Patent Publication Number: US-9840950-B2

Title: Oil pan

Description:
TECHNICAL FIELD 
     The present invention relates to a double sump oil pan having an inner sump and an outer sump. 
     BACKGROUND ART 
     Conventionally, double sump oil pans have been known, which include a separator installed therein to partition the interior into an inner sump and an outer sump from each other. Refer, for example, to Patent Document 1. In such an oil pan, only the oil that is stored in the inner sump is circulated after the engine is started to quickly increase the temperature of the oil, thereby reducing friction at parts requiring lubrication. 
     PRIOR ART DOCUMENT 
     Patent Document 
     Patent Document 1: Japanese Laid-Open Patent Publication No. 2011-226394 
     SUMMARY OF THE INVENTION 
     Problems that the Invention is to Solve 
     When oil is used for lubrication of an internal combustion engine, the oil temperature is increased. The heated oil then trickles down the inner wall of the cylinder block. When such trickled oil enters the outer sump, the amount of oil returned to the inner sump is reduced. This delays increase in the temperature of the oil in the inner sump. 
     Accordingly, it is an objective of the present invention to provide an oil pan that restricts oil trickling down the inner wall of a cylinder block from entering an outer sump, thereby allowing the oil in the inner sump to be easily heated. 
     Means for Solving the Problems 
     To achieve the foregoing objective and in accordance with one aspect of the present invention, a double sump oil pan is provided that includes a separator made of plastic that partitions an interior of the oil pan into an inner sump and an outer sump, a plate, and an elastically deformable sealing member attached to the plate. The sealing member closely contacts an inner wall of the oil pan, thereby sealing the outer sump. The plate and the separator are fixed to each other. 
     According to the above configuration, when the separator is installed in the oil pan, the sealing member is elastically deformed to closely contact the inner wall of the oil pan, thereby sealing the outer sump. This restricts oil trickling down the inner wall of the cylinder block from entering the outer sump, thereby allowing the oil in the inner sump to be easily heated. 
     Depending on the shape or the size of the separator, the sealing member cannot be directly attached to the separator in some cases. In this regard, the above described configuration includes a plate that is smaller in size than the separator and is easy to handle, and the sealing member for sealing the outer sump is attached to the plate. The plate with the sealing member is fixed to the separator. This allows the sealing member to be easily attached to the separator. 
     In such a configuration, the separator preferably has a protrusion, and the plate preferably has an insertion hole, which receives the protrusion. Also, the plate and the separator are preferably fixed to each other by heat-swaging the protrusion. This allows the sealing member to be arranged at a desired position on the separator. 
     The sealing member of the double sump oil pan is preferably a rubber lip. The rubber lip is easily elastically deformed to conform to the shape of the inner wall of the outer sump, thereby further closely contacting the inner wall. This further improves the sealing property of the outer sump. 
     In the double sump oil pan, the plate preferably has a ring-like shape, and the sealing member is preferably attached to an entire perimeter of the plate. This improves the sealing property of the outer sump, thereby allowing the oil to be more easily heated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view schematically illustrating the structure of an oil pan; and 
         FIG. 2  is a cross-sectional view schematically illustrating flow of oil in the oil pan. 
     
    
    
     MODES FOR CARRYING OUT THE INVENTION 
     A double sump oil pan according to one embodiment will now be described with reference to  FIGS. 1 and 2 . 
     As shown in  FIG. 1 , a cylinder block  1  of an internal combustion engine includes a crankshaft  2  and an oil drain passage  3 . An oil pan  4  is attached to the bottom of the cylinder block  1 . The oil pan  4  has such a shape that the distance between the opposed faces of an inner wall  10  decreases toward the lower end. A box-shaped separator  5  with an open upper end is installed in the oil pan  4 . The separator  5  is made of plastic. 
     The separator  5  divides the interior of the oil pan  4  into an inner sump  6  and an outer sump  7 . The inner sump  6  accommodates an oil strainer  8 , which pumps up stored oil. The separator  5  has through holes  9  in the side walls to connect the inner sump  6  and the outer sump  7  to each other. The separator  5  further has a flange  11 , which protrudes outward from the upper end, that is, toward the inner wall  10  of the oil pan  4 . The flange  11  extends over the entire perimeter of the separator  5 . The flange  11  has protrusions  12 , which are arranged at intervals along the perimeter. 
     As shown in  FIG. 2 , the separator  5  has, at its upper end, a ring-shaped plate  13 , which is made of plastic and extends over the entire perimeter. A sealing member, which is a rubber lip  14 , is attached to the outer side of the plate  13  to extend over the entire perimeter of the plate  13 . The rubber lip  14  extends upward from the plate  13 . The upper part of the rubber lip  14  closely contacts the inner wall  10  of the oil pan  4 . This seals the outer sump  7 . The rubber lip  14  can be attached to the plate  13 , for example, by injection molding. 
     The plate  13  has insertion holes  15 , which are arranged at intervals along the perimeter. The insertion holes  15  each receive one of the protrusions  12  of the separator  5 . The protrusions  12  are heat-swaged so that the distal ends of the protrusions  12  and the upper surface of the flange  11  hold the plate  13 , so that the plate  13  is fixed to the separator  5 . 
     Operation of the oil pan  4  having the above described structure will now be described. 
     After the engine is started, the oil pump is activated to pump up oil from the inner sump  6  via the oil strainer  8 . The pumped-up oil lubricates engine components and is heated. Thereafter, the oil is returned to the oil pan  4  via the oil drain passage  3  and an oil passage formed inside the crankshaft  2 . Some of the oil is scattered by rotation of the crankshaft  2  and trickles down the inner wall of the cylinder block  1  to be returned to the oil pan  4 . 
     In the present embodiment, the rubber lip  14 , which is attached to the plate  13 , seals the outer sump  7 . Therefore, as shown in  FIG. 2 , oil that has trickled down the inner wall of the cylinder block  1  does not flow into the outer sump  7 , but enters the inner sump  6 . As a result, the temperature of the oil in the inner sump  6  is quickly increased. 
     When the engine is stopped, pumping up of oil is stopped and oil that has lubricated engine components is returned to the inner sump  6 . This raises the level of the oil stored in the inner sump  6 , so that some of the stored oil flows to the outer sump  7  through the through holes  9 . Since oil flows from the inner sump  6  to the outer sump  7  and is dispersed, deterioration of the oil in the inner sump  6  is reduced. 
     Depending on the shape or the size of the separator  5 , the rubber lip  14  cannot be directly attached to the separator  5  in some cases. In this regard, the present embodiment includes the plate  13 , which is smaller in size than the separator  5  and is easy to handle, and the rubber lip  14  for sealing the outer sump  7  is attached to the plate  13 . The plate  13  is fixed to the separator  5  by heat-swaging. This allows the rubber lip  14  to be easily attached to a desired position on the separator  5 . 
     When attaching the separator  5 , to which the plate  13  is fixed, to the oil pan  4 , the separator  5  is inserted into the oil pan  4  such that the rubber lip  14  on the plate  13  is elastically deformed to closely contact the inner wall  10  of the oil pan  4 . The oil pan  4  has such a shape that the distance between the opposed faces of the inner wall  10  decreases toward the lower end. Therefore, by pressing the separator  5  toward the bottom of the oil pan  4 , the rubber lip  14  is caused to tightly contact the inner wall  10  of the oil pan  4 . As a result, the separator  5  is attached to the oil pan  4  while sealing the outer sump  7 . 
     The above described embodiment has the following advantages. 
     (1) Oil trickling down the inner wall of the cylinder block  1  is restricted from entering the outer sump  7 , so that the oil in the inner sump  6  is allowed to be easily heated. The present embodiment includes the plate  13 , which is smaller in size than the separator  5  and is easy to handle, and the rubber lip  14  for sealing the outer sump  7  is attached to the plate  13 . The plate  13  is fixed to the separator  5 . This allows the rubber lip  14  to be easily attached to the separator  5 . 
     (2) The plate  13  is fixed to the separator  5  by heat-swaging. This allows the rubber lip  14  to be easily arranged at a desired position on the separator  5  and facilitates the work. 
     (3) The rubber lip  14 , which seals the outer sump  7 , is easily elastically deformed to conform to the shape of the inner wall  10  of the oil pan  4 . This allows the rubber lip  14  and the inner wall  10  to tightly contact each other, thereby further improving the sealing property of the outer sump  7 . 
     (4) The plate  13  has a ring-like shape, and the rubber lip  14  is attached to the entire perimeter of the plate  13 . The rubber lip  14  closely contacts the inner wall  10  of the oil pan  4 . This improves the sealing property of the outer sump  7 , thereby allowing the oil to be more easily heated. 
     The above illustrated embodiment may be modified as follows. 
     In the above illustrated embodiment, the rubber lip  14  is attached to the perimeter of the plate  13 . However, as long as the outer sump  7  can be sealed, the manner in which the rubber lip  14  is attached is not limited. 
     The plate  13  does not necessarily need to have a ring-like shape, but may be split into several pieces. In this case, a rubber lip is attached to each of the pieces. 
     In the illustrated embodiment, a rubber lip is employed as a sealing member for sealing the outer sump  7 . However, other types of sealing members such as a liquid gasket may be employed. This configuration also achieves the same advantages as the above described advantages (1) and (2). 
     In the illustrated embodiment, plastic is used as the material of the plate  13 . However, the plate  13  may be made of other material such as metal. 
     In the above illustrated embodiment, the separator  5  and the plate  13  are fixed to each other by the heat-swaging. However, if metal is used as the material of the plate  13 , the plate  13  may be mechanically swaged to be fixed to the separator  5 . 
     In the illustrated embodiment, the separator  5  and the plate  13  are fixed to each other by swaging. However, the separator  5  and the plate  13  may be fixed to each other by other methods. For example, adhesive may be applied to the separator  5  and the plate  13  and the separator  5  and the plate  13  may be bonded to each other. The separator  5  and the plate  13  may also be welded to each other. Alternatively, the separator  5  and the plate  13  may be fastened to each other with bolts. As other methods for fixing, the protrusions  12  of the separator  5  may be formed with hooks and the plate  13  may be fixed to the separator  5  by snap-fitting. Further, the separator  5  and the plate  13  may be integrated with clips. These configurations at least achieve the same advantage as the advantage (1).