Patent Application
20110286862
This application claims priority to German Patent Application No. 102010022137.6, filed May 20, 2010, which is incorporated herein by reference in its entirety.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and:
a shows a perspective top view of the pump of
b shows a top view of the pump of
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.
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.
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.
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.
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.
a shows a perspective top view of the pump 1 of
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.
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.
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.
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.
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.
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.
In
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102010022137.6 | May 2010 | DE | national |
