U.S. patent application number 15/185266 was filed with the patent office on 2016-10-13 for subassembly with a dividing body and a magnetic field generating device.
The applicant listed for this patent is INVENTUS ENGINEERING GMBH. Invention is credited to STEFAN BATTLOGG, MICHAEL KIEBER.
Application Number | 20160298715 15/185266 |
Document ID | / |
Family ID | 48948377 |
Filed Date | 2016-10-13 |
United States Patent
Application |
20160298715 |
Kind Code |
A1 |
BATTLOGG; STEFAN ; et
al. |
October 13, 2016 |
SUBASSEMBLY WITH A DIVIDING BODY AND A MAGNETIC FIELD GENERATING
DEVICE
Abstract
A subassembly and a method of producing a subassembly. The
subassembly has a dividing body or separating body and at least one
flow channel formed on the dividing body and extending along it
with at least one flow path to influence a flow of a
magneto-rheological fluid along the flow channel of the dividing
body. The dividing body includes a magnetic field generation device
for generating a magnetic field and a field closing device. At
least the magnetic field generation device and the field closing
device are filled with at least one solidifying medium using a
placeholder which can be removed to form the three-dimensionally
predefined flow channels on the dividing body.
Inventors: |
BATTLOGG; STEFAN; (ST. ANTON
I. M., AT) ; KIEBER; MICHAEL; (SCHRUNS, AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INVENTUS ENGINEERING GMBH |
St. Anton I. M. |
|
AT |
|
|
Family ID: |
48948377 |
Appl. No.: |
15/185266 |
Filed: |
June 17, 2016 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14413836 |
Jan 9, 2015 |
|
|
|
PCT/EP2013/002002 |
Jul 8, 2013 |
|
|
|
15185266 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01F 41/06 20130101;
Y10T 29/49071 20150115; F16F 9/535 20130101; F16F 9/3214 20130101;
Y10T 29/49826 20150115; Y10T 29/49075 20150115; Y10T 29/49815
20150115; Y10T 29/49821 20150115 |
International
Class: |
F16F 9/53 20060101
F16F009/53; F16F 9/32 20060101 F16F009/32 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 9, 2012 |
DE |
102012013480.0 |
Claims
1. A subassembly, comprising: a dividing body formed with at least
one flow passage extending along the dividing body and having at
least one flow path for influencing a flow of a magnetorheological
fluid along the flow passage of the dividing body; said dividing
body having at least one magnetic field generating device
configured for generating a magnetic field and one field closing
device; and a solidifying medium filling said field closing device
with said magnetic field generating device while using at least one
placeholder, such that said dividing body has at least one three
dimensionally predefined flow passage.
2. The subassembly according to claim 1, wherein the placeholder is
a reusable placeholder.
3. The subassembly according to claim 1, which comprises at least
one dividing wall disposed to divide said at least one flow passage
into at least two flow paths.
4. The subassembly according to claim 3, wherein said dividing wall
has at least one latching device.
5. The subassembly according to claim 1, wherein said at least one
magnetic field generating device is an electric coil device with at
least one core of a ferromagnetic material.
6. The subassembly according to claim 5, wherein said core is
formed with at least one lateral constriction transversely to a
longitudinal axis thereof.
7. The subassembly according to claim 5, wherein at least one flow
path is formed between a pole cap of said core and said field
closing device.
8. The subassembly according to claim 1, wherein said dividing body
is a piston movably guided in a piston guide, and wherein said
piston is connected to a piston rod.
9. The subassembly according to claim 8, wherein an axis of said
electric coil device is aligned transversely to a longitudinal axis
of said piston guide.
10. The subassembly according to claim 8, wherein said field
closing device forms a piston main body of said piston and said
piston main body has at least one undercut formed therein.
11. The subassembly according to claim 8, wherein said flow
passages in said piston are at least partially delimited by said
solidifying medium.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of copending application
Ser. No. 14/413,836, filed Jan. 9, 2015, which was a .sctn.371
national stage of international application PCT/EP2013/002002,
filed Jul. 8, 2013, which designated the United States; this
application also claims the priority, under 35 U.S.C. .sctn.119, of
German patent application No. DE 10 2012 013 480.0, filed Jul. 9,
2012; the prior applications are herewith incorporated by reference
in their entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to a subassembly and to a
method for producing a subassembly, wherein the subassembly
comprises a divider with a flow passage extending thereon. The flow
of a magnetorheological fluid along the flow passage is influenced
by a magnetic field generating device in order to produce defined
conditions.
[0003] The prior art has disclosed subassemblies in which the flow
of a magnetorheological fluid is selectively attenuated or even
prevented by adjustment of a corresponding magnetic field on the
flow passage.
[0004] For example, dampers have been disclosed which comprise a
damper piston with a magnetorheological valve, wherein the degree
of damping depends on the magnetic field applied. A damping piston
of this kind with a magnetorheological valve comprises a
multiplicity of parts, which have to be produced carefully in order
to be able to make available reproducible assembly and thus dampers
without excessive series variability and hence differences in
performance.
[0005] An electrically operated magnetorheological damping valve
comprises an electric coil wound onto a core, a damping gap,
through which the magnetorheological fluid passes, and a magnetic
conductor, which closes the magnetic field. The individual
components must be carefully assembled and sealed off from one
another in order to ensure the desired operation, sometimes at
pressures of up to 600 bar. This requires considerable effort, and
therefore manufacture of such subassemblies is complex and thus
relatively expensive.
[0006] US 2002/0130001 A1 has disclosed a magnetorheological fluid
damper in which a piston has over its circumference an annular gap
divided into four channel segments. The piston has an outer flow
ring and an inner piston core, around the longitudinal axis of
which a magnetic coil is wound. Four cross-shaped fastening
grooves, which are provided with inward-leading through holes, are
introduced into the outer surface of the flow ring in a manner
distributed over the circumference. To connect the flow ring to the
piston core, plastic is injected from the outside at the fastening
grooves, passing through the through holes and the annular gap and
forming sprues with radial projections which extend as far as the
magnetic coil on the piston core. Here, the quantity injected is
chosen so that a significant portion of the annular gap remains
free for the flow of the magnetorheological fluid. However, a fluid
damper of this kind has the disadvantage that the radial
projections of the sprues have to bear very high shear forces when
subjected to loading, and this can lead to problems with
durability. Moreover, although using the injected quantity of
plastic is supposed to ensure that a significant portion of the
annular gap is left free, it is not possible to ensure a constant
and reproducible shape of the annular gap that remains free since
the liquid plastic flows into the annular gap differently on each
occasion, and therefore considerable series variability is to be
expected in manufacture.
[0007] U.S. Pat. No. 7,849,983 B2 has disclosed a
magnetorheological fluid damper which has a piston with poles at
the axial ends and a coil wound around the longitudinal axis of the
piston. The piston runs within a cylindrical housing and divides a
first magnetorheological damper chamber from a second
magnetorheological damper chamber. The damping gap is provided
radially between the outer surface of the piston and the radially
inner surface of the cylindrical housing. During manufacture, the
piston with the metallic poles and the electric coil is introduced
into a casting mold, and a polymer is injected under pressure. The
piston with the polymer on the outer surface thus provides a
defined outer surface. However, the disadvantage of this is that
the piston has to be guided with extreme accuracy in the
cylindrical housing by means of a bearing arrangement in order to
avoid a nonuniform gap around the circumference and to avoid
contact between the piston and the inner surface of the cylindrical
housing. Moreover, the cylindrical housing must be formed from a
magnetically conductive material in order to be able to close the
magnetic field.
[0008] It is therefore the object of the present invention to make
available a method for producing a subassembly and to make
available a subassembly of this kind, thus allowing reproducible
production of such subassemblies at low cost.
BRIEF SUMMARY OF THE INVENTION
[0009] This object is achieved by a method having the features as
claimed. The subassembly according to the invention is the subject
matter of a further claim. Preferred developments are the subject
matter of the dependent claims. Further advantages and features of
the present invention will emerge from the general description and
from the description of the illustrative embodiments.
[0010] The method according to the invention is used to produce a
subassembly having a divider and at least one flow passage arranged
thereon or provided therein and extending along or in the divider
and having at least one flow path in order to influence a flow of a
magnetorheological fluid along the flow passage or a subsection of
the flow passage of the divider. In this case, the divider
furthermore has a plurality of components, including at least one
magnetic field generating device for generating a magnetic field
and at least one field closing device. The magnetic field
generating device and the field closing device are filled with at
least one solidifying medium, while using at least one placeholder,
to form the or at least part of the flow passage, in order to form
on the divider at least one three dimensionally predefined flow
passage, which is available after the removal of the
placeholder.
[0011] The space maintained by the placeholder during filling is
available as a three dimensionally predefined flow passage after
the removal of the placeholder.
[0012] Particularly for the hydraulically leaktight connection of
the components of the divider, at least the magnetic field
generating device with the field closing device of the divider is
encapsulated with a solidifying medium in the form of, for example,
an encapsulating compound, or is overmolded with at least one
injected plastic. The method according to the invention has many
advantages since it allows simple production of a subassembly
according to the invention. A subassembly produced by a method
according to the invention has a high reproducibility and can be
subjected to high loads. The method is very cost-effective for the
quality achieved.
[0013] In the sense according to the present invention, the phrase
stating that a flow passage extends "along" the divider is taken to
mean that the flow passage extends from one end to the other end.
The flow passage can be of linear design, but it can also have
turns or extend in coils or obliquely from one end to the other
end.
[0014] The flow of the magnetorheological fluid is influenced at
least by means of a subsection of the flow passage. It is not
necessary to exert an influence over the entire length.
[0015] The core is preferably surrounded by a coil holder, which is
composed of plastic, for example. An electric coil device is
preferably wound onto the coil holder.
[0016] The connection formed by the solidifying medium is
preferably hydraulically pressuretight, forcing the
magnetorheological fluid to flow via the flow passage.
[0017] It is advantageous if the magnetic field generating device
is wound onto the core or the coil holder first, before filling.
The core can be introduced into the magnetic field generating
device before filling. At least one placeholder is positioned in
the field closing device. The core with the magnetic field
generating device and the field closing device is then filled,
ensuring that, after the subsequent removal of the placeholder or
placeholders, the at least one flow passage is available, while the
divider per se is hydraulically leaktight.
[0018] It is advantageous if at least one dividing wall is arranged
on the coil holder in order to divide the flow passage into two or
more flow paths.
[0019] For production, an insert or an inserted part or a push-in
part is formed, being formed, for example, from a stack comprising
a first dividing template as a placeholder, at least one dividing
wall and at least one second dividing template as a
placeholder.
[0020] It is also possible here for an insert to be formed from one
or more placeholders. An individual placeholder or a placeholder
made up of one or more parts is used, for example, if a flow
passage is not divided into partial passages. If, on the other
hand, the flow passage is to be divided into a plurality of flow
paths, the insert comprises a stack of different components, which
are stacked one on top of the other.
[0021] During assembly, the core is preferably introduced with the
coil holder and the electric coil device and at least one insert
into the field closing device. The field closing device is
preferably introduced into a mold before or afterward.
Encapsulation with the solidifying medium in the form, for example,
of an encapsulating compound is then carried out, or plastic or
other materials advantageous for this purpose is/are injected.
Encapsulation can take place at normal pressure, but can also take
place using reduced pressure and/or excess pressure.
[0022] In all the embodiments, the solidifying medium is preferably
cured after the casting operation. Curing can be assisted by
temperature adjustment. The use of UV radiation or some other
radiation, for example, is also possible in order to accelerate the
solidification process. The use of chemical agents is also
possible.
[0023] Analogously, some other suitable method, such as injection
molding (of plastics) can be used instead of encapsulation.
[0024] The embodiments illustrated show the use of a structure
according to the invention in a damper, e.g. as a shock damper in a
vehicle, bicycle or prosthesis. Analogously, the structure can be
used without a movable piston and piston rod as a valve.
[0025] In all embodiments, at least one placeholder is removed
after the curing process in order to free the flow passage and/or
the flow paths of the flow passage.
[0026] In particular, a subassembly according to the invention is
produced by one of the methods described above. The subassembly
according to the invention has a divider and at least one flow
passage provided thereon and extending through the divider or along
the divider and having at least one flow path in order to influence
a flow of a magnetorheological fluid along the flow passage--or in
subsections thereof--of the divider. The divider comprises at least
one magnetic field generating device for generating a magnetic
field and one field closing device. The field closing device with
the magnetic field generating device is filled with a solidifying
medium, while using at least one placeholder, such that the divider
has at least one three dimensionally predefined flow passage. After
the removal of the placeholder, the flow passage is available.
[0027] The subassembly according to the invention has many
advantages since it can be produced easily and reproducibly and
allows functionally reliable operation.
[0028] The subassembly according to the invention preferably makes
available a hydraulically leaktight divider which, in particular,
allows flow only through the flow passage arranged thereon or
through the flow connections provided thereon. In this case, the
flow capacity depends, in particular, on the magnetic field of the
magnetic field generating device. Without a magnetic field, a
magnetorheological fluid can pass substantially unhindered through
the flow passage. With a strong magnetic field, the through flow of
a magnetorheological fluid can also preferably be completely
prevented.
[0029] The solidifying medium can be at least one encapsulating
compound or contain such a compound. The solidifying medium can be
cast or injected. For example, it is possible to use at least one
medium which is or becomes liquid under certain conditions and is
then cast or injected and then cures. The solidifying medium can be
a medium which cures or can contain at least one such medium, for
example.
[0030] The magnetic field generating device with the field closing
device of the divider is preferably filled and/or encapsulated
and/or overmolded with a solidifying medium.
[0031] Owing to the fact that the components of the divider are, in
particular, encapsulated together and are thus firmly connected to
one another by the solidifying medium, durable functioning can be
reliably ensured. In the case of subassemblies from the prior art,
in contrast, it is generally necessary to connect each individual
component to the other components and seal them off from the other
components in a complex process. Such an assembly process is
complex and, at the same time, prone to error. The subassembly
according to the invention, on the other hand, makes available a
functionally reliable subassembly in a simple manner. At the same
time, the solidifying medium ensures a firm and permanently
leaktight connection between the individual components, even if
these exhibit inaccuracies owing to relatively large variations in
the manufacturing tolerances or indeed surface imperfections or
roughness.
[0032] As a solidifying medium, it is possible, for example, to use
an encapsulating compound and/or a solidifying and, in particular,
curing casting compound. It is possible, for example, for a two
component material to be used as a solidifying medium, which is
initially capable of being processed in a flexible manner and then
automatically cures. Here, curing can take place under defined
conditions, e.g. an increased temperature. However, it is also
possible for curing to take place without special conditions, e.g.
at room temperature.
[0033] In particular, a hydraulically leaktight connection between
the components of the divider is made possible. In particular, the
solidifying medium restricts the flow of the magnetorheological
fluid substantially and preferably virtually completely to the flow
passages. However, it is also possible for at least one separate
bypass passage to be provided.
[0034] Through the use of one or, indeed, at least one placeholder,
a spatially precisely defined shape of the flow passage is made
possible. The placeholder can be of one-piece design. The
placeholder can also consist of a plurality of individual parts.
After filling, the placeholder is removed and is preferably
reusable. The placeholder can consist of a dividing template or can
comprise at least one such template. The dividing template can be
metallic or can consist of some other suitable material.
[0035] The use of a placeholder composed of a material such as wax
or the use of a eutectic metal is also possible. After the filling
process, the placeholder can then be washed out or melted out of
the divider. Dissolving with chemical agents is also possible.
[0036] The placeholder itself or the melted material can be
reused.
[0037] At least one flow passage is preferably divided by at least
one dividing wall into at least two flow paths. Here, a flow path
can also be regarded as a partial passage. The at least two flow
paths are preferably divided from one another at least partially
and, in particular, completely over the entire length thereof. By
means of such a dividing wall, which can be embodied essentially as
a thin and, preferably, ferromagnetic dividing plate, for example,
without being restricted thereto, the flow passage is divided by
simple means into two partial passages or flow paths. Even more
effective influencing of the flow through the flow passage is
thereby possible. In simple cases, a thin dividing plate is used as
a dividing wall. The dividing wall is preferably thin relative to
the height of a flow path of the flow passage. As a result, the
full flow cross section is reduced only slightly, thereby making it
possible to maintain a small overall size. In this case, the faces
of the dividing wall can have contours which are advantageous in
terms of flow engineering.
[0038] As a particularly preferred option, the dividing wall is
designed as a separate dividing plate and is encapsulated with the
divider by means of the solidifying medium. Simple manufacture and
a durable subassembly are thereby made possible.
[0039] The dividing wall preferably has at least one latching
device, which latches with the solidifying medium and/or with other
components of the divider, thus making it possible to ensure
reliable operation, even at high pressures. In particular, two,
three or more latching devices in the form of latching teeth,
latching hooks, latching eyes or latching grooves or the like, for
example, are provided in order to allow a firm connection between
the dividing wall and the divider.
[0040] In all the embodiments, at least one flow path has a shallow
cross section in the flow direction, wherein said cross section can
be straight or in an arc shape. In particular, a width of the flow
path is more than twice and, in particular, at least four times a
height of the flow path in the direction of the field lines. In
particular, the length of the flow path in the flow direction is
greater than a height of the flow path transversely to the flow
direction. Effective influencing of the magnetorheological
particles in the magnetorheological fluid is made possible by a
shallow gap as a flow path, making possible finely graduated or
continuous adjustment of the flow resistance through the flow
passage, right up to blocking.
[0041] In all the embodiments, there is a particular preference for
at least one magnetic field generating device to be designed as an
electric coil device, to which at least one core composed of a
ferromagnetic material is assigned. In particular, the electric
coil device and the core are encapsulated with the divider by means
of the solidifying medium.
[0042] An electric coil device allows a flexible, quick and defined
change in the effective magnetic field in a short time, thus making
possible real-time control of the influencing of the flow
resistance through the flow passage of the dividing device, for
example.
[0043] In particularly preferred embodiments, the core has at least
one lateral constriction transversely to the longitudinal axis
thereof. This constriction can be formed on one or more
longitudinal sides and/or end faces of the core or can be designed
to run completely around the core. As a result, a smaller overall
volume is made possible, offering considerable advantages in the
case of subassemblies where overall volume is a difficult
issue.
[0044] By means of the constriction, the ferromagnetic material of
the core, the saturation flux density of which is generally
significantly higher than the saturation flux density of the
flowing fluid, is better utilized. Moreover, the mean winding
length of the coil can be reduced, which can significantly improve
the electrical properties thereof.
[0045] It is advantageous if the core is surrounded by a coil
holder, on which the electric coil device is mounted.
[0046] The coil holder can be composed of a plastic, for example,
and facilitates the winding of the coil. At the same time, damage
to the windings at the edges of the iron core is avoided during
winding or during subsequent operation. It is also possible to wind
the coil directly onto the coil holder and to insert the core
later. The coil holder preferably allows coaxial positioning, e.g.
if the divider is designed as a piston.
[0047] At least one flow path is preferably arranged between a pole
cap of the core and the field closing device. Such an embodiment
allows particularly effective use of the magnetic field which
emerges from the pole cap, crosses the flow path and is directed
back via the field closing device, thus making available an
effective subassembly.
[0048] In particular, at least one pole cap is rounded and is
preferably designed substantially as a cylinder segment and at
least substantially adjoins a flow path.
[0049] In preferred embodiments, the divider is designed as a
piston and, as such, is arranged movably in a piston guide. The
piston is preferably connected to a piston rod. However, the piston
can also be connected to piston rods on both sides--i.e. what is
referred to as a continuous piston rod. At least one piston rod is
preferably screwed on, in or against.
[0050] In such embodiments, it is preferred if the electric coil
device is aligned transversely to a longitudinal axis of the piston
guide. This means that the electric coil device is not arranged
parallel to the piston movement but, in particular, is arranged
perpendicularly thereto. However, it is also possible for the coil
device to be embodied parallel to the piston movement (coaxial
coil).
[0051] An axis of the electric coil device is preferably aligned
transversely to a longitudinal axis of the piston guide. The field
closing device preferably forms a piston main body. The piston main
body is composed of a ferromagnetic material, such as a ferrous
material, for example.
[0052] In such embodiments, the field closing device preferably
surrounds the electric coil device in a circumferential direction
of the piston. In the case of a horizontal arrangement of the
electric coil device, when the electric coil device is arranged
transversely to the longitudinal axis of the piston, it is thereby
possible for the field closing device to effectively close the
field, thus allowing a simple and effective structure.
[0053] In all the embodiments, it is particularly preferred if the
piston main body has at least one undercut, grooves, slots,
irregularities, a very rough surface or the like, which are filled
at least partially with the solidifying medium or the encapsulating
or injection compound. By means of such an embodiment, a
particularly firm connection is ensured within the divider, thus
ensuring that the subassembly is sufficiently stable, even at high
and very high differential pressures on both sides of the divider
of 100, 200, 400 or even 600 bar.
[0054] Further advantages and properties of the present invention
will emerge from the description of the illustrative embodiments,
which are explained below with reference to the attached
figures.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0055] FIG. 1 shows a schematic cross section through a subassembly
according to the invention, which is embodied as a damper;
[0056] FIG. 2 shows a schematic cross section through a subassembly
1;
[0057] FIG. 3 shows a cross section through the subassembly
according to FIG. 2, at right angles to the illustration according
to FIG. 2;
[0058] FIG. 4 shows a piston for a subassembly according to the
invention;
[0059] FIG. 5 shows a core for the subassembly according to FIG.
2;
[0060] FIG. 6 shows a dividing wall for the subassembly according
to FIG. 2;
[0061] FIG. 7 shows the core with a coil holder and dividing walls
for the subassembly according to FIG. 2;
[0062] FIG. 8 shows a perspective illustration of the subassembly 1
without a field closing device;
[0063] FIG. 9 shows a perspective illustration of the subassembly 1
without the field closing device;
[0064] FIG. 10 shows a schematic illustration of a stack;
[0065] FIG. 11 shows a highly schematized cross-sectional
illustration of another subassembly;
[0066] FIG. 12 shows a highly schematized front view of another
subassembly; and
[0067] FIG. 13 shows a cross-sectional illustration of the
subassembly according to FIG. 12.
DESCRIPTION OF THE INVENTION
[0068] In FIG. 1, a damper 50 according to the invention is
depicted in a highly schematized cross section. The damper 50 has a
housing 43, in which the subassembly 1 acts as a piston 30.
Connected to the piston 30 is a piston rod 32, which extends
outward out of the housing 43.
[0069] It is likewise possible for a valve according to the
invention to be made available. The invention is not restricted to
the structure of a damper but can also be directed to a valve. In
this case, such a valve can be inserted in a damper, for example,
although this is not the only possibility. As a valve for a damper,
it can be inserted in the piston or take the form of an external
valve, for example.
[0070] In the damper 50 in FIG. 1, a compensating space 42, which
is separated from the remaining volume of the damper 50 by a
dividing piston 41, is provided to compensate for the volume of the
piston rod 32. It is also possible to use a respective piston rod
on each face of the piston, thereby allowing the compensating space
and the dividing piston to be eliminated. The seal 51 serves as a
sealing means (sliding seal) between the moving piston 35 and the
housing 43. The seal 51 can also be a permanent magnet seal.
[0071] The subassembly 1 serving as a piston 30 serves as a divider
2 and has a magnetic field generating device 8, which is here
designed as an electric coil device 19.
[0072] In the section according to FIG. 1, the core 20 can be seen,
which is surrounded by a coil holder 23 made of plastic. The
electric coil device is wound around the coil holder 23.
[0073] The piston 30 comprises the piston main body 35, which
simultaneously serves as a field closing device 9 and is here
designed as a ring-shaped conductor. In the illustration according
to FIG. 1, the flow passages 3 and 4 can be seen, which are each
divided here into two respective flow paths 5 and 6 by dividing
walls 11.
[0074] FIG. 2 shows, in a somewhat enlarged view, a subassembly 1,
which is here likewise embodied as a piston 30. The piston 30 is
connected to a piston rod 32. The piston main body 35 and the core
20 and the coil holder 23 each form components 7, which are here
connected to one another within the divider 2 by the solidifying
medium 10 in the form, for example, of an encapsulating compound 10
or of a plastic. Flow through the piston 30 can take place in the
flow direction 15 through the flow passages 3 and 4.
[0075] FIG. 3 shows the subassembly 1 according to FIG. 2 in a
section which is arranged at right angles to the section according
to FIG. 2. Here, the core 20 is depicted along the longitudinal
extent 26 thereof. The core 20 is surrounded by the coil device 19,
the individual windings of which here extend substantially parallel
to the plane of the paper. Provided in the piston main body 35 is
an undercut 45 or a groove, which has filled with the solidifying
medium 10 during the encapsulation or injection process. After
curing, the undercut 45 forms an effective safeguard (positive
engagement), reliably preventing the electric coil devices 19 from
being pulled or pushed out of the piston main body 35, even at high
pressures.
[0076] In addition, FIG. 3 also shows a mold 40, into which the
subassembly 1 is inserted during assembly, before the solidifying
medium is added in order to ensure a hydraulically leaktight
connection within the divider 2. The mold 40 has a form matched to
the envisaged external shape of the subassembly 1. By means of the
external shape, the piston and, especially, the approach-flow
region of the flow passages 3, 4 can be optimized in terms of flow
engineering, and, in this case, the solidifying medium 10 in the
form of the encapsulating compound, for example, can cover
virtually the entire end-face area of the piston main body 35.
[0077] Additional molds can be used analogously to mold 40, e.g. in
order to configure the opposite area. The flow passages formed by
the piston main body in FIG. 3 and the fastening of the piston rod,
in particular, can also be accomplished by a correspondingly shaped
solidifying medium.
[0078] FIG. 4 shows a piston main body 35 for the subassembly 1
according to FIG. 2 or FIG. 1. Here, the piston main body 35 serves
as a field closing device and carries the magnetic field back again
after passage through the flow passage. The flow passages 3 and 4
are clearly visible here. The flow passages 3 and 4 each have a
shallow cross section 39. Assembly holes 44 are furthermore
provided, being used, for example, for handling with a matching
tool. The inflow and outflow contours of the flow passages 3 and 4
can be embodied in an advantageous way in terms of flow engineering
by rounding the edges, profiling etc.
[0079] An embodiment which is preferred in the case of cost
sensitive applications, in which the ferromagnetic piston main body
35 is dispensed with or can be composed of plastic or a comparable
material, is not shown. In this case, the piston main body can be
produced in the working step in which the coil is encapsulated or
overmolded and the dividing walls are fixed. It is particularly
advantageous to encapsulate or overmold the piston rod in the same
operation.
[0080] With such a structure, the magnetic circuit can be closed by
means of the housing 43. If the dividing walls or flow passages are
situated radially on the very outside of the piston, there is no
plastic or no encapsulating compound in the magnetic circuit.
[0081] It is also possible, in addition to the flow passage 3 (and
4) situated in the magnetic field, to produce at least one flow
passage not situated in the magnetic field, e.g. in the form of a
simple hole, by means of the methods described above (bypass
passage). One possible position would be between the passages 3 and
4 viewed in relation to the end face, as an extension of the
assembly hole 44, giving rise to a bypass passage. By way of
example, this can be accomplished by means of a placeholder 29 in
the form of a simple wire, which is removed after the encapsulation
process. This wire can be between 0.1 mm and 10 mm thick, for
example. The placeholder 29 can also be encased, wherein the outer
circumferential surface bonds to the encapsulating compound, and
the placeholder (wire) can be pulled out. It is thereby possible to
dispense with a release agent for easier removal, and this
facilitates the process. The inner circumferential surface can
preferably be provided with an antifriction layer, thereby
facilitating removal.
[0082] FIG. 5 shows the core of the subassembly 1 from FIG. 2,
illustrated separately and an enlarged scale. The pole caps 24 and
25 are rounded and are here matched to the radius of the piston 30
or to the internal radius of the flow passages 3 and 4. Pole cap 24
adjoins the damping passage 3 and, in particular, the flow path 6
of flow passage 3. Here, pole cap 25 directly adjoins the flow path
6 of flow passage 4. It is also possible for the pole caps 24 and
25 to be coated with a thin layer, for example, with the result
that there is a small spacing between the actual pole caps 24 and
25 and the flow passages 3 and 4 respectively.
[0083] The core 20 can also be produced from a plurality of parts,
wherein these core parts can have different magnetic properties. In
this case, regions of the core can be hard-magnetic and other
regions can be magnetically nonconductive (not ferromagnetic. The
multi-part structure of the core also makes it possible to insert
the core into the coil holder 23 only after the winding of the
coil.
[0084] FIG. 6 shows a dividing wall 11 embodied as a dividing plate
12, which here has latching devices 13 in the form of latching
teeth 14. By means of the latching devices 13 or latching teeth 14,
the dividing wall 11 interlocks with the solidifying medium during
encapsulation, ensuring that the dividing wall 11 is accommodated
in the subassembly 1 reliably and in a defined and spatially fixed
manner.
[0085] At least one film, adhesive tape, layer or coating which
forms the placeholder during the encapsulation process and is then
chemically dissolved, etched away or melted out can be applied to
the dividing plate 12 in the central area and preferably on both
sides. The flow passage is thereby formed. The placeholder can also
be composed of a eutectic metal, which is melted and removed again
after the encapsulation process.
[0086] FIG. 7 shows the core 20, which is surrounded by a coil
holder 23 and on which two dividing plates 12 are additionally
placed. A flow path 6 of the flow passages 3 and 4 can be seen
between each of the pole caps 24 and 25 and the dividing plates 12.
Latching means 34, which are used to receive the dividing walls 11
in a defined manner, are provided on the coil holder 23.
[0087] Transversely to its longitudinal axis 21, the core 20 here
has constrictions 22, thus saving overall volume in the axial
direction of the piston 30. Owing to the constrictions 22, the coil
19 expands less far in the axial direction, thus allowing an
axially shorter subassembly 1.
[0088] Here, the flow passages 3 and 4 have a length 18 in flow
direction 15 which is considerably greater than a height 17 in the
direction of the longitudinal axis 21 of the core 20. Here, the
width 16 of the flow paths 5 and 6 of the flow passages 3 and 4
extends along a curved line and is likewise considerably greater
than the height 17 of the individual flow paths 5 and 6.
[0089] Typical values for the length 18 of the flow passages 3 and
4 are between about 10 and 60 mm. The width 16 is generally between
about 5 mm and 20 mm, and preferred passage heights 17 are between
about 0.2 and 2 mm.
[0090] In this case, a plurality of flow paths can be provided. For
example, five, six, eight, nine or ten flow paths can be associated
with one flow passage. It is also possible for three, four or more
flow passages to be provided. Typically, the wall thickness of the
dividing walls 11 is between 0.1 mm and 1 mm.
[0091] The free flow cross section as the sum of all the flow
passages is dependent on the shape of the passages, the fluid used,
the piston area and the desired force range. Typical flow cross
sections are in a range between about 10 mm.sup.2 and about 200
mm.sup.2. Mean flow velocities of up to 30 m/s or even 60 m/s or
above are possible. Of course, the volume flow depends on the
dimensions and, in some examples, can reach and exceed 100 ml per
second. Indeed, values of 200 ml per second or 300 ml per second
and even more are also possible. The electric coil device 19 can be
composed of different materials. For example, it can be formed from
copper or even from anodized aluminum or the like. It is also
possible for a plurality of coil devices 19 to be provided.
[0092] The dividing plate 12 can also be embodied as a planar
plate, and this, together with a core 20 with planar pole caps 24,
gives a planar flow passage situated therebetween.
[0093] A subassembly 1 without the piston main body 35 is depicted
in perspective view in FIG. 8. The cables 38, which lead to the
electric coil device 19 in the interior, and the dividing plates
12, which divide each of the flow passages 3 and 4 into two flow
paths 5 and 6, respectively, are clearly visible. The latching
means 34 for the axial fixing of the dividing walls 11 or dividing
plates 12 are visible and, in the fully assembled state, rest
against the inside of the piston main body 35. FIG. 8 and also FIG.
9 show the state after encapsulation with the solidifying medium,
although the piston main body 35 has been omitted in the
illustrations for greater clarity in each case.
[0094] The offset 46, which consists of the solidifying medium 10
and, in this case, of the encapsulating compound or of an injected
plastic 10 and fills the undercut 45 in the piston main body 35, is
also clearly visible.
[0095] In FIG. 9, the placeholders 29 in the form of dividing
templates 36 and 37 are still inserted in the subassembly 1. After
curing, the dividing templates 36 and 37 can be removed, leaving
the flow channels 3 and 4 or flow paths 5 and 6 with precisely
defined dimensions. For this purpose, the dividing templates 36 and
37 are pulled out in an axial direction. The dividing templates can
also be part of the mold 40 shown in FIG. 3. The dividing templates
are also pulled out in an axial direction along with or after the
removal of the mold 40.
[0096] The dividing templates 36 and 37, which can thus be reused,
can be brought precisely to the desired dimensions by means of a
grinding operation or the like, for example, allowing highly
accurate subassemblies 1 to be manufactured in a reproducible
manner.
[0097] It is also possible to chemically dissolve or melt the
placeholders 29 or dividing templates 36 and 37, for example. In
that case, new dividing templates 36 and 37 are required for each
subassembly. However, the melted material can be reused directly or
after cleaning or filtering.
[0098] It is also possible to surround the placeholder 29 or
dividing templates 36 and 37 with a movable shell/sleeve, wherein
the outer circumferential surface bonds to the encapsulating
compound and the placeholder 29 can be pulled out. FIG. 10 shows a
stack 28 as a placeholder 29, which serves as an insert in a
subassembly 1. For this purpose, the dividing template 36 or 37 is
first of all laid down, and the dividing wall 11 is then applied
before the second dividing template 37 or 36 is laid down. Together
with the core 20, which is surrounded by the coil holder 23 and the
coil 19, the insert 27 is introduced into the piston main body 35.
Both are introduced into the mold 40 before the cavities are filled
with solidifying medium 10. In order to avoid air inclusions, it is
possible to operate under a vacuum and/or under excess
pressure.
[0099] Instead of the stack 28 described above, consisting of a
dividing wall 11 and respective dividing templates 36 and 37, it is
also possible to install in the same overall volume a stack
consisting of, for example, two thinner dividing walls combined
with three thinner dividing plates. The dimensions and shapes of
the core 20, of the piston main housing 35 and of the coil holder
23 together with the coil 19 do not have to be altered for this
purpose since the solidifying medium compensates for the
differences and fixes all the components as it solidifies. It is
thus possible to produce different flow passage designs (variants)
without major effort.
[0100] A stack can contain any number of dividing walls 11, it
being possible for typical stacks to contain one to ten or twenty
or more dividing walls. For assembly, the number of dividing
walls+a placeholder 29 is generally used.
[0101] FIG. 11 shows a highly schematized cross-sectional
illustration of another subassembly 1 according to the invention,
which comprises a divider 2. The divider 2 has a field closing
device 9, a flow passage 3 in the divider 2, a core 20 and an
electric coil as a field generating device 8. The divider 2 is
filled by means of a solidifying medium 10. Before filling, an
insert 27 has been introduced as a placeholder 29. The placeholder
29 ensures the formation of a spatially defined and reproducible
flow passage 3 in the divider 2. The placeholder can be designed as
a dividing template or can be composed of a material which can be
washed out, melted or dissolved, which is removed again after
solidification or curing. Consequently, the placeholder can be
composed of metal or, alternatively, can be manufactured from wax,
for example.
[0102] To ensure a pressuretight connection (leaktightness . . . )
between the component 7 and the field closing device 9 in the
regions which are not fully encapsulated (e.g. relative to the flow
passage), the core 20 has in these regions at least one recess
which is filled with encapsulating compound or the medium 10 during
the encapsulation process.
[0103] FIG. 12 shows a highly schematized front view of another
subassembly 1, which, as in the example shown in FIG. 11, comprises
a flow passage 3 with just a single flow path. Here, the flow
passage 3 is not subdivided. FIG. 13 shows a cross-sectional
illustration of the subassembly 1 shown in FIG. 12. Once again, the
divider 2 has a field closing device 9, a flow passage 3 in the
divider 2, a core 20 and an electric coil as a field generating
device 8.
[0104] A space must remain free between the magnetic field
generating device 8 and the inner end face of the field closing
device 9. This is achieved by inserting a placeholder 29 made of
wax, for example. After encapsulation, this is removed by melting.
It is also possible to use other materials customary for
encapsulation processes instead of wax. The placeholder 29 can also
be shaped in such a way that it shapes the flow passage in a
corresponding way. The space to be kept free or in a multiplicity
thereof can be at any desired position of the subassembly.
[0105] It is also possible to use other meltable media,
thermoplastics etc. as placeholders 29 in order to enable the
placeholder 29 to be removed again by melting after filling.
[0106] Here, a collecting space 48 is provided at one end of the
divider 2, said space being connected to the adjacent chamber by a
plurality, in this case three, openings 49. It is also possible for
two different placeholders 29 to be inserted, namely, for example,
a dividing template 36 for the formation of the flow passage 3 and
another placeholder to form the collecting space 48.
[0107] The field closing device 9 can be provided at one or both
ends with threads, on which a piston rod, for example, is
secured.
[0108] Through the defined method of working and the defined
dimensions of the dividing walls and of the dividing templates it
is possible to produce highly accurate subassemblies at low cost
and in a simple manner in relatively large numbers. By virtue of
the accurate tolerances, it is also possible to divide a flow
passage into many flow paths, which are divided from one another by
the dividing walls as partitions. Since all the individual parts
are manufactured with high accuracy, the cumulative tolerance is
low. That is very advantageous since considerable loads can act on
the individual flow paths or flow passages if the dimensions of the
individual flow passages or flow paths are different, and these can
lead to bending of dividing walls 11 or dividing plates 12.
[0109] In all cases, the dividing walls can be embodied as bent
partitions in a round piston. The piston rod can be screwed or
adhesively bonded.
[0110] If a large number of dividing walls 11 are stacked as
partitions, the individual tolerances accumulate to give a larger
cumulative tolerance, which can be disadvantageous in the case of
the series-produced part. In that case, the performance of
individual actuators can differ widely. To manufacture the
individual parts with high accuracy, so that the cumulative
tolerance is low, is complex and expensive in series production.
The invention makes available an advantageous subassembly 1 and an
advantageous method for production. It is thus possible to make
available a subassembly with lower overall tolerances with
mass-produced individual parts having, in some circumstances, even
greater tolerances (=cheaper).
[0111] In particular, it is also possible for all components to be
hydraulically leaktight, even in the case of high
pressures/forces.
[0112] The subassembly can respond adaptively through magnetic
field changes, resulting as it were in a change in viscosity of the
liquid. The control of high pressures is a significant advantage of
the partitioned structure (in the case of a small overall volume,
especially of short length).
[0113] The dividing walls 11--also referred to as partitions--are
often embodied so as to be thin and, in preferred embodiments, have
thicknesses 47 between about 0.3 mm and 0.7 mm. It is thereby
possible to save overall volume and overall height. The height 17
of the flow paths 5, 6 is, in particular, between 0.2 mm and 2 mm.
In the case of certain structures, e.g. energy absorbers for
steering systems, a multiplicity and, specifically, fourteen
dividing walls 11 as partitions, for example, can be stacked one on
top of the other. With two such packs, it is possible to make
available a total of 30 passages or more, which are subjected to
pressures of up to 600 bar or high surface loads of 60 N/mm.sup.2
or above resulting therefrom.
[0114] However, if the flow paths 5, 6 each have very different
spacings, this results in a different magnetic field strength when
a magnetic field is applied: the magnetic field in the higher flow
path is lower than in the gap which is not so high or in the lower
flow path. The different magnetic field influences the
magnetorheological fluid differently, and a lower pressure is
established in the higher flow path, and a higher pressure is
established in the lower flow path. This can lead to considerable
transverse loads on the dividing walls 11, which may bend and even
be destroyed.
[0115] However, irrespective of this, even if the magnetic field is
absolutely the same, the height of the gap or of the flow path in
the direction of the field lines is decisive since a lower height
leads to a higher possible counterpressure. Different heights of
different flow paths lead to different counterpressures and, as a
result, to pressure differences.
[0116] The pressure differences between individual dividing walls
11 lead to force differences on the dividing walls 11, which can
lead to deformations of the thin partitions 12. Particularly at
high pressures, such a deformation can cause material overloading
and deficient functioning of the actuator. This can even be to the
extent that two dividing plates 12 touch owing to the deformation,
leading to a magnetic short circuit and hence to an almost complete
pressure drop in one flow passage or in one flow path. Unforeseen
leaks in individual passages (leakage) may cause similar loads or
disadvantages.
[0117] Through uniform approach flow, the invention enables bending
of the dividing plates 12 to be avoided.
[0118] One advantage of encapsulation-induced or adhesive bonding
of the electric coil device 19 to the dividing walls 11 is that the
dividing walls 12 are also fixed during the encapsulation
process.
[0119] The toothing in the lateral outer region of the dividing
walls 11 allows positive engagement in the divider 2. The
constriction of the iron core 20 allows a saving the of overall
volume, this being important for the stroke length and overall
length.
[0120] The undercut 45 in the piston 30 serves for positive
engagement of the assembly comprising the electric coil device 19,
the core 20 and the coil holder with the piston 30. The undercut 45
can also be embodied as a round or angular notch or as toothing.
The undercut also ensures leaktightness.
[0121] Here, bent dividing walls 11 offer better energy efficiency.
Straight dividing walls have advantages in terms of production
costs.
[0122] The coil holder 23 holds the dividing walls 11 in the axial
direction before encapsulation. The dividing walls 11 are held in
the radial direction by means of the dividing templates 36 and 37
before encapsulation.
[0123] During the production process, the parts which cannot be
removed from the mold are first of all cleaned. The parts which can
be removed from the mold are greased or oiled. A special release
agent can also be used.
[0124] The cable 38 is then soldered on or connected to the coil
19. The piston 30 is screwed and/or adhesively bonded to the piston
rod 32.
[0125] A sandwich of the coil 19, dividing templates 36 and 37 and
dividing walls 11 is assembled with the inserted part 27 or stack
28. All tolerances are compensated for by the thickness, especially
the defined thickness, of the dividing walls 11 of the partition
plate.
[0126] The sandwich is pushed into the piston 30. If an
encapsulating compound or a plastic is used as the solidifying
medium, this may be heated up. If a vacuum unit is used, the piston
is positioned in an appropriate manner, the vacuum bell is closed
and the vacuum pump is switched on. Owing to the vacuum, the air is
sucked out of the piston 30, and the solidifying medium 10 flows
into the piston, ensuring that as few air inclusions as possible
occur. Air inclusions can have a bad effect on leaktightness and on
the fixing of the components.
[0127] After curing, release from the mold can take place, with the
dividing templates 36 and 37 being pulled out of the piston. The
dividing templates 36 and 37 can also be part of the mold 40 or can
be connected detachably to the mold and removed jointly during mold
release.
[0128] Finally, the remaining solidifying medium or encapsulating
compound 10 is cleaned off the flow passages 3, 4, if
necessary.
[0129] The latching devices 13 on the dividing walls 11 can be
round, triangular or polygonal, for example. Barbs can be provided.
The teeth can also be bent and turned downward, for example.
[0130] The dividing walls 11 are preferably composed of a
magnetically conductive (ferromagnetic) material. The wall
thickness is preferably constant but can also differ. The thickness
of the dividing wall can also vary (e.g. conically) over the width
16, as seen transversely to the flow direction or in the flow
direction. The dividing walls can also have any other shapes, e.g.
corrugated. It is also possible for two or more dividing walls with
different configurations, shape or material to be arranged one
behind the other. It is also possible to leave a gap between the
dividing walls arranged one behind the other, as seen in the flow
direction, before encapsulation, said gap subsequently being filled
by the solidifying medium. It is also possible to integrate a
sensor, e.g. a magnetic field strength or temperature sensor, into
said gap and then to encapsulate or overmold it.
[0131] In the case of high pressure actuators, high forces may
arise in the flow direction due to the end face and the dissipation
of the shear stresses of the magnetorheological fluid (MRF).
Overlapping encapsulation enables this to be dissipated efficiently
and acts like an extensive adhesive bond.
[0132] The surface of the dividing walls 11 can be smooth, but is
preferably rough or roughened, at least locally. This gives a
better bond with the solidifying medium.
[0133] The core composed of a ferromagnetic material can be
constricted at the end faces and/or laterally, thus allowing more
windings for the same overall volume. It is also possible for the
core to be composed of hard magnetic material, e.g. AlNlCo, or a
permanent magnet can also be integrated into the core in order to
produce a defined magnetic field without a current so as to achieve
a defined basic force.
[0134] Since the dividing templates 36 and 37 as placeholders 29
can preferably be used several times, they can be produced with
high accuracy, e.g. by grinding. In this way, the higher production
costs of the dividing templates are spread over a large number of
components.
[0135] In order virtually to eliminate manufacturing tolerances,
the precision dividing templates are combined with dividing walls
of the correct thickness and then installed.
[0136] The placeholders 29 or 36, 37 can also be manufactured with
an undersize and shaped in such a way that they distribute the
height tolerance as uniformly as possible between all the flow
channels through thickness tolerances of the dividing walls 11. The
inclusions of solidifying medium or of the encapsulating compound
which may occur in the flow passages here are generally very thin
walled and can subsequently be removed.
[0137] The cable 38 is preferably encapsulated in the piston rod 32
at the same time. In addition to cable 38, it is also possible for
further cables, e.g. for temperature sensors etc., to be
encapsulated at the same time. It is then no longer necessary to
seal the piston rod 32. It is also possible to integrate an
anti-twist safeguard for the piston rod. The piston rod can be
shaped in the connection region in such a way that a positive
connection to the piston is obtained through overlaps with the
solidifying medium.
[0138] As an alternative, the cable 38 can also be additionally
sealed (0-rings; special screwed joint etc.). For this purpose,
soldering pins or finished plug-in parts can be molded in or cast
in directly on the coil and/or the piston.
[0139] In order to ensure leaktightness between the inserted part
after overmolding with injected plastic or the encapsulating
compound 10, they can be coated with hot melt adhesive or the like.
It is thereby possible to compensate for stresses which arise
between the various components, especially in the event of
temperature changes.
[0140] The wire used for the electric coils 19 can be provided with
a shrink-on sleeve, which is coated internally, externally or
internally and externally with hot melt adhesive.
[0141] Use is preferably made of the arrangement visible in FIG. 2
having a "horizontal" electric coil device 19, in which the coil
holder 23, the core 20 and the dividing walls 11 are encapsulated.
For this purpose, a corresponding mold 40 and, in particular, a
negative mold, is preferably used. This unit can then be inserted
into the remainder of the magnetic field circuit, e.g. a piston 30
or a valve. After this, a firm and leakedtight connection is
produced, which is stable at least up to certain axial forces. The
connection can be accomplished by adhesive bonding, ultrasonic
welding, hot melt adhesive or a thread.
[0142] It is also possible to produce the connection by means of an
injection process. For this purpose, it is also possible for the
solidifying medium or the encapsulating compound to be injected.
"Encapsulation" is also intended to include injection. Preferably,
overmolding is performed with plastic.
[0143] In one variant, the coil device 19 can be ready-overmolded
and, in this case, preferably forms "partition holders" projecting
slightly outward. Together with the dividing wall 11 (partition),
the coil device 19 is pushed into the piston 30, as a result of
which the partition holders are pressed inward and firmly clamp the
dividing wall 11.
[0144] In another variant, it is possible to use partition holders
which are similar to those above but are part of the coil holder.
The core, the coil holder with the coil device 19 and the dividing
walls 11 are pushed into the piston, during which process the
projecting tabs of the partition holder bend and are pressed
against the dividing wall 11. By this means, the dividing wall 11
is held in position and the flow passage is sealed off from the
coil device 19, simplifying encapsulation.
[0145] Also possible is ultrasonic welding, during which the unit
influencing the flow passage is produced. A dividing wall 11 can be
incorporated or welded in subsequently by means of ultrasonic
welding. In this case, the dividing wall 11 can be encased in the
solidifying medium or in the encapsulating compound at the faces or
radially from the outside inward (in the direction of the core
center).
[0146] An alternative production method envisages encapsulating or
overmolding the core together with the coil holder and coil with
plastic in a mold in such a way that the regions of the flow
passages and dividing walls remain free. This part is secured in
the piston main body in a further work step, together with the
dividing walls.
[0147] As a particularly preferred option, the plastic is injected
with a slight oversize or through a particular mold in the region
of the dividing walls in such a way that the dividing walls are
clamped by the plastic when pressed into the piston main body.
[0148] The mold for the plastic can also have latching hooks and
the like in order to allow simple fixing in the piston main body.
The piston rod or dividing walls can likewise be fastened.
[0149] It is not absolutely necessary that the divider 2 should
influence the entire flow of the magnetorheological fluid along the
resulting flow passage 3, 4. The structure can also have one or
more flow passages which can extend outside and/or inside the
subassembly.
[0150] It is not absolutely essential that a plurality of dividing
plates 12 within one variant should have the same dimensions. They
can also be different.
[0151] It is also possible for a core 20 to be constructed from a
multiplicity of flow passages with dividing plates 12.
[0152] In all the embodiments, at least one dividing wall 11 can
also be made a fixed component part of the field closing device 9
or of the magnetic field generating device 8 by means of at least
one narrow web, without being restricted thereto, if said web is
produced by wire cutting, precision casting or a similar method for
producing fine structures, for example.
[0153] The magnetic field does not always have to be closed via the
field closing device 9, as illustrated in FIG. 2 for example, but
can be closed exclusively via component 43 (cylinder . . . ). For
example, the piston shown in FIG. 8 can run directly in a cylinder,
without a rear collar 46. The magnetic field can also be closed via
the field closing device 9 and component 43 (cylinder . . . ). In
that case, however, the cylinder 43 must have at least partially
ferromagnetic properties.
LIST OF REFERENCE SIGNS
[0154] 1 subassembly [0155] 2 divider [0156] 3 flow passage [0157]
4 flow passage [0158] 5 flow path [0159] 6 flow path [0160] 7
component [0161] 8 magnetic field generating device [0162] 9 field
closing device [0163] 10 solidifying medium [0164] 11 dividing wall
[0165] 12 dividing plate [0166] 13 latching device [0167] 14
latching tooth [0168] 15 flow direction [0169] 16 width [0170] 17
height [0171] 18 length [0172] 19 electric coil device [0173] 20
core [0174] 21 longitudinal axis [0175] 22 constriction [0176] 23
coil holder [0177] 24 pole cap [0178] 25 pole cap [0179] 26 axis
[0180] 27 insert [0181] 28 stack [0182] 29 placeholder [0183] 30
piston [0184] 31 piston guide [0185] 32 piston rod [0186] 33
longitudinal axis [0187] 34 latching means [0188] 35 piston main
body [0189] 36 dividing template [0190] 37 dividing template [0191]
38 cable [0192] 39 shallow cross section [0193] 40 mold [0194] 41
dividing piston [0195] 42 compensating space [0196] 43 housing
[0197] 44 assembly hole, bypass passage [0198] 45 undercut, groove
[0199] 46 offset [0200] 47 thickness [0201] 48 collecting space
[0202] 49 opening [0203] 50 damper [0204] 51 seal
* * * * *