Abstract:
A filter for use in engines or transmissions is provided comprising an inlet-side cover having a wave-like region along the periphery of the inlet-side cover, an outlet-side cover having a wave-like region along the periphery of the outlet-side cover where the outlet-side cover wave-like region is in a complementary alignment with the inlet-side cover wave-like region and filter media fixed in a non-planar configuration between the wave-like regions of the inlet-side and outlet-side covers.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to transmission or engine filters. More particularly, the present invention relates to non-planar media suction filters for transmissions or engines. 
     BACKGROUND OF THE INVENTION 
     In response to industry demand, transmission and engine manufacturers continue to optimize the size of their transmissions and engines. Accordingly, transmission and engine manufacturers have required smaller components from their suppliers. The imposition of smaller spatial constraints has introduced a number of challenges to suppliers of transmission and engine components, particularly in the area of filtration. 
     In many cases, spatial constraints have reduced the available footprint for a powertrain filter. The reduced filter footprint has reduced the available filter media surface area inside the filter. In some cases, the reduced surface area provided by conventional filter media and filter designs has introduced a number of problems including maintaining a low pressure differential across the filter during cold start-up as well as during high temperature operating conditions. As one skilled in the art will readily appreciate, maintaining a low pressure differential across the filter during cold start facilitates quick priming of the fluid pump. As one skilled in the art will also appreciate, maintaining a low pressure differential across the filter during hot operation prevents pump cavitation. 
     One approach to providing a low pressure differential across a filter, given a limited packaging space, has been to use less efficient filtration media. Less efficient media is less restrictive, which permits fluids to pass through the media more freely, resulting in a lower pressure differential. One drawback to this approach, however, is that using filter media that is less efficient allows larger contaminants to pass through the filter. Allowing larger contaminants to pass through the filter media is not desirable because the presence of large contaminants in the system may lead to poor shift quality or premature failure of the transmission. Another drawback to this approach is that as the filter gets smaller, the available media area also reduces causing the velocity through the media to increase resulting in lower filtration efficiency. 
     Another approach to providing a low pressure differential across a filter given a limited surface area has been to increase the surface area of the filter media by using it in a non-planar configuration. The most predominant non-planar media configuration that substantially improves surface area is pleating. Pleating the filter media provides a greater surface area than filter media used in a conventional bag or single layer filter configuration. The increased surface area of the filter media serves to lower the pressure differential across the filter media. One of the drawbacks to prior filter design approaches using pleated filter media is that these designs are expensive. Prior pleated filter designs have been more expensive to manufacture than a conventional transmission filter. One prior design approach requires several plastic joining operations whereas the manufacturing process for a conventional filter having media in single layer or bag format may only require one plastic joining or metal crimping operation. For example, one design of prior pleated filters requires a separate manufacturing process to form the filter media into pleats by creating a pleat-pack by way of over-molding or urethane casting. Once a pleat pack has been manufactured, the pleat pack is joined in a first plastic joining operation to a first cover and then joined to a second cover in a separate plastic joining operation. Another drawback to pleated existing non-planar media configurations is that they hold the media in a “saw-tooth” configuration in which the fluid cross-section, in the direction of fluid flow, decreases along the pleat until reaching a line at the apex of the pleat. This reduction in fluid flow area results in a higher pressure differential than would be provided by gradually reducing fluid cross-section as would be provided by more of a “trapezoidal wave” or sinusoidal non-planar fold media configuration. Some designs that make use of standard pleats hold the filter media folded at a very tight angle, perhaps as small as 15°. In such a design, the initial pleating operation may damage the media at the outset. Another drawback of such a design is that by holding the media at tight angles under high fluid velocities may result in media damage and cause lower filtration efficiency. 
     Accordingly, it is desirable to provide a transmission filter with a sufficiently low pressure differential across filter media within given spatial constraints without reducing the efficiency of the filter media, thereby permitting large contaminants to pass through the filter. It is also desirable to provide a transmission filter design with adequate filter media surface area without incurring the manufacturing expense or design drawbacks of prior pleated filter designs. 
     SUMMARY OF THE INVENTION 
     The foregoing needs are met, to a great extent, by the present invention, wherein in one aspect an apparatus is provided that increases the surface area of transmission filter media while avoiding the expense incurred by prior pleated filter designs. 
     In accordance with one embodiment of the present invention, a filter for use in engines or transmissions is provided which includes an inlet-side cover having a wave-like region along the periphery of the inlet-side cover, an outlet-side cover having a wave-like region along the periphery of the outlet-side cover where the outlet-side cover wave-like region is in complementary alignment with the inlet-side cover wave-like region and filter media fixed in a non-planar configuration between the wave-like regions of the inlet-side and outlet-side covers. These wave like regions could take several forms including but not limited to sinusoidal-like or more similar to a trapezoidal-wave. 
     In accordance with another embodiment of the present invention, a filter for use in engines or transmissions is provided which includes an inlet-side cover having inlet-side media supports and a non-planar region along the periphery of the inlet-side cover, an outlet-side cover having outlet-side media supports and a non-planar region along the periphery of the outlet-side cover where the outlet-side cover non-planar region is complementary in shape and alignment with the inlet-side cover non-planar region and filter media fixed in a non-planar configuration between the non-planar regions of the inlet-side and outlet-side covers. 
     In accordance with another embodiment of the present invention a filter for use in engines or transmissions is provided which includes an inlet-side cover having alternating convex and concave regions along the periphery of the inlet-side cover, an outlet-side cover having alternating convex and concave regions along the periphery of the outlet-side cover which are in a complementary alignment with the convex and concave regions of the inlet-side cover and filter media fixed in a non-planar configuration between the alternating convex and concave regions of the inlet-side cover and the outlet-side cover. 
     In accordance with yet another embodiment of the present invention a filter for use in engines or transmissions is provided which includes an inlet-side cover with media retention tray having convex and concave regions along the periphery, an outlet-side cover having alternating convex and concave regions along the periphery of the outlet-side cover which are in a complementary alignment with the convex and concave regions of the inlet-side cover and filter media fixed in a non-planar configuration between the alternating convex and concave regions of the inlet-side cover and the outlet-side cover. 
     There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
     As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating components of a transmission filter according to a preferred embodiment of the invention. 
         FIG. 2  is a perspective view illustrating an alternate view of the components of the transmission filter of  FIG. 1 . 
         FIG. 3  is a sectional view of an inlet-side cover of a transmission filter according to a preferred embodiment of the invention. 
         FIG. 4  is a sectional view of an outlet-side cover of a transmission filter according to a preferred embodiment of the invention. 
         FIG. 5  is a width-oriented cutaway view illustrating a section of the transmission filter according to a preferred embodiment of the invention. 
         FIG. 6  is a cutaway view illustrating a lateral section of an outlet-side cover of a transmission filter according to a preferred embodiment of the invention. 
         FIG. 7  is a cutaway view illustrating a lateral section of a transmission filter according to a preferred embodiment of the invention. 
         FIG. 8  is a perspective view illustrating components of a transmission filter according to an alternate preferred embodiment of the invention. 
         FIG. 9  is a perspective view illustrating an alternate view of the components of the transmission filter of  FIG. 8 . 
         FIG. 10  is a perspective view illustrating a media retention tray according to an alternate embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. An embodiment in accordance with the present invention provides increased filter media surface area over the surface area that would be available using a conventional filter design having media in single-layer or bag configuration. The increased filter media surface area provided by a filter in accordance with the present invention is necessary to provide a low pressure differential across filter media when it would not be possible to do so with a conventional filter designs in a reduced filter footprint. Another benefit of a filter in accordance with the present invention is that the design permits the components of the filter to be joined using a single joining operation. A single joining operation reduces the time and expense required to manufacture a filter. Another benefit of a filter in accordance with the present invention is that the non-planar media shape can be configured to minimize pressure differential without damaging the media. 
     An embodiment of the present inventive apparatus is illustrated in  FIG. 1 .  FIG. 1  is a perspective view illustrating components of a transmission filter  10  which includes an outlet-side cover  12 , filter media  14  and an inlet-side cover  16 . The outlet-side cover  12  further includes a fluid outlet  18  and the inlet-side cover  16  includes a fluid inlet  20 . In a preferred embodiment, the outlet-side cover  12  and inlet-side cover  16  are thermoplastic, however, other materials including a combination of materials such as thermoplastic and metal may be used. 
     In a preferred embodiment the filter media  14  is non-woven felt that is approximately 2 mm thick. It should be noted that other filter media materials, thicknesses, configurations and combinations of different filter media materials may be used. For example, the filter media may include non-woven polyester material bonded with a polyester screen backing. 
     It should also be noted that while the filter media  14  is shown in a sinusoidal-like configuration, other non-planar configurations may be used. For example, the media may be used in a undulated, corrugated or in another wave-like configuration. The shape of the pleats may be contoured for lower pressure differential without requiring non-standard pleating operations, such as heat forming or insert-molding. The shape of the pleat is introduced to the filter media  14  when it is installed in the outlet-side cover  12 . 
     According to a preferred embodiment of the invention, the outlet-side cover  12  and the inlet-side cover  16  are joined using a single plastic-to-plastic bonding process such as vibration welding, however, other plastic bonding processes including laser welding and ultrasonic welding may also be employed. It should be appreciated that other joining processes, such as crimping, may be used in accordance with the invention when practiced with composite or metal materials. 
     The inlet-side cover  16  includes a plurality of media retention fingers  22  and media retention recesses  24  positioned along the periphery of two sides of the inlet-side cover  16 . The inlet-side cover  16  also includes a crimp rib  26  which runs along the periphery of the inlet-side cover  16 . The crimp rib  26  also runs along the upper portion of the media retention fingers  22  and media retention recesses  24 . 
     The inlet-side cover  16  also includes one or more media supports  28 . According to a preferred embodiment in accordance with the preferred invention, the media supports  28  further include one or more media support fingers  30  and media support recesses  32 . The orientation of the media supports  28  is such that the media support fingers  30  and media support recessions  32  are aligned with the respective media retention fingers  22  and media retention recesses  24  positioned along the periphery of the inlet-side cover  16 . The media supports  28  keep the filter media  14  properly oriented. It should also be noted that the number and position of the media supports  28  may be optimized for a particular application of the filter  10 . 
       FIG. 2  is a perspective view illustrating an alternate view of the components of the transmission filter of  FIG. 1 . As previously described with respect to  FIG. 1 , the transmission filter  10  includes an outlet-side cover  12 , filter media  14  and an inlet-side cover  16 . The outlet-side cover  12  further includes a fluid outlet  18  and the inlet-side cover  16  includes a fluid inlet  20 . Also shown on the inlet-side cover  16  are a plurality of media retention fingers  22 . Present, but not visible on the inlet-side cover  16 , are a plurality of media retention recesses  24  as were described with respect to  FIG. 1 .  FIG. 2  also provides a view of the underside of the inlet-side cover  16 . The underside of the inlet-side cover  16  includes a plurality of spacer elements  36  which provide separation between fluid inlet  20  of the inlet-side cover  16  and a transmission pan. 
     The outlet-side cover  12  includes a plurality of media retention fingers  22  and media retention recesses  24  arranged along the periphery of two sides of the outlet-side cover  12 . The media retention fingers  22  and recesses  24  of the outlet-side cover  12  are aligned so they interface with the media retention recesses  24  and fingers  22 , respectively, of the inlet-side cover  16 . The outlet-side cover  12  also includes a crimp recess  34  which is aligned to interface the crimp rib  26  of the inlet-side cover  16  when the covers are joined. The crimp recess  34  runs along the entire periphery of the outlet-side cover  12  and along the upper portion of the media retention fingers  22  and media retention recesses  24  thereon. 
     The outlet-side cover  12  includes one or more media supports  28  which include one or more media support fingers  30  and media support recesses  32 . As was the case with the inlet-side cover  16 , the orientation of the media supports  28  in the outlet-side cover  12  is such that the media support fingers  30  and the media support recesses  32  are aligned with the respective media retention fingers  22  and media retention recesses  24  positioned along the periphery of the outlet-side cover  12 . 
     The media supports  28  of the inlet-side cover  16  are lined up with the media supports  28  of the outlet-side cover  12  so the media supports  28  of the outlet-side cover  12  support the filter media  14  while the media supports  28  of the inlet-side cover  16  serve as a stop to prevent deflection of the inlet-side  16  and outlet-side  12  covers under suction conditions. Additionally, the media supports  28  of the inlet-side cover  16  and outlet-side cover  12  are sized so a small gap remains between the respective media support fingers  30  and media support recesses  32  when the filter is assembled. This slight gap controls filter collapse under suction conditions. 
       FIG. 3  is a sectional view of an inlet-side cover  16  of a transmission filter according to a preferred embodiment of the invention.  FIG. 3  shows media retention fingers  22  and media retention recesses  24  as well as a crimp rib  26  formed along the tops of the fingers  22  and recesses  24 . The crimp rib  26  is continuous along the periphery of the inlet-side cover. It should be noted that other means of securing the filter media such as spikes may be used in addition to, or in place of the crimp rib  26 . The media retention finger  22  also includes a support rib  36  in this embodiment. 
       FIG. 4  is a sectional view of an outlet-side cover of a transmission filter according to a preferred embodiment of the invention.  FIG. 4  shows media retention fingers  22  and media retention recesses  24  and the crimp recess  34  formed along the tops of the fingers  22  and recesses  24 . 
       FIG. 5  is a width oriented cutaway view illustrating a section of the transmission filter according to a preferred embodiment of the invention.  FIG. 5  shows the filter media  14  crimped in place between the media retention fingers  22  and media retention recesses  24  of the outlet-side cover  12  and the inlet-side cover  16 . The filter media  14  is most compressed between the crimp rib  26  and the crimp recess  34 . 
       FIG. 6  is a cutaway view illustrating a lateral section of an outlet-side cover of a transmission filter according to a preferred embodiment of the invention. The pleated shape is introduced to the filter media  14  when the media is applied to the outlet-side cover  12  and conforms to the contours of the media retention fingers  22  and media retention recesses  24  along the periphery of the cover. 
       FIG. 7  is a cutaway view illustrating a lateral section of a transmission filter according to a preferred embodiment of the invention. The filter media  14  is held in a pleated configuration when it is compressed between the media retention fingers  22  of the inlet-side cover  16  and the media retention recesses  24  of the outlet-side cover  12  and vice-versa when the filter is assembled. 
       FIG. 8  is a perspective view illustrating components of a transmission filter according to an alternate preferred embodiment of the invention.  FIG. 8  shows a transmission filter  100  which includes an outlet-side cover  102 , filter media  106 , media retention tray  108 , and an inlet-side cover  110 . The media retention tray  108  is positioned between the inlet-side cover  110  and the filter media  106 . The outlet-side cover  102  further includes a fluid outlet  104  and the inlet-side cover  110  includes a fluid inlet  112 . 
     In an alternate preferred embodiment in accordance with the present invention, the inlet-side cover  110  is metal and the outlet-side cover  102  and media retention tray  108  are thermoplastic, however, it will be readily appreciated by one skilled in the art that other materials may be used for the outlet-side cover  102 , the media retention tray  108  and inlet-side cover  110 . In accordance with an alternate preferred embodiment of the present invention, the filter media  106  is crimped between the media retention tray  108  and the outlet-side cover  102  during filter assembly. The media retention tray  108  is held in position by the inlet-side cover  110  when the outlet-side cover  102  and the inlet-side cover  110  are joined together using a crimping operation. An advantage of using a crimping operation to join the covers is that a crimping operating is faster and typically more economical than a plastic joining operation. 
     The media retention tray  108  includes a plurality of media retention fingers  114  and media retention recesses  116  positioned along the periphery of two sides of the media retention tray  108 . The media retention tray  108  also includes a crimp rib  126  which runs along the periphery of the media retention tray  108 . The crimp rib  126  also runs along the upper portion of the media retention fingers  114  and media retention recesses  116 . 
     The media retention tray  108  also includes a frame  118  and one or more media supports  120  positioned thereon. It should be noted that media retention tray  108  may also include a full tray bottom with a fluid inlet and is not limited to using the frame  118  shown in  FIG. 8 . According to a preferred embodiment in accordance with the preferred invention, the media supports  120  further include one or more media support fingers  122  and media support recesses  124 . The orientation of the media supports  120  is such that the media support fingers  122  and media support recesses  124  are aligned with the respective media retention fingers  114  and media retention recesses  116  positioned along the periphery of the media retention tray  108 . The media supports  120  keep the filter media  106  properly oriented. It should also be noted that the number and position of the media supports  120  may be optimized for a particular application of the filter  100 . 
       FIG. 9  is a perspective view illustrating an alternate view of the components of the transmission filter of  FIG. 8 . As previously described with respect to  FIG. 8 , the transmission filter  100  includes an outlet-side cover  102 , filter media  106 , a media retention tray  108 , and an inlet-side cover  110 . The media retention tray  108  is positioned between the inlet-side cover  110  and the filter media  106 . The outlet-side cover  102  further includes a fluid outlet  104  and the inlet-side cover  110  includes a fluid inlet  112 . 
     The outlet-side cover  102  includes a plurality of media retention fingers  114  and media retention recesses  116  arranged along the periphery of two sides of the outlet-side cover  102 . The media retention fingers  114  and recesses  116  of the outlet-side cover  102  are aligned so they interface with the media retention recesses  116  and fingers  114 , respectively, of the media retention tray  108 . The outlet-side cover  102  also includes a crimp recess  128  which is aligned to interface the crimp rib  126  of the media retention tray  108  when the inlet-side cover  110  and outlet-side covers are joined. The crimp recess  128  runs along the entire periphery of the outlet-side cover  102  and along the upper portion of the media retention fingers  114  and media retention recesses  116  thereon. 
     The outlet-side cover  102  includes one or more media supports  120  which include one or more media support fingers  122  and media support recesses  124 . As was the case with the media retention tray  108 , the orientation of the media supports  120  in the outlet-side cover  102  is such that the media support fingers  122  and the media support recesses  124  are aligned with the respective media retention fingers  122  and media retention recesses  124  positioned along the periphery of the outlet-side cover  102 . 
     The media supports  120  of the media retention tray  108  are lined up with the media supports  120  of the outlet-side cover  102  so the media supports  120  of the outlet-side cover  102  support the filter media  106  while the media supports  120  of the media retention tray  108  serve as a stop to prevent deflection of the inlet-side  110  and outlet-side  102  covers under suction conditions. Additionally, the media supports  120  of the media retention tray  108  and outlet-side cover  102  are sized so a small gap remains between the respective media support fingers  122  and media support recesses  124  when the filter is assembled. This slight gap controls filter collapse under suction conditions. 
       FIG. 10  is a perspective view illustrating a media retention tray according to an alternate preferred embodiment of the invention.  FIG. 10  shows a media retention tray  108  with a plurality of media retention fingers  114  and media retention recesses  116  positioned along the periphery of two sides of the media retention tray  108 . The media retention tray  108  also includes a crimp rib  126  which runs along the periphery of the media retention tray  108 . The crimp rib  126  also runs along the upper portion of the media retention fingers  114  and media retention recesses  116 . The media retention tray  108  also includes a frame  118  and one or more media supports  120  positioned thereon. It should be noted that the size of the frame  118  may be adjusted to suit the particular application of the filter. Accordingly, as previously mentioned, the number and position of media supports  120  may be adjusted to suit the particular application of the filter. 
     The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.