FR2486413A1 - FILTER FOR HYDRAULIC TRANSMISSION FLUID - Google Patents

Abstract

THE INVENTION RELATES TO A FILTER FOR HYDRAULIC TRANSMISSION. IT RELATES TO A FILTER INCLUDING, BETWEEN A TANK 12 AND A LID 20, A FILTRATION MATERIAL INCLUDING A FINE FILTRATION FELT 50 HAVING AN OPENING COVERED BY A COARSE FILTRATION MATERIAL 54. IN COLD, MATERIAL 54 TRANSMITS THE MINIMUM FLOW. THEN THE FINE FILTRATION MATERIAL 50 REMAINS THE SMALLEST PARTICLES. APPLICATION TO HYDRAULIC TRANSMISSIONS OF MOTOR VEHICLES.

Description

The present invention relates to filters for the fluid of

  hydraulic transmissions and more precisely

  continuous flow filters for transmission

  hydraulic systems with a predetermined minimum temperature

  operation. In transmissions for medium-sized automobiles, a filter for the transmission fluid, having a formed active material, is commonly used.

  a canvas or grid of natural or synthetic fibers

  theories or wire, for example. These materials

  filtration systems can retain particles with a di-

  or average diameter of 130 microns and have been used satisfactorily for a number of years. However, the current trend towards

  dimensions of automobiles, and in particular of the structure

  transmission, requires more efficient filtration.

  ficace, up to particle sizes of the order of

  microns for example. Filtration materials have been proposed.

  to improve particle filtration

  in the transmission fluid, up to a smaller di-

  particle size. However, under cold start and operating conditions, when the transmission fluid has significantly thickened, little fluid passes through the filter felt and thus prevents normal gear shifting and operation.

the transmission.

  The invention relates to a filter for transmitting

  to provide a minimum flow rate of transmission fluid necessary for proper operation of the transmission at a minimum operating temperature, predetermined by the transmission manufacturer and which, under the conditions

  normal operation, has an increased efficiency of

  compared to conventional web filters and grids.

  Other features and advantages of the

  will become apparent from the following description,

  with reference to the accompanying drawings, in which: - Figure 1 is a plan view of a first embodiment of filter for transmission fluid; according to the invention - Figures 2 and 3 are sections along the lines 2-2 and 3-3 respectively of Figure 1; and - Figure 4 is an exploded perspective of the

filter of Figures 1 to 3.

  The illustrated transmission fluid filter embodiment comprises a base vessel having

  a substantially flat bottom 12 having ribs or

  parallel and longitudinal lies 14 which protrude upwards. A peripheral flange 16 is placed around the tank, at a distance from the plane of the wall 12. A cover 18 has a substantially flat wall 20 and several parallel and longitudinal ribs 22 which protrude towards the wall.

  low and are in solidarity. A peripheral edge 24

  turn the cover 18 and is at a distance from the plane of the wall 20 as clearly indicated in FIGS. 2 and 3. A filter element 26, in the form of a sheet

  elongated rectangle, is folded in the direction of its

  geur and is placed between the cover 18 and the tank 10, the three unfolded edges of the element 26 being arranged around the flange 16. A flange 28 secured to the flange 16

  and protruding from it is crimped on a lip 30 exceeding

  radially from the rim 24 of the cover so that it

  hold the filter element and the lid against the

rim of the tank.

  An inlet port 32 (FIG. 4) formed in the element 26 is aligned with a corresponding inlet orifice 34 of the cover 20, and is sealingly secured by an eyelet 36 whose circumference is continuous. A

  suction pipe 38 rises from a port 40 of

  formed in the cover 18 and is placed at the remote end 42 of the cover so that it is force-fitted into the fluid suction port of a pump 44. An annular lip 46 surrounds the tubing 38, at the area

  externally, so that the introduction of the suction pipe

  in the housing 44 of the pump is limited. The pipe

  terie 38 thus has the dual role of connecting the orifice 40

  output of the filter to the housing 44 of the pump, and sus-

  hang the filter in a housing containing the transmission fluid as represented by the reference 46 on the

  Figure 3. The arrows in Figure 3 indicate that the fluid

  of transmission is sucked through the orifice 36 into the

  between the folded and intermediate planar parts

  components of the filter element 26, and passes through the

  before penetrating the cavities de-

  The filtered fluid then circulates between the ribs 14 supporting the base and the ribs 22 of the lid (which also support the parts of the filter which are subjected to the suction of the filter). pump 44) to the outlet port 40 and then to the suction pipe 38 and the pump housing. The base tank 10 is preferably in the form of a stamped metal sheet. The cover 18 and the pipe 38 are advantageously formed by molding in

  one piece of a nylon reinforced with fibers ("nylon").

  According to the invention, the filter element 26 is a composite assembly comprising a first material 50

  fine filtration in the form of a sheet having a

  or a port 52 in its filtering surface, and a second coarse filtration material 54 attached to the material 50 on the orifice 52. The materials 50 and 54 form parallel and separate continuous paths of the circulation of the penetrating transmission fluid. eyelet 36. He

  It is clear that the amount of fluid that

  material 50, 54 depends on the resistance opposed by the corresponding material, depending in turn on the

  viscosity and temperature of the fluid. According to one

  important feature of the invention, the ratio of

  surfaces of the coarse filtration material 54 and the

  50 of fine filtration is empirically chosen

  minimum ratio which is sufficient for the circulation of a

  of the transmission fluid required for

  at a particular minimum temperature predetermined by the transmission manufacturer. In other words,

  the surface or amount of filtration material 54

  is equal to the minimum area required for

  the minimum flow required at a minimum temperature of

  specified number of operations, and the rest of the

  filtering element 26 is formed by the filter material 50.

  which is more efficient. This report of

  faces is determined by operating a transmission at the specified minimum temperature and by varying the

  ratio of coarse and fine filtration

  that the fluid flow obtained has the minimum value

  male. It is advantageous for the coarse dewatering material to be in the form of a 0.21 mm polyester monofilament web that can retain particles of at least 130 microns in size. The

  fine filtration material 50 is an im-

  phenolic resin-impregnated, able to retain particles having a minimum size of 60 microns. In the particular filter shown, the coarse filter 54 occupies 15%

  about the total filtration area. This construction

  The particular flow rate gives the minimum flow required for

  temperature of -340C, for a typical transmission of

  as indicated by tests.

  It should be noted that the particular filter represented

  suitable for a particular transmission. However,

  can be applied to other types of filters

  coming to other types of transmissions. Two filters

  Additionally, other filtration materials than polyester webs and resin-impregnated polyester felts can be used, as can be seen in US Pat. No. 4,136,011. desired filtration should be larger or smaller. Likewise, the ratio of the coarse and fine filtration surfaces of the composite filter

  according to the invention varies according to the structure of the

  the nature of transmission and temperature

  predetermined minimum operating level, as indicated in

cédemment. -

Claims (5)

  1. Filter for transmission fluid, of the type that   includes a filter element, a support of this element   ment, allowing circulation of the transmission fluid in the element to a cavity defined between the support and the filter element, and a fluid outlet out of the cavity, said filter being characterized in that it comprises a material (50 ) of fine filtration carried in a plane   and having an opening (52), and a filter material (54)   coarse, fixed to the fine filter material and covering the opening (52) in the plane of the fine filter material, so that fine and coarse filtration materials form parallel continuous paths   and separated from circulation of the filtered fluid to the cavity.   2. Filter intended for a circulation circuit of   fluid of an automobile transmission having a temperature   predetermined minimum operating temperature and   both a minimum flow of fluid to operate at said   predetermined minimum operating temperature, the   said filter being of the type which comprises a casing having an unfiltered fluid inlet and an outlet, and a filter material placed in the casing between the inlet and the outlet, said filter being characterized in that the filter material comprises separate fine and coarse filtering materials (50, 54) arranged in such a manner that the fluid flows continuously in parallel through said materials, the ratio of the surfaces of the coarse filtration material (54) to the material (50) fine filtration with a minimum value that is sufficient for the flow   the minimum value at the minimum temperature operation.   3. Filter according to one of claims 1 and 2,   characterized in that the bulk filtration material (54) is   is a web of fibers, and the material (50) of filament   Fine tration is a felt impregnated with resin.   4. Filter according to claim 3, characterized in   what the ratio of the surfaces of the filament material (54)   coarse treatment with fine filtering material (50) is substantially equal to 85/15.   5. Filter according to one of claims 1 and 2,   characterized in that the filter material (54) is   is a 0.21 mm polyester monofilament web capable of retaining 130 micron diameter particles, and the fine filtering material (50) is a polyester felt impregnated with phenolic resin, capable of   retain particles of diameter equal to 60 microns.