Note: Descriptions are shown in the official language in which they were submitted.
n
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Coaxial Connector
The invention relates to a coaxial connector
adapted to be mounted at a printed circuit board, having one
or several double coaxial contacts which on one side
comprise a plug-in connecting end and on the other side,
towards the printed circuit board, a connecting end, the
coaxial contact being comprised of an electrically
conductive outer jacket and a signal contact being formed in
one part and being isolated with respect to the outer jacket
by means of a dielectric.
Coaxial connectors adapted to be soldered to a
printed circuit board are known from the brochure "har-pak,
High Density Connector System, 26 6, MO/16.10.98/6.0" of
Harting, which however are not suitable for the SMT
technique. These coaxial connectors are provided with
press-in contacts, and the mechanical attachement on the
printed circuit board is achieved by means of press-in pins.
Coaxial connectors adapted to be mounted at a
printed circuit board and suitable for the SMT technique are
known from the Siemens company brochure "A connection which
has a plurality of advantages, Siemax - the first mufti coax
plug connector: 12/98".
It is there provided that the complete coaxial
connector is positioned on the printed circuit board for
reflow soldering. In order to ensure that the reflow
soldering technique can be used and in order to allow an
inspection of the soldered points, the signal connector must
not be completely shielded. This, however, limits the
transmission characteristics.
As the connector protrudes over the printed
circuit board edge and the regular limit which is set by the
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measurements of the printed circuit board is exceeded,
additional steps are required during soldering.
The problem with connectors with SMT terminals and
adapted to be mounted at the edge of printed circuit boards
is that the pressing and traction forces of the
complementary connector must under no circumstances act on
the soldering pads as these, due to their low holding
strength, would be torn from the printed circuit board.
Rather, measures are to be taken for a strong mechanical
attachment of the edge connector to the printed circuit
board.
The object of the invention is to improve a
coaxial connector of the type mentioned above so that at
least the signal contacts are provided with SMT terminals
and that an automatic standard mounting process can be used
without requiring special measures with respect to an edge
connector for a printed circuit board. Further, a reliable
and endurable contact is to be achieved, even in cases of
different expansion coefficients, during a temperature rise,
and the coaxial connector is nevertheless to be mechanically
fixed to the printed circuit board in. Furthermore, the
signal contacts axe to be completely shielded for higher
transmission speeds.
This object is achieved by forming the connecting
end of a signal contact in a plug-like manner and by
inserting the connecting end into a contact sleeve which is
held at a printed circuit board and is electrically
connected thereto, the signal contact being connected in an
electrically conductive manner in the printed circuit board.
In a broad aspect of the invention, there is
provided a coaxial connector adapted to be mounted at a
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printed circuit board, having one or several double coaxial
contacts, which at one side have a plug-in connecting end
and at the other side, towards the printed circuit board,
have a connecting end, the coaxial contact being comprised
of an electrically conductive outer jacket and a signal
contact formed in a single part and being isolated with
respect to the outer jacket by means of a dielectric,
characterized in that the connecting end of the signal
contact is formed in the form of a plug and in that the
contact end is inserted into a contact sleeve held at the
printed circuit board and being electrically connected
thereto so that the signal contact is connected to the
printed circuit board in an electrically conductive manner.
The advantages achieved with the invention are in
particular that the coaxial connector, due to the good
shielding effect, reliably transmits even signals with
higher frequency. The improved shielding is achieved by
having the shield of the entire coaxial connector reach all
the way down to the printed circuit board in a closed
manner.
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Further, the coaxial connector formed as edge connector for a printed circuit
board
can be mounted at the printed circuit board and subsequently soldered thereto
in a
reflow technique in a fully automatic manner without special measures of
precaution,
with the visual inspection of the soldering points being highly simplified as
the
soldering points at the printed circuit board are directly accessible. An
improved
mounting of the coaxial connector is the result of a division of the coaxial
connector
into a contact carrier housing having the double coaxial contacts, and a
carrier frame
having contact sleeves by means of which the signal contacts to be soldered
are
fixed to the printed circuit board. A significant advantage of this invention
is that a
reliable and endurable contact is achieved even in case of different material
expansion of the coaxial connector and the printed circuit board during
operation as
the contact end of the signal contact formed as spherical heads in cooperation
with
correspondingly formed contact sleeves allow a compensation. Further, a good
mechanical strength is ensured since the signal contacts and the contact
carrier
housing are fixed at the printed circuit board independent of each other.
An embodiment of the invention is shown in the drawing and explained in detail
below. fn the drawings,
Fig. 1 shows a coaxial connector mounted at a printed circuit board,
Fig. 2 shows a coaxial connector which has not yet been mounted at a printed
circuit
board provided with a carrier frame,
Fig. 3 shows an exploded view of a printed circuit board, a carrier frame and
a
contact carrier housing having double coaxial contacts,
Fig. 4 shows an enlarged view of the carrier frame,
Fig. 5 shows a cross-section through an angled coaxial connector,
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Fig. 6 shows an enlarged view of a signal contact end in a contact sleeve,
Fig. 7 shows an enlarged view of an obliquely oriented signal contact end in a
contact sleeve,
Fig. 8 shows an enlarged perspective view of a double coaxial contact,
Fig. 9 shows a plurality of terminal embodiments of the contact sleeves,
Fig. 10 shows a straight coaxial connector in a sectional view, and
Fig. 11 shows an exploded perspective view of a straight coaxial contact.
A coaxial connector 1 shown in Fig. 1 in a perspective view is formed as a so-
called
edge connector for a printed circuit board and comprises a plurality of double
coaxial
contacts 3 arranged in a contact carrier housing 2 and mounted together with a
sandwiched carrier frame 4 at a printed circuit board 5.
In Fig. 2 is shown the carrier frame 4 which is already mounted at the printed
circuit
board 5 and on which the contact carrier housing 2 with the double coaxial
contacts
3 is to be mounted in a further step.
Fig. 3 shows in an exploded view the components printed circuit board 5,
carrier
frame 4 and coaxial connector 1 having the contact carrier housing 2 and the
double
coaxial contacts 3 mounted therein. On the printed circuit board 5, the plug-
in
configuration required for mounting the coaxial connector and having solder
pads 6
and bores 7, 8, 9 can be seen.
During mounting the coaxial connector, first the carrier frame 4 with
positioning
sockets 11 and 11' is positioned in bores 9 and 9' on the printed circuit
board 5
which positively results in the contact sleeves 14 held in reception sockets
15 at
interconnection webs 16 of the carrier frame 4 being placed on soldering pads
6.
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In this mounting condition, the carrier frame 4 together
with the contact sleeves 14 held in reception sockets 15 is
connected to the printed circuit board 5 in a reflow
soldering bath.
5 The contact carrier housing 2 having the double
coaxial contacts 3 inserted therein is mounted subsequent to
the soldering process.
During mounting, the contact carrier housing 2 is
pressed in a single step with the press-in pins 10 into
bores 8 and 8' of the printed circuit board while additional
holding pins 12 and 12' are inserted into opening 13 of
positioning sockets 11 and 11' of the carrier frame 4.
Furthermore, outer contact terminals 24 provided at the
bottom region 26 of the double coaxial contacts 3 are
pressed into bores 7 assigned thereto and arranged in the
printed circuit board 5 in order to transmit the shielding
effect of an outer jacket formed by an outer contact socket
28 and an outer contact body 29 to the ground potential of
the printed circuit board 5. The positioning sockets 11
and 11' may be slit at their plug-in side.
Fig. 4 shows an enlarged view the carrier frame 4
with the comb-like interconnecting webs 16 at which the
contact sleeves 14 shown in detail in Fig. 9 are
accommodated in corresponding reception sockets 15.
Furthermore, the positioning sockets 11 provided
for positioning at the printed circuit board 5 are formed
with openings 13, the lower region of the positioning
sockets being slotted in the longitudinal direction and a
transverse direction, respectively, so as to compensate for
possible position variations between the carrier frame and
the printed circuit board.
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Forming the interconnection webs in this comb-like
manner provides the advantage that the free spaces 17 and 23
achieved thereby can be used for a ground shield between the
individual contacts on the printed circuit board.
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The entire structure of an angled coaxial connector 1 mounted at a printed
circuit
board 5 is shown in Fig. 5 in a sectional view. A double coaxial contact 3
with two
signal contacts 21 is provided in the contact carrier housing 2, the signal
contacts
each being electrically isolated from the outer jacket and embedded in a
dielectric
25.
The outer jacket is formed by the outer contact body 29 and the outer contact
sockets 28 which are connected in an electrically conductive manner. The
spherical
ends 19 of the two signal contacts 21 are inserted into the contact sleeves 14
and
are conductively connected to the printed circuit board 5 through the solder
pads 6,
the contact sleeves 14 being held in the reception sockets 15 of the carrier
frame 4
on the printed circuit board 5.
A free space 20 is provided below the reception sockets 15 for the solder
flowing
when heated.
The shielding as a whole comprises the contact carrier housing 2, the outer
contact
sockets 28, the outer contact body 29 and a shielding block 22 arranged
between
the two signal contacts 19, and extends into the bottom region 26 down to the
surface of the printed circuit board 5, the transmission being made through
the outer
contact terminals 24 to conducting tracks of the printed circuit board.
Fig. 6 shows in a strongly enlarged sectional view the manner in which the
contact
end of a signal contact 21, formed as spherical head 19, is inserted into the
recess
18 of a contact sleeve 14. Any misalignment which possibly occurs, as shown in
Fig.
7, is largely compensated by means of the spherical configuration of the
signal
contact so as to prevent that a torque or shearing forces are transmitted from
the
signal contacts 21 to the contact sleeves 14.
Fig. 8 shows in an enlarged perspective view the individual double coaxial
contacts
3 as viewed from the contact terminals. The signal contacts 21 are arranged in
the
interior of the outer contact body 29 formed as a shielded housing and of the
outer
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contact sockets 28 attached thereto in an electrically conductive manner, the
signal
contacts 21 protruding with their spherical ends 19 into the bottom region 26.
The
mechanical attachment of the double coaxial contacts is achieved by means of
the
outer contact terminals 24 which are pressed into corresponding bores 7 at the
printed circuit board 5. In order to achieve that the coaxial contact 3 is
placed closely
to the printed circuit board and to thereby achieve a good shielding, recesses
27 are
provided at the longer of the side walls of the outer contact body 29, into
which the
interconnection webs 16 of the carrier frame 4 may be inserted during the
final
mounting.
Fig. 9 shows contact sleeves 14, 14.1, 14.2, 14.3 with outer contours formed
in
different manners, which are provided for insertion of the signal contacts 21,
in
particular of the spherical head ends 19. The contact sleeves 14 are typically
held in
the reception sockets 15 of the carrier frame 4.
According to an alternative, the carrier frame 4 together with the reception
sockets
15 can be removed from the printed circuit board after the soldering process
so that
the contact sleeves 14 remain on the printed circuit board.
Fig. 10 shows a modified coaxial connector 1' which is, with respect to the
signal
contacts 21', not formed in an angled version, but in a straight version.
Fig. 11 shows in an exploded perspective view the inner, signal transmitting
components which regarding their construction correspond to the embodiment
described above.
Reference numerals used in Figs. 10 and 11 correspond to those used for the
angled coaxial connector, but are provided with a prime for differentiation.
