JP2002191914A - Oil strainer and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid increase of suction resistance by extending a substantial filtering area. SOLUTION: The oil strainer 1 of an automatic gearbox is equipped with an oil strainer case 3, which has an oil inlet 13 and of which the central part is depressed so as to leave a peripheral flange 11 to form an oil chamber 12, a lattice-like flat retainer plate 4 joined to the peripheral flange 11 of the oil strainer case and the filter element 5 comprising a sheetlike nonwoven fabric held between the oil strainer case 3 and the retainer plate 4. A large number of beads 27 expanded toward the oil chamber 12 are formed to the filter element 5 within the region corresponding to the oil chamber by press molding. The filtering area is extended by the beads 27. Since the beads 27 form an individually independent shape, shape stability is high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil strainer for removing foreign matter from oil, and more particularly to an oil strainer suitable for filtering hydraulic oil of an automatic transmission of an automobile.

[0002]

2. Description of the Related Art In an automatic transmission widely used in automobiles, a control valve case which constitutes a hydraulic circuit including a spool valve is provided on a lower surface of a transmission housing accommodating an auxiliary transmission mechanism such as a planetary gear mechanism. Is mounted, and an oil pan is mounted so as to cover the lower surface of the control valve case. Hydraulic oil recovered in the oil pan is sucked up and circulated by an oil pump via an oil strainer. It has a configuration. Here, the oil strainer is
For example, as disclosed in Japanese Patent Application Laid-Open No. H10-85522, the flat valve is attached to the control valve case in an oil pan, and has a small vertical thickness along the shape of the space in the oil pan. It has a shape.

[0003] The oil strainer described in the above publication has a configuration in which a filter member made of a wire mesh is disposed so as to overlap a lattice-shaped retainer plate. As a filter material, a material using a nonwoven fabric tends to be adopted. In an oil strainer using such a nonwoven fabric, as a trade-off for high trapping performance, the suction resistance of the oil strainer increases, so it is necessary to secure a large filtration area.For example, the nonwoven fabric is folded into an envelope shape, A configuration that allows oil to pass therethrough is in practical use.

[0004]

However, as described above, in the configuration in which the nonwoven fabric is folded into an envelope,
Since the bag-shaped filter medium needs a portion to be connected to the oil inlet of the oil strainer case, and a gap serving as a flow path must be secured around the filter medium, the filtration area is actually large enough. It is not possible.

[0005] As an air cleaner element for filtering air, a structure in which a nonwoven fabric is folded so as to have a large number of pleats in order to increase a filtration area is known (for example, see Japanese Patent Application Laid-Open No. 8-257335). In the case of an oil strainer, since a large force acts on the filter medium as oil passes, simply pleating the non-woven fabric will result in insufficient shape stability, and the pleats may be deformed during actual use. The interval between the pleats may be shifted. In particular, in the filtration of high-temperature oil, it is difficult to keep the shape of each pleat.

[0006]

According to a first aspect of the present invention, there is provided an oil strainer having an oil inlet and an oil recessed at a center portion to form an oil chamber except for a peripheral flange. A strainer case, a flat retainer plate joined to a flange around the oil strainer case, and having a large number of openings formed therein; and the retainer plate sandwiched between the oil strainer case and the retainer plate. A filter element made of a non-woven fabric in which a large number of protrusions swelling toward the oil chamber are formed in a region corresponding to the oil chamber and having a sheet shape disposed along the oil chamber. It is characterized by that.

According to a second aspect of the invention, which is a more specific version of the first aspect of the invention, the protruding portion includes an elongated bead and includes a bead having a different cross-sectional shape or length.

The above oil strainer case is combined with another oil strainer case, or
It is directly fixed to a housing or the like provided with an oil pump. The oil then flows into the oil chamber from the oil inlet and flows across the filter element.

The filter element is basically in the form of a sheet, and is firmly supported from the back by a retainer plate having a large number of openings. The filter element has a large number of protrusions formed by press forming, which bulges toward the oil chamber, so that the filter area is enlarged and the filter element is substantially adhered to a portion having no opening of the retainer plate. A significant loss of filtration area is avoided.
For example, it is possible to secure a filtration area twice or more as large as the projected area of the opening of the oil chamber in which the filtration element is provided. Here, since the protrusions are press-formed in a sheet-shaped nonwoven fabric in an independent form, the shape stability is high.

According to a second aspect of the present invention, beads having different cross-sectional shapes and different lengths may be formed in consideration of the flow of oil in the oil chamber or the height of each part of the oil chamber. It is possible.

Further, according to the third aspect of the present invention, the oil chamber has a mounting portion formed by abutting a boss portion provided on an oil strainer case with a retainer plate at a central portion of the oil chamber. The filter element is sandwiched between the portion and the retainer plate, and a portion of the filter element corresponding to the mounting portion is flat without the projection.

The mounting portion is used for mounting an oil strainer. For example, the oil strainer is fixed to a valve case or the like of an automatic transmission by a bolt penetrating the mounting portion. When the mounting portion is located at the center in this manner, the substantial oil chamber is formed in a ring shape around it, but the projection of the filter element corresponds to the substantial oil chamber. Is formed. In other words, the protrusions can be properly arranged while leaving the attachment portion.

[0013] The invention of claim 4 relates to a method of manufacturing such an oil strainer, wherein an oil strainer case having an oil inlet and having a central portion depressed so as to form an oil chamber while leaving a peripheral flange. When,
A flat retainer plate joined to a flange around the oil strainer case and having a large number of openings formed therein, sandwiched between the oil strainer case and the retainer plate, and arranged along the retainer plate; A filter element made of a non-woven fabric in which a large number of projections swelling toward the oil chamber are formed in a region corresponding to the oil chamber, and a filtration element formed of a non-woven fabric. In the manufacturing method, after the filter element is impregnated with a thermosetting resin into a non-woven fabric obtained by mixing a low-melting binder fiber with a base fiber, and preheating this at a temperature lower than the melting point of the binder fiber, Hot-press molding at a mold temperature near the melting point of the binder fiber to form the projections. .

For example, polyester having a melting point of about 260 ° C. is used as a fiber serving as a base material of the nonwoven fabric, and polyester having a melting point of about 200 ° C. is used as a binder fiber. In the case of a nonwoven fabric having such a melting point, the preheating temperature is suitably from 80 ° C. to 130 ° C., and the die temperature for hot press molding is from 190 ° C. to 2 °
10 ° C. As the thermosetting resin, for example, the above-mentioned phenol resin that cures at 190 ° C. to 210 ° C. is used. By mixing the binder fibers having a relatively low melting point as described above, the intersections of the fibers are bonded by hot press molding, and further, the thermosetting resin is cured, so that the shape of the projections is reliably maintained. In particular, by including a thermosetting resin, the shape of the projection is maintained even when used for filtering high-temperature oil. In addition, it is also possible to use a lower melting point polyester as the binder fiber as the low melting point polyester.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an embodiment of an oil strainer 1 according to the present invention. This oil strainer 1
Is used for an automatic transmission of an automobile as described above, and is attached to the lower surface of the control valve case 2 and filters oil sucked up by an oil pump (not shown).

The oil strainer 1 includes an oil strainer case 3 formed by press-forming a metal plate, a lattice-shaped retainer plate 4 formed of a flat metal plate, and a gap between the oil strainer case 3 and the retainer plate 4. And a filter element 5 made of a sheet-like nonwoven fabric sandwiched between the filter elements.

As shown in FIG. 2, the center portion of the oil strainer case 3 is depressed so as to form an oil chamber 12 while leaving a flange 11 around the oil strainer case 3. Oil inlet 1 opening toward
3 is formed in a cylindrical shape. A mounting hole 15 through which the mounting bolt 14 penetrates is appropriately formed in the flange 11. Further, in this embodiment, a boss portion 16 serving as an attachment portion is formed in a cylindrical shape at the center of the oil chamber 12, and its tip end surface is configured to have the same plane as the surrounding flange 11. At the same time, a mounting hole 17 through which the mounting bolt 14 passes is formed at the center.

As shown in FIG. 3, the retainer plate 4 is provided with a flange 11 of the oil strainer case 3.
It has an outer shape along the outer edge and is integrated with the oil strainer case 3 by winding the outer peripheral edge together with the flange 11 as shown in FIG. The retainer plate 4 has a large number of openings 18 except for a portion corresponding to the flange 11, and is formed in a lattice shape formed of thin beams. The opening 18 has a substantially triangular shape except for the peripheral portion. Further, a mounting hole 19 corresponding to the mounting hole 15 is formed in a peripheral portion overlapping the flange 11. Further, a circular portion 20 having no opening 18 is provided corresponding to the boss portion 16, and at the center thereof,
A mounting hole 21 corresponding to the mounting hole 17 is open.

The filter element 5 made of a nonwoven fabric is shown in FIG.
As shown in FIG. 5 and FIG. 5, it has an outer shape along the outer edge of the flange 11 of the oil strainer case 3 and the outer edge of the retainer plate 4, and is disposed along the retainer plate 4. Flange 11
And the periphery of the retainer plate 4.
In addition, the mounting hole 1 is also provided around the filtering element 5.
The through-holes 25 corresponding to the mounting holes 17 and 21 are opened in the center part. A large number of projections, more specifically, a large number of elongated beads 27 are formed on the filtration element 5 by hot press molding, which will be described later. This bead 2
7 is a region excluding a peripheral portion sandwiched between the flange 11 and the peripheral portion of the retainer plate 4, that is, an oil chamber 12;
And bulges toward the oil chamber 12 with a substantially U-shaped or substantially V-shaped cross-section as shown in FIG. In this embodiment, a number of beads 27 are formed in parallel with each other as shown in FIG. 4, and each length is set corresponding to the width of each part of the oil chamber 12. Further, the width and height of the cross-sectional shape of each bead 27 are all set equal. Further, no bead 27 is formed around the through hole 26, specifically, in a range corresponding to the boss portion 16, so that the bead 27 is formed on both sides thereof in a divided form.

When the filter element 5 is assembled together with the oil strainer case 3 and the retainer plate 4, as shown in FIG.
And the periphery of the retainer plate 4, and the periphery of the through hole 26 is sandwiched between the boss portion 16 serving as an attachment portion and the circular portion 20 of the retainer plate 4.
Therefore, even in this assembled state, each bead 27 is not crushed by the oil strainer case 3 but swells as it is in the originally formed shape.

The oil strainer 1 configured as described above
Is, for example, a suction port 31 directly attached to the control valve case 2 and communicating with an oil pump (not shown).
It is arranged so as to partition between the low-pressure chamber 32 provided with.
Accordingly, oil collected in an oil pan (not shown) enters the oil chamber 12 from the oil inlet 13 and flows through the filter element 5 to the low-pressure chamber 32, where the oil is collected by the suction port 31.
Sucked into.

Instead of forming the low-pressure chamber 32 in the control valve case 2, an upper oil strainer case made of a metal plate is provided, and the low-pressure chamber 32 is formed in the upper oil strainer case. Oil strainer case and the above oil strainer case 3
May be configured to be attached to the control valve case 2.

According to the structure of the above embodiment, since the filtration element 5 made of a nonwoven fabric is provided with a large number of beads 27, the filtration area is increased, for example, twice or more the opening area of the oil chamber 12. The filtration area can be secured. In addition, a portion of the retainer plate 4 that is in close contact with the beam portion is reduced, and a substantial decrease in the filtration area due to close contact between the two can be minimized. Therefore, it is possible to ensure high capture performance by the nonwoven fabric and to avoid an increase in suction resistance. When oil passes through the filter element 5, the filter element 5 receives a relatively large force. However, the filter element 5 is supported from the back by the retainer plate 4, and each bead 27 is individually independent. Since the bulge is formed in the shape, the shape stability is high, and the bead 27 is not crushed or offset by the fluid pressure. Also, a boss 1 serving as an attachment portion is provided at the center.
Even if 6 is present, it is possible to minimize the reduction of the filtration area.

The filtration element 5 has a melting point of 260 ° C.
A polyester fiber having a melting point of about 200 ° C. is added to the base polyester fiber as a base fiber and a binder fiber is added to the base fiber, and a sheet-like nonwoven fabric impregnated with a phenol resin which is a thermosetting resin is used. Then, the sheet-shaped nonwoven fabric is heated to 80 ° C.
After preheating to 130 ° C., hot press molding is performed. As for the pressing conditions, the mold temperature is set to 190 ° C. to 210 ° C. and pressure is applied for about 20 to 40 seconds at which the phenol resin is sufficiently cured in order to complete the shape retention after molding.

By adding a phenol resin and performing hot press molding, the shape of the bead 27 can be reliably maintained even when used for filtering high-temperature oil.

In the present invention, the shape of the bead 27 serving as a projection can be arbitrarily changed, and the degree of design freedom is high. Therefore, considering the shape of the oil chamber 12, the position of the oil inlet 13, the direction in which the oil flows, and the like, the beads 27
Can be optimally configured in size, shape or arrangement.

As an example, FIG. 7 shows an embodiment of the filter element 5 in which the cross section of each bead 27 has a different height and width. This is in consideration of the height of the oil chamber 12, and by increasing the height of the bead 27 in the central portion where the height of the oil chamber 12 is large, the filtration area is further enlarged.

FIG. 8 shows an embodiment in which the arrangement of the beads 27 is changed in consideration of the oil flow. As shown in this example, the beads 27 need not be simple straight lines.

[0030]

As is apparent from the above description, according to the oil strainer of the present invention, the substantial filtration area of the filtration element can be greatly expanded by the projections formed on the nonwoven fabric. In addition, it is possible to ensure a high capturing performance by the nonwoven fabric, and to avoid an increase in suction resistance. And since the filtration element is supported from the back by the retainer plate and each projection is formed to bulge into an independent shape,
The shape stability is high, and the desired filtration area can be maintained without being crushed or offset by the fluid pressure.

Further, according to the method for manufacturing an oil strainer according to the present invention, even when used for filtering high-temperature oil, the shape of each projection can be reliably maintained and good filtration performance can be maintained. it can.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view taken along line AA of FIG. 2 showing one embodiment of an oil strainer according to the present invention.

FIG. 2 is a plan view of an oil strainer case.

FIG. 3 is a plan view of a retainer plate.

FIG. 4 is a plan view of a filtration element.

FIG. 5 is a perspective view of a filtration element.

FIG. 6 is a sectional view of the filtration element taken along line BB of FIG. 4;

FIG. 7 is a sectional view similar to FIG. 6, showing a different embodiment of the filtration element.

FIG. 8 is a plan view showing still another embodiment of the filtration element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Oil strainer 3 ... Oil strainer case 4 ... Retainer plate 5 ... Filtration element 12 ... Oil chamber 16 ... Boss 27 ... Bead

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J063 AA02 AC04 BA01 BA10 BA11 CA01 CD70 XA25 XC10 XD03 XE04 XF21 4D064 AA23 BM13

Claims (4)

[Claims] 1. An oil strainer case having an oil inlet and having a central portion depressed so as to form an oil chamber while leaving a peripheral flange, and a plurality of openings joined to the peripheral flange of the oil strainer case. A flat retainer plate having an opening formed therein is formed between the oil strainer case and the retainer plate, and has a sheet shape disposed along the retainer plate, and has an area corresponding to the oil chamber. An oil strainer comprising: a filtration element made of a nonwoven fabric in which a large number of projections swelling toward the oil chamber are press-formed. 2. The projection according to claim 1, wherein the projection comprises an elongated bead,
The oil strainer according to claim 1, further comprising beads having different cross-sectional shapes or lengths. 3. A central portion of the oil chamber has a mounting portion formed by abutting a boss provided on an oil strainer case with a retainer plate. In the mounting portion, the mounting portion is provided between the boss and the retainer plate. The oil according to claim 1, wherein the filter element is sandwiched, and a portion of the filter element corresponding to the mounting portion is flat without the projection. strainer. 4. An oil strainer case having an oil inlet and having a central portion depressed so as to form an oil chamber while leaving a peripheral flange, and a plurality of openings joined to the peripheral flange of the oil strainer case. A flat retainer plate having an opening formed therein is formed between the oil strainer case and the retainer plate, and has a sheet shape disposed along the retainer plate, and has an area corresponding to the oil chamber. A filter element comprising a non-woven fabric formed by press-molding a large number of protrusions swelling toward the oil chamber, wherein the filter element comprises a low melting point binder fiber as a base material. Impregnated with a thermosetting resin into a non-woven fabric mixed with the fibers of After preheating at a low temperature, and heat-pressed at mold temperature near the melting point of the binder fibers, the production method of the oil strainer and forming the protrusion.