Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
The present invention is directed to a US transducer,
particularly for air and gas flow measurement, and is also directed
to a method for the manufacture thereof.
Methods for the manufacture of such US transducers that have
been hitherto disclosed are cost-intensive and time-consuming in
view of the number of manufacturing steps and/or the expense of
manufacturing equipment.
In view of the constantly increasing need for cost-
beneficial US transducers, there is the desire to create a method
for the manufacture of such US transducers which makes fewer
demands both of the time expenditure as well as of the apparatus
expense for the manufacturing process, and thus offers the
possibility of manufacturing cost-beneficial US transducers.
~UMMARY OF T~E INVENTION
An object of the invention is to specify a method for
manufacturing a US transducer for sound emission and for sound
reception, for example for air and gas flow measurement, with which
US transducers of the type initially cited can be reliably
manufactured with low time expenditure and/or apparatus expense.
For achieving this object, a method for manufacturing a US
transducer for air and gas flow measurement is proposed which is
inventively characterized in that steps are provided for casting
a transducer core composed of a castable damping material in a core
mold or shape. The transducer core is composed of a piezoceramic
wafer which has its thickness partially exposed at one side of a
damping member and is composed of the dampingl member. The
piezoceramic wafer is partially connected with leads which can be
conducted toward the outside. The transducer core is enveloped
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with a castable adapter material in a bipartite f~rm for the
formation of an adapter and assembly member.
BRIEF DESCRIPTION OF TNE_DRAWING~
Figures lA, lB, and lC schematically show the steps required
for the manufacture of a transducer core;
Figure 2 shows a schematic sectional view from which a step
for enveloping the transducer core manufactured according to Figure
1 with a castable adapter material A in a bipartite mold proceeds;
Figure 3 shows a schematic illustration of a procedure for
enveloping the transducer core manufactured according to Figure 1
with an evaluatable adapter material according to a second
exemplary embodiment;
Figure 4 shows a schematic sectional view of a transducer
core having a pot of adapter material surrounding it, whereby anti-
twist terminal pins are provided which are conducted radially out
of the transducer core from a piezoceramic wafer;
Figure 5 shows a schematic sectional view of a transducer
core which is provided with a pot of adapter material, whereby
connector plugs for the piezoceramic wafer of the transducer which
are aligned parallel to the rotational axis of the structure are
provided in the transducer core;
Figure 6 shows a schematic sectional view with a
corresponding bottom view of an exemplary embodiment of a
transducer core having a channel for the anti-twist protection
thereof;
Figure 7 shows a further exemplary embodiment of the
transducer core manufactured in accordance with Ithe invention,
whereby a rubber ring for holding the transducer core is introduced
into a channel;
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Figure 8 shows another exemplary embodiment of an
inventively manufactured transducer core, whereby a bead 10 for
decoupling structure-borne noise having an edge enlargement 11 for
holding the damping member connected thereto is designed at a
collar of the damping member; and
Figure 9 schematically shows the various manufacturing steps
of the invention for manufacturing a US transducer and sho~s a
schematic, sectional view of the overall structure of a US
transducer manufactured with these steps which can be utilized as
a gas counter.
DE8CRIPTION OF THE PREFERRED EMBODIMEN~8
As already stated, Figure 1 schematically shows the steps
required for the inventive manufacture of a transducer core. For
casting a transducer core, the piezoceramic wafer 1 provided with
leads (not shown) that can be conducted toward the outside is
placed into a core mold Fl for the formation of the transducer core
1/2. This core mold Fl has a recess F11 intended for the
acceptance of the piezoceramic wafer 1. Damping material D is
subsequently cast into the core mold F1. The core mold F1 is
designed such that the damping member 2 is designed with a collar
2a at its side facing away from the piezoceramic wafer 1~ The
finished transducer core 1/2 removed from the core mold F1 has its
collar 2a introduced into a recess F2a of a first shaped part F2
of a mold F2/F3 for the formation of an adapter and assembly member
3, see Figure 2. A second shaped part F3 of the mold F2/F3 is
introduced into the first shaped part F2 for forming an adapter and
assembly member 3 such that the collar 2a of the ~ransducer core
1/2 is at least partially enclosed by, first, the first shaped part
F2 and, second, by the second shaped part F3. Subsequently, an
adapter material A is injected into the mold F2/F3 formed by the
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first shaped part F2 and by the second shaped part F3 for the
formation of the adapter and assembly member 3. This is undertaken
in order to design the adapter and assembly member 3 so that it
completely surrounds the transducer core 1/2, except for an exposed
part of the collar 2a.
A further, preferred method conforming to an exemplary
embodiment of the invention provides that the piezoceramic wafer
1 provided with leads (not shown) that can be conducted toward the
outside is placed into the core mold F1 for the formation of the
transducer core 1/2, this core mold Fl comprising a recess F11
intended for the acceptance of the piezoceramic wafer 1.
Subsequently, damping material D is cast into the core mold Fl.
The core mold F1 is designed such that the damping member 2 has a
collar 2a at its side facing away from the piezoceramic wafer 1.
The finished transducer core 1/2 removed from the core mold F1 has
its collar 2a introduced into a recess F2a of a first shaped part
F2 of a mold F2/F3 for the formation of the adapter and assembly
member 3. For the formation of the adapter and assembly member 3,
a second shaped part F3 of the mold F2/F3 having an upwardly
directed opening F3a which accepts the transducer core is partially
filled with adapter material. Subsequently, the first shaped part
F2 together with the transducer core 1/2 directed down toward the
opening F3a of the second shaped part F3 is pressed into the
opening F3a of the second shaped part F3 until the two shaped parts
F2/F3 enter into engagement with one another. Thus, the adapter
material contained in the second shaped part F3 is displaced and
ascends around the entering transducer core 1/2 to form the adapter
and assembly member 3 (see Figure 3).
The aforementioned leads la, lb are preferably connected by
soft soldering to terminal pins 5a, 5b. These terminal pins 5a,
5b are enclosed in the damping member 3 such that they preferably
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radially project toward the outside from the collar 2a in an anti-
twist fashion (see Figure ~).
According to another embodiment of the invention, the leads
la, lb, which are preferably connected by soft soldering to
terminal plug pins 6a, 6b are held at a connector plug socket 6
where they can be connected to. The connector plug socket is
enclosed in the damping member 2 when the damping member 2 is cast
such that the terminal plug pins 6a, 6b are aligned parallel to the
rotational axis of the transducer core 1/2 and are integrated in
the damping member 2 projecting from the side thereof facing away
from the piezoceramic wafer 1. The collar 2 is preferably designed
with a channel 7 for anti-twist protection (see Figures 5 and 6).
According to another embodiment of the invention, a step can
be provided for designing the adapter and assembly member 3 with
an annular channel 8 for the acceptance of a rubber ring 9 for
holding the adapter and assembly member 3 ~Figure 7).
The adapter and assembly member 3 can be designed as a
hollow cylinder closed at its ends; however, it can also be
expedient for assembly reasons that the end closing the hollow
cylinder is designed in the shape of a truncated cone.
It can be advantageously provided according to another
embodiment of the invention that the collar 2a is designed with a
ridge 10 for decoupling structure-borne noise and i8 provided with
an edge enlargement 11 for holding the damping member 2.
Although various minor changes and modifications might be
proposed by those skilled in the art, it will be understood that
we wish to include within the claims of the patent warranted hereon
all such changes and modifications as reasonably come within our
contribution to the art.
