Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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CA 02351933 2001-06-27
SUMP ARRANGEMENT HAVING A FILTIER WITH STANDOFFS
PROVIDED TO MAINTAIN FLO~rV CHANNELS
The present invention relates to a sump arrangement with a filter having
standoffs
provided to maintain a liquid flow channel. More particularly, the present
invention
relates to such a sump arrangement for use with transmissions and engine
lubricating
systems.
Background of the Invention
Generally, transmissions used with automotive vehicles and lubricating systems
for engines used to power automotive vehicles include oil sumps. The oil sumps
have
some type of filtering device to remove particulates from transmission and
lubricating
oil as the oil circulates. There has been considerab'.~e interest in providing
oil sump
arrangements wherein a filter element is located in an oil pan on a partition
which
extends across the oil pan in spaced relation to thc~ floor of the oil pan.
With this
arrangement, transmission oil in the transmission case: pools on the partition
and passes
through the filter element by gravity and due to suction created from an oil
pump which
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recirculates clean oil from a chamber between the floor of the oil pan and the
partition.
This suction creates a low pressure area beneath the filter element. It has
proven difficult
to maintain the gap between the bottom of the filter element and the flaor of
the pan.
Consequently, flow to the suction tube of recirculated fluid pump becomes
restricted,
blocking or partially blocking, the flow channels to the suction pump tube.
Since this can
result in oil starvation in both transmissions and engines, it is desirable to
prevent this
phenomenon. The phenomenon is especially insidious because it may occur only
during
engine acceleration when there is a sudden demand for oil. During acceleration
surges
if oil is not available then the engine or transmission is subject to far more
wear than
occurs during normal cruising operation. Discovering 'that flexing of the
partition can be
the cause of oil starvation was also a problem because the phenomenon is
hidden within
the transmission or lubricating oil pan.
In order to save weight and expense, there is continuing incentive to reduce
the
thickness of components in situations where components are shielded from
external
impacts and abrasions. When weight reduction occurs with partitions within
sump pans,
the partitions tend to become more flexible which results in the partitions
flexing under
pressure which tends to close flow channels and restrict the amount of fluid
available
during recirculation. Accordingly, there is a need to permit weight and
material reduction
while avoiding flow channel restriction. With respect to filter components,
which have
materials which it is desirable to recycle, reducing the amount of material to
be recycled
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is very desirable. Moreover, even if these materials .are disposed of dump
sites, it is
desirable to reduce their volume by reducing the amount of material utilized.
In view of the aforementioned considerations, the present invention is
directed
to a sump with an integral filter wherein the sump is used as a device that
employs
recirculating oil. The sump comprises a sump pan having a floor and a side
wall adapted
to be mounted beneath the housing of the device. The sump pan defines a space
of a
selected height to accommodate a volume of fluid a:nd has an inlet of a
suction tube
adapted to cormect with a suction pump. A partition wall is suspended within
the space
defined by the sump pan and divides the space into an upper chamber and a
lower
chamber, the partition wall having an area which overlies the floor of the
sump pan and
having a major opening therethrough. The filter element is disposed in the
major
opening. The filter element has a dirty side and a clean side and includes a
filter media
disposed in a frame that extends downwardly toward the floor of the sump pan.
A
plurality of spacers are disposed between the filter frame and the floor of
the sump pan,
the spacers being distributed so as to allow liquid flow in all directions
around the
spacers toward the suction tube for recirculation through the device utilizing
the oil. The
spacers are engaged by both the frame and the floor when suction is applied to
the
suction pump inlet, to maintain adequate clearance between the frame and the
floor so
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as to provide sufficient flow of filtered fluid in a direction toward the
inlet of the suction
tube.
In a further aspect of the invention, the filter media is a pleated filter
media and
in still a further aspect of the invention, the pleated filter media has
pleats which extend
transverse to the direction in which the fluid flows toward the inlet of the
suction tube.
In still a further aspect of the invention the frame is molded unitary with
the
partition and has flanges which extend substantially paxallel to the direction
in which the
liquid flows toward the inlet of the suction pump.
In still a further aspect of the invention, the partition wall in the sump pan
includes a minor opening therethrough wherein the suction tube extends through
the
minor opening and is integral with the partition:
In another aspect of the invention, the partition within the sump has a side
wall
and a peripheral flange which overlies a peripheral flange on the sump pan to
suspend the
partition wall within the space defined by the sump pan.
In accordance with still additional aspects of the invention, the spacers are
either
an the frame of the filter element or the spacers project from the floor of
the sump pan,
the spacers being either separate elements fixed to the floor of the sump pan
or elements
unitary with the floor of the sump pan.
In most aspects of the invention; both the sump pan and the partition are made
of
plastic material.
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Various other features and attendant advantages of the present invention will
be
more fully appreciated as the same becomes better understood when considered
in
conjunction with the accompanying drawings, in 'which like reference
characters
designate the same or similar parts through the several views, and wherein:
Figure 1 is a side elevation of a prior art oil sump arrangement shown
attached
to a transmission case;
Figure 2 is a perspective view, in elevation, of a portion of the sump
arrangement
of Figure 1, but modified in accordance with the principles of the present
invention;
Figure 3 is a side view of the sump arrangement of Figure 2;
Figure 4 is an end elevation of a second embodiment of the invention;
Figure 5 is a side elevation of the second embodiment of the invention; and
Figure 6 is a side view elevation of a third embodiment of the invention.
Referring now to Figure 1, there is shown a sump 10 with an integral filter
element 12 wherein the sump is attached to a transmission case 14. While a
transmission
case 14 is illustrated, it is within the scope of this invention to. utilize
the sump
arrangement of Figure 1 as a lubricating oil sump for m internal combustion
engine (not
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shown). The sump comprises a pan 16 and a partition v~all 18 wherein the
partition wall
has a major opening 20 in which the filter element 12 is positioned and a
minor opening
22 which receives therethiough a suction tube 24 fon a transmission oil
recirculating
pump 26.
The partition wall 18 divides the sump pan 1fi into an upper chamber 28 and a
lower chamber 29. Dirty transmission oil 30 or lubricating oil depending on
the
application of the sump 10, pools on top of the partition wall 18 in the upper
chamber 28.
Gravity and suction created by the recirculating pump 26 through the suction
tube 24
pulls the dirty oil 30 through the filter element 12 and into the lower
chamber 29 to
provide a supply of clean oil 32 that has had the p~articulates removed by the
filter
element.
Operation of the suction pump 26 creates a lower pressure within the lower
chamber 29 than the upper chamber 28: As the suction tube 24 pulls the clean
oil 32 from
the lower chamber 29, the partition 18 flexes enough so that the bottom 34 of
the filter
element 12 approaches or contacts the floor 36 of the aump pan 16. Normally,
there is a
gap 38 between the bottom of the filter element 12 and the floor 36 of the
sump pan 16
which provides a channel for the clean oil 32 to flow to the suction tube 24.
When the
partition 18 flexes downwardly, the gap 38 is restricted and may bcome closed
altogether,
thereby starving the transmission served by the sump l0 of oil. The same
phenomenon
may also occur with an engine if the oil being recirculated is lubricating
oil.
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The problem being solved is a vexing one, because it is necessary to keep the
pan
16 as shallow as possible in order to conserve space and road clearance, while
keeping
the pan 16 and associated structure, such as the partition wall 18 and filter
element 12
as light as possible in order to minimize weight without sacrificing strength.
As is seen from the top in Figure 2, the filter element 12 is comprised of a
frame
42 having two side plates 44 and 46 as well as at least one intermediate plate
48. While
one intermediate plate 48 is shown there may be two or more intermediate
plates. In any
event, between the illustrated plate 48 and the adjacent plates which happen
to be plates
44 and 46, there are disposed filter media 52 and 54. Filter media 52 and 54
are pleated
filter media which have peaks 56 and valleys 58 which extend perpendicular to
the extent
of the plates 44,46 and 48 which comprise the frame 4.?. Consequently, the
valleys 58 of
the filter media present a substantial barner to fluid flow through the gap 38
to suction
tube 24. This can seriously restrict flow because the filter media 52 and 54
then become
dams forcing fluid flow around the filter element 12 instead of beneath the
filter element
i.e., through the gap 38.
Referring now to Figures 3 and 4, applicant has solved this vexing problem by
disposing spacers 70 along bottom edges 72 of the plates 44, 46 and 48. When
pressure
increases enough to cause the partition 18 to flex, the spacers 70 prevent
flexing by
engaging the upper surface 74 of the floor 36 of pan 16. Consequently, the gap
38
remains open providing clearance and a substantially obstruction free channel
to the
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suction tube 24. The spacers 70 are spaced from one another in all directions
so that fluid
may flow with lateral components as well as mainly longitudinal components
toward the
suction tube 24, thereby substantially reducing restriction to flow which may
have
otherwise occurred. As is apparent from Figures 3 and 4, the spacers 70 are
unitary with
the plates 44, 46 and 48, the plates being preferably unitary with the
partition wall 18.
The partition wall 18 is preferably a molded unit which can be molded in a
single
molding operation because it is comprised of a horizontally extending surface
76 and a
generally vertically extending wall 78. The vertically f;xtending wall 78 has
a flange 79
with a plurality of bolt holes 80 therethrough which receive bolts 82 for
fastening to the
housing 14 of the transmission or to an engine block i;not shown), if the pan
16 is used
to collect and recirculate lubricating oil.
Referring now to Figures 5 and 6 there is shown a second embodiment of the
invention wherein spacers 90 are employed to engage plates 44', 46' and 48',
the spacers
90 being formed on. the floor 36' of the sump pan 16. As is clear from Figures
5 and 6,
the spacers 90 are not ribs but are rather singular projections which are
aligned with the
bottom surfaces 72' of the plates 44, 46 and 48 that comprise of the frame 42
of filter
element 12. While the arrangement of Figures 5 and ti is preferred, it is also
within the
purview of this invention to simply provide ribs which extend parallel with
the
longitudinal extent of plates 44, 46 and 48, however, by having parallel ribs
flow is
generally restricted to a direction toward the suction tube 24, and therefore
does not
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accommodate with lateral flow components situations where one filter media or
one
portion of a filter media may become excessively clogged and thus obstruct
flow toward
the suction tube 24. Consequently, the arrangement o:E'Figures 3-6 is
preferred.
Referring now to Figure 7, there is shown another embodiment in which spacers
96 are simply discreet elements which are fixed to the ;Floor 74 of the pan 16
by welding,
adhesive or magnetic attraction. With the arrangement of Figure 7, the spacers
96 are not
permanently affixed and may be deleted or moved depending on considerations
such as
the vertical height of the plates 44, 46 and 48 or the vertical height of the
specific filter
media 52 or 54 being employed.
From the foregoing description, one skilled in the art can easily ascertain
the essential characteristics of this invention and, witlhout departing from
the spirit and
scope thereof, can make various changes and modifications of the invention to
adapt it
to various usages and conditions.
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