Abstract:
A pump is provided for a lubricating system of a combustion engine that includes, but is not limited to a housing and a lid that together define a pump hollow space in which a pump mechanism for the pumping of lubricant of the lubricating system is arranged. The pump hollow space includes, but is not limited to at least one intake opening and at least one discharge opening. The pump additionally includes, but is not limited to a regulating valve for regulating a flow of the lubricant through the pump, which is integrated in the lid.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to German Patent Application No. 102010022137.6, filed May 20, 2010, which is incorporated herein by reference in its entirety. 
       TECHNICAL FIELD 
       [0002]    The technical field relates to a pump for a lubricating system of a combustion engine, more preferably of a combustion engine of a motor vehicle. 
       BACKGROUND 
       [0003]    US 2007 0224067 A1 discloses a lubricating system for a combustion engine with an oil pump with variable displacement in which a pump outlet pressure is used to preload the position of a slide and by doing so change the eccentricity of the pump and consequently vary the pump displacement. By varying the pump displacement relative to the pump outlet pressure, the pump outlet pressure can be controlled on the basis of engine flow requirements. The pressure regulating characteristics of the pump are determined through calibrating a reaction spring, which balances the hydraulic forces acting on the slide. The lubricating system also comprises a valve which is switched dependent on the engine speed. At low engine speeds the valve is opened in order to introduce lubricant in the form of oil into a second chamber of the pump. At higher engine speeds the valve is closed, upon which the second chamber is emptied. Since the valve is electrically actuated there is a certain space requirement for the pump, the valve and the associated cables of the lubricating system. 
         [0004]    It is desirable to reduce the fuel consumption of combustion engines. This can be achieved at least in part through a weight reduction and/or reduction in size of the component. Consequently it is also desirable to reduce the space requirement of the lubricating system in order to reduce the weight, and/or to optimize the space requirement of the lubricating system in order to be able to install additional components in the same space. 
         [0005]    At least one object therefore is stating an optimization of the space requirement and/or a reduction in size of the lubricating system of a combustion engine. In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background. 
       SUMMARY 
       [0006]    In an exemplary embodiment of the invention a pump for a lubricating system of a combustion engine is stated, which comprises a housing and a lid, which together define a pump hollow space in which a pump mechanism for the pumping of lubricant of the lubricating system is arranged. The pump furthermore comprises a regulating valve for regulating a flow of the lubricant in or out of a regulating chamber of the pump, wherein the regulating valve is integrated in the lid or in the housing. 
         [0007]    The regulating valve is thus neither arranged separately from the pump nor connected to the housing of the pump, for instance with screws, but directly integrated in the lid of the pump. This arrangement has the advantage that the space requirement of the pump and the regulating valve compared with a separate arrangement of the component can be reduced. Furthermore, producing the pump with an arrangement in which the regulating valve is connected to the housing or arranged in the housing is simplified, since on the one hand the lid has a simple plate-like shape and on the other hand the lid can be favorably produced as individual part with a casting method. Consequently, further processing steps for producing bores for the inlet and outlet openings between the valve and the pump hollow space in the housing and/or in the lid are no longer necessary, since these are directly molded in the casting process. The regulating valve can be a switching valve, wherein the switching valve is switched in order to regulate the flow of the lubricant into or out of the regulating chamber. The regulating valve can be a proportional valve, wherein the flow of the lubricant into or out of the regulating chamber can be increased or reduced in order to regulate the flow. 
         [0008]    In an exemplary embodiment the regulating valve is an electromagnetically actuated valve. This type of valve is connected to a power source in order to be able to selectively switch the valve. An electromagnetically actuated valve can also be switched dependent on the operating conditions of the combustion engine since because of the power supply it can be controlled by the engine control unit. In an exemplary embodiment the electromagnetically actuated valve comprises a valve housing in which an electromagnetic actuation device is arranged, and a valve body. The valve body is displaceable with the electromagnetic actuation device in order to regulate the flow of the lubricant. More preferably, the valve body can has a soft magnetic material and the actuation device can comprise a coil that generates a magnetic field when current flows through the coil. The magnetic field generated by the coil results in the displacement of the soft magnetic valve body in order to open or to close the valve and in order to regulate the flow of the lubricant through the pump. 
         [0009]    In an exemplary embodiment the lid is designed so that it comprises a valve hollow space for accommodating the valve body of the regulating valve. The lid can be shaped so that in addition to its function as a lid, it also provides the valve hollow space. The valve hollow space comprises at least one inlet opening through which the lubricant can flow into the valve hollow space and at least one outlet opening through which the lubricant can flow out of the valve hollow space. The valve body is moveable in the hollow space in order to open and to close the inlet opening and/or the outlet opening and in order to regulate the flow of the lubricant in or out of the regulating chamber of the pump. 
         [0010]    In an exemplary embodiment the regulating valve is a three-way valve, so that lubricant can be selectively steered into the regulating chamber or into a second control chamber or lubricant from the regulating chamber or from the second control chamber into the oil pan. Dependent on the engine rotational speed the lubricant can be steered into the second control chamber. In this exemplary embodiment the valve hollow space comprises three openings. Lubricant can enter the valve hollow space from the first control chamber through a first opening. A second opening makes possible steering the lubricant from the first control chamber into the second control chamber via the valve hollow space. A third opening makes possible flowing of lubricant from the second control chamber into the oil pan. Furthermore, the lid can comprise a flange to which the valve housing is connected, wherein the valve housing can be connected to the flange via a seal. If the regulating valve is electrically activatable the valve housing can additionally comprise a cable connection so that the regulating valve can be supplied with energy from an external source. 
         [0011]    In an exemplary embodiment the regulating valve is designed so that it is actuated dependent on an engine rotational speed of the combustion engine in order to regulate an outlet pressure of the lubricant from the pump dependent on the engine rotational speed. For example, the regulating valve can be opened at low engine rotational speeds and closed above a predetermined limit value of the engine rotational speed in order to guarantee a variable lubricant pressure in the combustion engine dependent on the engine rotational speed. 
         [0012]    In principle, the pump can comprise any pump mechanism within the housing and the lid with integrated regulating valve. In an exemplary embodiment the pump is a vane pump with variable displacement. A pump of this type is disclosed for example in US 2007 0224067 A1. With a vane pump with variable displacement the generated outlet pressure can be regulated particularly accurately. 
         [0013]    In an exemplary embodiment the pump or the vane pump with variable displacement comprises a plurality of pump chambers with variable volume. The pump chambers are defined through sliding vanes carried by a rotor. The rotor is rotatably mounted in the housing in order to pump the lubricant from the inlet opening to the pressurized outlet opening. The rotor can be driven by the combustion engine. Furthermore, the pump can comprise a slide for the displacement control, wherein the slide is rotatably connected to a wall of the housing through a rotary axis. The slide is internally in engagement with the vanes, wherein the volume of the respective pump chamber upon rotating of the slide is variable. 
         [0014]    The pump or the vane pump with variable displacement can additionally comprise an elastic element such as one or a plurality of springs which preloads the slide in one direction. The lubricant exerts a force in the pump chambers on the slide in a direction that is opposite to the direction in which the elastic element preloads the slide. In an exemplary embodiment of the invention a lubricating system of a combustion engine of a motor vehicle with a pump according to any one of the previously described exemplary embodiments is stated. 
         [0015]    As already mentioned above, the lid in which the regulating valve is integrated can consist of a shaped individual part which states the function of a lid for the pump as well as a valve hollow space and if applicable a flange for a valve housing of the regulating valve. The lid can also be in the form of an aluminum casting. Consequently in a further exemplary embodiment a lid of a pump for a lubricating system of a combustion engine is stated, wherein the lid comprises a valve hollow space for accommodating the valve body of a regulating valve. The valve hollow space comprises at least one inlet opening through which lubricant can flow into the valve hollow space and at least one outlet opening, through which the lubricant can flow out of the valve hollow space. The rim of the lid can comprise one or a plurality of bores in which screws can be arranged, so that the lid can be fastened to the housing by means of the screws. 
         [0016]    In a further exemplary embodiment the lid additionally comprises a flange to which the valve housing of the regulating valve can be connected. For example, the valve housing can be connected to the flange via a seal, such as an O-ring, so that the valve can be replaced. In this case the flange can also comprise a suitable groove for the seal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and: 
           [0018]      FIG. 1  shows a perspective top view of a pump for a lubricating system of a combustion engine with an integrated regulating valve; 
           [0019]      FIG. 2  shows a perspective top view of the lid of the pump of  FIG. 1 ; 
           [0020]      FIG. 3  shows a perspective view of the bottom of the lid of  FIG. 2 ; 
           [0021]      FIG. 4   a  shows a perspective top view of the pump of  FIG. 1 , in which the lid is not shown; 
           [0022]      FIG. 4   b  shows a top view of the pump of  FIG. 4   b;    
           [0023]      FIG. 5  shows a cross section of a lid according to an exemplary embodiment; 
           [0024]      FIG. 6  shows a perspective view of a regulating valve of  FIG. 1 ; and 
           [0025]      FIG. 7  shows a perspective view of a comparison pump with the regulating valve is arranged in the housing. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    The following detailed description is merely exemplary in nature and is not intended to limit application and uses. Furthermore, there is no intention to be bound by any theory presented in the preceding background or summary or the following detailed description. 
         [0027]      FIG. 1  shows a perspective top view of a pump  1 , more preferably an oil pump, for a lubricating system  2  of an only partially shown combustion engine  3 . The pump  1  comprises an integrated regulating valve  4 .  FIG. 2  shows a perspective top view of the lid  7  of the pump  1  of  FIG. 1  and  FIG. 3  shows a perspective view of the bottom of the lid  7  of  FIG. 2 . Same parts are shown with the same reference characters. 
         [0028]    The pump  1  comprises a housing  5  with a housing wall  6  and a lid  7  which is connected to the housing  5  or to the housing wall  6  with a plurality of screws  29 . The inner surfaces of the housing wall  6  and the lid  7  define a pump hollow space  8  in which the pump mechanism  9  is arranged, with which lubricant of the lubricating system  2  is pumped. Typically the lubricant is oil. 
         [0029]    The regulating valve  4  is also described as a so-called “oil control valve” and in this exemplary embodiment is a switching valve that is actuated electromagnetically. The regulating valve  4  is arranged on the lid  7  of the pump  1 . The regulating valve  4  is a three-way valve.  FIG. 6  shows a perspective view of the regulating valve  4  and  FIG. 5  shows a cross section of the lid  7  with a regulating valve  4  integrated in the lid  7 . As is shown in the cross section of  FIG. 5  the regulating valve  4  comprises an electromagnetic actuation device  10  having a coil  11  that is activatable with an external power source that is not shown via a cable  16 . The coil  11  generates a magnetic field when the power source is connected in order to displace a magnetic valve body  12  within a valve hollow space  13 . 
         [0030]    The valve hollow space  13  comprises a first opening  14 , through which oil from a first control chamber of the pump  1  can enter the valve hollow space. The valve hollow space  13  comprises a second opening  15  through which oil can flow into the second control chamber  27  of the pump  1 . The valve hollow space  13  comprises a third opening  30  through which oil can flow from the second chamber  27  into an oil pan which is not shown. On actuating the regulating valve  4  the oil from the lubricating system can thus be selectively steered into the second control chamber  27  of the pump  1  or oil can flow from the second control chamber  27  of the pump  1  into the oil pan in order to empty the second control chamber  27 . 
         [0031]    The regulating valve  4  is directly arranged on the lid  7  of the pump  1 , so that it is integrated in the lid  7 . More preferably the lid  7  is shaped so that it forms the valve hollow space  13 . Furthermore, the lid is shaped so that the valve hollow space comprises a flange  17  to which a valve housing  18  of the regulating valve  4  is connected, so that the valve body  12  is arranged within the valve hollow space  13 , while the valve housing  18 , in which the electromagnetic actuation device  10  is located, is arranged outside the lid  7  and outside the pump  1 . A seal  28  can be present between the valve housing  18  and the flange  17  in order to seal the electromagnetic actuation device  10  against the oil. The lid  7  can be an individual part that can be produced of aluminum of an aluminum alloy using a casting method. 
         [0032]      FIG. 4   a  shows a perspective top view of the pump  1  of  FIG. 1 , wherein the lid  7  has been omitted.  FIG. 4   b  shows a schematic top view of the pump  1  of  FIG. 4   a . In the  FIG. 4   a  and  FIG. 4   b  the pump mechanism can be seen.  FIG. 4   a  and  FIG. 4   b  show that the pump  1  of this exemplary embodiment is a vane pump with variable displacement. This vane pump  1  with variable displacement ensures improved regulation of the pump outlet flow pressure within a narrow range of a desired pressure during different engine operating conditions. 
         [0033]    The vane pump  1  comprises a rotor  19  with a plurality of sliding vanes  20  which is rotatable in the housing  5  on a fixed axis  21 . The rotor  19  can be driven by a transverse axis hexagon shaft drive of the combustion engine or another suitable drive means driven by the combustion engine. 
         [0034]    The sliding vanes  20  are internally in engagement with a slide  22  in order to define a plurality of pump chambers  23  within the slide  22 . The slide  22  is rotatably connected to the housing wall  6  through a rotary axis  24  and is rotatable in order to vary the displacement of the pump chambers  23 . The displacement of the pump  1  is proportional to the eccentricity of the slide  22  relative to the axis  21  of the rotor  19 . 
         [0035]    When the pump  1  is in a state of rest the slide  22  is forced into a position of maximum eccentricity relative to the rotor  19 . When the pump operates and the slide  22  is in that position, the displacement of the pump is at its maximum value. When the slide  22  turns away from a position of maximum eccentricity the displacement of the pump is reduced and the output flow of the pump generally decreases. When the middle of the slide  22  is turned into a position in which it is aligned with the axis of the rotor  19 , the slide  22  is located at an eccentricity of approximately 0% (i.e., approximately 100% of its maximum eccentricity) and the pump  1  operates at a displacement of approximately zero. 
         [0036]    The pump  1  also has an oil inlet channel which is not shown in the figures, which provides a first intake opening and is formed on an inlet side of the housing  5 . A pressure oil outlet channel which is likewise not shown in the figure provides for a discharge opening and is formed on an opposite outlet side of the housing. The inlet and outlet channels preferentially communicate with the pump chambers  23  on opposite lower and upper sides of the rotor  19  in order to prevent trapping of gases in the pump chambers  23 . Rotation of the rotor  19  at a certain eccentricity level causes the pump chambers  23  to expand. This change of the chamber volume in turn causes a decompression of the pump chambers, which causes the oil to be sucked through the inlet channel into the pump chambers  23  and then expelled from the pump chambers  23  through the outlet channel when the chambers contract. The pump  1  comprise a first control chamber  26  which is located between the outer side of the slide  22  and the housing wall  6  and comprises a second control chamber  27  which likewise forms between the outside of the slide  22  and the housing wall  6 . The second control chamber  27  is arranged next to the first control chamber  26  and can be selectively filled and emptied upon actuation of the regulating valve  4 . There are thus three possible oil paths, A, B and C. Path A steers oil from the first control chamber  26  into the regulating valve through the second opening  15 . Path B steers oil from the first control chamber  26  via the regulating valve  4  into the second control chamber  27 . The third path C steers oil from the second control chamber  27  into the oil pan via the third opening  30  in order to empty the second control chamber. The regulating valve  4  is thus a three-way valve. 
         [0037]    An elastic element  25  which in this exemplary embodiment is a spring, is arranged between the housing wall  6  and the slide  22 . The elastic element  25  is in engagement with the slide  22  and forces the slide  22  in the direction of the first control chamber  26 . The elastic element  25  counteracts the hydraulic force exerted by the oil in the first control chamber  26  and the adjacent second control chamber  27  on the slide  22 . 
         [0038]    The regulating valve is actuated dependent on the engine rotational speed of the combustion engine. At low engine rotational speed the regulating valve  4  is energized so that the second control chamber  27  is filled. At higher engine rotational speeds the regulating valve  4  is not energized, it thus remains current less, so that oil from the second control chamber  27  is steered into the oil pan. 
         [0039]      FIG. 7  shows a comparison pump  1 ′, which likewise comprises a pump mechanism with a vane pump with two control chambers  26 ′,  27 ′, a slide  22 ′ and a three-way regulating valve  4 ′. In the comparison pump l′ the regulating valve  4 ′ is integrated in the housing  5 ′ of the pump  1 ′ and more preferably in the housing wall  6 ′. The regulating valve  4 ′ comprises a valve housing  18 ′ with cable  16 ′, in order to supply the coil which is not shown of the actuation device which is not shown with current, and a valve body  12 ′, which is arranged in a valve hollow space  13 ′ in the housing wall  6 ′. 
         [0040]    In  FIG. 7 , the three flow directions of the oil are shown by the arrows A, B and C. These flow directions are equal to that in the pump  1  of  FIG. 1  to  FIG. 6 . Arrow A indicates the flow from the first control chamber  26 ′ to the valve hollow space  13 ′. Arrow B indicates the flow from the valve hollow space  13 ′ to the second control chamber  27 ′, wherein the oil is steered from the first control chamber into the second control chamber. Arrow C shows the flow of oil from the second control chamber  27 ′ into the oil pan in order to empty the second control chamber  27 ′. 
         [0041]    While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.