Oil sump with integral filter

An oil sump with an integral filter includes an upper sump having a major opening therethrough which contains the integral filter and a minor opening through which projects a tube which is connected to the inlet of a suction pump. Beneath the upper sump is a lower sump into which the tube projects and with which the opening with the filter is in communication. Both the upper sump and lower sump are made of a plastic material, such as a thermoplastic or thermosetting material, which includes enforcing fibers. A lower sump is fixed to the upper sump by either a strong permanent adhesive or by welding, using known welding processes such as ultrasonic welding, vibration welding or friction welding.

FIELD OF THE INVENTION
 The present invention relates to oil sumps with integral filters and more
 particularly, the present invention relates to a transmission oil sump
 with an integral filter.
 BACKGROUND OF THE INVENTION
 A typical transmission oil sump is configured as a stamped steel pan bolted
 to the transmission case with a separate gasket between the pan and
 transmission case. Typically, a separate filter element is situated in the
 sump and connected to the inlet of a suction pump to filter oil as the oil
 is drawn from the sump and recirculated back through the transmission. By
 having separate components, the current arrangement requires assembly
 steps at the transmission factory, which separate assembly steps provide
 an opportunity for assembly errors, increased labor costs, and expense. In
 addition, stamped steel pans in and of themselves are relatively
 expensive. Moreover, the steel is expensive to recycle. An additional
 consideration is weight savings because by saving weight, fuel consumption
 and the resulting pollution is reduced. Over the years, enormous weight
 savings are accomplished by the cumulative effect of reducing weight in
 numerous small components wherein the weight reduction is sometimes in the
 form of ounces rather than pounds.
 An approach is to make transmission oil sumps from plastic. Again, weight
 considerations are important. Accordingly, where components would not be
 robust because they are shielded from impacts by other components, they
 may be of lightweight construction. If components are of lightweight
 construction, then there need to be associated structures, also
 lightweight, which negate any problems which may occur due to lightweight
 construction. Therefore, savings in weight also may make desirable
 structural configurations which permit weight savings.
 SUMMARY OF THE INVENTION
 In view of the aforementioned considerations, the present invention is
 directed to an arrangement for filtering recirculating transmission oil,
 comprising an upper sump and a lower sump wherein both the upper and lower
 sumps are concave and have floors. The floor of the upper sump has a major
 opening therethrough which receives a filter element that filters
 transmission oil pooled in the upper sump as that oil flows through the
 major opening to the lower sump. The return pump inlet communicates with
 the lower sump and is adapted to connect to the inlet of a suction pump
 for recirculating transmission oil to the transmission in which the
 filtering arrangement is used.
 In a further aspect of the invention, the return pump inlet is a tubular
 member which extends through a minor opening in the floor of the upper
 sump into the lower sump.
 In still a further aspect of the invention, the lower and upper sumps are
 made of a lightweight material such as a plastic material.
 In an additional aspect of the invention, the lower and upper sumps are
 made of plastic and are welded or otherwise bonded to one another.

DETAILED DESCRIPTION
 Referring now to FIG. 1, there is shown a transmission oil sump 10
 configured in accordance with the principles of the prior art, wherein a
 steel pan 12 is attached to a transmission case 14. Transmission oil 16
 pools in the steel sump pan 12 and is pulled through inlet 18 of a filter
 element 20 by suction pump inlet 22 for recirculation back through the
 associated transmission (not shown). As is apparent from FIG. 1, it is
 necessary to assemble the filter element 20 and steel sump pan 12 at the
 transmission assembly site. Moreover, the filter element 20 and steel pan
 12 tend to be relatively heavy.
 Referring now to FIGS. 2-4, wherein an oil sump 30 with an integral filter
 32, configured in accordance with the principles of the present invention,
 is shown. As is seen in FIG. 2, the transmission oil sump 30 is comprised
 of an upper sump 34 and a lower sump 36. The upper sump 34 has a floor 38
 with a major opening 40 therethrough in which is positioned the filter
 element 32. The floor 38 further has a minor opening 42 therethrough which
 is formed by a tube 44 having a lower end 46 within the lower sump 36 and
 an upper end 48 which is adapted to be connected to a suction pump inlet
 50. The suction pump inlet 50 is connected to a suction pump (not shown)
 so as to withdraw transmission oil from the lower sump 36 and to
 recirculate that oil through the associated automatic transmission (not
 shown).
 The upper sump has an outwardly extending mounting flange 52 which extends
 around the perimeter thereof and is fixed to the housing 54 of the
 transmission by a plurality of bolts 56. Inboard of the bolts 56 is a
 gasket 58 which is seated within a slot 60 in the flange 52 between the
 bolts 56 and the concave portion 37 of the upper sump 34.
 The lower sump 36 has a floor 64 which is spaced a distance D from the
 bottom of the filter element 32. The lower sump 36 further includes a
 peripheral wall 66 having a laterally projecting flange 68. The laterally
 projecting flange 68 seats against the bottom surface 69 of the floor 38
 and is surrounded by a peripheral lip 70 which projects downwardly from
 the floor of the upper sump 34. The lower sump 36 is fixed to the bottom
 surface of the floor 38 of the upper sump 34 by utilizing an adhesive
 material, by friction welding, ultrasonic welding, vibration welding, or
 any other permanent bonding process in which the lower sump 36 remains
 fixed to the upper sump 34. An example of friction welding occurs in U.S.
 Pat. No. 5,853,577 issued Dec. 29, 1998 and incorporated herein in its
 entirety by reference. Additional possible approaches are to snap the
 sumps 34 and 36 together at the floor 38 of the upper sump, or to bolt the
 lower sump to the upper sump, in each case with a gasket therebetween.
 As is seen in FIG. 4, the filter element 32 preferably comprises a frame
 portion 70 which is unitary with the floor 38 of the upper sump 34. The
 frame portion 70 is comprised of a pair of side panels which have peaks
 and valleys 72 and 74 respectively formed in side panels. The side panels
 76 have edge portions 78 of a filter media 80 inserted therein in order to
 support the filter media. Preferably, the filter media 80 is a pleated
 paper filter media, but may also be comprised of other materials or
 fabrics such as, for example but not limited to, polyester fiber.
 The preferable material for the upper pan 34 and the lower pan 36 is
 preferably a composite material such as a polyamide material, or a
 thermoplastic or thermosetting material which may include reinforcement
 such as fiberglass strands.
 The aforedescribed sump 30 with an integral filter accomplishes cost
 savings because multiple components are combined into one. Moreover, it is
 lighter in weight than the prior art of FIG. 1.
 From the foregoing description, one skilled in the art can easily ascertain
 the essential characteristics of this invention and, without departing
 from the spirit and scope thereof, can make various changes and
 modifications of the invention to adapt it to various usages and
 conditions.