GB2100140A

GB2100140A - Oil filter

Info

Publication number: GB2100140A
Application number: GB8118687A
Authority: GB
Original assignee: General Motors Ltd
Current assignee: General Motors Ltd
Priority date: 1981-06-17
Filing date: 1981-06-17
Publication date: 1982-12-22

Abstract

An oil filter 10 of the disposable type comprising a cup-shaped pressed sheet metal casing 12 containing a tubular filter element 14 has a relatively thick end plate 21 which seats against a bead 24, impressed in the casing 12, and is retained in place by folding over the free edge portion of the casing 12. The edge portion may be folded inwards or outwards and may be further deformed after folding. Preferably a layer of viscous heat-curable sealant 27 is applied to the inside surface of the side wall of the casing immediately above the upper bead 24 prior to insertion of the end plate 21 into the casing 12 to act as an additional seal between the end plate 21 and the folded seam rim 29. <IMAGE>

Description

SPECIFICATION Oil filter This invention relates to oil filters for use in filtering the oil in an internal combustion engine lubrication system, and more particularly to oil filters of the kind disclosed in the specification of our prior patent 1 449 853.

Such oil filters (hereinafter designated as "the kind referred to") typically comprise a cup-shaped pressed sheet metal casing formed intermediate its ends with a radially inwardly directed annular bead impressed in the side wall thereof; an end plate of substantially thicker metal than said casing, an outer peripheral portion of which end plate is secured to a rim of the casing, said end plate having a central internally threaded neck which is surrounded by a plurality of inlet openings and is adapted to be screwed on to a complementary threaded portion of a mount for the filter; a hollow tubular filter element centred in said casing by engagement of the filter element outer periphery with said bead; a perforate centre tube on which said element is mounted, the end of said centre tube adjacent said end plate projecting beyond the adjacent end of the element; a spring plate formed with a central dished portion providing an annular shoulder, which fits into and forms a seal with the other end of the element, and formed with a stepped portion which engages the base of the cup to centre the plate therein and presses said element towards said end plate; and an annular elastomeric seal member which fits over the projecting end of the centre tube and is resiliently compressed between the adjacent end of the element and said end plate to form a seal therewith. The central dished portion of the plate may incorporate a pressure relief valve, as disclosed in our prior patent application 79 30 905.

The hollow tubular filter element used in such an oil filter is usually formed from a strip of synthetic resin-impregnated filter paper joined at its ends and folded about transverse fold lines into a series of accordion pleats, the element being centred in said casing by engagement of the outer pleat folds with said bead.

It has been customary in such oil filters to secure to the outer peripheral portion of the end plate an annular sheet metal disc, the outer peripheral portion of which is secured to the rim of the casing by a spun-over rolled seamed joint.

The present invention was devised with a view to removing the need for providing such an annular metal disc and securing it to the end plate of the filter during the manufacture of such oil filters on an assembly line employing automatic machinery for all, or substantially all, of the assembly operations.

According to one embodiment of the present invention, in an oil filter of the kind referred to, the cup-shaped casing is initially formed with a side wall longer than the length of the oil filter, there is a further annular bead impressed in said side wall, immediately below the position occupied by a lower outer edge of the end plate, said further bead locating the end plate in its desired position when inserted into the open end of the casing during assembly of the filter manually or on an automatic assembly line; and the rim of the casing is formed by curling over the free end of said side wall adjacent said end plate so as to form a folded seam which sealingly clamps the outer peripheral portion of the end plate against said further bead in the side wall.

Preferably there is interposed between the outer periphery of the end plate and the adjacent side wall of the casing a layer of sealant, applied to the side wall immediately above said further bead, prior to the insertion of the end plate in the open end of the casing.

During insertion of the end plate into the casing and a subsequent spinning operation in which the outer peripheral portion of the end plate is secured and sealed in position against said further bead by curling over the free end of the side wall to form the folded seam rim, the sealant previously deposited is compressed between the outer periphery of the end plate and the adjacent side wall of the casing and forms a seal thereat by which the escape of oil from the filter assembly when installed on an engine is minimized or prevented.

Advantageously, the outer edge of the outer peripheral portion of the end plate is provided with flat portions, corrugated portions or similar formations thereon to assist in preventing the development of any relative movement between the end plate and the folded seam rim of the casing when the filter subsequently is being fitted or removed from said complementary threaded portion of the mount for the filter.

The invention and how it may be performed are hereinafter particularly described with reference to the accompanying drawings, in which: Figure 1 is a vertical section through an oil filter of the kind referred to, incorporating the invention; Figure 2 is an enlarged detail view of a portion of the oil filter shown in Fig. 1 during assembly of the oil filter; Figure 3 is a similar enlarged detail view of the same portion of the oil filter shown in Fig.

1 after assembly of the oil filter; Figure 4 is a similar enlarged view as shown in Fig. 3, illustrating a modification of the oil filter shown in Fig. 1; Figure 5 is a similar enlarged view as shown in Fig. 3, illustrating an alternative embodiment of the invention; and Figure 6 is a similar enlarged view as shown in Fig. 5, illustrating a modification to the alternative embodiment of the invention shown in Fig. 5.

Fig. 1 shows an oil filter 10 of the kind referred to, having a casing 12 with an annular bead 13 impressed therein intermediate its ends in order to centre therein a pleated filter paper element 14 mounted on a perforate centre tube 15, the upper end of which projects beyond the upper end of the element 14 and has mounted thereon an annular elastomeric seal member 16. This seal member 16 can be of a simple rectangular crosssection as shown in the drawings, or can be an annular elastomeric seal member which incorporates a flexible radially outwardly extending extension thereon which is biased into contact with said end plate and covers said plurality of inlet openings, said annular elastomeric seal member acting as an anti-drain member when said oil filter is removed from said mount after use.An example of such an anti-drain annular elastomeric seal member is disclosed in our prior patent 978517.

The ends of the pleats of the filter element 14 are individually sealed, and at its lower end the central opening of the element is sealed by a central dished portion 17 of a spring plate 18 which incorporates a relief valve 19, the plate 18 having a deformable rim 20 which engages with the base of the casing 12 and presses the element 14 and seal member 16 into engagement with an end plate 21 of the filter, which is of substantially thicker metal than the casing and has a central internally threaded neck 22 which is surrounded by a plurality of inlet openings 23 and is adapted to be screwed on to a complementary threaded portion (not shown) of a mount for the filter. A seal ring 26 is retained adjacent an outer peripheral portion of the end plate 21.

Adjacent a lower edge of the outer peripheral portion of the end plate 21, the casing 12 is formed with a further annular bead 24 impressed therein which provides a location for the end plate 21 when inserted into the open end of the casing 12 during assembly of the filter. As can be seen in Fig. 2, the further annular bead 24 is impressed in the side of the casing 12 a predetermined distance from the free end 25 of the side wall, since the casing 12 is initially formed with a side wall longer than the oil filter 10 shown in Fig. 1.

Prior to the insertion of the end plate 21, an annular layer of sealant 27 is applied to the inner surface of the casing 12 above the further bead 24 so that, when the end plate 21 is inserted into the open end of the casing 12 it engages the sealant layer and is then located in position in the casing 12 by the further bead 24, the movement of the end plate 21 into the open end of the casing 12 causing compression of the sealant layer 27 and the formation of a ring 28 of sealant adjacent the further bead 24, the sealant thereby providing an effective seal between the outer periphery of the end plate 21 and the adjacent wall of the casing and between the lower edge of the end plate and the further bead 24.

The thickness of the sealant 27, 28 shown in Fig. 2 has been exaggerated for the sake of clarity.

The sealant is conveniently a viscous heatcurable synthetic material which can be injected into its required position and is cured during subsequent heat treatment to cure the synthetic resin of the filter element, the sealant material thereby being cured to set and form a stable seal between the casing 12 and the end plate 21.

The end plate 21 is sealingly clamped against the further bead 24 by curling over the free end 25 of the side wall of the casing 12 until it comes into contact with the outer peripheral portion of the end plate 21, as shown in Fig. 3. The curled-over free end 25 of the side wall forms a folded seam rim 29 for the oil filter which also serves as a locating buttress for the annular seal ring 26, which is either an interference fit within the inner periphery of the rim 29 or is held in place by means of adhesive applied between said annular ring and either the rim 29 or the outer peripheral portion of the end plate 21.

Additional clamping strength between the rim 29 and the end plate 21 can be obtained as shown in Fig. 4 by further deforming the folded seam rim 29 around the outer peripheral portion of the end plate 21 using either profiled rollers or a proprietary Magnaform machine.

An alternative embodiment of the invention is illustrated in Fig. 5, in which the folded seam rim 29' is produced by curling over the free end 25' of the side wall of the casing 12' outside the casing 12'. In such an alternative embodiment, the free end 25' of the side wall is positioned below the further bead 24' in the casing 12' to strengthen the side wall adjacent the further bead 24'. Additional clamping strength between the rim 29' and the end plate 21' can be obtained as shown in Fig. 6 by a similar further deformation of the folded seam rim 29' around the outer peripheral portion of the end plate 21' using either profiled rollers or a propietary Magnaform machine.

The outer edges of the outer peripheral portions of the end plates 21,21' are provided with flat portions (not shown) which aid in locking the end plates 21,21' in position against the respective further beads 24,24' so as to substantially prevent any relative movement occurring between the end plates 21,21' and the respective casings 12,12' when the filter is being fitted or removed from a complementary threaded mount.

An oil filter according to the~present invention represents a significant improvement over known oil filters of the type referred to hereinbefore in that it eliminates the annular sheet metal disc customarily used in such known oil filters and thus saves on material cost, and it eliminates the process steps involving this annular sheet metal disc during assembly of the known oil filters, thus saving both time and money.

Claims

.1. An oil filter comprising a cup-shaped pressed sheet metal casing containing therein a filter element, and an end plate of substantially thicker metal than said casing, an outer peripheral portion of which end plate is secured to a rim of the casing, said end plate having a central internally threaded neck which is surrounded by a plurality of inlet openings and is adapted to be screwed on to a complementary threaded portion of a mount for the filter; characterised in that the cupshaped casing is initially formed with a side wall longer than the length of the filter; there is an annular bead impressed in said side wall immediately below the position occupied by a lower outer edge of the end plate, said annular bead locating the end plate in its desired position when inserted into the open end of the casing during assembly of the filter; and the rim of the casing is formed by curling over the free end of said wall adjacent said end plate so as to form a folded seam which sealingly clamps the outer peripheral portion of the end plate against said annular bead in the side wall.
2. An oil filter according to claim 1, characterised in that there is interposed between the outer periphery of the end plate and the adjacent side wall of the casing a layer of sealant applied to the side wall immediately above said annular bead.
3. An oil filter according to claim 2, characterised in that the layer of sealant is a viscous heat-curable synthetic material.
4. An oil filter according to any one of the preceding claims, characterised in that the free end of the side wall of the casing adjacent the end plate is curled over the inside of the casing to form said folded seam rim.
5. An oil filter according to claim 4, characterised in that said folded seam rim is further deformed around the outer periphery of the end plate.
6. An oil filter according to any one of claims 1 to 3, characterised in that the free end of the side wall of the casing adjacent the end plate is curled over on the outside of the casing until said free end is juxtaposed to said further bead, to form said folded seam rim.
7. An oil filter according to claim 6, characterised in that said folded seam rim is further deformed around the outer periphery of the end plate.
8. An oil filter according to any one of the preceding claims, characterised in that the outer periphery of the end plate is provided with formations thereon to assist in preventing relative movement occurring between the end plate and the folded seam rim of the casing during subsequent use of the filter.
9. An oil filter according to any one of the preceding claims, in which the cup-shaped pressed sheet metal casing is formed intermediate its ends with a radially inwardly directed annular bead impressed in the side wall thereof; said filter element is a hollow tubular filter element centred in said casing by engagement of the filter element outer periphery with said radially inwardly directed annular bead; there is a perforate centre tube on which said element is mounted, the end of said centre tube adjacent said end plate projecting beyond the adjacent end of the element; there is a spring plate formed with a central dished portion providing an annular shoulder, which fits into and forms a seal with the other end of the filter element, and formed with a stepped portion which engages the base of the cup-shaped casing to centre the plate therein and to press said filter element towards said end plate; and there is an annular elastomeric seal member which fits over the projecting end of the centre tube and is resiliently compressed between the adjacent end of the filter element and said end plate to form a seal therewith, characterised in that the spring plate pressing the filter element towards the end plate includes a pressure relief valve.
10. An oil filter according to claim 9 characterised in that the annular elastomeric seal member between the filter element and the end plate incorporates a flexible radially outwardly extending extension thereon which is biased into contact with said end plate and covers said plurality of inlet openings, said annular elastomeric seal member acting as an anti-drain member when said oil filter is used in an inverted position or is removed from said mount after use.
11. An oil filter substantially as hereinbefore particularly described and as shown in Figs. 1, 2 and 3 of the accompanying drawings.
12. An oil filter substantially as hereinbefore particularly described and as shown in Figs. 1 to 3, as modified by Fig. 4, of the accompanying drawings.
13. An oil filter substantially as hereinbefore particularly described and as shown in Figs. 1 and 5 of the accompanying drawings.
14. An oil filter substantially as hereinbefore particularly described and as shown in Figs. 1 and 5, as modified by Fig. 6, of the accompanying drawings.