Patent Publication Number: US-2018045091-A1

Title: Oil pan assembly

Description:
RELATED APPLICATIONS 
     This application relates to and claims priority benefits from U.S. Provisional Patent Application No. 62/143,970 entitled “Oil Pan Assembly,” filed Apr. 7, 2015, which is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF EMBODIMENTS OF THE DISCLOSURE 
     Embodiments of the present disclosure generally relate to oil pan assemblies, such as may be used with transmissions and internal combustion engines of vehicles. 
     BACKGROUND 
     Various vehicles include transmissions and internal combustion engines having components that are lubricated with oil. An oil pans is often used to retain oil within an portion of a vehicle when the oil is not circulating through a transmission or an engine. 
     Known oil pans may be formed of thermoplastic resin (such as Nylon 6/6). Other known oil pans may be formed from other materials, such as metal and rubber for impact resistance, strength, and the like. Some known oil pans integrate other components into the pan, such as suction and pressure side filters, windage trays, and baffling. Examples of oil pans are described in EP 1276974, entitled “Oil Pan Module for Internal Combustion Engines,” EP 1511924, entitled “Oil Pan,” U.S. Pat. No. 4,930,469, entitled “Oil Pan for an Internal Combustion Engine,” U.S. Pat. No. 6,131,543, entitled “Oil Pan for an Internal Combustion Engine,” U.S. Pat. No. 6,584,950, entitled “Oil Pan,” U.S. Pat. No. 6,705,270, entitled “Oil Pan Module for Internal Combustion Engines,” and U.S. Pat. No. 7,481,196, entitled “Oil Pan Useful for an Internal Combustion Engine.” 
     In order to reduce mass and increase fuel economy, plastics may be used to form certain engine and transmission parts. Corporate Average Fuel Economy (CAFE) standards represent regulations that were enacted to improve the average fuel economy of vehicles, such as automobiles and light trucks, which are produced for sale in the United States. A particular CAFE standard of 55 miles per gallon by the year 2025 has incentivized manufacturers to seek to produce lighter vehicles. Notably, a component that is made of plastic is typically lighter than a metal version of the component. As such, various vehicle components may be made of plastic in order to reduce overall vehicle weight. Injection-molded N 6/6 represents a common material used to form plastic oil pans. 
     However, due to temperature concerns, some manufacturers form oil pans from metals, such as stamped aluminum. That is, at higher temperatures, such as within and/or proximate to an operating internal combustion engine and/or exhaust lines, plastic components may deform. Therefore, metals are still used to form various components, as the metals are able to withstand higher temperatures. Yet, as can be appreciated, metals, such as aluminum or steel, have design limitations with respect to the types of shapes that may be produced, and typically weigh more than twice the weight of plastic pans. 
     SUMMARY OF EMBODIMENTS OF THE DISCLOSURE 
     A need exists for a lighter oil pan that maintains structural integrity when subjected to increased temperatures, impact, and/or forces, such as may be caused through operation of a transmission and/or an internal combustion engine. A need exists for an oil pan that may be formed in various shapes to accommodate limited spaces within a vehicle. Further, a need exists for an oil pan that is less costly to manufacture. 
     With those needs in mind, certain embodiments of the present disclosure provide an oil pan assembly that includes a first portion formed of a first plastic, and a second portion formed of a second plastic that differs from the first plastic. The first portion is securely coupled to the second portion. The first plastic may be a thermoset or a thermoplastic, while the second plastic may be the other of the thermoset or the thermoplastic. In at least one embodiment, the thermoset is Sheet Molding Compound, and the thermoplastic is Nylon 6/6. 
     The first portion may be configured to be subjected to one or both of higher temperatures or higher forces than the second portion. In at least one embodiment, the first portion is configured to be positioned proximate to one or more exhaust routings. 
     The first portion may include a perimeter wall, and the second portion may include a base and a flange secured to the perimeter wall. An oil collection chamber is defined between the base and the perimeter wall. The base may have a thickness at least twice a thickness of the perimeter wall. 
     The first portion may be formed through compression molding. The second portion may be overmolded onto the first portion. 
     Certain embodiments of the present disclosure provide a method of forming an oil pan assembly. The method may include forming a first portion of the oil pan assembly from a first plastic, forming a second portion of the oil pan assembly from a second plastic that differs from the first plastic, and securely coupling the first portion to the second portion. 
    
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  illustrates a perspective top view of an oil pan assembly, according to an embodiment of the present disclosure. 
         FIG. 2  illustrates a cross-sectional view of a base coupled to a perimeter wall of an oil pan assembly, according to an embodiment of the present disclosure. 
         FIG. 3  illustrates a perspective top view of a perimeter wall, according to an embodiment of the present disclosure. 
         FIG. 4  illustrates a flow chart of a method of forming an oil pan assembly, according to an embodiment of the present disclosure. 
     
    
    
     Before the embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The disclosure is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. 
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE DISCLOSURE 
     Embodiments of the present disclosure provide an oil pan assembly that may include two different portions, each of which may be formed of a different plastic. In at least one embodiment, the oil pan assembly may include a first portion that may be formed of a thermoplastic, such as Nylon 6/6 (N 6/6), and a second portion that may be formed of a thermoset, such as Sheet Molding Compound (SMC). Each plastic has unique properties and different material costs. As such, the two plastics may be used to form the respective first and second portions, which are combined to form an oil pan assembly that maximizes or otherwise increases performance for adverse environments (such as proximate to an internal combustion engine of a vehicle), while minimizing or otherwise reducing cost. 
     Embodiments of the present disclosure provide an oil pan assembly that may include thermoset materials (thermosets) in areas that are configured for high impact and/or high temperature that are typically beyond the performance capabilities of thermoplastic materials (thermoplastics). A thermoset is a highly-crosslinked polymer that has a molecular mesh or network of polymer chains akin to a three-dimensional net. Once cured, thermosets cannot be melted or remolded, and are resistant to solvents. In short, a thermoset cures irreversibly, such that once a thermoset is formed, it is permanently set. Due to a tightly-crosslinked structure, thermosets resist higher temperatures and provide increased structural stability as compared to thermoplastics. 
     A thermoplastic is a type of plastic that becomes pliable or moldable above a specific temperature, has a defined melting point, and solidifies upon cooling. Polymer chains of thermoplastics associate through intermolecular forces, which weaken rapidly with increased temperature, yielding a viscous liquid. As such, thermoplastics may be reshaped by heating and are typically used to form components through injection molding, compression molding, calendering, extrusion, and/or the like. 
     As compared to thermoplastics, thermosets have significantly higher temperature resistance (for example, 400-500 degrees F.). In contrast, a maximum long term temperature resistance of N 6/6 or similar derivatives is approximately 300-350 degrees F. However, a thermoset, particularly a carbon fiber version, is typically much costlier than a thermoplastic. For example, a carbon fiber thermoset may currently range in price from $5-$20 per pound, while thermoplastic N 6/6 or high temperature derivatives such as PPA may currently average in price from $1.75-$3.75 per pound. 
     Accordingly, certain embodiments of the present disclosure provide an oil pan assembly that includes a first portion formed of a thermoset, and a second portion formed of a thermoplastic. Optionally, the first portion may be formed of a thermoplastic, while the second portion may be formed of a thermoset. The first portion is configured to be at or proximate to an area that may be subjected to high temperatures and/or forces that may otherwise deform and/or degrade a thermoplastic. The second portion may not be susceptible to such high temperatures and/or impacts, and may therefore be formed of the thermoplastic, in order to reduce the overall cost of the oil pan assembly. 
     In at least one embodiment, an oil pan assembly may include a thermoset perimeter or annular wall that is coupled to a thermoplastic base. The oil pan assembly may include the annular wall and the base, each of which is formed of a separate plastic material, to form a unique plastic hybrid design that provides temperature and impact resistance, while minimizing or otherwise reducing overall cost through the use of a lower cost thermoplastic resin at areas that are not susceptible to impacts and/or elevated temperatures. 
     The areas of the oil pan that are formed of thermoset may be molded from thermoset SMC in a compression molding tool, for example. Various shapes and geometries may be used. In comparison to steel pans, thermoset SMC pans may be drawn deeper and are lighter. 
     Temperature resistance may be desired along the sides of the oil pan assembly due to exhaust routing along either side. Other areas of the oil pan assembly, including the bottom and flange sections, may be molded from a thermoplastic, such as N 6/6, which allows the efficient use of lower cost resin, and the flexibility to insert mold torque limiters or torque limiters with threaded fasteners (bolts). Portions of the oil assembly that are not to be subjected to impacts or elevated temperatures may be overmolded onto the thermoset molding. For example, the base and/or flange of the oil pan assembly may be formed of injection molded Nylon 6/6 33GF. 
     Certain embodiments of the present disclosure provide a method of manufacturing an oil pan assembly. The method may include compression molding a thermoset SMC portion, inserting the thermoset SMC portion into an injection molding tool, and over-molding the SMC portion with N 6/6 or another thermoplastic to form the oil pan assembly. 
     Alternatively, if there are areas for other transmission and chassis combinations that are susceptible to impact forces and temperatures beyond thermoplastic resin capability, SMC or another thermoset may be used in those areas. Embodiments of the present disclosure may strategically use materials to maximize benefits of their unique properties. 
       FIG. 1  illustrates a perspective top view of an oil pan assembly  100 , according to an embodiment of the present disclosure. The oil pan assembly  100  may include a base  102  coupled to a perimeter wall  104  that upwardly extends from outer edges of the base  102 . An upper flange  106  may outwardly extend from a top edge of the perimeter wall  104 . The upper flange  106  may include a plurality of fastener retainers  108 , each of which may be configured to receive a portion of a fastener that is used to secure the oil pan assembly  100  to a portion of a vehicle, such as an interior metal frame. An oil collection chamber  110  is defined between an upper surface  112  of the base  102 , and interior surfaces  114  of the perimeter wall  104 . The oil collection chamber  110  is configured to receive and retain transmission or motor oil. As shown, the base  102  may angle upwardly from an end  116  to an end  118 , in order to facilitate the flow of oil from the end  118  to the end  116  by way of gravity. 
     Alternatively, the oil pan assembly  100  may be sized and shaped differently than shown. For example, the oil pan assembly  100  may be circular in shape. The oil pan assembly  100  may include more or less fastener retainers than shown. In at least one embodiment, the flange  106  may not be contiguous around the perimeter of the oil pan assembly  100 . In at least one other embodiment, the oil pan assembly  100  may not include the flange. Further, the angle from the end  116  to the end  118  may be steeper or shallower than shown. 
     The base  102  and the perimeter wall  104  may be formed of two different plastics. The base  102  (and the flange  106 ) may be a thermoplastic, such as Nylon 6/6 (N 6/6), while the perimeter wall  104  may be a thermoset, such as Sheet Molding Compound (SMC). The thermoplastic base  102  and the thermoset perimeter wall  104  (and optionally the flange  106 ) combine to form the oil pan assembly  100 , which is configured to increase performance for adverse environments (through the thermoset perimeter wall  104 , which is configured to be proximate to areas of elevated temperature, for example) while minimizing or otherwise reducing overall cost (through use of the thermoplastic base  102  at locations that are not susceptible to elevated temperatures and/or forces). 
     The perimeter wall  104  is configured to be at or proximate to a location that may be subjected to high temperatures and/or impacts that may otherwise deform and/or degrade a thermoplastic. The base  102  is at a location that may not be susceptible to such high temperatures and/or impacts, and may therefore be formed of the thermoplastic, in order to reduce the overall cost of the oil pan assembly  100 . The oil pan assembly  100  provides a unique plastic hybrid design that provides temperature and impact resistance, while minimizing or otherwise reducing overall cost through the use of a lower cost thermoplastic resin at locations that are not susceptible to elevated temperatures and/or forces. 
     In at least one embodiment, the perimeter wall  104  is formed of thermoset SMC. The perimeter wall  104  may be formed through compression molding. Various shapes and geometries may be used. The thermoset SMC may be drawn deeper and is lighter than various metals. 
     Temperature resistance may be desired along sides  118  of the oil pan assembly  100  due to exhaust routing  120  along the sides  118 . The exhaust routing  120  may generate elevated temperatures that may potentially deform and/or degrade a thermoplastic. Accordingly, the perimeter wall  104  includes the sides  118 , which are formed of the thermoset. Other areas of the oil pan assembly  100 , such as the base  102  and the flange  106 , may be formed from a thermoplastic, such as Nylon 6/6, which allows the efficient use of lower cost resin, and the flexibility to insert mold torque limiters or torque limiters with threaded fasteners (bolts), such as within the fastener retainers  108  of the flange  106 . In short, areas that are not to be subjected to elevated temperatures and/or forces may be overmolded onto the thermoset portions of the oil pan assembly  100 . 
     Alternatively, various other portions of the oil pan assembly  100  may be formed from thermoset or thermoplastic. In at least one embodiment, at least a portion of the base  102  may be formed of a thermoset, while at least a portion of the perimeter wall  104  may be formed of a thermoplastic, depending on the locations that may be subjected to elevated temperatures, impact, and/or forces. 
       FIG. 2  illustrates a cross-sectional view of the base  102  coupled to the perimeter wall  104  of the oil pan assembly  100 , according to an embodiment of the present disclosure. As shown, the base  102  may be a generally flat, planar piece having outer edges  130  that securely connect to interior edges of a base-connecting portion  132  of the perimeter wall  104 . The base-connecting portion  132  may generally be parallel to the base  102 , and may connect to an upstanding rim  134  through a curved transition  136 . The upstanding rim  134  may be approximately perpendicular to the base-connecting portion  132 . The flange  106  outwardly extends from an upper portion  138  of the upstanding rim  134 . 
     As shown, the base  102  may have a thickness  140  that is greater than a thickness  142  of the perimeter wall  104 . For example, the thickness  140  may be at least twice the thickness  142 . The base  102  may be thickened as shown to achieve adequate structural strength of desired molding properties. Alternatively, the thickness  140  and  142  may be greater or less than shown. 
       FIG. 3  illustrates a perspective top view of the perimeter wall  104 , according to an embodiment of the present disclosure. As noted, the perimeter wall  104  may be formed of a thermoset, such as through compression molding. An opening  160  is formed through the perimeter wall  104 . The opening  160  is sized and shaped to accommodate the base  102  (shown in  FIGS. 1 and 2 ). 
     Referring to  FIGS. 1-3 , after the base  102 , the perimeter wall  104 , and the flange  106  are formed, the base  102  is positioned within the opening  160  and coupled to the perimeter wall  104 , such as through bonding, adhesives, welding, and/or the like. Similarly, the flange  106  is secured to the perimeter wall  104 , such as through bonding, adhesives, welding, and/or the like. In at least one embodiment, the fully-formed perimeter wall  104  may be positioned within a chamber of a mold, and thermoplastic may be injection molded into the chamber onto portions of the perimeter wall  104  to form the base  102  and/or the flange  106 . 
       FIG. 4  illustrates a flow chart of a method of forming an oil pan assembly, according to an embodiment of the present disclosure. At  200 , a first portion of an oil pan assembly may be formed of a first plastic. The first portion may be a portion that is configured to be subjected to elevated temperatures and/or forces. For example, the first portion may be a perimeter wall, and the first plastic may be a thermoset. In at least one embodiment, the first portion may be formed by compression molding, and the first plastic may be thermoset SMC. 
     At  202 , a second portion of an oil pan assembly is formed from a second plastic that differs from the first plastic. The second portion may be a portion that is not to be subjected to elevated temperatures and/or forces. For example, the second portion may be a base, and the second plastic may be a thermoplastic. It is to be understood that  202  may optionally occur concurrently with, before, or after  200 . 
     At  204 , the first portion is coupled to the second portion to form the oil pan assembly. For example, the first portion may be securely coupled to the second portion through chemical bonding, heating, adhesives, fasteners, welding, and/or the like. In at least one embodiment, the first portion formed of the first plastic (such as thermoset SMC) may be positioned within an injection molding tool, and the second plastic may be over-molded onto the first portion. For example, the first portion may be formed of thermoset SMC and placed into a mold. The second plastic, such as N 6/6 or the like may be injection molded into the mold over the first portion of the thermoset SMC. 
     Referring to  FIGS. 1-4 , embodiments of the present disclosure provide a hybrid oil assembly having portions that are formed of different plastics. Portions that are to have greater resistance to temperature, impact, and external forces are formed of a thermoset, while areas that are not susceptible to elevated temperatures and/or forces are formed of a thermoplastic, in order to reduce the overall cost of the oil pan assembly. 
     Accordingly, embodiments of the present disclosure provide a lightweight oil pan assembly (in that it is not formed of metals) that maintains structural integrity when subjected to increased temperatures and/or forces. At the same time, embodiments of the present disclosure provide a lightweight assembly that is efficiently manufactured in a cost-effective manner. 
     While various spatial and directional terms, such as top, bottom, lower, mid, lateral, horizontal, vertical, front and the like may be used to describe embodiments of the present disclosure, it is understood that such terms are merely used with respect to the orientations shown in the drawings. The orientations may be inverted, rotated, or otherwise changed, such that an upper portion is a lower portion, and vice versa, horizontal becomes vertical, and the like. 
     Variations and modifications of the foregoing are within the scope of the present disclosure. It is understood that the embodiments disclosed and defined herein extend to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present disclosure. The embodiments described herein explain the best modes known for practicing the disclosure and will enable others skilled in the art to utilize the disclosure. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art. 
     To the extent used in the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, to the extent used in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. §112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure. 
     Various features of the disclosure are set forth in the following claims.