Oil filter structure

An oil filter includes a magnetic filtering device disposed inside the canister of the filter. The magnetic filtering device includes a pair of oppositely arranged particle collection members each having a recess in contact engagement with each other so as to define a ring space to secure therein a ring magnet. Each of the particle collection members has a plurality of particle collection slots formed thereon and located in close proximity of the magnetic poles of the ring magnet. A top member is mounted to the upper one of the particle collection members to define an upper oil path and a base member is mounted to the lower one of the particle collection members to support the magnet in position and define a lower oil path for conduction of the oil through the particle collection slots of the upper and lower particle collection members to have ferrous metal particle carried by the oil attracted and collected within the particle collection slots of the upper and lower particle collection members.

FIELD OF THE INVENTION 
The present invention relates generally to an oil filter for use with an 
automobile engine and in particular to an oil filter using magnet to 
remove ferrous metal particles carried by the oil flow. 
BACKGROUND OF THE INVENTION 
Oil has been a must for lubrication and cooling of an internal combustion 
engine. The quality of the oil plays an important roll for the 
service-life and the operation of the engine. Besides the quality of the 
oil, particles, especially metallic particle (basically ferrous metal 
particles), which are generated during the operation of the engine are 
also a factor that affects the service life of the engine. These metal 
particles are destructive to the engine, for they circulate with the oil 
to the moving parts of the engine and cause wearing and abrasion on the 
moving parts which in turn generate more ferrous metal particles. To 
overcome such a problem, an oil filter is devised to filter and clean the 
oil. The oil filter has been well known and being improved for may years. 
In general, an oil filter comprises a canister housing inside which 
filtering means, such as filtering paper or other porous material which 
allows the oil to flow through but stops the ferrous metal particles and 
thus cleans the oil. An example is disclosed in Taiwan patent publication 
No. 170,160. 
Oil filters of this structure have been a standard for many years. However, 
due to the requirement of the minimum flow rate of the oil for lubrication 
and cooling of the engine, this oil filter structure is incapable to 
filter out minute particles, for it must have large enough openings to 
establish the required oil flow rate. 
To overcome such a problem, magnet means has been disposed inside the oil 
filter to attract and thus remove the minute ferrous metal particles out 
of the oil flow. Some examples of the magnetic oil filters are 
demonstrated in U.S. Pat. Nos. 4,450,075, 4,613,435, 4,826,592, 4,851,116, 
5,078,871 and 5,228,990 and Taiwan patent publication Nos. 165,334, 
181,638 (which is corresponding to U.S. Pat. No. 5,228,990) and 195,840. 
All these patents comprise magnet means in different forms disposed inside 
the oil filter canister for removing ferrous metal particle out of oil 
flow within the canister. 
Although the conventional magnetic oil filters mentioned above do work well 
in removing minute metal particles from the oil flow, they have at least 
one major problem, namely, these oil filters comprise no metal particle 
collection means to allow the particles to be collected and securely held. 
Without the particle collection means, the ferrous metal particles that 
are attracted by the magnet means will gather around the magnet means and 
held thereon only by the magnetic force. The gathering of the metal 
particles may form a blockage to the oil flow. 
Furthermore, since the metal particles are only held by the magnetic force 
and since the magnetic force to some extent may be overcome by the 
vibration and shake of the engine or the automobile on which the engine is 
mounted during their operations, the ferrous metal particles that are 
attracted around the magnet means may re-enter the oil flow. This reduces 
the effectiveness of the conventional magnetic oil filters. 
An even more serious problem caused by the metal particles that are shaken 
to release from the magnet means and re-enter the oilflow is that these 
particles may be magnetized to some degree by the magnet means during 
their contact engagement with the magnet means and thus in their 
re-circulation within the engine, they may attract each other and form a 
large particle which causes a more serious damage to the engine if allowed 
to circulate with the oil flow. 
Moreover, in some of the conventional magnetic oil filters, such as U.S. 
Pat. No. 5,228,990, the magnet means is fixed inside the canister by means 
of adhesive. Due to the high temperature condition during the normal 
operation of the engine, the oil flow that is thus maintained in a 
substantial high temperature deteriorates the adhesive and thus may cause 
failure of the adhesive. The failure of the adhesive results in 
un-securing the magnet means and thus damaging the oil filter. In certain 
conditions, the un-secured magnet means may also block the oil outlet and 
this causes an even more dangerous problem to the operation of the engine. 
In some other magnetic oil filters, the magnetic means and the related 
parts are held inside the filter canister by means of frictional force 
provided by elastic deformation of the parts. However, due to the fact 
that to avoid unnecessary magnetization of the parts, some of the parts 
are made of aluminum which, as is generally well known, is less flexible 
and thus may not be able to provide desired elastic deformation for the 
provision of frictional force to hold the parts in position. As a result, 
the vibration and shake of the engine and/or the automobile may cause the 
magnet means and the related parts to disengage and thus damage the 
function of the oil filter. 
SUMMARY OF THE INVENTION 
It is therefore a primary object of the present invention to provide an 
improvement of the magnetic oil filter which substantially overcomes the 
above-mentioned problems and drawbacks of the conventional magnetic oil 
filters. 
In accordance with a first aspect of the present invention, particle 
collection means is provided inside the filter canister to collect and 
hold the ferrous metal particles therein so as to prevent the ferrous 
metal particles from disengaging from the magnet means and re-entering the 
oil flow and also prevent these particles from piling up to form a 
blockage to the oil flow. 
In accordance with a second aspect of the present invention, oil flow paths 
are provided inside the filter canister in such a way as to conduct the 
oil to flow around the locations where the magnetic force provided by the 
magnet means is strongest, such as the locations that are in proximity of 
the magnetic poles of the magnet means. 
In accordance with a third aspect of the present invention, securing means 
rather than adhesive is provided to securely fix the magnet means, 
together with its support member, inside the filter canister. 
In accordance with a fourth aspect of the present invention, the magnet 
means is secured on its support by means of fastener, such as rivet, 
rather than by means of frictional force induced by elastic deformation. 
In accordance with a fifth aspect of the present invention, the support of 
the magnet means comprises a non-magnetizable material so as to allow the 
magnetic flux emitting from the magnet means to be concentrated at desired 
orientation and location to enhance the attraction of the ferrous metal 
particles carried by the oil flow. 
In accordance with a sixth aspect of the present invention, the support of 
the magnet comprises such a structure and is so fixed inside the filter 
canister that the oil flow is completely conducted through the magnet 
means to have the ferrous metal particle carried thereby substantially 
removed out of the oil flow. 
Further aspects of the present invention are to provide a magnet means to 
be used inside an oil filter which is simple in structure and thus 
inexpensive in cost, the magnet means being able to disposed inside the 
filter canister without any modification and change to the original 
structural design and the original requirement of the oil flow rate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
With reference to the drawings and in particular to FIG. 1, wherein an oil 
filter constructed in accordance with the present invention, generally 
designated with the reference numeral 10, is shown, the oil filter 10 
comprises a housing 12 having a bottom 13 on which an oil outlet 16, 
preferably centrally located, is formed with a plurality of oil inlets 14 
among which only one is shown in the drawings, formed around the central 
outlet 16. In general, the outlet 16 is inner-threaded to be engageable to 
an engine (not shown). The oil flows into the oil filter 10 via the inlets 
14, circulates through the oil filter 10 and then exits the oil filter 10 
via the outlet 16 to return back to the engine. 
The oil filter 10 comprises a foraminated sleeve 18, having formed thereon 
a plurality of apertures 20, preferably in a uniformly distributed manner, 
disposed inside the housing 12 to define a first space 19 of a first 
diameter encircled by the foraminated sleeve 18. The centrally located oil 
outlet 16 is thus located within the first space 19 and enclosed by the 
foraminated sleeve 18 preferably in a substantially separated manner. The 
foraminated sleeve 18 is disposed to be separated from the housing 12 so 
as to define therebetween a second, cylindrical space 21 within which a 
filter material, such as multiple-folded filtering paper core 22 as 
conventionally used, is disposed. A spring 24 is disposed on a top side of 
the filtering paper core 22 to bias both the filtering paper core 22 and 
the foraminated sleeve 18 toward the bottom 13 of the housing 12 so as to 
secure the foraminated sleeve 18 and the filtering paper core 22 in 
position as is conventionally known. 
Inside the first space 19 defined by the foraminated sleeve 18, magnetic 
filtering means constructed in accordance with the present invention, 
generally designated with the reference 26 is mounted. 
The magnetic filtering means 26, as shown in FIGS. 2-4, which are 
respectively a perspective view, an exploded perspective view and a 
cross-sectional view of the magnetic filtering means 26, comprises a base 
28, which is particularly shown in FIG. 7 as a hollow shell member, having 
a generally cylindrical lower portion 29 and a truncated-conic ,upper 
portion 31 integrally formed as a unitary member that has an open, large 
diameter bottom side and a closed, reduced diameter top side. The diameter 
of the cylinder 29 of the base 28 is substantially equal to the first 
diameter of the first space 19 defined by the foraminated sleeve 18 so as 
to allow the cylinder 29 of the base 20 to be forcibly fit into the 
foraminated sleeve 18 and thus secured therein. This arrangement allows 
the base 28 to completely cover the outlet 16 formed on the bottom 13 of 
the housing 12 with the open, bottom side thereof. 
Preferably, the cylinder 29 of the base 28 comprises a plurality of radial 
tabs 30 which extend,radially outward from a lower circumference 33 of the 
cylinder of the base 28 to insert into between the foraminated sleeve 18 
and a fixed surface 72 (FIG. 1) mounted to or forming a portion of the 
bottom 13 of the housing 12 to be further secured in position by being 
nipped between the foraminated sleeve 18 and the bottom 13 of the housing 
12 under the action of the biasing spring 24. Preferably, the tabs 30 are 
soldered to the sleeve 18. 
The base 28 also comprises a central hole 32 formed on the top side thereof 
with a plurality of fan- or sector-shaped slots 34, serving as oil 
passages, formed around the central hole 32. As is apparent to those 
having ordinary skills, the oil passages 34 may assume any other shapes 
without departing from the spirit and scope of the invention. The oil 
passages 34 allow the oil to flow into the base 28 and then discharge via 
the outlet 16 enclosed within the base 28. 
In the embodiment illustrated, the base 28 is preferably made of thin steel 
plate of 0.3 mm thickness. The diameter of the cylinder 29 of the base 28 
is about 32 mm and that of the top side is about 27 mm. The overall height 
of the base 28 is approximately 18 mm. The diameter of the central hole 32 
may be 3.6 mm. This is only an example of the detailed dimension of the 
base 28 and it is quite obviously that the base 28 may be modified to give 
different dimension for use in oil filters having different designs and 
sizes. 
On the top side of the base 28, an elongated spacer 35, preferably in the 
form of a long cylinder as shown in the drawings, is fixed to support 
thereon a pair of oppositely arranged particle collection members, the 
upper member 36 and the lower member 37, between which magnet means 38 is 
retained. The spacer 35 serves to separate the lower particle collection 
member 37 away from the base 28 by a predetermined distance, such as 5 mm, 
so as to define a lower oil path 39 therebetween, as illustrated in FIG. 
4. The spacer is formed of a non-ferromagnetic material such as aluminum. 
The upper particle collection member 36 is identical to the lower particle 
collection member 37 and the only difference is that the lower member 37 
is disposed in an side-down manner relative to the upper member 36. Thus, 
the description herein regarding the upper particle collection member 36 
is also applicable to the lower particle collection member 37. 
The structure of the particle collection members 36 and 37 is particularly 
shown in FIG. 6. As shown, the particle collection member 36 or 37 
comprises a pan-shaped body made of a thin metal plate, preferably a 
ferrous metal, having a central recess 40 with a circumferential flange 45 
integrally formed around the recess 40. The recess 40 is defined by an 
inclined side wall 41 and a substantially flat bottom wall 42. A central 
hole 44 is formed on the bottom wall 42, opposing the central hole 32 
formed on the top side of the base 28. A plurality of sloes 46 in the form 
of fan or sector are formed around the central hole 44 to provide an oil 
passage to be described hereinafter. 
By having the lower member 37 oriented up side down and having the flat 
bottoms 42 of the recesses 40 of the upper and lower particle collection 
members 36 and 37 contacting and PG,12 resting upon each other, a ring 
space 48 (see FIG. 4) is formed between the flanges, 45 of the upper and 
lower members 36 and 37, which surrounds the inclined side walls 41 or the 
upper and lower particle collection members 36 and 37, to receive and hold 
therein the magnet means 38. Using ferromagnetic metal, such as steel, to 
manufacture the upper and lower particle collection members 36 and 37 
allows the magnetic flux of the magnet means 38 to be directed to desired 
locations and orientations. The use of steel plate to form the upper and 
lower particle collection members 36 and 37 also provides suitable 
resiliency of the flanges 45 to securely hold the magnet means 38 
therebetween. 
As shown in, FIGS. 3, 4 and 6, each of the particle collection members 36 
and 37 comprises particle collection slots 50 and 52 formed on the flange 
45 thereof. The particle collection slots 50 and 52 are defined by a 
plurality of upright cylindrical strips 54, 56 and 58. The outer strip 54 
may be formed by bending the outer circumference of the flange 45 upward. 
The middle strip 56 and the inner strip 58 may be formed by cutting the 
plate material of the flange 45 in such a manner to allow the cut material 
to connect to the remaining material of the flange 45 along an edge 
thereof and then bending the cut material upward. Preferably, the inner 
and middle strips 56 and 58 are formed to have substantially the same 
height and the outer strip 54 has a less height. The outer and middle 
strips 54 and 56 together define the outer collection slot 50 therebetween 
and the middle and inner strips 56 and 58 together define the inner 
collection slot 52 therebetween. Preferably, the outer strip 54 is formed 
in a slightly upward diverging manner to incline outward. 
Alternatively, the strips 54, 56 and 58 may be formed by separate material 
and then fixed to the flange 45 of the particle collection member 36 or 37 
by means of, for example, welding or soldering. However, this alternative 
requires additional material and thus increases overall weight and cost. 
The magnet means 38 is so disposed between the flanges 45 of the upper and 
lower particle collection members 36 and 37 as to have the magnetic poles 
thereof located in the proximity of the particle collection slots 50 and 
52 of both the upper and lower particle collection members 36 and 37. This 
allows the ferrous metal particles to be attracted and collected within 
the particle collection slots 50 and 52 by the most powerful magnetic 
force that can by supplied by the magnet means 38. 
In an embodiment of the present invention, the particle collection members 
36 and 37 may be manufactured from steel plate of 0.3 mm thickness. The 
overall diameter of the particle collection members 36 and 37, is about 27 
mm and that of the recess 40 is approximately 16.5 mm. The central hole 44 
is about 3.6 mm in diameter. 
Unlike the conventional structure disclosed in, for example, U.S. Pat. No. 
5,228,990 which requires the size of the magnets to be limited within a 
strict range, the structure of the present invention allows the size of 
the magnet means 38 to be varied in a wider range so that the magnet means 
38 may comprise only a single large magnet in the form of a ring, as shown 
in the drawings. In accordance with the present invention, the magnet 
means 38 that is adapted by the present invention may generate a magnetic 
field that is as strong as 1,100 Gauss which may apply an attraction force 
of 180 grams to the ferrous metal particles. As compared to the 800 Gauss 
magnetic field that is used in some of the conventional devices, the 
present invention obviously provides a better ferrous metal particle 
removal rate than the conventional devices. 
Although it is shown in the drawings, that the magnet means 38 comprises 
only a single large magnet, it is also possible to use a number of small 
magnets disposed in the ring space 48 around the recesses 40 of the upper 
and lower particle collection members 36 and 37. Quite obviously, there 
are other different magnet means can be used to replace the one described 
in the preferred embodiment and shown in the drawings without departing 
from the spirit and scope of the present invention. 
The magnetic filtering means 26 also comprises a top member 60, preferably 
in the form of a circular pan as that shown in FIG 5, having a central 
recess 62 with a circumferential flange 64 mounted to and surrounding the 
recess 62. The central recess 62 is defined by a substantially flat bottom 
surrounded by an upward diverging side wall, the circumferential flange 64 
being attached to the diverging side wall. The top member 60 comprises a 
central hole 66 formed on the bottom of the recess 62, opposing the 
central hole 44 of the upper particle collection member 36. A fastener, 
such as rivet 70 (see FIGS. 3 and 4), extending in sequence through the 
central hole 32 of the base 28, the spacer 35, the central holes 44 of the 
upper and lower particle collection members 36 and 37 and finally the 
central hole 66 of the top member 60 to secure all these member together 
to form the magnetic filtering means 26. The magnet means 38 is retained 
between the upper and lower particle collection members 36 and 37 by their 
being secured together by the fastener 70. 
To avoid un-desired attraction to the ferrous metal particles by the 
fastener 70 and the top member 60 which interferes with the collection of 
the ferrous metal particles within the particle collection slots 50 and 
52, the fastener 70 and the top member 60 are preferably made of a 
non-magnetized or non-ferromagnetic material, such as aluminum. Also, the 
spacer 35 is preferably made of a non-ferromagnetic material, such as 
aluminum. 
The recess 62 of the top member 60 has such a depth that when the recess 62 
is secured within the recess 40 of the upper particle collection member 36 
by the fastener 70, the circumferential flange 64 thereof is spaced from 
the circumferential flange 45 of the upper particle collection member 36 
by a pre-determined distance, such as 5 mm, and the diverging side wall of 
the central recess 62 of the top member 60 is also spaced from the 
inclined side wall 41 of the recess 40 of the upper particle collection 
member 36 by a predetermined distance, such as 3.5 mm, so as to define an 
upper oil path 72 between the top member 60 and the upper particle 
collection member 36. 
In operation, the oil that contains ferrous metal particles is conducted to 
flow through both the upper path 72 above the upper particle collection 
member 36, as indicated by arrow A of FIG. 4, and the lower path 39 below 
the lower particle collection member 37, as indicated by arrow B of FIG. 
4. Both these two paths 172 and 39 bring the oil through nearby the 
particle collection slots 50 and 52 of the upper and lower particle 
collection members 36 and 37. As mentioned previously, the magnetic poles 
of the magnet means 38 are located in the close proximity of the particle 
collection slots 50 and 52 and thus the ferrous metal particles that are 
carried by the oil flow will be attracted and collected in the particle 
collection slots 50 and 52. The oil that flows through the upper path 72 
is further conducted to pass through the passages formed by the slots 46 
of the upper and lower particle collection members 36 and 37, as indicated 
by arrow C of FIG. 4 to join the oil flow through the lower path 39. All 
the oil will flow into the base 28 through the slots 34 formed on the top 
side of the base 28 to exit the oil filter 10 through the outlet 16. 
It is apparent that although the invention has been described in connection 
with the preferred embodiment, it is contemplated that those skilled in 
the art may make changes to the preferred embodiment without departing 
from the scope of the invention as defined in the appended claims.