Iron powder attracting magnet

An iron powder attracting magnet, wherein a plurality of spaces are formed to open to an iron powder attracting surface and partitioned by a partition for attracting and removing iron powder contained in a fluid. The iron powder attracting magnet is made of a magnetic material which is prepared by impregnating a strontium ferrite into a synthetic resin.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an iron powder attracting magnet for 
attracting and removing iron powder contained in a fluid such as a liquid. 
2. Description of the Prior Art 
In a transmission or a differential gear to be used in an automobile or an 
industrial vehicle, for example, oil is used for lubrication so as to 
prevent a plurality of gears for drive power transmission from seizing and 
wearing. As the running time elapses, the gears will wear so that the 
resultant iron powder will mix into the oil. This iron powder will raise 
problems to wear the gears abnormally and to accelerate the aging of the 
oil. Efforts have been made to solve those problems by mounting an iron 
powder attracting magnet in a transmission case or a gear case which 
accommodates the gears and stores the oil, to attract and remove the iron 
powder from the oil. 
As shown in FIGS. 7 and 8, iron powder attracting magnets 1a and 1b 
existing in the prior art have rectangular or disc shapes and are made of 
a sintered magnetic material. These magnets 1a and 1b have their upper 
surfaces 2 act as iron powder attracting surfaces to attract and remove 
the iron powder. 
Since the iron powder attracting magnets of the prior art are made of a 
sintered magnetic material, as described above, they are heavy and liable 
to crack, chip or break. From the molding restrictions, the magnets cannot 
be molded into other than the simple shapes such as the rectangular or 
disc shapes, as shown in FIGS. 7 and 8. Thus, the magnets have a small 
degree of freedom of the shapes, a low sizing accuracy and a restriction 
upon the attracting ability. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide an iron powder attracting 
magnet which can be lightened without lowering the iron powder 
attractability and can be formed into an arbitrary shape with an excellent 
sizing accuracy. 
According to the present invention, there is provided an iron powder 
attracting magnet which is made by molding a magnetic material of a 
synthetic resin and includes: a plurality of spaces opened to an iron 
powder attracting surface; and a partition partitioning said spaces. 
By using a synthetic resin as the magnetic material, the iron powder 
attracting magnet of the present invention can be molded into a shape 
having a plurality of spaces, by which a surface area is increased and a 
magnetic field for attracting the iron powder is exerted to effectively 
attract the iron powder. 
The other objects and features of the present invention will become 
apparent from the following description with reference to the accompanying 
drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In FIG. 1, there is shown a first embodiment of the present invention, 
which is sized and shaped according to the iron powder attracting magnet 
1a having been described in connection with the prior art with reference 
to FIG. 7. An iron powder attracting magnet 11a is made of a magnetic 
material of a synthetic resin, which is prepared by impregnating a 
magnetic material of strontium ferrite into a synthetic resin such as 
nylon. The magnet 11a is formed into a rectangular shape by a rectangular 
frame 12 formed therein with a pair of rectangular spaces 14 opened to 
upper and lower surfaces 13, which are partitioned by a partition 15 to 
provide upper and lower regions of N and S poles, respectively. 
In FIG. 2, on the other hand, there is shown a second embodiment which is 
sized and shaped according to the iron powder attracting magnet 1b having 
been described in connection with the prior art with reference to FIG. 8. 
An iron powder attracting magnet 11b is also made of a magnetic material 
of a synthetic resin, which is prepared by impregnating a magnetic 
material of strontium ferrite into a synthetic resin such as nylon. The 
magnet 11b is formed into a disc shape by an annular frame 12 formed 
therein with a plurality of sector spaces 14 opened to upper and lower 
surfaces 13, which are partitioned by perpendicularly crossing particles 
15 to provide upper and lower regions of N and S poles, respectively. 
Moreover, the iron powder attracting magnets 11a and 11b of the 
aforementioned respective embodiments are made of a material of the 
synthetic resin so that they are resistant against impact, tension and 
bending and are not likely to crack, chip or break. Thus, the magnets 11a 
and 11b can be easily molded highly accurately into complicated shapes. 
Still moreover, the magnets 11a and 11b are free from changes in shape and 
magnetic force when they are used in a transmission or the like at normal 
service temperature as will be described later. 
The comparisons between the iron powder attracting magnets 11a and 11b of 
the above embodiments and the iron powder attracting magnets 1a and 1b 
made of the sintered magnetic material according to the prior art will be 
enumerated in the following table: 
__________________________________________________________________________ 
Iron Powder Attracting Magnets 
__________________________________________________________________________ 
Sintered Molded of Synthetic Resin 
Shape Small Freedom .fwdarw. Simple 
Large Freedom .fwdarw. Complex 
Low Sizing Accuracy 
High Sizing Accuracy 
Magnet 1a .fwdarw. 27 g 
Magnet 11a .fwdarw. 
10 g 
Magnet 1b .fwdarw. 43 g 
Magnet 11b .fwdarw. 
14 g 
Weight Magnet 11a .fwdarw. 
Reduction of 17 g (63%) 
Magnet 11b .fwdarw. 
Reduction of 29 g (67%) 
Magnet 1a .fwdarw. 950-1,000 gausses 
Magnet 11a .fwdarw. 
930-960 gausses (on Surface) 
Density of 
Magnet 1b .fwdarw. 1400-1450 gausses 
200-220 gausses (at Space Center) 
Magnetic 
Flux on Magnet 11b .fwdarw. 
740-800 gausses (on Surface) 
Surface 200-220 gausses (at Space Center) 
Amount of Iron 
Magnet 1a .fwdarw. 21.7 g 
Magnet 11a .fwdarw. 
21.7 g 
Powder 
Attracted 
Magnet 1b .fwdarw. 27.3 g 
Magnet 11b .fwdarw. 
31 g 
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Incidentally, the above comparisons are accomplished by giving the same 
respective external sizes to the corresponding magnets of the rectangular 
or disc shape and by using the upper surface 2 of the iron powder 
attracting magnets 1a and 1b and the upper surface 13 (including the inner 
sides facing the spaces 14) of the iron powder attracting magnets 11a and 
11b as the iron powder attracting surfaces. 
First of all, in terms of the shape, the magnets made of the sintered 
magnetic material have a small degree of freedom in shape so that their 
shapes are restricted to simple ones with a low sizing accuracy because of 
their molding characteristics. In the case of the magnetic material of the 
synthetic resin, on the other hand, the magnets can be easily molded just 
as with usual synthetic resin and have a large degree of freedom in shape 
so that they can be formed into such a complex shape as to increase the 
iron powder attractability and to permit flexibility in mounting place and 
manner with a high sizing accuracy. 
In terms of weight, on the one hand, the magnets made of the sintered 
magnetic material have a weight of 27 g in the case of the rectangular 
magnet 1a and a weight of 43 g in the case of the disc magnet 1b. Since, 
on the other hand, the molded magnets of the synthetic resin are lighter 
because of their lighter material and several spaces 14 formed therein, 
the rectangular magnet 11a is as light as 10 g, and the disc magnet 11b is 
as light as 14 g. This means that the rectangular shape has the weight 
reduced by 17 g whereas the disc shape has the weight reduced by 29 g, or 
63 and 67% reduction. 
In terms of density of the magnetic flux on the surface, in the case of the 
sintered magnetic material, the iron powder attracting magnet 1a having 
the rectangular shape has a density of 950 to 1,000 gausses whereas the 
iron powder attracting magnet 1b having the disc shape has a density of 
1,400 to 1,450 gausses. In the case of the magnetic synthetic resin, on 
the other hand, the rectangular-shaped iron powder attracting magnet 11a 
has density of 930 to 960 gausses on the surface and 200 to 220 gausses at 
the center of the spaces 14 whereas the disc-shaped iron powder attracting 
magnet 11b has density of 740 to 800 gausses on the surface and 200 to 220 
gausses at the center of the spaces 14. This means that only a small 
reduction occurs in the density of magnetic flux. Here, the reason why the 
magnetic fluxes are generated in the spaces 14 is that the individual 
magnetic fields of the frame 12 and the partitions 15 of the iron powder 
attracting magnet 11b act as inverse magnetic fields in the individual 
spaces 14, as seen from the analytic diagram of the magnetic fields of 
FIG. 4 (which presents the sectional view taken on line IV--IV of the iron 
powder attracting magnet 11b and is similar to that of the other magnet 
11a). The magnetic forces at the respective centers of the inverse 
magnetic fields in the spaces 14 are as high as 200 to 220 gausses in 
terms of the values of inverse magnetic poles, which are sufficient for 
attracting the iron powder. 
In terms of the amounts of the iron powder attracted, the 
rectangular-shaped magnet 1a of the sintered magnetic material has an 
amount of 21.7 g whereas the disc-shaped magnet 1b has an amount of 27.3 
g. In the case of the molded magnets of the synthetic resin, on the other 
hand, the formation of the spaces 14 increases the surface area such that 
the disc-shaped magnet 11b provides an increased amount of 31 g although 
the rectangular magnet 11a provides a substantially equal amount of 21.7 
g. 
In terms of the amounts of the iron powder attracted, moreover, the iron 
powder can be collected toward and stored at the centers of the spaces 14 
by the actions of the aforementioned inverse magnetic fields generated in 
the spaces 14. This storage of the iron powder in the spaces 14 allows the 
magnets to exhibit a higher attractability than the prior art in which the 
iron powder is attracted only by one side of each of the surfaces. 
The shape may be modified, as in a third embodiment shown in FIG. 3, such 
that a disc-shaped iron powder attracting magnet 11c is molded to have its 
inside partitioned into three spaces 14 of the same size by partitions 15. 
The magnet shape may be further modified by arbitrarily setting the 
external shape and the shape, size and the number of the spaces 14. These 
modifications can be made tailored to any shape because the magnets are 
molded of the synthetic resin, as has been described hereinbefore. 
Therefore, the iron powder attracting magnets 11a, 11b, and 11c, include a 
magnet having opposite sides and a periphery and further having a 
plurality of unconnected spaces located inwardly of the periphery and 
opening to the opposite sides so as to define a partition between each 
pair of adjacent spaces, where the number of spaces equal the number of 
partitions, and so as to define an outer frame portion located between 
each space and the outer periphery, all surfaces of the magnetic surfaces 
capable of removing iron powder contained in fluid in contact with magnet, 
each outer frame portion and each partition exhibiting a magnetic field, 
and, with respect to a given space, the outer frame portion confronting 
the given space exhibits a polarity in the given space which is opposite 
to the polarity in the given space exhibited by the partition confronting 
the given space. Each partition may have one end connected to the outer 
frame portion of the magnet and the other end connected to the other 
partitions. 
Turning to FIGS. 5 and 6, the use of the iron powder attracting magnet 11a 
(or the magnets 11b and 11c of the other embodiments) will be described in 
the following. FIG. 6 shows a transmission 21 for an automobile or other 
industrial vehicles, in which the rotations of an engine are transmitted 
in a variable speed through various gears 22 to a drive shaft 23. A case 
24 for accommodating those gears 22 and drive shaft 23 is charged with oil 
25 for lubricating the gears 22 to prevent the same from seizing or 
wearing. Here, the iron powder attracting magnet 11a is fitted in a 
mounting groove 27 of a mounting frame 26, which is formed in a position 
immersed in the oil 25 at the bottom of the case 24. Thus, the magnet 11a 
is in direct contact with the oil 25 so that it attracts and removes the 
iron powder which is generated due to the wear of the gears 22 and 
contained in the oil 25, to prevent the gears 22 from abnormal wear and 
the oil 25 from aging. Incidentally, the iron powder attracting magnet 11a 
may be mounted on the case 24 by means of mounting fittings or bolts. 
In addition, the use of this magnet 11a should not be limited to the 
transmission 21 but can be applied to a differential gear or the like. 
By using a synthetic resin as the material for the iron powder attracting 
magnet, according to the present invention, the magnet can be lightened 
and formed into an arbitrary complicated shape having a plurality of 
spaces with high sizing accuracy. Moreover, the spaces can retain a 
sufficient surface area and can establish magnetic fields therein for 
attracting the iron powder so that the iron powder attractability can be 
enhanced to attract and remove the iron powder very effectively.