WO2022223118A1 - Variable displacement lubricant vane pump - Google Patents

Variable displacement lubricant vane pump Download PDF

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Publication number
WO2022223118A1
WO2022223118A1 PCT/EP2021/060528 EP2021060528W WO2022223118A1 WO 2022223118 A1 WO2022223118 A1 WO 2022223118A1 EP 2021060528 W EP2021060528 W EP 2021060528W WO 2022223118 A1 WO2022223118 A1 WO 2022223118A1
Authority
WO
WIPO (PCT)
Prior art keywords
pump
control ring
pressure
valve
variable displacement
Prior art date
Application number
PCT/EP2021/060528
Other languages
French (fr)
Inventor
Fabio GUGLIELMO
Massimiliano Lazzerini
Federico BETTI
Original Assignee
Pierburg Pump Technology Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pierburg Pump Technology Gmbh filed Critical Pierburg Pump Technology Gmbh
Priority to PCT/EP2021/060528 priority Critical patent/WO2022223118A1/en
Publication of WO2022223118A1 publication Critical patent/WO2022223118A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
    • F01C21/00—Component parts, details or accessories not provided for in groups F01C1/00 - F01C20/00
    • F01C21/10—Outer members for co-operation with rotary pistons; Casings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
    • F04C14/18—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by varying the volume of the working chamber
    • F04C14/22—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by varying the volume of the working chamber by changing the eccentricity between cooperating members
    • F04C14/223—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by varying the volume of the working chamber by changing the eccentricity between cooperating members using a movable cam
    • F04C14/226—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by varying the volume of the working chamber by changing the eccentricity between cooperating members using a movable cam by pivoting the cam around an eccentric axis
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/30—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
    • F04C2/34—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members
    • F04C2/344—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member
    • F04C2/3441—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member the inner and outer member being in contact along one line or continuous surface substantially parallel to the axis of rotation
    • F04C2/3442—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member the inner and outer member being in contact along one line or continuous surface substantially parallel to the axis of rotation the surfaces of the inner and outer member, forming the working space, being surfaces of revolution

Definitions

  • Variable displacement lubricant vane pump The invention is related to a variable displacement lubricant vane pump for providing pressurized lubricant with a pump outlet pressure, in particular to a mechanically driven variable displacement lubricant vane pump for providing pressurized lubricant having a positive pump outlet pressure for the lubrication of an internal combustion engine.
  • the mechanical lubricant vane pump is mechanically driven by the engine, for example via a gear or a belt, and is flu id ically coupled to the combustion engine for pumping the pressurized lubricant having the pump outlet pressure to and through the engine.
  • the pump outlet pressure or the gallery pressure of the lubricant in the engine or at the lubricant outlet of the engine needs to be controlled and stabilized to a set pressure value.
  • WO 2015/074700 A1 discloses a typical variable displacement lubricant vane pump being part of a lubrication circuit also comprising an internal combustion engine and a complex hydraulic control valve for controlling the set pump outlet pressure.
  • the lubricant vane pump is provided with a static pump housing, a shiftable control ring and a rotatable pump rotor comprising several rotor vanes rotating within the shiftable control ring.
  • the control ring is shiftable with respect to the pump rotor to thereby vary the eccentricity of the control ring with respect to the pump rotor for controlling the displacement and, as a result, the volumetric pump performance of the pump.
  • the pump is provided with a control ring preload spring preloading and pushing the shiftable control ring into the high eccentricity direction.
  • the pump is further provided with a control chamber which is loaded with the pump outlet pressure which causes the shiftable control ring to move into the low eccentricity direction against the control ring preload spring.
  • the pump is also provided with a complex control valve which allows choosing between different set pump outlet pressures.
  • WO 2014 187 503 A1 discloses a variable displacement lubricant vane pump as part of a lubrication circuit wherein the set pressure of the pump is the gallery pressure of the engine.
  • WO 2019/024997 A1 discloses a variable displacement lubricant vane pump comprising a pilot control chamber which is provided with an over- atmospheric pressure.
  • the pump is further provided with a calibrated hydraulic channel which permanently flu id ically connects the pilot control chamber with the suction port to provide a volume flow from the pilot control chamber to the suction port and to thereby define a equilibrium pressure in the pilot control chamber.
  • a simple proportional two-way valve is provided for activating/deactivating the supply of the pilot control chamber with over-atmospheric pressure from the engine's oil gallery.
  • the variation of the pilot control chamber pressure via a proportional two- way valve on the basis of the pump outlet pressure can be slow and imprecise.
  • the pump outlet pressure is not constant, but deviates upwards or downwards from the preferably constant set outlet pressure. This deviation is the result of the dependence of the pilot control chamber pressure on the pump outlet pressure or on the gallery pressure.
  • the pump volume flow controlled by a simple two-way valve is not suitable to achieve a reliable adaption of the pilot control chamber pressure.
  • variable displacement lubricant vane pump which provides a constant pump outlet pressure in particular at higher rotational speed. This object is solved with a variable displacement lubricant vane pump with the features of main claim 1.
  • variable displacement lubricant vane pump is provided with a static pump housing surrounding a pumping chamber wherein a shiftable control ring is provided.
  • the shiftable control ring can be supported at the housing and being shiftable in a strictly linear direction or can be provided pivotable so that the control ring is shifted along an arch-like path.
  • a rotatable pump rotor is arranged within the control ring.
  • the pump rotor comprises several rotor vanes rotating within the control ring and separating the pumping chamber into several rotating pumping compartments.
  • the rotation axis of the pump rotor is static so that the shifting of the control ring changes the eccentricity of the control ring with respect to the pump rotor to thereby control the pump's displacement and the pump's volumetric performance.
  • a control ring preload spring is provided for preloading and pushing the shiftable control ring into the high eccentricity position which is the position in which the pump has the highest displacement and volumetric performance referring to a constant rotational speed.
  • the pump is provided with a pilot control chamber which is responsible for the precise pressure control of the pump.
  • the pilot control chamber causes the shiftable control ring to move against the control ring preload spring into the low eccentricity direction.
  • the pilot control chamber is selectively pressurized with pressurized lubricant having an over-atmospheric pressure.
  • the pilot control chamber is selectively pressurized via an electric adjustment valve.
  • the electric adjustment valve can be, for example, a simple two-way valve with a single hydraulic inlet and a single hydraulic outlet.
  • the pressurized lubricant which is selectively directed to the pilot control chamber via the adjustment valve is preferably the lubricant having the engines gallery pressure.
  • the engines gallery pressure is the set pressure parameter of the pump if the electric adjustment valve is at least open in part so that the pressurized lubricant loads the pilot control chamber.
  • the pilot control chamber is additionally hydraulically connected to atmospheric pressure via a pressure relief channel directly connecting the pilot control chamber with atmospheric pressure, preferably connecting the pilot control chamber with a pump inlet where lubricant of atmospheric pressure is always present.
  • the pilot control chamber is pressurized with atmospheric pressure from the pump inlet. If the electric adjustment valve is completely opened or partly opened, the hydraulic pilot control chamber is pressurized with over-atmospheric pressure. The resulting equilibrium pressure in the control chamber then substantially depends on the volume flow flowing through the pressure relief channel.
  • the pressure relief channel has a substantial hydraulic resistance which is defined by its cross-sectional area. Generally, the hydraulic resistance defines the volume flow flowing through the pressure relief channel.
  • the pressure relief channel is provided with an automatically self-adapting flow control valve which is preferably a mechanical throttle valve.
  • the flow control valve is provided with an effective valve opening area being dependent on the control ring position. Accordingly, the effective valve opening area is variable and preferably continuously variable.
  • the hydraulic resistance of the pressure relief channel is varied such that the volume flow flowing from the pilot control chamber, preferably to the pump inlet or any other chamber at atmospheric pressure, is increased or decreased.
  • the pilot control chamber equilibrium pressure is defined by both the electric adjustment valve and the flow control valve, provided that the adjustment valve is open. If the effective valve opening area of the flow control valve is at maximum, the hydraulic resistance is at minimum and is substantially defined by the smallest pressure relief channel cross-sectional area. If the effective valve opening of the flow control valve is not at maximum, but is reduced referring to the maximum effective valve opening area, the hydraulic resistance of the pressure relief channel is increased. As a result, the volume flow leaking from the pilot control chamber is decreased resulting in a rising pilot control chamber equilibrium pressure.
  • the control chamber equilibrium pressure can be reduced by increasing the effective valve opening area.
  • the flow control valve is automatically self-adapting, i.e., the effective valve opening area is adapting in dependance on the pressure conditions of the pump outlet and the rotational speed of the pump. In particular at higher rotational speed in the so-called regulation phase, a constant pump outlet pressure is required. Therefore, the eccentricity of the control ring is reduced with increasing rotational speed and increasing pump outlet pressure to provide a substantially constant outlet pressure in the regulation phase.
  • the constancy of the outlet pressure is not sufficient enough.
  • the outlet pressure can slightly fluctuate or deviate upwards or downwards referring to the set outlet pressure.
  • the flow control valve in combination with the electronic adjustment valve defines a fine control measure that compensates these slight fluctuations and deviations.
  • the flow control valve comprises a valve opening and a valve body.
  • the flow control valve controls the volume flow by varying the hydraulic cross-section of the valve opening using the valve body.
  • the valve body defines an effective valve opening area which defines the released hydraulic cross-section and, as a result, defines the hydraulic resistance of the flow control valve.
  • the full hydraulic cross-section is released so that the maximum volume flow flows from the pilot control chamber through the pressure relief channel into the pump inlet.
  • the maximum pressure relief of the pilot control chamber is provided resulting in a decreasing pilot control chamber equilibrium pressure.
  • the effective valve opening area defining the released hydraulic cross-section of the valve opening is reduced, so that the volume flow flowing through the pressure relief channel is decreased.
  • the pressure relief is decreased resulting in an increasing pilot control chamber equilibrium pressure.
  • the valve opening is continuously openable and closeable.
  • the flow control valve is defined such that the effective valve opening area is continuously variable so that the released hydraulic cross-section can be continuously increased or decreased.
  • the volume flow can be controlled in a needs-based manner allowing a relatively precise control of the pilot control chamber equilibrium pressure.
  • the effective valve opening area is defined by the eccentricity position of the control ring. The movement of the control ring is therefore directly or indirectly coupled to the opening or closing movement of the flow control valve.
  • the valve opening or the valve body can be coupled to the control ring, so that the movement of the control ring causes a relative movement between the valve body and the valve opening which defines the effective valve opening area.
  • the valve body of the flow control valve is defined by the pump housing body.
  • the pressure relief channel is defined by a pressure relief channel groove within the control ring. Referring to the pump housing body, the pressure relief channel groove is arranged such that depending on the eccentricity of the control ring, a defined section of the pressure relief channel is opened and another defined section of the pressure relief channel is blocked by the pump housing body.
  • the pressure relief channel is preferably provided with at least two different cross-sectional areas, namely a pressure relief channel section with either a small or a large cross-sectional area.
  • the cross-sectional area of the pressure relief channel together with the valve body defines the effective valve opening area of the flow control valve and, as a result, defines the released hydraulic cross-section.
  • the pressure relief channel is preferably at least partially tapering.
  • the tapering channel section is preferably arranged such, that the cross- sectional area of the pressure relief channel can be continuously variated by releasing a defined tapering channel section.
  • a plurality of releasable hydraulic cross-sections of different sizes is provided which substantially defines the effective valve opening area.
  • the cross-sectional area of the pressure relief channel groove decreases with decreasing eccentricity of the control ring, so that the volume flow through the pressure relief channel decreases with increasing rotational speed.
  • the pilot control chamber equilibrium pressure must be increased to correct the position of the control ring to a lower eccentricity.
  • an increasing released cross-sectional area with decreasing eccentricity of the control ring can be used to correct a downwards deviating pump outlet pressure.
  • the adjustment valve is a two- way valve with a single hydraulic inlet and a single hydraulic outlet.
  • the adjustment valve is not provided with any additional hydraulic input or output.
  • the adjustment valve is a proportional valve.
  • the pressure relief channel can be permanently open.
  • the adjustment valve is preferably provided with a valve inlet which is connectable to the lubricant gallery pressure of an internal combustion engine.
  • the internal combustion engine is preferably supplied with the pressurized lubricant coming from a pump outlet and having the pump outlet pressure.
  • the adjustment valve is further provided with a valve outlet, which is connectable to the pilot control chamber, to supply the pilot control chamber with pressurized lubricant from the engines oil gallery.
  • the pilot control chamber is not provided with over-atmospheric pressure, for example, with lubricant from the engine's oil gallery. As a result, the pilot control chamber is substantially at an atmospheric equilibrium pressure so that the control ring is pushed by the pre-loaded spring into the maximum eccentricity position. If the adjustment valve is open, the pilot control chamber is provided with over- atmospheric pressure, for example, with lubricant from the engine's oil gallery. In that case, the lubricant flows from the pilot control chamber to the pump inlet chamber. As a result, the pilot control chamber equilibrium pressure depends on the pump outlet pressure and the effective valve opening area of the flow control valve so that the control ring is pushed against the spring force into a non-maximum eccentricity position.
  • variable displacement lubricant vane pump With the flow control valve in combination with a simple adjustment valve, the pilot control chamber equilibrium pressure is simply and reliably controllable.
  • the variable displacement lubricant vane pump according to the invention provides a reliably constant outlet pressure with a relatively low effort.
  • figure 1 shows a first embodiment of an opened variable displacement lubricant vane pump according to the invention with a flow control valve for decreasing the pressure relief channel volume flow with decreasing eccentricity of the control ring
  • figure 2 a second alternative embodiment of an opened variable displacement lubricant vane pump according to the invention with a flow control valve for increasing the pressure relief channel volume flow with decreasing eccentricity of the control ring
  • figure 3 a cross-sectional view of the flow control valve of the variable displacement lubricant vane pump of figure 1 with the control ring being at the maximum eccentricity position
  • figure 4 a cross-sectional view of the flow control valve of the variable displacement lubricant vane pump of figure 1 with the control ring being at the minimum eccentricity position
  • figure 5 a schematic view of an automotive lubrication circuit with a variable displacement lubricant vane pump, an electric adjustment valve and an internal combustion engine which is provided with pressurized lubricant generated by the vane pump.
  • Figure 1 and figure 2 each show an embodiment of a variable displacement lubricant vane pump 10 according to the invention for providing pressurized lubricant to a lubrication circuit 100 of an internal combustion engine 12.
  • the variable displacement lubricant vane pump 10 comprises a static pump housing 22 with a pump housing body 23 which encloses the internal pump components.
  • the pump 10 further comprises a shiftable control ring 24 being supported linearly slidable within the pump housing body 23 and a rotatable pump rotor 26.
  • the pump rotor 26 comprises nine radial vane slots 28 which are equiangularly arranged over the circumference of the pump rotor 26.
  • the vane pump 10 further comprises nine radially oriented rotor vanes 27 being slidably guided within the vane slots 28. At their radial inner end, the rotor vanes 27 contact an annular spring 29 which pre-loads the rotor vanes 27 such that their radial outer end is in a sealing contact with the control ring 24.
  • the control ring 24, the pump rotor 26 and the pump housing body 23 define a pumping chamber 14 which is a flu id ica lly separated by the rotor vanes 27 into nine pumping compartments 16.
  • the eccentricity of the control ring 24 can be varied with respect to the pump rotor 26.
  • the displacement of the pumping chamber 14 can be varied by increasing or decreasing the volume change of each pumping compartment 16 during one rotation of the pump rotor 26, so that a pump outlet pressure P0 can be varied.
  • the control ring 24 is at one side which is substantially perpendicularly arranged to the eccentricity direction h, I supported by a preload spring 36 pushing the control ring 24 into the high eccentricity position h.
  • the control ring 24 and the pump housing body 23 define a pilot control chamber 42.
  • the pilot control chamber 42 is pressurized with lubricant having an over atmospheric pressure PG which is provided by an oil gallery of an internal combustion engine 12, shown in figure 5.
  • FIG. 5 shows a lubrication circuit 100 comprising the variable displacement lubricant vane pump 10, the internal combustion engine 12 and an electric adjustment valve 50.
  • the internal combustion engine 12 is provided with lubricant being pressurized by the vane pump 10 and having a pump outlet pressure PO. Therefore, the internal combustion engine 12 is flu id ica lly connected to a pump outlet 32 of the vane pump 10.
  • the vane pump 10 sucks in lubricant having atmospheric pressure PA via a pump inlet 34, pressurizes the lubricant within the pumping chamber 14 and discharges the pressurized lubricant via the pump outlet 32.
  • the pressurized lubricant having the pump outlet pressure PO supplies the oil gallery of the internal combustion engine 12 defining the oil gallery pressure PG.
  • a partial volume flow is branched off of the total volume flow flowing through the oil gallery of the internal combustion engine 12. This partial volume flow flows through a pressure line to a valve inlet 56 of the electric adjustment valve 50. The remaining lubricant within the oil gallery of the internal combustion engine 12 flows back to an oil tank 70. Downstream of the electric adjustment valve 50, the pressure line is fluid ically connected to the pilot control chamber 42 of the vane pump 10.
  • the electric adjustment valve 50 is a proportional two-way valve so that the electric adjustment valve 50 substantially opens or closes the pressure line and thereby opens or closes the supply of the pilot control chamber 42 with lubricant from the oil gallery of the internal combustion engine 12. Thereby the pilot control chamber 42 can be selectively pressurized causing the control ring 24 to move against the preload spring 36.
  • the variable displacement lubricant pump 10 as shown in figures 1 and 2 further comprises a pressure relief channel 46 being defined by a pressure relief channel groove 47 within the control ring 24.
  • the pressure relief channel groove 47 is arranged at one axial end surface of the control ring 24 and fluidically connects the pilot control chamber 42 with the pumping chamber 14, in particular with the suction side of the pumping chamber 14 which is fluidically connected to the pump inlet 34.
  • the pressure relief channel groove 47 comprises three sections 471, 472, 473 which are arranged one after another with respect to the sliding direction h, I of the control ring 24.
  • the three sections 471, 472, 473 of the pressure relief channel groove 47 are arranged such that the first semi- cylindrical large section 471 connects to the pumping chamber 14, whereas the third semi-cylindrical small section 473 connects to the pilot control chamber 42.
  • the three sections 471, 472, 473 of the pressure relief channel groove 47 are arranged such that the first semi-cylindrical large section 471 connects to the pilot control chamber 42, whereas the third semicylindrical small section 473 connects to the pumping chamber 14.
  • the arrangement of the three sections 471, 472, 473 of the pressure relief channel groove 47 in embodiment two of figure 2 is inversed to the three sections 471, 472, 473 of the pressure relief channel groove 47 in embodiment one of figure 1.
  • the pressure relief channel groove 47 of the first embodiment tapers in the low eccentricity direction I, whereas the pressure relief channel groove 47 of the second embodiment tapers in the high eccentricity direction h.
  • the pressure relief channel 46 of the variable displacement lubricant vane pump 10 as shown in figures 1 and 2 is provided with an automatically self- adapting flow control valve 60 which is a throttle valve.
  • the flow control valve 60 comprises a valve opening 61 and a valve body 62.
  • the valve body 62 is defined by the pump housing body 23, which is shaped such that depending on the eccentricity position of the control ring 24, one of the three sections 471, 472, 473 of the pressure relief channel groove 47 is active.
  • the cross-sectional area of the active section 471, 472, 473 defines the effective valve opening area xl, x2 and defines the hydraulic cross- section of the pressure relief channel 46, shown in figures 3 and 4.
  • the pump housing body 23 is provided with a cut-out 63 which is defined by a not shown part of the pump housing body 23 which defines the cover of the vane pump 10 and axially closes the shown opened vane pump 10.
  • the valve body 62 defines a valve opening edge 64 being arranged perpendicularly to the sliding direction of the control ring 24.
  • the valve opening edge 64 of the cut-out 63 moves along the pressure relief channel groove 47 and covers a defined section 471, 472, 473 of the pressure relief channel groove 47, whereas another section 471, 472, 473 remains uncovered.
  • the effective valve opening area xl, x2 and, as a result the hydraulic cross- section of the flow control valve 60 is varied.
  • the hydraulic cross-section is continuously variable.
  • the pump housing body 23 is provided with a separate cut-out 63 defining a single pocket within the pump housing body 23 and being provided with the trapezoid shape.
  • the cut-out 63 is permanently fluidically connected to the pilot control chamber 42.
  • the valve opening edge 64 of the cut-out 63 is located in the first semi-cylindrical large section 471 with the first large cross-sectional area of the pressure relief channel groove 47 so that the valve opening 61 is completely open. Accordingly, the cut-out 63 bypasses the small section 473 of the pressure relief channel groove 47 so that the maximum effective valve opening area xl is open, shown in figures 1 and 3.
  • the pressure relief channel groove 47 moves relatively to the cut-out 63.
  • the valve opening edge 64 is located in the in the third semicylindrical small section 473 of the pressure relief channel groove 47 so that the cut-out 63 does not bypass the small section 473 of the pressure relief channel groove 47 anymore.
  • the small cross-sectional area of the pressure relief channel groove 47 is active so that the valve opening 61 is partially closed and the effective valve opening area x2 is at minimum, shown in figure 4.
  • the cut-out 63 is provided with a substantially triangular shape.
  • the cut-out 63 is fluidically connected to the pumping chamber 14.
  • the valve opening edge 64 is arranged perpendicularly to the sliding direction of the control ring 24 and is located in the small section of the pressure relief channel groove 47 at a maximum eccentricity position of the control ring 24. Thereby the small cross-sectional area of the pressure relief channel groove 47 is active so that the flow control valve 60 is partially closed at the maximum eccentricity position of the control ring 24 and, as a result, the effective valve opening area xl is at minimum.
  • the flow control valve 60 is fully open at the minimum eccentricity position of the control ring 24. If the control ring 24 moves into the minimum eccentricity position the valve opening edge 64 of the cut-out 63 is located in the large section of the pressure relief channel groove 47 so that the effective valve opening area x2 is at maximum opening the maximum hydraulic cross-section.
  • the pump inlet 34 and the pilot control chamber 42 are permanently flu id ica lly connected by the pressure relief channel 46. If the electric adjustment valve 50 is closed, the pilot control chamber 42 equilibrates with pump inlet side of the pumping chamber 14. As the resulting pressure force generated by the lubricant being at atmospheric pressure PA in the pilot control chamber 42 is lower than the spring force of the pre-load spring 36, the control ring 24 is pushed by the preload spring 36 into the maximum eccentricity position. If the electric adjustment valve 50 is open, the pilot control chamber 42 is provided with pressurized lubricant from the oil gallery of the internal combustion engine 12 having the gallery pressure PG.
  • a defined volume flow of the lubricant flows from the pilot control chamber 42 into the pump inlet 34 so that the pilot control chamber 42 is at a defined pilot control chamber pressure PC.
  • the pressure force resulting from the pilot control chamber pressure PC pushes the control ring 24 against the spring force of the preload spring 36 so that the control ring 24 is moved into the lower eccentricity direction I.
  • the outlet pressure PO With increasing rotational speed, the outlet pressure PO is rising, resulting in an increased gallery pressure which causes the pilot control chamber pressure PC to increase. Accordingly, the pilot control chamber pressure PC depends on the outlet pressure PO.
  • the flow control valve 60 allows to increase or decrease the pilot control chamber pressure PC independent of the outlet pressure PO, provided that the valve opening position of the electric adjustment valve 50 is constant so that a constant volume flow is provided.
  • variable displacement lubricant vane pump 10 can be used to increase the pilot control chamber pressure PC independent of the outlet pressure PO by reducing the hydraulic cross-section of the pressure relief channel 46 with the flow control valve 60. Thereby the outlet pressure PO can be corrected downwards so that a relatively constant outlet pressure PO can be provided.
  • variable displacement lubricant vane pump 10 can be used to decrease the pilot control chamber pressure independent of the outlet pressure PO.
  • the outlet pressure PO can be corrected upwards to provide a relatively constant outlet pressure PO.

Abstract

The invention relates to a variable displacement lubricant vane pump (10) for providing pressurized lubricant with a pump outlet pressure (P0), with a static pump housing (22) comprising a pump housing body (23), a shiftable control ring (24) and a rotatable pump rotor (26) comprising several rotor vanes (27) rotating within the control ring (24), the control ring (24) being shiftable with respect to the pump rotor (26) to thereby vary the eccentricity of the control ring (24) with respect to the pump rotor (26) for controlling the volumetric pump performance. The vane pump (10) further comprises a control ring preload spring (36) preloading and pushing the shiftable control ring (24) into the high eccentricity direction (h), a pilot control chamber (42) causing the shiftable control ring (24) to move against the control ring preload spring (36) and being selectively pressurized with pressurized lubricant having an over-atmospheric pressure (PG), an electric adjustment valve (50) for selectively directing pressurized lubricant having the over-atmospheric pressure (PG) to the pilot control chamber (42), and a pressure relief channel (46) directly connecting the pilot control chamber (42) with atmospheric pressure (PA). The pressure relief channel (46) is provided with an automatically self-adapting flow control valve (60) with an effective valve opening area (x1, x2) being dependent on the control ring position to define the volume flow flowing through the pressure relief channel (46) to thereby adjust the hydraulic pilot control chamber pressure (PC) so that deviations of the pump outlet pressure (P0) from the set outlet pressure can be compensated.

Description

D E S C R I P T I O N
Variable displacement lubricant vane pump The invention is related to a variable displacement lubricant vane pump for providing pressurized lubricant with a pump outlet pressure, in particular to a mechanically driven variable displacement lubricant vane pump for providing pressurized lubricant having a positive pump outlet pressure for the lubrication of an internal combustion engine.
The mechanical lubricant vane pump is mechanically driven by the engine, for example via a gear or a belt, and is flu id ically coupled to the combustion engine for pumping the pressurized lubricant having the pump outlet pressure to and through the engine. The pump outlet pressure or the gallery pressure of the lubricant in the engine or at the lubricant outlet of the engine needs to be controlled and stabilized to a set pressure value.
WO 2015/074700 A1 discloses a typical variable displacement lubricant vane pump being part of a lubrication circuit also comprising an internal combustion engine and a complex hydraulic control valve for controlling the set pump outlet pressure. The lubricant vane pump is provided with a static pump housing, a shiftable control ring and a rotatable pump rotor comprising several rotor vanes rotating within the shiftable control ring. The control ring is shiftable with respect to the pump rotor to thereby vary the eccentricity of the control ring with respect to the pump rotor for controlling the displacement and, as a result, the volumetric pump performance of the pump.
The pump is provided with a control ring preload spring preloading and pushing the shiftable control ring into the high eccentricity direction. The pump is further provided with a control chamber which is loaded with the pump outlet pressure which causes the shiftable control ring to move into the low eccentricity direction against the control ring preload spring. The pump is also provided with a complex control valve which allows choosing between different set pump outlet pressures. WO 2014 187 503 A1 discloses a variable displacement lubricant vane pump as part of a lubrication circuit wherein the set pressure of the pump is the gallery pressure of the engine.
WO 2019/024997 A1 discloses a variable displacement lubricant vane pump comprising a pilot control chamber which is provided with an over- atmospheric pressure. The pump is further provided with a calibrated hydraulic channel which permanently flu id ically connects the pilot control chamber with the suction port to provide a volume flow from the pilot control chamber to the suction port and to thereby define a equilibrium pressure in the pilot control chamber. A simple proportional two-way valve is provided for activating/deactivating the supply of the pilot control chamber with over-atmospheric pressure from the engine's oil gallery.
The variation of the pilot control chamber pressure via a proportional two- way valve on the basis of the pump outlet pressure can be slow and imprecise. In addition, it is recognized that at higher rotational speed, the pump outlet pressure is not constant, but deviates upwards or downwards from the preferably constant set outlet pressure. This deviation is the result of the dependence of the pilot control chamber pressure on the pump outlet pressure or on the gallery pressure. The pump volume flow controlled by a simple two-way valve is not suitable to achieve a reliable adaption of the pilot control chamber pressure.
It is an object of the invention to provide a simple and relatively cost- efficient variable displacement lubricant vane pump which provides a constant pump outlet pressure in particular at higher rotational speed. This object is solved with a variable displacement lubricant vane pump with the features of main claim 1.
The variable displacement lubricant vane pump is provided with a static pump housing surrounding a pumping chamber wherein a shiftable control ring is provided. The shiftable control ring can be supported at the housing and being shiftable in a strictly linear direction or can be provided pivotable so that the control ring is shifted along an arch-like path. A rotatable pump rotor is arranged within the control ring. The pump rotor comprises several rotor vanes rotating within the control ring and separating the pumping chamber into several rotating pumping compartments. The rotation axis of the pump rotor is static so that the shifting of the control ring changes the eccentricity of the control ring with respect to the pump rotor to thereby control the pump's displacement and the pump's volumetric performance.
A control ring preload spring is provided for preloading and pushing the shiftable control ring into the high eccentricity position which is the position in which the pump has the highest displacement and volumetric performance referring to a constant rotational speed.
The pump is provided with a pilot control chamber which is responsible for the precise pressure control of the pump. The pilot control chamber causes the shiftable control ring to move against the control ring preload spring into the low eccentricity direction. The pilot control chamber is selectively pressurized with pressurized lubricant having an over-atmospheric pressure. The pilot control chamber is selectively pressurized via an electric adjustment valve. The electric adjustment valve can be, for example, a simple two-way valve with a single hydraulic inlet and a single hydraulic outlet.
The pressurized lubricant which is selectively directed to the pilot control chamber via the adjustment valve is preferably the lubricant having the engines gallery pressure. As a result, the engines gallery pressure is the set pressure parameter of the pump if the electric adjustment valve is at least open in part so that the pressurized lubricant loads the pilot control chamber.
The pilot control chamber is additionally hydraulically connected to atmospheric pressure via a pressure relief channel directly connecting the pilot control chamber with atmospheric pressure, preferably connecting the pilot control chamber with a pump inlet where lubricant of atmospheric pressure is always present.
If the electric adjustment valve is completely closed, the pilot control chamber is pressurized with atmospheric pressure from the pump inlet. If the electric adjustment valve is completely opened or partly opened, the hydraulic pilot control chamber is pressurized with over-atmospheric pressure. The resulting equilibrium pressure in the control chamber then substantially depends on the volume flow flowing through the pressure relief channel. The pressure relief channel has a substantial hydraulic resistance which is defined by its cross-sectional area. Generally, the hydraulic resistance defines the volume flow flowing through the pressure relief channel.
The pressure relief channel is provided with an automatically self-adapting flow control valve which is preferably a mechanical throttle valve. The flow control valve is provided with an effective valve opening area being dependent on the control ring position. Accordingly, the effective valve opening area is variable and preferably continuously variable.
With the automatically self-adapting flow control valve, the hydraulic resistance of the pressure relief channel is varied such that the volume flow flowing from the pilot control chamber, preferably to the pump inlet or any other chamber at atmospheric pressure, is increased or decreased. Thereby the pilot control chamber equilibrium pressure is defined by both the electric adjustment valve and the flow control valve, provided that the adjustment valve is open. If the effective valve opening area of the flow control valve is at maximum, the hydraulic resistance is at minimum and is substantially defined by the smallest pressure relief channel cross-sectional area. If the effective valve opening of the flow control valve is not at maximum, but is reduced referring to the maximum effective valve opening area, the hydraulic resistance of the pressure relief channel is increased. As a result, the volume flow leaking from the pilot control chamber is decreased resulting in a rising pilot control chamber equilibrium pressure. Vice versa, if the effective valve opening area is not at maximum, the control chamber equilibrium pressure can be reduced by increasing the effective valve opening area. The flow control valve is automatically self-adapting, i.e., the effective valve opening area is adapting in dependance on the pressure conditions of the pump outlet and the rotational speed of the pump. In particular at higher rotational speed in the so-called regulation phase, a constant pump outlet pressure is required. Therefore, the eccentricity of the control ring is reduced with increasing rotational speed and increasing pump outlet pressure to provide a substantially constant outlet pressure in the regulation phase.
As the control ring defines a rough control measure only, the constancy of the outlet pressure is not sufficient enough. In fact, the outlet pressure can slightly fluctuate or deviate upwards or downwards referring to the set outlet pressure. The flow control valve in combination with the electronic adjustment valve defines a fine control measure that compensates these slight fluctuations and deviations. By varying the effective valve opening area in dependance on the control ring's eccentricity position, the flow control valve adjusts the equilibrium pressure in the pilot control chamber in addition to the adjustment valve and thereby eliminates relevant pressure fluctuations and deviations of the pump outlet pressure in the regulation phase.
Preferably, the flow control valve comprises a valve opening and a valve body. The flow control valve controls the volume flow by varying the hydraulic cross-section of the valve opening using the valve body. By relatively moving the valve body with respect to the valve opening, the valve body defines an effective valve opening area which defines the released hydraulic cross-section and, as a result, defines the hydraulic resistance of the flow control valve. At a maximally opened valve opening, the full hydraulic cross-section is released so that the maximum volume flow flows from the pilot control chamber through the pressure relief channel into the pump inlet. Thereby, the maximum pressure relief of the pilot control chamber is provided resulting in a decreasing pilot control chamber equilibrium pressure. By partially closing the valve opening, the effective valve opening area defining the released hydraulic cross-section of the valve opening is reduced, so that the volume flow flowing through the pressure relief channel is decreased. As a result, the pressure relief is decreased resulting in an increasing pilot control chamber equilibrium pressure.
In a preferred embodiment of the invention, the valve opening is continuously openable and closeable. Accordingly, the flow control valve is defined such that the effective valve opening area is continuously variable so that the released hydraulic cross-section can be continuously increased or decreased. Thereby the volume flow can be controlled in a needs-based manner allowing a relatively precise control of the pilot control chamber equilibrium pressure. In an advantageous embodiment of the invention, the effective valve opening area is defined by the eccentricity position of the control ring. The movement of the control ring is therefore directly or indirectly coupled to the opening or closing movement of the flow control valve. For example, the valve opening or the valve body can be coupled to the control ring, so that the movement of the control ring causes a relative movement between the valve body and the valve opening which defines the effective valve opening area.
In a particularly preferred embodiment of the invention, the valve body of the flow control valve is defined by the pump housing body. In addition, the pressure relief channel is defined by a pressure relief channel groove within the control ring. Referring to the pump housing body, the pressure relief channel groove is arranged such that depending on the eccentricity of the control ring, a defined section of the pressure relief channel is opened and another defined section of the pressure relief channel is blocked by the pump housing body.
The pressure relief channel is preferably provided with at least two different cross-sectional areas, namely a pressure relief channel section with either a small or a large cross-sectional area. The cross-sectional area of the pressure relief channel together with the valve body defines the effective valve opening area of the flow control valve and, as a result, defines the released hydraulic cross-section.
The pressure relief channel is preferably at least partially tapering. The tapering channel section is preferably arranged such, that the cross- sectional area of the pressure relief channel can be continuously variated by releasing a defined tapering channel section. Thereby, a plurality of releasable hydraulic cross-sections of different sizes is provided which substantially defines the effective valve opening area. In a preferred embodiment of the invention, the cross-sectional area of the pressure relief channel groove decreases with decreasing eccentricity of the control ring, so that the volume flow through the pressure relief channel decreases with increasing rotational speed. As the pump outlet pressure most commonly deviates upwards, i.e., is higher than the set outlet pressure, the pilot control chamber equilibrium pressure must be increased to correct the position of the control ring to a lower eccentricity. Alternatively, an increasing released cross-sectional area with decreasing eccentricity of the control ring can be used to correct a downwards deviating pump outlet pressure.
In a preferred embodiment of the invention, the adjustment valve is a two- way valve with a single hydraulic inlet and a single hydraulic outlet. The adjustment valve is not provided with any additional hydraulic input or output. Preferably, the adjustment valve is a proportional valve. As a result, the pressure relief channel can be permanently open. The adjustment valve is preferably provided with a valve inlet which is connectable to the lubricant gallery pressure of an internal combustion engine. The internal combustion engine is preferably supplied with the pressurized lubricant coming from a pump outlet and having the pump outlet pressure. The adjustment valve is further provided with a valve outlet, which is connectable to the pilot control chamber, to supply the pilot control chamber with pressurized lubricant from the engines oil gallery.
If the adjustment valve is closed, the pilot control chamber is not provided with over-atmospheric pressure, for example, with lubricant from the engine's oil gallery. As a result, the pilot control chamber is substantially at an atmospheric equilibrium pressure so that the control ring is pushed by the pre-loaded spring into the maximum eccentricity position. If the adjustment valve is open, the pilot control chamber is provided with over- atmospheric pressure, for example, with lubricant from the engine's oil gallery. In that case, the lubricant flows from the pilot control chamber to the pump inlet chamber. As a result, the pilot control chamber equilibrium pressure depends on the pump outlet pressure and the effective valve opening area of the flow control valve so that the control ring is pushed against the spring force into a non-maximum eccentricity position.
With the flow control valve in combination with a simple adjustment valve, the pilot control chamber equilibrium pressure is simply and reliably controllable. In contrast to a pump with a complex control apparatus or a complex multiport valve, the variable displacement lubricant vane pump according to the invention provides a reliably constant outlet pressure with a relatively low effort.
Two embodiments of the invention are described with reference to the enclosed drawings, wherein figure 1 shows a first embodiment of an opened variable displacement lubricant vane pump according to the invention with a flow control valve for decreasing the pressure relief channel volume flow with decreasing eccentricity of the control ring, figure 2 a second alternative embodiment of an opened variable displacement lubricant vane pump according to the invention with a flow control valve for increasing the pressure relief channel volume flow with decreasing eccentricity of the control ring, figure 3 a cross-sectional view of the flow control valve of the variable displacement lubricant vane pump of figure 1 with the control ring being at the maximum eccentricity position, figure 4 a cross-sectional view of the flow control valve of the variable displacement lubricant vane pump of figure 1 with the control ring being at the minimum eccentricity position, and figure 5 a schematic view of an automotive lubrication circuit with a variable displacement lubricant vane pump, an electric adjustment valve and an internal combustion engine which is provided with pressurized lubricant generated by the vane pump.
Figure 1 and figure 2 each show an embodiment of a variable displacement lubricant vane pump 10 according to the invention for providing pressurized lubricant to a lubrication circuit 100 of an internal combustion engine 12. The variable displacement lubricant vane pump 10 comprises a static pump housing 22 with a pump housing body 23 which encloses the internal pump components. The pump 10 further comprises a shiftable control ring 24 being supported linearly slidable within the pump housing body 23 and a rotatable pump rotor 26. The pump rotor 26 comprises nine radial vane slots 28 which are equiangularly arranged over the circumference of the pump rotor 26. The vane pump 10 further comprises nine radially oriented rotor vanes 27 being slidably guided within the vane slots 28. At their radial inner end, the rotor vanes 27 contact an annular spring 29 which pre-loads the rotor vanes 27 such that their radial outer end is in a sealing contact with the control ring 24. The control ring 24, the pump rotor 26 and the pump housing body 23 define a pumping chamber 14 which is a flu id ica lly separated by the rotor vanes 27 into nine pumping compartments 16.
By shifting the control ring 24 with in the pump housing body 23, the eccentricity of the control ring 24 can be varied with respect to the pump rotor 26. Thereby, the displacement of the pumping chamber 14 can be varied by increasing or decreasing the volume change of each pumping compartment 16 during one rotation of the pump rotor 26, so that a pump outlet pressure P0 can be varied. The control ring 24 is at one side which is substantially perpendicularly arranged to the eccentricity direction h, I supported by a preload spring 36 pushing the control ring 24 into the high eccentricity position h. At the other side opposite to the preload spring 36, the control ring 24 and the pump housing body 23 define a pilot control chamber 42. The pilot control chamber 42 is pressurized with lubricant having an over atmospheric pressure PG which is provided by an oil gallery of an internal combustion engine 12, shown in figure 5.
Figure 5 shows a lubrication circuit 100 comprising the variable displacement lubricant vane pump 10, the internal combustion engine 12 and an electric adjustment valve 50. The internal combustion engine 12 is provided with lubricant being pressurized by the vane pump 10 and having a pump outlet pressure PO. Therefore, the internal combustion engine 12 is flu id ica lly connected to a pump outlet 32 of the vane pump 10. The vane pump 10 sucks in lubricant having atmospheric pressure PA via a pump inlet 34, pressurizes the lubricant within the pumping chamber 14 and discharges the pressurized lubricant via the pump outlet 32. The pressurized lubricant having the pump outlet pressure PO supplies the oil gallery of the internal combustion engine 12 defining the oil gallery pressure PG. A partial volume flow is branched off of the total volume flow flowing through the oil gallery of the internal combustion engine 12. This partial volume flow flows through a pressure line to a valve inlet 56 of the electric adjustment valve 50. The remaining lubricant within the oil gallery of the internal combustion engine 12 flows back to an oil tank 70. Downstream of the electric adjustment valve 50, the pressure line is fluid ically connected to the pilot control chamber 42 of the vane pump 10. The electric adjustment valve 50 is a proportional two-way valve so that the electric adjustment valve 50 substantially opens or closes the pressure line and thereby opens or closes the supply of the pilot control chamber 42 with lubricant from the oil gallery of the internal combustion engine 12. Thereby the pilot control chamber 42 can be selectively pressurized causing the control ring 24 to move against the preload spring 36. The variable displacement lubricant pump 10 as shown in figures 1 and 2 further comprises a pressure relief channel 46 being defined by a pressure relief channel groove 47 within the control ring 24. The pressure relief channel groove 47 is arranged at one axial end surface of the control ring 24 and fluidically connects the pilot control chamber 42 with the pumping chamber 14, in particular with the suction side of the pumping chamber 14 which is fluidically connected to the pump inlet 34. The pressure relief channel groove 47 comprises three sections 471, 472, 473 which are arranged one after another with respect to the sliding direction h, I of the control ring 24. A first semi-cylindrical large section 471 with a first large cross-sectional area, followed by a second semi-conical tapering section 472, finally followed by a third semi-cylindrical small section 473 with a second small cross-sectional area.
In the embodiment of figure 1, the three sections 471, 472, 473 of the pressure relief channel groove 47 are arranged such that the first semi- cylindrical large section 471 connects to the pumping chamber 14, whereas the third semi-cylindrical small section 473 connects to the pilot control chamber 42.
In contrast, in the embodiment of figure 2, the three sections 471, 472, 473 of the pressure relief channel groove 47 are arranged such that the first semi-cylindrical large section 471 connects to the pilot control chamber 42, whereas the third semicylindrical small section 473 connects to the pumping chamber 14. The arrangement of the three sections 471, 472, 473 of the pressure relief channel groove 47 in embodiment two of figure 2 is inversed to the three sections 471, 472, 473 of the pressure relief channel groove 47 in embodiment one of figure 1.
Accordingly, the pressure relief channel groove 47 of the first embodiment tapers in the low eccentricity direction I, whereas the pressure relief channel groove 47 of the second embodiment tapers in the high eccentricity direction h.
The pressure relief channel 46 of the variable displacement lubricant vane pump 10 as shown in figures 1 and 2 is provided with an automatically self- adapting flow control valve 60 which is a throttle valve. The flow control valve 60 comprises a valve opening 61 and a valve body 62. The valve body 62 is defined by the pump housing body 23, which is shaped such that depending on the eccentricity position of the control ring 24, one of the three sections 471, 472, 473 of the pressure relief channel groove 47 is active. The cross-sectional area of the active section 471, 472, 473 defines the effective valve opening area xl, x2 and defines the hydraulic cross- section of the pressure relief channel 46, shown in figures 3 and 4. The pump housing body 23 is provided with a cut-out 63 which is defined by a not shown part of the pump housing body 23 which defines the cover of the vane pump 10 and axially closes the shown opened vane pump 10. The valve body 62 defines a valve opening edge 64 being arranged perpendicularly to the sliding direction of the control ring 24. By moving the control ring 24 along the sliding direction h, I, the valve opening edge 64 of the cut-out 63 moves along the pressure relief channel groove 47 and covers a defined section 471, 472, 473 of the pressure relief channel groove 47, whereas another section 471, 472, 473 remains uncovered. Thereby the effective valve opening area xl, x2 and, as a result, the hydraulic cross- section of the flow control valve 60 is varied. In the semi-conical tapering section 472, the hydraulic cross-section is continuously variable.
In the embodiment of figure 1, the pump housing body 23 is provided with a separate cut-out 63 defining a single pocket within the pump housing body 23 and being provided with the trapezoid shape. The cut-out 63 is permanently fluidically connected to the pilot control chamber 42. At the maximum eccentricity position, the valve opening edge 64 of the cut-out 63 is located in the first semi-cylindrical large section 471 with the first large cross-sectional area of the pressure relief channel groove 47 so that the valve opening 61 is completely open. Accordingly, the cut-out 63 bypasses the small section 473 of the pressure relief channel groove 47 so that the maximum effective valve opening area xl is open, shown in figures 1 and 3.
If the control ring 24 moves into the low eccentricity direction I, the pressure relief channel groove 47 moves relatively to the cut-out 63. At the minimum eccentricity position of the control ring 24, the valve opening edge 64 is located in the in the third semicylindrical small section 473 of the pressure relief channel groove 47 so that the cut-out 63 does not bypass the small section 473 of the pressure relief channel groove 47 anymore. Thereby the small cross-sectional area of the pressure relief channel groove 47 is active so that the valve opening 61 is partially closed and the effective valve opening area x2 is at minimum, shown in figure 4.
In the embodiment of figure 2 the cut-out 63 is provided with a substantially triangular shape. The cut-out 63 is fluidically connected to the pumping chamber 14. The valve opening edge 64 is arranged perpendicularly to the sliding direction of the control ring 24 and is located in the small section of the pressure relief channel groove 47 at a maximum eccentricity position of the control ring 24. Thereby the small cross-sectional area of the pressure relief channel groove 47 is active so that the flow control valve 60 is partially closed at the maximum eccentricity position of the control ring 24 and, as a result, the effective valve opening area xl is at minimum.
As the arrangement of the three sections 471, 472, 473 of the pressure relief channel groove 47 in the second embodiment is inversed to the arrangement of the three sections 471, 472, 473 in the first embodiment, the flow control valve 60 is fully open at the minimum eccentricity position of the control ring 24. If the control ring 24 moves into the minimum eccentricity position the valve opening edge 64 of the cut-out 63 is located in the large section of the pressure relief channel groove 47 so that the effective valve opening area x2 is at maximum opening the maximum hydraulic cross-section.
The pump inlet 34 and the pilot control chamber 42 are permanently flu id ica lly connected by the pressure relief channel 46. If the electric adjustment valve 50 is closed, the pilot control chamber 42 equilibrates with pump inlet side of the pumping chamber 14. As the resulting pressure force generated by the lubricant being at atmospheric pressure PA in the pilot control chamber 42 is lower than the spring force of the pre-load spring 36, the control ring 24 is pushed by the preload spring 36 into the maximum eccentricity position. If the electric adjustment valve 50 is open, the pilot control chamber 42 is provided with pressurized lubricant from the oil gallery of the internal combustion engine 12 having the gallery pressure PG. As a result of the pressure difference between the pilot control chamber 42 and the pump inlet 34 of the vane pump 10, a defined volume flow of the lubricant flows from the pilot control chamber 42 into the pump inlet 34 so that the pilot control chamber 42 is at a defined pilot control chamber pressure PC. The pressure force resulting from the pilot control chamber pressure PC pushes the control ring 24 against the spring force of the preload spring 36 so that the control ring 24 is moved into the lower eccentricity direction I. With increasing rotational speed, the outlet pressure PO is rising, resulting in an increased gallery pressure which causes the pilot control chamber pressure PC to increase. Accordingly, the pilot control chamber pressure PC depends on the outlet pressure PO. As a relatively constant outlet pressure PO is required, the flow control valve 60 allows to increase or decrease the pilot control chamber pressure PC independent of the outlet pressure PO, provided that the valve opening position of the electric adjustment valve 50 is constant so that a constant volume flow is provided.
If the outlet pressure P0 deviates upwards from the set outlet pressure, the first embodiment of the variable displacement lubricant vane pump 10 can be used to increase the pilot control chamber pressure PC independent of the outlet pressure PO by reducing the hydraulic cross-section of the pressure relief channel 46 with the flow control valve 60. Thereby the outlet pressure PO can be corrected downwards so that a relatively constant outlet pressure PO can be provided.
If the outlet pressure PO deviates down wards from the set outlet pressure the second embodiment of the variable displacement lubricant vane pump 10 can be used to decrease the pilot control chamber pressure independent of the outlet pressure PO. By increasing the hydraulic cross-section of the pressure relief channel 46 with the control valve 60 the outlet pressure PO can be corrected upwards to provide a relatively constant outlet pressure PO.

Claims

C L A I M S
1. A variable displacement lubricant vane pump (10) for providing pressurized lubricant with a pump outlet pressure (P0), with a static pump housing (22) comprising a pump housing body (23), a shiftable control ring (24) and a rotatable pump rotor (26) comprising several rotor vanes (27) rotating within the control ring (24), the control ring (24) being shiftable with respect to the pump rotor (26) to thereby vary the eccentricity of the control ring (24) with respect to the pump rotor (26) for controlling the volumetric pump performance, the vane pump (10) further comprising a control ring preload spring (36) preloading and pushing the shiftable control ring (24) into the high eccentricity direction (h), a pilot control chamber (42) causing the shiftable control ring (24) to move against the control ring preload spring (36) and being selectively pressurized with pressurized lubricant having an over-atmospheric pressure (PG), an electric adjustment valve (50) for selectively directing pressurized lubricant having the over-atmospheric pressure (PG) to the pilot control chamber (42), and a pressure relief channel (46) directly connecting the pilot control chamber (42) with atmospheric pressure (PA), wherein the pressure relief channel (46) is provided with an automatically self- adapting flow control valve (60) with an effective valve opening area (xl, x2) being dependent on the control ring position to define the volume flow flowing through the pressure relief channel (46) to thereby adjust the hydraulic pilot control chamber pressure (PC).
2. The variable displacement lubricant vane pump (10) according to claim 1, wherein the flow control valve (60) comprises a valve opening (61) and a valve body (62), the valve body (62) and the valve opening (61) together defining the effective valve opening area (xl, x2).
3. The variable displacement lubricant vane pump (10) according to claim 1, wherein the valve opening (61) is continuously openable and closable.
4. The variable displacement lubricant vane pump (10) according to claim 1, wherein the effective valve opening area (xl, x2) is defined by the eccentricity position of the control ring (24).
5. The variable displacement lubricant vane pump (10) according to claim 1 or 2, wherein the valve body (62) is defined by the pump housing body (23).
6. The variable displacement lubricant vane pump (10) according to one of the preceding claims, wherein the pressure relief channel (46) is substantially defined by a pressure relief channel groove (47) within the control ring (24).
7. The variable displacement lubricant vane pump (10) according to claim 6, wherein the pressure relief channel groove (47) is provided with at least two different cross-sectional areas.
8. The variable displacement lubricant vane pump (10) according to claim 6 or 7, wherein the effective valve opening area (xl, x2) is substantially defined by the cross-sectional area of the pressure relief channel groove (47).
9. The variable displacement lubricant vane pump (10) according to claim 6 or 7, wherein the cross-sectional area of the pressure relief channel groove (47) decreases with decreasing eccentricity of the control ring (24).
10. The variable displacement lubricant vane pump (10) according to one of the claims 4-8, wherein the pressure relief channel groove (47) is at least partially tapering.
11. The variable displacement lubricant vane pump (10) according to one of the preceding claims, wherein the flow control valve (60) is a throttle valve.
12. The variable displacement lubricant vane pump (10) according to one of the preceding claims, wherein the adjustment valve (50) is a two- way valve and wherein the pressure relief channel (46) is permanently open.
13. The variable displacement lubricant vane pump (10) according to one of the preceding claims, wherein the pressure relief channel (46) connects the pilot control chamber (42) with a pump inlet (34).
14. The variable displacement lubricant vane pump (10) according to one of the preceding claims, wherein the adjustment valve (50) is a proportional valve.
15. The variable displacement lubricant vane pump (10) of one of the preceding claims, wherein the adjustment valve (50) is provided with a valve inlet (56) which is connectable to the lubricant gallery pressure (PG) of an internal combustion engine (12) being supplied with the pressurized lubricant coming from a pump outlet (32) and having the pump outlet pressure (P0).
PCT/EP2021/060528 2021-04-22 2021-04-22 Variable displacement lubricant vane pump WO2022223118A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
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Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2021/060528 WO2022223118A1 (en) 2021-04-22 2021-04-22 Variable displacement lubricant vane pump

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014146675A1 (en) * 2013-03-18 2014-09-25 Pierburg Pump Technology Gmbh Lubricant vane pump
WO2014187503A1 (en) 2013-05-24 2014-11-27 Pierburg Pump Technology Gmbh Variable displacement lubricant pump
WO2015074700A1 (en) 2013-11-21 2015-05-28 Pierburg Pump Technology Gmbh Variable displacement lubricant pump
WO2019024997A1 (en) 2017-08-03 2019-02-07 Pierburg Pump Technology Gmbh Variable displacement lubricant vane pump
US20200248686A1 (en) * 2019-01-31 2020-08-06 Stackpole International Engineered Products, Ltd. Panic valve integrated in pivot pin of pump

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014146675A1 (en) * 2013-03-18 2014-09-25 Pierburg Pump Technology Gmbh Lubricant vane pump
WO2014187503A1 (en) 2013-05-24 2014-11-27 Pierburg Pump Technology Gmbh Variable displacement lubricant pump
WO2015074700A1 (en) 2013-11-21 2015-05-28 Pierburg Pump Technology Gmbh Variable displacement lubricant pump
WO2019024997A1 (en) 2017-08-03 2019-02-07 Pierburg Pump Technology Gmbh Variable displacement lubricant vane pump
US20200248686A1 (en) * 2019-01-31 2020-08-06 Stackpole International Engineered Products, Ltd. Panic valve integrated in pivot pin of pump

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