Abstract:
A lip seal has an internal spring element disposed in an elastomeric ring. The spring element has a cervical angle cross-sectional with inwardly directed angled fingers

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to the field of resilient seals, and more particularly pertains to the sealing of the an item, such as for example a transmission filter having a neck, within a bore of a piece of machinery, such as for example a transmission. More particularly, the invention in some aspects pertains to a seal referred to as a “lip seal”.  
       BACKGROUND OF THE INVENTION  
       [0002]     There are wide variety of circumstances in which a compressible resilient lip seal is desired. One of these applications is the connection of a fluid filter, such as for example a transmission filter, with respect to a bore or orifice in a device such as for example a vehicular transmission. In the case of a transmission filter, the filter typically has a neck extending from the filter, which typically provides either the inlet or outlet of fluid with respect to the filter casing. This neck is typically inserted into a bore or socket that is part of the transmission or a transmission component to provide fluid communication between the filter and the transmission or transmission component. For example, the neck of the filter may be put into fluid communication with a pump inlet, a valve body, or a case casting that leads to a pump inlet.  
         [0003]     In order to provide a seal between the filter neck and the inlet bore, it has been known to provide an elastic resilient sealing ring, or “lip seal”, which surrounds the outside of the filter neck, and sealingly fits within the bore.  
         [0004]     A transmission filter is typically installed into the transmission during original equipment manufacture of the transmission, and may eventually be replaced by a service technician. During such an installation process, the filter neck with the resilient seal already on it is typically manually inserted in the fluid inlet bore of the transmission or transmission component. Typically, the sealing ring is inserted onto the filter neck either during assembly of the filter or at some other stage prior to insertion of the filter neck into the transmission bore. It will be appreciated that during this installation phase it is desirable to retain the sealing ring at a desired location on the neck (i.e., to prevent the seal from sliding or rolling down the neck) while also permitting the sealing ring to slide into the bore while still being compressed enough to maintain a seal between the filter neck and the bore once installed.  
         [0005]     Various methods have been employed in order to retain the seal in its proper location on the filter neck during the installation phase. For example, the seal typically has an inner diameter when relaxed that is slightly less then the outer diameter of the location at the neck where it will be placed, so that the seal is frictionally gripping the neck. Further, a shoulder is sometimes provided on the neck to meet the edge of the seal which resists movement of the seal along the neck during the insertion phase.  
         [0006]     During the life of a transmission, however, the filter may sometimes need to be replaced. During this replacement servicing, the filter neck is typically manually withdrawn out of the inlet bore and the filter is discarded and replaced with a new filter that is inserted in much the same fashion that is described above. This filter removal step has presented several challenges with respect to the lip seal. Oftentimes, when the filter is manually removed, the lip seal tends to slide off the neck and stay within the inlet. This problem is exacerbated by the fact that the outside of a filter neck is typically very smooth, due to the fact that the filter neck is usually an injection molded part. The inlet bore, on the other hand, tends to be a more roughly machined surface. The problem of the lip seal frictionally being left behind in the inlet, after sliding off the filter neck is also driven in part by the fact that the filter neck, which is usually an injection molded plastic part, tends to shrink due to the heat cycles experienced during its life. Some efforts at alleviating this problem have involved roughing or providing ribs or other features on the outside of the filter neck in order to help engage the lip seal during removal. This solution is not always desirable, however, as it can cause extra efforts or difficulties with respect to the injection molding process for the filter casing itself. The occurrence of the lip seal sliding off the filter neck during filter removal and being left behind in the inlet bore can have some adverse consequences. For example, the servicing technician may use tools to try to pull or scrape out the seal that has been left behind which may cause some scratching, scoring, or other damage to the inside of the bore which may then lead to a loss of a positive seal in the subsequently installed filter and sealing ring. Another disadvantage to leaving behind a lip seal is that the repair technician may not realize it has been left behind and may simply insert a new filter with its own seal into the bore, causing a stack-up of sealing rings that could cause the new sealing ring not to be seated properly or the filter not to fit correctly in the transmission.  
         [0007]     In view of the foregoing, it would be desirable to have an improved lip seal and sealing method for sealing around the outside of a neck that is inserted into a larger bore. It would be desirable if such as seal could at least to some extent enhance the retention of the seal on the neck when the seal is removed from the bore.  
       SUMMARY OF THE INVENTION  
       [0008]     In some aspects of some embodiments of the present invention, an improved lip seal and sealing method is provided. It would be desirable to have an improved lip seal and sealing method for sealing around the outside of a neck that is inserted into a larger bore. It would be desirable if such as seal could at least to some extent enhance the retention of the seal on the neck when the seal is removed from the bore.  
         [0009]     In accordance with one embodiment of the present invention, a lip seal for sealing between the outside surface of a neck and the inside surface of a bore, comprises; an elastomeric portion; and a spring element disposed within the elastomeric portion, with at least a portion of the element being angled with respect to a plane in which the seal lies.  
         [0010]     In accordance with another embodiment of the present invention, a lip seal for sealing between the outside surface of a neck and the inside surface of a bore, comprises; an elastomeric position and spring means disposed within the elastomeric portion.  
         [0011]     In accordance with yet another embodiment of the present invention, a method of sealing between the outside surface of a neck and the inside surface of a bore using a lip seal, comprises; providing a lip seal having an elastomeric portion and a spring element disposed within the elastomeric portion; and inserting the lip seal onto the neck.  
         [0012]     There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein 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.  
         [0013]     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.  
         [0014]     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  
       [0015]      FIG. 1  is a cross-sectional view of a lip seal according to a preferred embodiment of the present invention in an installed state on a filter neck and in an operational orientation with respect to an inlet housing of a transmission component.  
         [0016]      FIG. 2  is a cutaway top view of the lip seal shown in  FIG. 1 .  
         [0017]      FIG. 3  is a cross-sectional view taken though line  3 - 3  of  FIG. 2  of the lip seal.  
         [0018]      FIG. 4  is a top view of a washer element that is part of the lip seal shown in  FIG. 3 .  
         [0019]      FIG. 5  is the perspective view of the washer element shown in  FIG. 4 . 
     
    
     DETAILED DESCRIPTION  
       [0020]     In some embodiments of the present invention, an improved lip seal and sealing method is provided for sealing around the outside of a neck that is inserted into a larger bore. In some embodiments an element is added to the seal that at least to some extent enhances the retention of the seal on the neck when the seal is removed from the bore. Preferred embodiments of the invention will now be further described with reference to the drawing figures in which like reference numerals refer to like parts throughout.  
         [0021]      FIG. 1  illustrates a lip seal  10  according to a preferred embodiment of the present invention. The lip seal  10  is shown in an installed configuration in a layout view. The lip seal  10  provides sealing between the outside of a neck  12  of a transmission filter and an inlet bore  14  of a transmission component  16 . The neck  12  is typically an injection molded feature, which may be integral with an outer casing of a transmission or other fluid filter. The transmission component  16  may be a transmission casting, a valve body or a pump inlet, or another component of a transmission that utilizes fluid. Further, although transmission components and transmission filters are given as examples of applicability of the invention, the lip seal  10  may be utilized anywhere that a lip seal is desired to seal between the outer surface of a neck and an inner surface of a corresponding bore.  
         [0022]     The lip seal  10  is also shown in a layout format view in  FIG. 1 . That is, the lip seal  10  is depicted in its relaxed geometry, and thus its edges appear to overlap with the neck and the inlet respectively. One skilled in the art will recognize that in the actual install state, the lip seal  10  will be compressed. The lip seal inner diameter will be expanded to fit around the neck, and its outer diameter will compressed to fit within the neck.  
         [0023]     The lip seal  10  is generally composed of two parts: a resilient elastomeric part  16  and a more rigid washer element  18 . These components are described in further detail below. The geometry and placement of the washer element  18  is within the elastomeric section  16  provides an overall lip seal  10  that is easy to insert onto the neck  12  (that is it has a relatively low insertion force so that it can manually or with a tool could be installed easily onto the neck  12  during manufacturing of the filter); and also provides a relatively low insertion force for the filter and the lip seal together being inserted into the bore  14 . Furthermore, the provision of the washer element  18  additional provides the benefit that the force to remove the lip seal  10  from the neck  12  is relatively high. Thus, when the filter neck is removed or pulled out of the bore  14 , the lip seal tends to stay in place on the neck  12  rather than sliding off the neck  12  and being left behind in the bore  14 .  
         [0024]     In some embodiments this “one-way” feature of the seal  10  may be accomplished to the extent that the seal is relatively easy to slide onto a neck, but is difficult or in some embodiments virtually impossible to slide off of the neck without destroying the seal.  
         [0025]     Turning to  FIGS. 2 through 5 , the seal  10  will now be described in additional detail. The seal  10  includes an elastomeric polymer portion  16  which may be made of for example a polymer such as Viton or Vamac, or a high temperature rubber. The elastic portion  16  is generally over-molded onto the washer element  18 . The washer element  18  may be made of any of a variety of materials, including for example spring steel. Other metals or rigid plastics may also be implemented.  
         [0026]     The washer element  18  may be configured generally in the profile of a Belleville washer, having inwardly protruding teeth. For example, the exemplary ring  18  has an outer ring section  20  which is canted upward slightly from horizontal, and a number of inwardly protruding teeth  22  which are canted upward at a greater angle with respect to horizontal. This geometry is similar to a Belleville washer and provides an internal spring characteristic. The angle of the outer ring  20  with respect to horizontal is generally selected to be between 10 and 15 degrees relative to horizontal, but may encompass other angles. The upward angle of the fingers  22  may be selected to be from 15 to 45 degrees relative to horizontal, or may be any other angle. The fingers  22  and the outer ring  20  provide a toggling or jamming effect that resists removal of an installed seal  10  from the neck  12 . That is, when the seal  10  is inserted over the neck  12 , the fingers  22  tend to deflect outward and upward as needed in order to permit a low insertion force for sliding the seal  10  onto the neck  12 . However, during removal of the filter, if the seal  10  tends to be tugged off of the neck  12 , the friction gripping of the inside surface  26  of the seal  10  will tend to push downward on the fingers  22 , which then deflect downward and radially inward, so that the seal  10  tends to grip more tightly onto the neck  12 . As the axial pulling force increases, the tightening or locking or gripping force provided by the combination of the washer element  18  and the remainder of the seal  10  tends to hold the seal on the neck  12 .  
         [0027]     In this embodiment, the ring  18  has at least to some extent a Belleville washer shape, and more preferably such a shape with inwardly protruding teeth, that provides a seal with an overall low insertion force and high removal force. This permits other advantages with respect to design of the seal. In some embodiments in particular, the outside surface of the seal  10  can include two or more outwardly protruding peaks  26  and valleys  28 . In the installed state, the peaks  26  are compressed to provide sealing contact. Due to the resistance to seal removal off the neck that is provided by the washer element  18 , the invention can provide some embodiments in which seals have greater degrees of protrusion of the peaks  26  (that is, the seal can be designed with a greater “void volume”) than would be accomplished using an elastomeric seal that does not have the washer element  18 . This is because having a high void volume without the washer element  18  may cause so much frictional contact with the inlet bore  14  that removal of the filter neck  12  would tend to leave behind the seal  10 . However, by virtue of the washer element  18 , a higher void volume can be accomplished if desired while still permitting removal of the seal  10  and the neck  12  together at the same time.  
         [0028]     While the preferred washer element  18  is shown having a outer ring region having some angle relative to horizontal and a plurality of inwardly projecting finger regions at a second angle, other embodiments are not limited to this combination of this of angles. For example, a suitable Belleville type washer element  18  or other washer element  18 , can include both an outer ring and inner fingers all having a common upward angle, or a outer ring having a generally flat horizontal configuration with inwardly and upwardly angled projecting fingers, or a conical ring section being provided instead of the fingers. Further, the washer element  18  does not need to be entirely circular, and instead could be provided by a series of arcast sections spaced apart from each other.  
         [0029]     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.