Note: Descriptions are shown in the official language in which they were submitted.
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ELECTROMAGNETICALLS~ OPERATED VALVE
The invention relates to electromagnetically operated valves which have an annular
magnetic coil sur~ounding a reciprocatible plunger of metallic material. More particularly,
. the invention is directed to electromagnetic valves which include a valve seat and sealing
~ body of elastomeric material for the closing of the valve seat, whereby the sealing body is
,. 5 mounted to that end of the plunger which is opposite the valve seat.
Such an electromagnetic valve is known frorn German Patent Application
P 43 09 739.1. However, the plunger in that valve which is made of metal has
elastomeric material sprayed thereonto which forms the sealing body. The achievement of
a reliable connection between the elastomer and the metallic material of the plunger is of
large importance for the operation of the valve. Detachrnent of the sealing body from the
plunger during the intended use of the valve must be prevented to ensure that constant
opening characteristics are m~in~ined over a long service period. To this end, an
adhesion promoter or bincler is generally applied to the elastomeric and metallic materials,
which provides for a secure connection of the two palrts.
. 15 It is now an object of this invention to provide a further improved valve of the
i:. above general construction which is more easily and cost efficiently manufactured.
'............. This object is achieved in accordance with the invention with a valve wherein the
' plunger and the sealing body are form-fittingly interconnected. It is an advantage of such
-. a construction that movement of the sealing body relative to and in axial direction of the
plunger, or det~rhment of the elastomer from the metallic material of the plunger, is
~ubsl~llially ~l~v~l-L~d. Tlhe form-fitting connection between the two parts obviates the
use of an adhesion promoter, which results in a simpler and more cost effilcientm~m-f~rtllre of the valve. Thus, the costs for the adhesion promoter or binder material
and for its application are saved with valves of such a construction. -~In a preferred embodiment, the plunger includes a circumferential, groove-shapedundercut recess at the end adjacent the valve seat and the sealing body extends into that
recess. A secure and reliable fastening of the sealing body to the plunger over the whole
service period is thereby guaranteed. The undercut recess is located immediately adjacent,
' in axial direction, to the contact surface between the sealing body and the valve seat so
that an exact, permanent fixation of the sealing body relative to the plunger is guaranteed
and changes in the opening cross section of the valve due to axial displacement of the
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sealing body relative to the valve seat are prevente:l. The sealing body and/or the recess
.. are preferably constructed in such a way that the two parts can be snapped together.
In another preferred embodiment, the plunger is provided with a through-going
passage which extends in the direction of movement of the plunger and is completely
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. 5 fillled with the elastomeric material of the sealing body. The elastomeric material extends
beyond that end of the passage which is remote from the valve seat, whereby the
elastomeric material provides a stopper on that end of the plunger which is directed away
from the sealing body. The stopper dampens the impact of the plunger when it reaches
,j the completely open position. This prevents knocking noises. The elastomeric material of
lû the sealing body and the stopper is preferably injected in a single process step into one end
.' of the through-going passage.
The elastomeric material is preferably form-fittingly connected with the wall of the
i~ through-going passage. Displacement of the elastomeric material of the sealing body
': relative to the metallic material of the plunger and/or detachment of the two parts from
~; 15 each other can thereby be substantially prevented. Another significant advantage of a
valve in accordance with the present invention is its economical manu~acture, since the use
of an adhesion promoter or binder and the application thereof during the manufacture of
the armature are no longer required. The reliable interconnection between the elastomeric
material of the sealing body and the metallic material of the plunger provides for constant
and good operating characteristics of the valve over a long service period. ..
. In the region of the through-going passage, the pl-mger is preferably provided with
recesses which have a depth of 0.5 to 3 mm. The recesses within the metallic material of
the plunger provide for a mechanical interlocking with the elastomeric material of the
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: sealing body which fills the through-going passage. The recesses can be produced by
machining on a lathe. In one particularly preferred embodiment, the through-going
passage of the plunger is provided with a thread. The manufacture of such recesses is
easily achievable. The elastomeric material injected into the through-going passage
completely fills the recesses and is form--fittingly interlocked therewith.
' In a further preferred embodiment, the through-going passage is conically widened
behind the sealing body. The wall of the through-going passage preferably encloses an
angle of 2 to 45D and more preferably 5 to 30~ with a longitll~in~l axis of the plunger.
: The positioning of the sealing body and its attachment to the metallic material of the
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plunger is even further improved if the plunger is provided in addition to the groove-
~, shaped undercut recess in the region of the sealing body with the conically widened
through-going passage. Even a vacuum at the valve seat can then no longer lead to
. detachment of the elastomeric sealing body -frs)m the metallic plunger.
The through-going passage preferably has a stepwise reduced cross-section in the. direction towards the sealing body. The transition regions between portions of di~ferent
cross sections can be conically shaped or rounded to Inilli",i,~ scoring of the elastomeric
, material which completely fills the through-going passage. The form f1tting connection
between the elastomeric material of the sealing body and the metallic material of the
, 10 plunger is also ensured with this construction. :
5~ The elastomeric material of the sealing body preferably has a shore A hardness of
F 40 to 100. This is advantageous, since such a material exhibits only minor relaxation
'; during the whole service period and, thus, is relatively rigidly fixed to the metallic
~, material of the plunger, which provides good sealing results in the closed condition of the
1 5 valve.
. Three preferred embodiments of an electromagnetically actuated valve in
~:~ accordance with the invention are discussed in more detail below with reference to the
,: attached drawings, wherein
.. ,' Figure 1 is a cross-sec-tion through a first preferred embodiment in accordance with
' 20 the invention wherein a thread is provided in the wall defining the through-going passage
~ of the plunger;
;, Figure 2 is a cross section through a second preferred embodiment in accordance
' with the invention wherein, contrary to the embodiment shown in Figure 1, the through-
going passage is of conical shape; and
. 25 Figure 3 is a cross section through a third preferred embodiment in accordance
with the invention wherein the through-going passage of the plunger has a stepwise
decreasing cross-section.
Figures 1, 2 and 3 respectively illustrate a portion of an electromagnetically
actuated valve 20 which is enclosed in a housing 1. The valve includes a valve opening
- 30 4.1 surrounded by a valve seat 4 and a sealing body 6 engageable with the valve seat for
the closing of the valve 20, and an annular magnetic coil 2, which is connectable to an
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electric power source (not shown) by an electric connector 12. The magnetic coil 2
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surrounds a plunger 3 which has first and second ends 107 1 I respectively remote from
and adjacent to the sealing body 6. The plunger 3 is reciprocatible in axial direction of
. . the coil between an open and closed positions (open position illustrated) and at the first
end 10 is supportecl on a mount 14 by a helical colllp.~ion spring 13. At the second end
.. 5 I l, the plunger 3 is connected with the sealing body 6 which is selectively engageable
,~ with the valve seat 4. The mount 14 in this embodiment consists of two parts, namely a
sleeve 15 which is rigidly connected with the housing I and a bolt 16 which is rotatably
received in the sleeve and functions as a set screw. The plunger 3 has a through-going
.- passage 9 which extends in longitudinal direction of the plunger. The through-going
. 10 passage 9 is completely filled with elastomeric material which also forms the sealing body
6 at the end adjacent the helical compression spring 13 is provided with an elastomeric
, material 9.1 which completely fills the through-going passage 9. At the first end 10 of the
plunger 3, the helical comples~ion spring 13 is received in a central recess 21 in the
elastomeric material. Opposite the mount 15 and raclially spaced from the spring receiving
l5 recess, the elastomeric material is formed into stoppers 17 which function as end position
buffers for the plunger 3. The through-going passage 9 of the plunger 3 is in all three -.
embodiments completely filled with the elastomeric material.
Figure 1 shows a first embodiment of the plunger 3, wherein the wall of the
: through-going passage 9 extending through the metallic material of the plunger 3 is
: 20 cylindrical and provided with a thread (not illuskatecl). The thread can be a single or
' multiple thread. The depth of the thread is 2.5 mm in this embodiment. At the second
end 11 close to the valve seat 4, the plunger 3 is provided with an undercut groove 7 into
.. which the sealing body 6 is snapped. The elastomeric material which fills the through-
. going passage 9 and of which the sealing body 6 is made, is thereby relatively rigidly
'~ 25 retained within and about the plunger 3 in the direction of movement 8 of the plunger.
. , Figure 2 shows a second preferred embodiment of the plunger 3, which difi~ers
.' -from the above described embodiment in the shape of the through-going p~ssage 9.
Starting *om the sealing body 6, which in this embodiment is also snapped into the
groove 7, the diameter of the through-going passage 9 increases continuously towards of
30 the helical spring 13 so that the passage has a conical cross section. The angle enclosed
.' by the wall of the through-going passage 9 and the axis of the plunger 3 is 5~ in this
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"~ embodiment. The larger the pretensioning forces of the helical spring 13 the larger this
v angle should be.
~i Figure 3 shows a third preferred embodiment of the plunger 3, wherein starting
from the sealing body 6, the cross-scction of the through-go;ng passage 9 increases
stepwise in direction of the helical spring 13. At the transition between portions of
different cross section, the wall of the through-going passage 9 is conical or rounded in ~ ;
j~ order to minimi7f~ scoring of the elastomeric material. The fastening of the sealing body 6
in the groove 7 is the same as described in relation to the embodiments of Figures 1 and
' 2.
In the embodiments of Figures I to 3, the plunger and the sealing body are form-fittingly connected and the elastomeric material is -form-fittingly held in the through-going
;- passage 9. This construction obviates an adhesive attachment of the elastic and metal
parts, which is of significant advantage both with respect to manufacture and cost.
Changes and modifications in the specifically described embodiments can be carried
lS out without departing from the scope of the invention which is intended to be limited only
by the scope of the appended claims.
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