Patent Publication Number: US-2021180484-A1

Title: Hybrid oil pan for vehicle

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Patent Application No. 10-2019-0164337, filed on Dec. 11, 2019, the entire contents of which is incorporated herein for all purposes by this reference. 
     BACKGROUND 
     The present invention relates to a hybrid oil pan for a vehicle and, more particularly, to a hybrid oil pan used in a vehicle for reducing weight and increasing dynamic rigidity. 
     Description of the Related Art 
     Typically, vehicles are equipped with oil pans to store engine oil. The oil pan is mounted to the lower side of an engine and fastened to the transmission side, and is divided into an integral type and a removable type. 
     Since heavy loads, such as transmissions, are fastened, the integral type oil pan cannot be applied with a plastic material with weak rigidity, and the integral type oil pan is formed of aluminum. The removable type oil pan consists of an upper pan part formed of an aluminum material and a lower pan part formed of a plastic material, combined with the upper pan part. 
     The oil pan to which a load such as a transmission is mounted may be deformed due to the dynamic behavior of the transmission, and thus, a plastic material having a weak rigidity cannot be used at a part engaged with the transmission. 
     Most oil pans are thus formed from a single piece using an aluminum material. However, such an integral type oil pan made of aluminum, due to the characteristics of the aluminum material, causes an increase in weight and in heat loss of engine oil, and deteriorates fuel efficiency due to the increase in heat loss of the engine oil. 
     In the case of the removable type oil pan, although only the upper pan part that is fastened to the transmission is made of aluminum, since the upper pan part and the lower pan part need to be assembled after being separately fabricated, the oil pan has problems including a reduction in design freedom and an increase in material and manufacturing costs. 
     SUMMARY 
     Accordingly, the present disclosure has been made keeping in mind the above problems occurring in the related art, and an objective of the present disclosure is to provide a hybrid oil pan for a vehicle, in which a body part of the oil pan is molded with a plastic material to reduce the weight, and a portion of the oil pan that is fastened to a transmission has increased dynamic rigidity to cope with the deformation caused by the dynamic behavior of the transmission. 
     In order to achieve the above objective, according to one aspect of the present disclosure, there is provided a hybrid oil pan for a vehicle, the hybrid oil pan including: a first body section having a transmission mounting part fastened to a transmission, the first body section being formed of a metal material; and a second body section having an oil storage space and integrally formed with the first body section, the second body section being formed of a plastic material. 
     The first body section may include a body overlapping part integrally formed with the transmission mounting part, and wherein the second body section includes a first oil storage part integrally formed with an inner surface of the body overlapping part to surround a first space side of the oil storage space, and a second oil storage part integrally formed with the first oil storage part to surround a second space side of the oil storage space. 
     The first space side may correspond to one side space of the oil storage space and the second spaced side may correspond to the other side space of the oil storage space. 
     The body overlapping part may have one or more coupling holes, and when the second body section is molded, a plastic resin of the plastic material for forming the second body section may be provided in the coupling holes to fill the coupling holes. 
     The coupling hole may be disposed on an edge portion of the body overlapping part adjacent to the second oil storage part. 
     A bottom portion of the body overlapping part may be provided with a first center floor having a predetermined height difference from a bottom portion of the second oil storage part, the first center floor having an arcuate cross-section bent toward the first space side. 
     The first center floor may be disposed at the center of the bottom portion of the body overlapping part. 
     The bottom portion of the body overlapping part may be provided with a second center floor disposed between the first center floor and the second oil storage part, the second center floor having an arcuate cross-section bent toward the first space side. 
     The first center floor may be provided with a plurality of holes, and when the second body section is molded, a plastic resin of the plastic material for forming the second body section may be provided in the holes to fill the holes. 
     The first center floor may comprise a grid-type reinforcement rib on an outer surface of the first center floor. 
     A partition rib may be provided on an outer surface of the body overlapping part, and during the molding of the first oil storage part, the plastic resin for forming the second body section may pass through the coupling holes on an inner side of the body overlapping part and fill up to an end of the partition rib. 
     According to the present disclosure, the first body section which is engaged with the transmission is molded with an aluminum material, and the second body section integrally formed with the first body section is molded with a plastic material, thereby increasing the dynamic rigidity of the oil pan while reducing the weight, and thus having effects of reducing the vibration and noise in the mid-high frequency range and improving the fuel efficiency. 
     In particular, since the oil pan has various structures capable of increasing the coupling force and rigidity of the first body section and the second body section during injection molding of the second body section, the oil pan may secure dynamic rigidity at the same level as a conventional aluminum oil pan. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objectives, features and advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view illustrating a hybrid oil pan for a vehicle according to an embodiment of the present disclosure; 
         FIG. 2  is a perspective view illustrating a hybrid oil pan for a vehicle according to a disclosure of the present disclosure; 
         FIG. 3  is a perspective view illustrating a first body section according to an embodiment of the present disclosure; 
         FIG. 4  is a cross-sectional view taken along line A-A of  FIG. 1 ; 
         FIG. 5  is a partial cross-sectional view in one direction illustrating the oil pan of the present disclosure; 
         FIG. 6  is a partial cross-sectional view in another direction illustrating the oil pan of the present disclosure; and 
         FIG. 7  is a cross-sectional view illustrating the first body section of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinbelow, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings to allow those skilled in the art to easily implement the embodiments. However, the present disclosure is not limited to those embodiments, but may be implemented into other forms. 
     A hybrid oil pan for a vehicle according to the present disclosure has a structure in which a body section of the oil pan is molded with a plastic material to reduce the weight, and a portion of the oil pan engaged with a transmission has increased dynamic rigidity to cope with the deformation caused by the dynamic behavior of the transmission. 
     As illustrated in  FIGS. 1 and 2 , the oil pan includes a first body section  10  having a transmission mounting part  12  and a second body section  20  integrally formed with the first body section  10 , wherein the second body section is formed of a plastic material. 
     The first body section  10  may be formed of a metal material such as aluminum, and may be fastened to one side of a transmission through the transmission mounting part  12 . 
     The second body section  20  is formed of a plastic material that is lighter than aluminum, and has an oil storage space S in which engine oil is accommodated. The oil storage space S consists of a first space part S 1  corresponding to one side of the oil storage space S and a second space part S 2  corresponding to the other side of the oil storage space S. That is, the oil storage space S is composed of a first space part S 1  constituting one side of the oil storage space S and a second space part S 2  constituting the other side of the oil storage space S. 
     The first body section  10  includes a transmission mounting part  12  coupled to a transmission and a body overlapping part  11  integrally formed with the transmission mounting part  12 . 
     The transmission mounting part  12  may be disposed adjacent to one end (i.e., the first end) of the body overlapping part  11 . In other words, the transmission mounting part  12  may be formed to extend from the first end of the body overlapping part  11 . 
     The body overlapping part  11  may be a metal structure surrounding the first space S 1  together with the second body section  20 . The body overlapping part  11  may be composed of a bottom  11   a  disposed on a bottom surface of the first space part S 1  and sidewalls  11   b  integrally formed on both ends of the bottom portion  11   a  and disposed on the lateral sides of the first space part S 1 . 
     As illustrated in  FIGS. 3 and 4 , the body overlapping part  11  may be provided with one or more coupling holes  13  to increase the coupling force between the first body section  10  and the second body section  20  integrally molded to the first body section  10 . The coupling hole  13  is filled with a plastic resin of the plastic material used for molding the second body section  20  during injection molding of the second body section  20 . 
     The second body section  20  may be formed by insert injection molding using a mold. That is, the second body section  20  is fabricated by injecting a plastic resin into a mold for the second body section  20  in a state in which the first body section  10  is inserted into the mold. Specifically, by injecting the plastic resin for molding the second body section  20  into the cavity in the mold in the state in which the first body section  10  is inserted and disposed at a predetermined position inside the mold, the second body section  20  is integrally molded with the first body section  10 . At this time, the plastic resin for forming the second body section  20  is provided in the coupling holes  13  to fill the coupling holes  13  (see  FIG. 4 ). That is, when the second body section  20  is molded, the plastic resin fills the coupling holes  13 . As the plastic resin is cured in a state of filling the coupling holes  13 , the first body section  10  and the second body section  20  can secure a coupling force using riveting. 
     As illustrated in  FIG. 3 , the coupling hole  13  may be disposed at an edge portion (i.e., an opposite edge portion of the transmission mounting part) of the body overlapping part  11  adjacent to a second oil storage part  22  of the second body section  20 . In addition, the coupling hole  13  may also be disposed at other positions of the body overlapping part  11 . 
     As illustrated in  FIGS. 1 and 2 , the second body section  20  may include a first oil storage part  21  integrally formed with an inner surface of the body overlapping part  11 , and a second oil storage part  22  integrally formed with the first oil storage part  21 . The first oil storage part  21  may be molded to surround the first space S 1  of the oil storage space S, and the second oil storage part  22  may be molded to surround the second space S 2  of the oil storage space S. The first oil storage part  21  may have a bottom portion  21   a  disposed on the bottom surface of the first space S 1  and sidewall portions  21   b  integrally formed with ends (i.e., edges) of the bottom portion  21   a  and disposed on lateral sides of the first space S 1 . The second oil storage part  22  may have a bottom portion  22   a  disposed on the bottom surface of the second space S 2  and sidewall portions  22   b  integrally formed with ends of the bottom portion  22   a  and disposed on lateral sides of the second space S 2 . 
     In addition, as illustrated in  FIGS. 3 and 5 , the bottom portion  11   a  of the body overlapping part  11  may be provided with a first center floor  14  having a height difference greater than a predetermined value from the bottom portion  22   a  of the second oil storage part  22 . In order to increase the coupling force between the first body section  10  and the second body section  20 , the first center floor  14  may preferably have an arcuate cross-sectional structure that is convexly curved toward the first space S 1 . That is, the first center floor  14  may have a curved structure that is bent toward the first space S 1 . The height difference may be a height difference on the basis of the height direction of the oil storage space S. 
     The load of the transmission fastened to the transmission mounting part  12  directly affects the center of the bottom portion  11   a  of the body overlapping part  11 . Therefore, the first center floor  14  is preferably disposed at the center of the bottom portion  11   a  of the body overlapping part  11 . The center of the bottom portion  11   a  is provided between both sidewall portions  11   b  of the body overlapping part  11 . 
     The first center floor  14  is disposed at the center of the body overlapping part  11 , thereby increasing structural rigidity of the body overlapping part  11 , as well as increasing the coupling force between the first body section  10  and the second body section  20 . 
     In addition, a second center floor  15  may be further provided at the bottom portion of the body overlapping part  11 . As illustrated in  FIG. 1 , the second center floor  15  is disposed between the first center floor  14  and the second oil storage part  22 . In order to increase the coupling force between the first body section  10  and the second body section  20 , the second center floor  15  may preferably have an arcuate cross-sectional structure that is convexly curved toward the first space S 1 . That is, the second center floor  15  may have a curved surface that is bent toward the second space S 2 . 
     A height difference exists between the second center floor  15  and the first center floor  14 , and thus an undercut portion  17  may be provided between the second center floor  15  and the first center floor  14 . As illustrated in  FIGS. 5 and 6 , the undercut portion  17  may be disposed vertically in the height direction of the oil storage space S. 
     Although the bottom portion  11   a  of the body overlapping part  11  may be configured as a flat plate, the bottom portion is preferably provided with the first center floor  14  and the second center floor  15  to prevent buckling caused by the load of the transmission. 
     In addition, the first center floor  14  may be provided with a plurality of holes  14   a.  The holes  14   a  may be arranged in multiple columns and rows on the first center floor  14 . When the second body section  20  is molded, a plastic resin for molding the second body section  20  may be provided in the holes  14   a  to fill the holes  14   a.  As the holes  14   a  are filled with the plastic resin, the coupling force between the first body section  10  and the second body section  20  may be further increased. 
     When the first oil storage part  21  is molded during the molding of the second body section  20 , the plastic resin flows over the inner surface of the bottom portion  11   a  of the body overlapping part  11  (see  FIG. 7 ). Therefore, since the holes  14   a  are formed in the first center floor  14 , when the first oil storage part  21  of the second body section  20  is molded, the area of the inner surface of the body overlapping part  11  that is in contact with the plastic resin may be reduced. 
     When the plastic resin comes into contact with the first body section  10  during the injection molding of the second body section  20 , the flowing characteristic (fluidity) of the plastic resin is deteriorated due to a much greater difference in temperature and thus the molding quality of the second body section  20  may be degraded. Accordingly, the injection molding quality of the second body section  20  may be increased by minimizing the area of the first body section  10  that is in contact with the plastic resin. 
     In addition, the outer surface of the first center floor  14  may be provided with a grid-type reinforcement rib  14   b.  The grid-type reinforcing rib  14   b  may protrude from the outer surface of the first center floor  14  and may be disposed at the lower outer side of the hole  14   a  (see  FIG. 7 ). 
     Due to the nature of the oil pan mounted on the lower part of an engine, the oil pan may be damaged by splashing of stones or the like on the road surface. The grid-type reinforcement rib  14   b  may increase rigidity of the oil pan against external impact. Therefore, since the first center floor  14  is provided with a grid-type reinforcement rib  14   b  together with the hole  14   a,  the injection molding quality and the rigidity of the oil pan may be increased. 
     Further, in order to increase the coupling force between the body overlapping part  11  and the first oil storage part  21 , the hole  14   a  of the first center floor  14  is preferably formed in a shape tapered from the inner side toward the outer side of the bottom portion  11   a  of the body overlapping part  11 . That is, the diameter of the hole  14   a  is preferably increased gradually from the inner side toward the outer side of the bottom portion  11   a.  The hole  14   a  may have various shapes such as honeycomb, rectangle, or the like. 
     In addition, a partition rib  16  may be provided on an outer surface of the bottom portion  11   a  of the body overlapping part  11 . The partition rib  16  may be disposed on the outer surface of the bottom portion  11   a  of the body overlapping part  11  according to a set pattern, and may be formed to protrude from the outer surface of the bottom portion  11   a.  The plastic resin for forming the second body section  20  passes through the coupling hole  13  on the inner side of the body overlapping part  11  and reaches and fills an end point (that is, an end height) of the partition rib  16  during molding of the first oil storage part  21  (see  FIG. 4 ). 
     Although not shown in the drawings, when injected into a mold for forming the second body section  20 , the plastic resin first fills the cavity for forming the second oil storage part  22  and then fills the cavity for forming the first oil storage part  21 . The plastic resin flows along the outer surface and the inner surface of the body overlapping part  11  for forming the first oil storage part  21 . At this time, the plastic resin flowing along the outer surface of the body overlapping part  11  flows only up to the partition rib  16 . The partition rib  16  may restrict and stop the flow of the plastic resin flowing along the outer surface of the body overlapping part  11 . 
     In addition, in  FIG. 1 , reference numeral H denotes a bolt hole H of the oil pan. The oil pan may be coupled to the lower part of an engine by a bolt member bolted through the bolt hole H. 
     Although the embodiments of the present disclosure have been described in detail, the scope of the present disclosure is not limited to the above-described embodiments, and various modifications and changes performed by those skilled in the art using the basic concepts of the present disclosure defined in the following claims are also included in the scope of the present disclosure.