Apparatus for feeding fuel from a supply tank to an internal combustion engine

An assembly for feeding fuel from a supply tank to an internal combustion engine, having a feed pump which is driven by an electric drive motor and is accommodated with the drive motor in a common housing. The housing is enclosed by means of a connection cap, which has a connection piece to a feed line and in which furthermore two plug connections connected to the drive motor are disposed. According to the invention, these plug connections comprise combined flat plugs with a round plug receptacle, and in them a flat plug protruding axially out of the outer face end of the connection cap has a round plug receptacle on its end protruding into the connection cap, and the combined flat plug and round plug receptacle is formed from a one-piece shaped sheet-metal part. This combined plug connection in a simple way enables both a direct electrical connection of the feed assembly and mounting of an additional electrical component, preferably an additional radio interference suppression unit, via a round plug connection.

BACKGROUND OF THE INVENTION 
The invention is directed to improvements in a feed assembly for an 
internal combustion engine. In a feed assembly of this kind, known from 
German Utility Model 91 04 728, a feed pump driven by an electric drive 
motor and disposed with it in a common housing feeds fuel from a supply 
tank to an internal combustion engine via a pressure line. The common 
housing, through which the fuel flows, is closed off by a connection cap, 
which on its outside has a connection piece for connection with the 
pressure line and two electrical plug connections embodied as flat plugs 
and connected to the drive motor. It is also known that electric drive 
motors, especially DC motors, have to be provided with radio interference 
suppression because of the brush firing occurring at the collector 
brushes; these radio interference suppression units, typically formed as 
capacitors and chokes, can be integrated into the connection cap, for 
instance. The known feed assemblies have the disadvantage, however, that 
these radio interference suppression units are not flexible or adaptable 
to prevailing conditions after installation of the feed, and the result is 
poorly adapted radio interference suppression units or major expense for 
installation and manufacture. 
OBJECT AND SUMMARY OF THE INVENTION 
It is a principal object of the invention to provide a feed assembly having 
the advantage over the prior art that by means of a combined flat and 
round plug connection on the connection cap with both a flat plug and a 
round plug receptacle, it is possible to mount the electrical connection 
for the electric drive directly on the connection cap, or if necessary to 
mount an additional electrical unit to the connection cap as well, 
preferably a radio interference suppression unit, by means of round plugs. 
It thus becomes possible to use a standardized connection cap for at least 
two feed assembly versions, or in other words with or without the 
additional radio interference suppression unit, which because of the 
number of common parts lowers the production cost. 
It is a further object of the invention to make possible without major 
installation effort or expense and without additional adaptors the 
installation of one additional radio interference suppression unit after 
installation of the feed assembly, so that the radio interference 
suppression of the feed assembly can be adapted better overall to 
prevailing requirements. 
It is another object, and especially desirable from a production standpoint 
to manufacture the combined flat and round plug connection element as a 
one-piece shaped sheet-metal part, which element can be inserted with its 
round plug receptacle, embodied as a slit sleeve, into a receiving bore of 
the connection cap and can then be extrusion coated with plastic in the 
connection cap by means of a U-shaped profile that receives the cable to 
the drive motor, and which with its flat profile protruding axially from 
the outside of the connection cap forms a flat plug in a known manner. 
It is still another object of the invention to provide an extrusion coating 
of the U-shaped part of the shaped sheet-metal part in the connection cap 
with plastic, which makes it possible not only to attain good sealing of 
the feed assembly but also to attain the requisite play, for the sake of a 
certain elasticity of the slit sleeve, between the sleeve and the 
receiving bore. 
Yet another object of the invention is attained by the simultaneous use of 
a round prong, disposed in the additional, mounted radio interference 
suppression unit, as a choke core and round plug, since in this way one 
additional component can be dispensed with, and this round prong and the 
choke slipped onto it are extrusion-coated with plastic. 
The invention will be better understood and further objects and advantages 
thereof will become more apparent from the ensuing detailed description of 
a preferred embodiment taken in conjunction with the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows a simplified view of an apparatus shown in FIG. 1 for feeding 
fuel from a supply tank 1 to an internal combustion engine 3 of a motor 
vehicle, not shown in detail, having a feed assembly 5 disposed in the 
supply tank 1 and communicating with the engine by means of a hydraulic 
connection piece 5 and a feed line 9 connected to that. 
The feed assembly 5, shown on a larger scale in FIG. 2, also has an 
electric drive motor 11, which drives a feed pump 13 to rotate; the feed 
pump may comprise a flow or positive displacement pump, and the feed pump 
13 and drive motor 11 are accommodated in a common housing 15, which is 
tightly enclosed by a connection cap 17 on its face end remote from the 
feed pump 13. 
The hydraulic connection piece 7, by way of which the feed line 9 is 
flanged to the feed assembly 5, is disposed in this connection cap 17, 
shown on a larger scale in FIG. 3. In addition, the connection cap 17 has 
two receiving bores 19, into each of which one combined flat round plug 
connection 21 is inserted, each of said plug connections include a slit 
sleeve 31 and a U-profile section the inside of the connection cap 17 
which is connected electrically to the drive motor 11; its connection 
cable is soldered into the flat plug with the round plug receptacle 21 in 
such a way that the connection cap 17 is tight. The combined flat and 
round plug receptacle 21 is embodied as a one-piece shaped sheet-metal 
part, which is shown in further detail in three views in FIGS. 4-6 and 
will now be described. 
The shaped sheet-metal part has three regions, of which a first region 25, 
beginning at a first face end 23, has a flat smooth profile forming the 
flat plug, and a through bore 27 for securing electrical connections is 
made in this region. On its end remote from the face end, the flat plug 25 
also has a pair of oppositely disposed, outward-protruding ribs 29, which 
ribs form a stop when the shaped sheet-metal part is inserted into the 
receiving bores 19. On the side of the rib 29 remote from the flat plug 
25, a second region 31 of the shaped sheet-metal part adjoins it in an 
axial extension; this region is embodied as an elongated slit sleeve, and 
the transition between the first region 25 and the second region 31 is 
rounded in order to prevent cracking at the level of the rib 29. 
The end of the slit sleeve 31 remote from the flat plug 25 is adjoined in 
an axial extension by a third region 33 of the shaped sheet-metal part, 
which is embodied as a U-profile section with rounded edge transitions; 
the transition between the slit sleeve 31 and the U-shaped profile 33 is 
likewise made via a radius-like recess 35, to avoid surges in tension that 
cause cracking. To ease production of the shaped sheet-metal part forming 
the combined flat and round plug receptacle 21, this part is made in one 
piece; the slit sleeve 31 and the U-shaped profile 33 are preferably 
produced by a stamping operation. To that end, the shaped sheet-metal part 
is embodied symmetrically for this purpose, so that the slit sleeve 31, 
U-shaped profile 33 and flat plug 25 have the same plane of symmetry 37, 
shown in FIG. 6, and the wall thickness of the slit sleeve 31 and of the 
U-shaped profile 33 is equal to the wall thickness of the flat plug 25, 
and the inside diameter of the slit sleeve 31 is larger than that of the 
U-shaped profile 33. Finally, a wall surface of the flat plug 25 defines a 
tangent to an inside wall surface of the round plug receptacle 31. 
For installation of the shaped sheet-metal part into the feed assembly 5, 
this connection element 21 is inserted with the U-shaped profile 33 and 
the slit sleeve 31, as shown in FIG. 3, into the receiving bore 19 of the 
connection cap 17 as far as the stop 29, therefore the flat plug end 25 
protrudes axially from the cap. The connection cable 34 of the drive motor 
11 is placed in the U-shaped profile 33 and soldered, and the shaped 
sheet-metal part is furthermore extrusion coated with plastic 36 in the 
region of the U-shaped profile 33 in the connection cap 17, so that the 
connection cap 17 seals off the interior of the feed assembly 5. 
FIG. 7 shows the connection cap 17 with an additional electrical unit 39 
electrically connected with the electrical elements 21 in the cap 17; in 
the exemplary embodiment, this unit 39 comprises a radio interference 
suppression unit. Two round prongs 43 are inserted into a cylindrical 
housing 41 of the radio interference suppression unit 39; a first portion 
forms a round plug 45 protruding axially out of the housing 41, and a 
second portion, separated from the first via an annular rib 49, forms a 
choke core 47, onto which a choke (coil) 51 is slipped. The choke 51 and 
the prongs 43 are extrusion coated with plastic inside the housing 41 and 
sealed off from one another. On its face end remote from the exit of the 
round plug 45, the housing 41 of the radio interference suppression unit 
39 has two axially protruding flat plugs 53, each of which is connected to 
one round prong 43 and serves as an electrical connection. Embodying the 
round prong 43 as a choke core 47 and simultaneously as a round plug 45 is 
especially advantageous for the sake of simple manufacture. To connect the 
radio interference suppression unit 39 with the connection cap 17, the 
ends of the round plugs 45 projecting axially from the housing 41, as 
shown in FIG. 7, protrude into the slit sleeves 31 forming the round plug 
receptacle; between the round plugs 45 and the plastic filling surrounding 
them, a flat slitlike recess 55 is provided, which is complemental to the 
form of the flat plugs 25 on the connection cap 17 and into which the flat 
plugs 25 protrude when the radio interference suppression unit 39 is 
mounted, which further improves the electrical contact and the firmness of 
the plug connection via an electrical contact between the flat plugs 25 
and the round prongs 43. 
It is thus possible, as a result of the simple expedient of a combined flat 
and round plug receptacle 21 in the connection cap 17 to connect the feed 
assembly 5 directly electrically as needed, or to mount an additional 
electrical component 39, in order to change the functional properties, 
such as radio interference suppression, of the feed assembly 5. 
The foregoing relates to a preferred exemplary embodiment of the invention, 
it being understood that other variants and embodiments thereof are 
possible within the spirit and scope of the invention, the latter being 
defined by the appended claims.