Abstract:
A filter device may include a filter housing cover defining a chamber and an annular filter element arranged within the receiving chamber. The filter device may further include a housing and at least one intermediate piece arranged between the filter housing cover and the housing when the cover is secured to the housing. An inlet duct may be in communication with an untreated side of the filter element and an outlet duct may be in communication with a clean side of the filter element. A drainage duct may be arranged in the housing for draining the chamber during removal of the cover. A closure device may be arrange in the intermediate piece and have a closure element configured to close the drainage duct.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation of U.S. patent application Ser. No. 13/380,206, filed Mar. 16, 2012, which claims priority to German Patent Application Nos. 10 2009 030 561.0 filed Jun. 24, 2009, and 10 2010 008 064.0 filed Feb. 16, 2010, and International Application No. PCT/EP2010/058618 filed Jun. 18, 2010, all of which are hereby incorporated by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a filter device for fluids, in particular an oil filter for the cleaning of lubricating oil for internal combustion engines of motor vehicles. 
       BACKGROUND 
       [0003]    Filter devices, in particular oil filters for internal combustion engines of motor vehicles usually have a so-called annular filter element, by means of which a fluid flowing through the filter device is filtered. Periodically, this annular filter element must be exchanged in order to be able to always ensure the filtering action of the filter device. By removal of a filter device from the housing, the annular filter element is also removed. Owing to the constantly increasing environmental specifications, the exchange of the annular filter element must be possible here without fluid, in particular oil, arriving into the environment. For this reason, conventional filter devices have in their housing, in addition to an inlet duct which communicates with an untreated side of the annular filter element and an outlet duct which communicates with a clean side of the annular filter element, also a drainage duct, through which a receiving chamber, in which the annular filter element is arranged, can be drained on unscrewing of the filter device. Of course, this drainage duct must be closed off when the filter device is ready for operation, because otherwise the clean side and the untreated side of the annular filter element would be short-circuited with each other and thereby the filter device could not deploy its filtering action. 
       SUMMARY 
       [0004]    The present invention is concerned with the problem of indicating for a filter device an improved or at least a different embodiment which makes possible an automatic opening or respectively closing off of a drainage duct on dismantling or respectively installing a filter device. 
         [0005]    This problem is solved according to the invention by the subject matter of the independent claim(s). Advantageous embodiments are the subject matter of the dependent claims. 
         [0006]    The invention is based on the general idea of providing an intermediate piece between a filter device, arranged vertically, and a housing arranged therebeneath, into which intermediate piece a closure device is integrated. The closure device is constructed here so as to be rotatable about the filter axis of the annular filter element, wherein the annular filter element itself is arranged in a receiving chamber, which is delimited by a filter housing cover. On the housing side, an inlet duct and an outlet duct are provided, wherein the inlet duct communicates with an untreated side of the annular filter element and the outlet duct communicates with a clean side of the annular filter element. A drainage duct is likewise provided in the housing, through which the receiving chamber can be drained on unscrewing of the filter device, so that no filter fluid, in particular no oil, can arrive into the environment. The closure device, which is arranged so as to be rotatable about the filter axis, has a closure element, by means of which the drainage duct can be closed off when the filter device is screwed fully onto the housing. Generally, the closure device is constructed so that, on screwing on of the filter device on the housing, it is fixed in a precisely defined position in which the closure element is arranged aligned to the drainage duct and is able to be adjusted into a position closing off the drainage duct by the screwing on of the filter device. In contrast to this, the closure device on unscrewing of the filter device from the housing is twisted and is moved at the same time axially away from the housing, so that the closure element on unscrewing of the filter device from the housing frees the drainage duct and makes possible a drainage of the intermediate piece and, if applicable, of the receiving chamber containing the annular filter element. Through the closure device according to the invention, which can be constructed for example as a favourably-priced plastic part with a closure element made of a different plastic, it is possible in the technically simplest manner to reliably close off the drainage duct with the filter device screwed on fully on the housing, and thereby to ensure a problem-free functioning of the filter device, wherein on an unscrewing of the filter device from the housing the drainage duct is automatically opened, so that the receiving chamber containing the annular filter element can drain and no filter fluid arrives into the environment. A separate opening or respectively closing of the drainage duct, connected with the possibility of forgetting this, can be reliably ruled out by the filter device according to the invention, whereby the maintenance process is to be arranged to be distinctly more reliable and in addition easier to arrange. Through the precisely fixed position of the closure device during the screwing-on process of the filter device on the housing, furthermore a laborious positioning or respectively aligning of the closure element with respect to the drainage duct which is to be closed off can be dispensed with, wherein it is always ensured that the drainage duct is reliably closed off with the filter device fully screwed on the housing. 
         [0007]    Expediently, the closure device is constructed as a plate and the closure device is constructed as a cap with a plate mounted rotatably therein, and the plate has a perforated lateral edge with openings. When the filter device is screwed on, a compression of the spring element then takes place, whereby an axial displacement of the closure element towards the drainage duct is prevented, so that the closure element rests on an opening of the drainage duct, and namely such that the drainage duct is tightly closed off. 
         [0008]    In a further advantageous embodiment of the solution according to the invention, the plate, on screwing on of the filter device with at least one rib, arranged on at least one lateral part of a perforated lateral wall, engages on the incline of the cap and through a further screwing on of the filter device is displaceable into its position closing off the drainage duct. 
         [0009]    In a further advantageous embodiment of the solution according to the invention, between the intermediate piece and the annular filter element arranged thereabove, a disc-like base and a simple spring element are provided, wherein the base has several through-openings distributed in circumferential direction. The non-co-rotation of the closure device on unscrewing of the filter housing cover from the housing brings about a lifting of the closure element and hence an axial displacement of the closure device together with the closure element, so that the closure element frees the opening of the drainage duct. The closure device therefore behaves completely differently in the screwing process or respectively unscrewing process of the filter device on/from the housing. 
         [0010]    On screwing of the filter device on the housing, the closure device, i.e. the spring arranged between closure device and base, is compressed until the closure element, arranged on the closure device, lies tightly on the drainage duct. Thereby, on screwing of the filter device on the housing, a reliable closing off of the drainage duct can be brought about, and on unscrewing of the filter device from the housing, a reliable opening and hence draining of the receiving chamber can be brought about. This ensures, on the one hand, a high functional reliability of the filter device, and on the other hand an emergence of filter fluid into the environment can be reliably avoided, because the drainage duct is preferably already fully opened with few rotations of the filter device, so that the receiving chamber can drain completely before the filter device is removed through further rotations. 
         [0011]    The emergence of fluid into the environment can be additionally prevented by an external axially and radially acting sealing combination, which ensures the closure function of the filter device with respect to the housing even when the flat seal has no contact to the housing. 
         [0012]    Further important features and advantages of the invention will emerge from the sub-claims, from the drawings and from the associated description of figures with the aid of the drawings. 
         [0013]    It is to be understood that the features mentioned above and to be explained further below are able to be used not only in the respectively indicated combination, but also in other combinations or in isolation, without departing from the scope of the present invention. 
         [0014]    Preferred example embodiments of the invention are illustrated in the drawings and are explained in further detail in the following description, wherein identical reference numbers refer to identical or similar or functionally identical components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    There are shown, respectively diagrammatically: 
           [0016]      FIG. 1  shows an external view of the filter device according to the invention 
           [0017]      FIG. 2  shows a detail of the external view 
           [0018]      FIG. 3  shows an external seal 
           [0019]      FIG. 4  shows the detail as exploded illustration 
           [0020]      FIG. 5  shows a detail in the top view from above 
           [0021]      FIG. 6  shows the plate in two views a) and b) 
           [0022]      FIG. 7  shows a section through the lower end of the filter device 
           [0023]      FIG. 8  shows the cap and the plate together 
           [0024]      FIG. 9  shows the housing 
           [0025]      FIG. 10  shows a section through the filter device on screwing on onto the housing 
           [0026]      FIG. 11  shows a section through the filter device in the screwed on state 
           [0027]      FIG. 12  shows a section through the filter device on unscrewing from the housing 
           [0028]      FIG. 13  shows a detail of  FIG. 11   
           [0029]      FIG. 14  shows an alternative embodiment 
           [0030]      FIG. 15  shows a cut-out of the plate of  FIG. 14   
           [0031]      FIG. 16  shows a view of the plate of  FIG. 14  from below 
           [0032]      FIG. 17  shows a view of the plate of  FIG. 14  with cap 
           [0033]      FIG. 18  shows a further alternative embodiment in exploded illustration 
           [0034]      FIG. 19  shows the lower end of the filter device to the further embodiment 
           [0035]      FIG. 20  shows the cap of the further embodiment 
           [0036]      FIG. 21  shows the plate of the further embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0037]    In  FIG. 1  the filter device  1  can be seen from the exterior. It consists of a filter housing cover  2 ; the latter forms in its interior a receiving chamber  5  in which the annular filter element  6  is arranged so that it separates a clean side from an untreated side. The internal structure is that of a conventionally used exchangeable filter which is suitable for the filtering of oil. An intermediate piece  3  is situated on the side of the filter device  1  facing the housing  4 . The housing  4 , on which the filter device  1  is securely screwed, can be, for example, a motor block housing or a cylinder housing. For the sake of simplicity, it is only named as housing  4 . The housing  4  is configured so that it has a dome  15  with thread, and the inlet duct  7 , the outlet duct  8  and the drainage duct  9  (see  FIG. 9 ). 
         [0038]    In  FIG. 2  the intermediate piece  3  is shown, which is tightly flanged with the filter housing cover  2  at the transition of the two parts. The intermediate piece  3  consists of an outer cap  37  and internal plate  63 . 
         [0039]    In  FIG. 3  the seal  50  is shown, lying externally around the cap  37 , which seal has in the direction of the housing  4  a lip  43 , lying externally against the cap  37 , having a radial sealing effect. This seal  50  seals in general the filter device  1  with respect to the environment, so that during the operation of the vehicle and on unscrewing of the filter device, no oil can arrive into the environment. To receive the seal  50 , an annular groove  47 , open in axial direction, is provided in the cap  37  in the region of the connection between filter housing cover  2  and cap  37  (see  FIG. 5 ). 
         [0040]    In  FIG. 4  the individual parts which together form the intermediate piece  3 , and further parts are illustrated. A base  16 , which has through-openings  33  through which oil can arrive into the receiving chamber  5 , forms the closure of the receiving chamber  5 . The central opening  34  has a thread or a threaded hollow pin, so that the filter device  1  can be screwed securely on the dome  15  of the housing  4 . Between the base  16  and plate  63  there is a spring element  17 , a conventional spiral spring in the example which is shown, but any suitable spring element  17  can be used. The spring element  17  has a bearing surface internally on the plate  63 . The plate  63  has a central opening  34  and a lateral edge  21 , which is perforated by openings  40 . The openings  40  are connected at their upper end by a connecting cross-piece  46 , which projects slightly in radial direction and thus forms a stop for the plate  63 . This stop forms at the same time the mounting of the plate  63  in the cap  37 . For this purpose, the cap  37  has an unbent edge  38  at the lower end. The plate  63  also has a flat annular groove  49  on the side facing the housing, into which the closure element  12  is inserted in the form of a flat O-ring seal. The sealing material can also be injected into the annular groove  49 . The precise shape of the closure element  12  is dependent on the respective case of application. 
         [0041]    All the named parts of the filter device  1 , except for the annular filter element  6  and the seals, can be made from metal or else from suitable plastics; in the latter case, however, the cap  37  would not be flanged with the filter housing cover  2 , but welded. 
         [0042]    The cap  37  and the plate  63  are illustrated again in detail in  FIGS. 5 and 6 . At least one projection  18  is situated in the cap  37 . The plate  63  is mounted so as to be rotatable as desired in the cap  37 . In the plate  63  on the inner side at least one delimiting nub  48  is arranged, which hold the spring element  17  in its place. 
         [0043]      FIG. 7  shows a section through the lower end of the filter device  1 . It can be seen here how it is assembled. In this example embodiment, the projections  18  form an upper stop for the plate  63 , so that the plate  63  can not be pressed into the cap  37 . 
         [0044]    In  FIG. 8  an oblique top view is to be seen onto the plate  11 , which is mounted rotatably in the cap  37 . As the two arrows indicate, the plate is freely movable in both directions of rotation. 
         [0045]    In  FIG. 9  an oblique top view is to be seen onto the housing  4 . The inlet duct  7 , the outlet duct  8  and the drainage duct  9  can be seen. 
         [0046]    In  FIG. 9  a ventilation opening is designated by  65 , through which, on unscrewing of the cover  2 , air can enter from the exterior into the receiving chamber  5 , but no oil can emerge. 
         [0047]    In  FIG. 10  the housing  4  is illustrated in section with filter device  1  during screwing on. On screwing on, the plate  63  can be co-rotated, because it is rotatably mounted in the cap  37 . However, the plate  63  can also only be moved axially whilst the filter device  1  is screwed on. When the closure element  12  comes to lie on the opening of the drainage duct  9 , the plate  63  no longer co-rotates further with the filter device  1 . The filter device  1  is further screwed securely until the seal  50  also comes to lie against the housing  4 , meanwhile the plate  63  is at rest. In this way, it is avoided that the seal  12  rubs over the opening of the drainage duct  9 . The lip  43  which is formed onto the seal  50  now lies against the inner wall of the mounting of the housing  4  and seals the filter device with respect to the environment. 
         [0048]    According to  FIG. 10 , the seal  50  can have an, in particular cylindrical, extension  43  or section  43 , which projects axially into an annular space  64  which is produced between the intermediate piece  3  or respectively the cap  37  and the housing  4 , when the cover  2  is screwed on, wherein the extension  43 , on unscrewing of the cover  2 , also still seals radially when the axial seal of the sealing element  50  is eliminated by lifting from the housing  4 . 
         [0049]    In  FIG. 11  the filter device is shown in the screwed on state. By screwing tightly, the connecting cross-piece  46  of the plate  63  is lifted from the bent edge  38  of the cap  37 . The spring element  17  presses the closure element  12  onto the opening of the drainage duct  9 . 
         [0050]    On unscrewing of the filter device  1  from the housing  4 , the plate  63  is not moved together with the filter device  1 , because it is rotatably mounted in the cap  37 . After one to two rotations of the filter device, the edge  38  of the cap  37  takes up the connecting cross-piece  46  of the plate  63  again, so that the drainage opening of the drainage duct  9  is freed, and the oil can flow off out from the receiving chamber  5  of the filter device  1  via the drainage duct  9  before the filter device  1  is unscrewed from the housing. 
         [0051]    In  FIG. 13  a detail of  FIG. 11  can be seen, where the filter device  1  is securely screwed on the housing  4 . The distances d and D determine the pressure loss of the oil on flowing through the filter device  1  in operation. 
         [0052]    In  FIGS. 14 to 17  an alternative embodiment can be seen. Here, likewise, the lateral wall  21  of the plate  63  is perforated. An incline  51  is situated on at least one partial piece  42  of the lateral wall  21 . On the one side, the incline  51  has a continuously rising surface, on the other side a straight edge which stands perpendicularly on the circumference of the lateral wall  21 . 
         [0053]    These inclines  51  cooperate with the projections  18  of the cap  37  in a form such that through the edge of the inclines  51  and thereby the entrainment of the plate  11  on unscrewing of the filter device  1  is guaranteed. Through the incline rise, the elastic force of the spring element  17  is overcome. The plate  11  is lifted here axially independently of the thread pitch. On unscrewing of the filter device  1 , the drainage opening of the drainage duct  9  is freed, so that the oil can flow off out from the receiving chamber  5 , before the seal  50  has axially left the contact surface of the housing  4 , i.e. distinctly before the filter device  1  is unscrewed fully from the housing  4 . 
         [0054]    On screwing on of the filter device  1 , the plate  63  is contingently mounted rotatably in the cap  37 . When the closure element  12  rests on the drainage opening of the drainage duct  9 , the plate  63  no longer moves axially and it also no longer co-rotates with the filter device  1 . 
         [0055]    The filter device  1  is then still screwed securely onto the housing. Thereby, there is no friction of the closure element  12  on the drainage opening. The drainage opening of the drainage duct  9  is tightly closed off through the elastic force of the spring element  17  which presses the closure element  12  onto the housing  4 . The edge  38  of the cap  37  lies at a suitable location against the outer circumference of the plate  63 , so that the plate  63  does not fall out from the cap  37  on mounting of the filter device  1 . 
         [0056]    In  FIGS. 18 to 21 , a further embodiment is illustrated. Here, the lateral parts  42  of the perforated lateral edge  21  of the plate  63  have a projection  62 , against which a bent projection  60 ,  62  of the cap  37  lies and namely such that the plate  63  is not pressed again inadvertently onto the opening of the drainage duct. This bent projection  60 ,  62  also comes into effect when the plate  63 , compared with the cap  37 , is rotated, does not move with the filter device, then the projection  61 ,  62  lies on the bent edge  38  of the cap  37  and in this position prevents the lowering of the plate  63  onto the drainage duct. On unscrewing of the filter housing cover  2 , the inclines  51  cooperate again with the projections  18  in the cap  37  and thus overcome the elastic force of the spring element  17 , so that the drainage opening of the drainage duct  9  is freed, before the seal  50  has axially left the contact surface of the housing  4  and the filter device  1  is completely unscrewed. The number of projections  60 ,  61 ,  62  is able to be selected as desired. 
         [0057]    On screwing on of the filter housing cover  2 , this embodiment behaves like the other two embodiments.