased. To the contrary, in 
many applications the acoustic damping characteristics with respect to the 
two parts to be connected elastically by the spring element can be 
improved. 
According to a further embodiment of the spring element of the present 
invention, the respective groups of channels define plane areas which are 
also arranged on top of each other, but in an oblique orientation to the 
direction of the load vector to be supported and parallel to each other 
such that they neither intersect nor contact each other. Accordingly, the 
corrugated areas named above may be arranged obliquely to the direction of 
the load vector to be supported. Projected onto the horizontal plane, the 
channels of each group are preferably arranged parallel to each other. In 
contrast to the horizontal arrangement of the channels according to the 
prior art, in this embodiment an additional material dislocation in the 
direction of the oblique planes defined by the groups of channels is 
achieved by the arrangement of the channels obliquely to the direction of 
the load vector. The deformation of the elastomer occurs by the 
translation of the sectors of the block parallel to each other, each 
defined by two adjacent oblique planes, as well as by an inner deformation 
of the cavities and the channels. However, the essential effect is that 
the way of the material deformation is extended by the oblique arrangement 
of the channels. The extent of the deformation of the block or its outer 
shape, respectively, surprisingly is relatively small and can be tolerated 
compared with the bulb deformations which have to be accepted otherwise. 
The local loads in the elastomer material can be reduced by the uniform 
distribution of the deformation forces caused by the load to be supported 
while, simultaneously, the spring characteristics can be improved, which 
means that a flat spring characteristic curve is achieved. At the same 
time, transversal loads acting between the two parts connected elastically 
by the spring element can be compensated. Accordingly, a harder elastomer 
material can be used alternatively without having to accept deteriorated 
spring characteristics. Therefore, the durability of a spring element 
according to the present invention can be extended while maintaining 
effectively the same spring characteristic curve.

BEST MODE FOR CARRYING OUT THE INVENTION 
According to FIGS. 1 and 2, spherical cavities 2 are distributed uniformly 
inside the whole block-shaped spring element 1 consisting of a resilient 
material such that they are located at the sites of a rhombohedral 
lattice. The cavities 2 are intersected by mutually parallel cylindrical 
(FIG. 6a) or prismatic channels 3 which do not contact each other. The 
channels 3 (e.g., FIG. 6b) form groups of channels defining planes stacked 
on top of each other extending obliquely to the direction of the vector F 
of the load to be supported, which vector F in FIG. 1 is perpendicular to 
the drawing plane and in FIG. 2 in the drawing plane oriented vertically. 
The planes defined by the groups of channels are mutually parallel, which 
means that the channels 3 neither intersect nor touch each other. The 
central axes 4 of the channels 3 extend through the centers 5 of the 
spherical cavities 2. Each of the channels 3 intersects a plurality of 
cavities 2, wherein the diameter of the cavities 2 is larger than the 
diameter of the channels 3, but not more than four times the diameter of 
the channels 3. The distance between each of the channels is constant. The 
channels 3 interspersing the whole block are either open at one side or 
open at both sides. 
When the spring element is compressed, the dislocated elastomer material 
reduces the volumes of the cavities and of the channels arranged in the 
spring block, whereat the local loads are reduced by the translational 
movement of the sections of the block defined by two groups of channels, 
each, across the planes defined by said groups of channels. 
According to the embodiment of the spring element 1 of the present 
invention shown in FIGS. 3 and 4, each group of channels defines a 
three-dimensionally-shaped area formed like the envelope of a cone instead 
of the obliquely arranged plane of the embodiment illustrated in FIGS. 1 
and 2. These envelopes of a cone are stacked on top of each other in the 
direction of the vector of the load to be supported such that their cone 
points are located on the central axis of the rubber block extending in 
the direction of the load vector to be supported, whereat the envelopes 
neither contact nor intersect each other. The channels 3 of every group of 
channels (envelope of a cone) are radially extending and, in particular, 
uniformly angularly spaced when projected onto the horizontal plane, 
whereat they neither touch not intersect each other in the center. 
Therefore, the channels 3 are open at one side, only, which means that the 
channels 3 are closed inwards and open outwards. Alternatively, an axial 
channel 6 extending centrally in the direction of the load vector can be 
provided. This central axial channel 6 is at least open at one side and 
neither intersects nor touches any of the cavities 2 or the channels 3, 
respectively, such that the configuration of the channels closed at one 
side remains unchanged. 
When an external force acts upon the spring element 1, the elastomer block 
is loaded in the direction of its longitudinal axis and the displaced 
elastomer material reduces the volumes of the cavities 2,3 and 6 inside 
the elastomer block. By the conical structure of the sections of the block 
stacked on top of each other as defined respectively by two groups of 
channels a stabilizing effect with respect to lateral displacement of the 
sections of the block is achieved by the interlacing arrangement. 
FIG. 5 is an illustration of another embodiment of the invention wherein 
channels 3 are stacked on each other to define corrugated areas 3'. 
The acoustic insulating characteristics with respect to the two parts 
connected elastically by the spring element are achieved by the oblique 
arrangement of the planes or the three-dimensionally-shaped areas, 
respectively, defined by the groups of channels as well as by the central 
axial channel. The improvement is caused by increasing the scattering 
effects in the cavities as well as by reducing material bridges acting as 
acoustic conductors.