EP4285027A1

EP4285027A1 - Automotive pendulum-slider pump

Info

Publication number: EP4285027A1
Application number: EP21702941.2A
Authority: EP
Inventors: Carmine Cuneo; Fabio FALOMI; Massimiliano Lazzerini; Fabio GUGLIELMO
Original assignee: Pierburg Pump Technology GmbH
Current assignee: Pierburg Pump Technology GmbH
Priority date: 2021-01-29
Filing date: 2021-01-29
Publication date: 2023-12-06
Also published as: CN116917622A; WO2022161617A1; US20240426296A1

Abstract

The invention is directed to an automotive pendulum-slider pump (10,10') for providing pressurized lubricant. The automotive pendulum-slider pump (10,10') comprises a non-rotatable rotor housing (12), a rotatable rotor ring (20,20') rotating within the rotor housing (12) and enclosing a pumping chamber (25) with a suction opening (18) and a discharge opening (19), a rotatable rotor hub (35) being co-rotatably connected with the rotor ring (20,20'), and a plurality of pendulum vanes (30) being equiangularly arranged over the circumference of the rotor ring (20,20') and each vane (30) being pivotably hinged by a separate pendulum hinge (32) at the rotor ring (20,20'). The pendulum vanes (30) fluidically separate the pumping chamber (25) into a plurality of pumping compartments (40), wherein the pumping chamber (25) is provided with an automatically switching pressure adaption valve (50,50') for pre-opening a fluidic connection between at least one pre-openable pumping compartment (40B) and the discharge opening (19) right before the pumping compartment (40B) has arrived at the discharge opening (19). The pre-open fluidic connection provides a pressure adaption of the pre-openable pumping compartment (40B) the discharge pressure to reduce the noise emissions resulting from pressure pulsations caused by the abrupt pressure equalization occurring when a pumping compartment (40) arrives at the discharge opening (19).

Description

D E S C R I P T I O N

Automotive pendulum-slider pump

The invention is directed to an automotive pendulum-slider pump for providing a lubrication system of an internal combustion engine with pressurized lubricant.

Pendulum-slider pumps are among the most frequently used pump types for providing lubricant to an internal combustion engine. Lubricant pumps of this type are usually designed as mechanical pumps and can, for example, be driven mechanically via the crankshaft of an internal combustion engine.

State-of-the-art internal combustion engines are subject to high requirements regarding noise emissions and vibrations. Accordingly, these high requirements also include the entire peripheral components of the combustion engine.

Lubricant pumps have a significant effect on the total noise emissions, so that the vehicle manufacturers request low-noise and low-vibration lubricant pumps from the pump manufacturers. Pendulum-slider pumps generate in particular a disruptive noise spectrum due to their high possible operating speed. The partially abrupt hydraulic pressure equalizations within the pumping chamber generate high-frequency pressure pulsations, which contribute to a major amount of noise and vibrations. The abrupt hydraulic pressure variations occur in particular at the discharge opening of the pump. Every time the fluidic connection between a single rotating pumping compartment and the discharge opening is opened, the hydraulic pressure is abruptly equalized resulting in an acoustic opening noise. Due to the equiangular arrangement of the pumping compartments, these abrupt pressure equalizations generate an accumulated and constant pressure pulsation frequency spectrum with a significant noise level.

DE 10 2010 023 068 Al discloses a pendulum-slider pump with an asymmetric arrangement of the pendulum vanes over the circumference of a pumping chamber. The resulting variation of the circumferential distance between the single pendulum vanes provides irregular opening intervals of the fluidic connection between each pumping compartment and the discharge opening, which result in an aperiodic and wide-spread pressure pulsation frequency spectrum, so that the noise emissions and the vibrations of the pump are reduced. The asymmetric arrangement of the pendulum vanes spreads the pressure pulsation frequency spectrum, but has no effect on the intensity of the acoustic opening noise resulting from the abrupt pressure equalizations, which generates the actual noise emissions.

It is an object of the invention to provide a cost-effective automotive pendulum-slider pump with particularly low noise emissions and an improved vibration behaviour.

This object is achieved by a variable displacement lubricant pump with the features of claim 1.

An automotive pendulum-slider pump according to the invention comprises a non-rotatable rotor housing, a rotatable rotor ring rotating within the rotor housing and enclosing a pumping chamber with a suction opening and a discharge opening. The pump further comprises a rotatable rotor hub, which is co-rotatably connected with the rotor ring and a plurality of pendulum vanes, which are preferably but not necessarily equiangularly arranged over the circumference of the rotor ring. Each pendulum vane is pivotably hinged by a separate pendulum hinge at the rotor ring. The pendulum vanes fluidically separate the pumping chamber into a plurality of pumping compartments.

The pressure difference between the suction opening and the discharge opening can be relatively high. Generally, the suction opening is at a low-pressure level and can be below atmospheric pressure. In contrast, the pressure level at the discharge opening is generally high compared to the suction opening pressure. The sudden opening of the fluidic connection between an arriving pumping compartment and the discharge opening results in an abrupt pressure equalization generating an audible acoustic opening noise. The acoustic opening noise appears with every pumping compartment arriving at the discharge opening causing a substantially constant pressure pulsation frequency spectrum. For modifying this pressure pulsation frequency spectrum, the pumping chamber is provided with an automatically switching pressure adaption valve for pre-opening a fluidic connection between at least one pre-openable pumping compartment and the discharge opening.

The pressure adaption valve is arranged such that the fluidic connection between the pre-openable pumping compartment and the discharge opening is provided right before the pre-openable pumping compartment has arrived at the discharge opening. Relevant hydraulic losses during the suction process are thereby avoided. The fluidic connection between the pre-openable pumping compartment and the discharge opening can be provided directly or indirectly. A direct fluidic connection can be realized by directly fluidically connecting the pre-openable pumping compartment with the discharge opening, for example, via a connection channel. Alternatively, an indirect fluidic connection can be provided by fluidically connecting the pre-openable pumping compartment with, seen in rotational direction, an adjacent leading pumping compartment which arrives at the discharge opening before the pre-openable pumping compartment. By fluidically connecting the pre-openable pumping compartment which has not arrived at the discharge opening with the leading pumping compartment which has already arrived at the discharge opening and is, as a result, at discharge pressure, the pre-openable pumping compartment is indirectly connected to the discharge opening. Thereby, the pressure of the pre-openable pumping compartment is adapted to the discharge pressure.

The adaption of the pressure in the pre-openable pumping compartment to the discharge pressure, before the pre-openable pumping compartment arrives at the discharge opening, reduces the relative pressure difference between the pre-openable pumping compartment and the discharge opening at the moment of arriving of the pre-openable pumping compartment at the discharge opening. This results in a less abrupt pressure equalization when the pre-openable pumping compartment arrives at the discharge opening and opens the actual direct fluidic connection for discharging the lubricant, so that the thereby caused hydraulic pressure pulsations and the acoustic opening noise at the discharge opening are reduced without relevantly affecting the pump efficiency. Accordingly, the pre-opened fluidic connection of the pre-openable pumping compartment only opens temporarily right before its arriving at the discharge opening, where the acoustic opening noise is most disruptive. The other non-pre-openable pumping compartments remain flu id ically separated from the discharge opening before and after the discharging process, so that the pumping efficiency is not substantially affected by the pressure adaption valve. Due to the pressure adaption valve, every pre-openable pumping compartment is flu id ically earlier connected to the discharge opening before the actual discharging process, respectively. As a result, the pressure pulsation frequency spectrum is spread, resulting in a lower noise emission of the pump. The combination of this wide-spread pressure pulsation frequency spectrum in combination with the reduced acoustic opening noise significantly reduces the noise emission and the vibrations of the pendulum-slider pump. The automatically switching pressure adaption valve is designed such that the switching functionality of the pressure adaption valve is preferably achieved by a temporary overlapping of specifically arranged valve openings, wherein the overlapping depends on the angular position of the rotor ring. One of the valve openings is preferably static and one of the valve openings is preferably co-rotating with the pre-openable pumping compartment, so that the valve openings are not permanently overlapping and overlap only temporarily at least once per full rotation of the rotor. Thereby, the switching functionality is provided fully automatically and without requiring any additional switching means or control devices. When the valve openings are overlapping, the pressure adaption valve and accordingly the fluidic connection is open. Otherwise, the pressure adaption valve and, as a result, the fluidic connection is closed.

The bypass flow quantity at every pressure adaption valve opening interval is preferably relatively low to avoid substantial pressure losses during the suction process or the discharging process. The valve opening area is relatively small to provide a throttling effect of the pressure adaption valve.

Generally, a similar pressure pulsation effect occurs at the opposite side of the pumping chamber, when the pumping compartments arrive at the suction opening after the discharging process. But the acoustic opening noise caused by the arriving of a pumping compartment at the suction opening is lower than the acoustic opening noise at the discharge opening, so that the pressure adaption is more relevant at the discharge opening. Thus, it can be advantageous to provide another pressure adaption valve at the suction opening.

In a preferred embodiment of the automotive pendulum-slider pump according to the invention, some but not all pumping compartments are pre-openable. The number of vanes is preferably odd and the number of pre-openable pumping compartments is smaller than the number of pendulum vanes divided by two. In this configuration, the pre-openable pumping compartments define an asymmetric arrangement over the circumference of the pumping chamber. Due to the odd number of vanes, a pump with, for example, seven pendulum vanes comprises three pre-openable pumping compartments being provided with a pressure adaption valve, so that the other four pumping compartments are not pre-openable. For example, the asymmetric arrangement of pre-openable pumping compartments (B) in relation to the non-pre-openable pumping compartments (A) can be defined as follows: B-A-B-A-B-A-A. This particularly preferred asymmetric arrangement causes more irregular opening intervals and thereby an even wider spreading of the noise spectrum than a pump with an even number of pendulum vanes does. As a result, the noise emissions and the vibrations are even more reduced.

In a preferred embodiment of the invention, the rotor housing is provided with one single static connection channel. The static connection channel comprises two openings. One opening is permanently connected to the discharge opening, so that the connection channel is permanently at discharge pressure. The other valve opening preferably temporarily corresponds to a valve opening of the pre-openable pumping compartment at the rotor ring in an overlapping manner. At least once during one full rotation of the rotor ring, the valve openings of every pre-openable pumping compartment successively overlap with the corresponding valve opening of the connection channel, so that the fluidic connection between the arriving pre-openable pumping compartment and the discharge opening is open for a defined pre-opening angle. After the valve opening of the pre-openable pumping compartment has passed the valve opening of the connection channel, the fluidic connection is closed. Thereby the pressure adaption valve switches automatically at least once per rotation of the rotor ring, so that the pressure adaption valve intermittently opens and closes the fluidic connection during one rotation of the rotor ring and thereby provides a pressure adaption of the pre-openable pumping compartment to the discharge pressure right before the pre-openable pumping compartment actually arrives at the discharge opening.

In an alternative embodiment, two adjacent pumping compartments within the pumping chamber, namely the pre-openable pumping compartment and a, seen in rotational direction, leading adjacent pumping compartment are flu id ica lly connected by an automatically switching pressure adaption valve. Therefore, the pressure adaption valve preferably comprises, in addition to the valve opening at the pre-openable pumping compartment, another separate valve opening at the adjacent leading pumping compartment, so that these two separate valve openings at the rotor ring define a valve opening pair. The two valve openings of the valve opening pair are preferably fluidically connected by a single static connection channel in the rotor housing to thereby allow a fluidic connection between the two adjacent pumping compartments. In contrast to a static connection channel which directly connects the pre-openable pumping compartment with the discharge opening, this embodiment with an alternative static connection channel connects the pre-openable pumping compartment with the adjacent leading pumping compartment. Thereby, the fluidic connection between the pre-openable pumping compartment and the discharge opening is provided via the leading pumping compartment being already in a direct fluidic contact with the discharge opening. Accordingly, the preopenable pumping compartment is indirectly connected to the discharge opening right before the pre-openable pumping compartment arrives at the discharge opening.

The resulting shortcut between the adjacent pumping compartments causes a bypassing flow between the pumping compartments to provide a pressure adaption of the pre-openable following pumping compartment to the pressure of the leading pumping compartment or vice versa. Because of the adaption of the pressure of the pre-openable pumping compartment to the pressure of the adjacent leading pumping compartment being already connected to the discharge opening and thereby being at discharge pressure, the pressure of the (following) pre-openable pumping compartment is indirectly adapted to the discharge pressure. Nevertheless, the pressure equalization between the pre-openable pumping compartment and the discharge opening is equally smooth and the resulting reduction of the noise emissions is substantially as effective as in an embodiment with a direct fluidic connection between the pre— openable pumping compartment and the discharge opening.

The alternative static connection channel is arranged such that the fluidic connection between the two valve openings of the valve opening pair is opened and closed intermittently, so that the indirect pressure adaption valve is also a switching valve. Each valve opening of the valve opening pair passing-by the connection channel is opened and closed by temporarily fluidically connecting the valve openings via the connection channel once per rotation of the pump, so that the pressure adaption valve is automatically and intermittently switching. The fluidic connection between the adjacent pumping compartments is thereby provided individually at a specific angular position within the pumping chamber and once per rotation. With this static connection channel, the fluidic connection is open at a defined position of the pumping chamber only, so that the fluidic connection is only open if needed. As a result, no pumping efficiency losses occur between the adjacent pumping compartments during the suction process or the discharging process.

When the valve opening of the leading compartment arrives at the opening edge of the connection channel, the connection channel is pre-filled with lubricant flowing-in from the leading compartment via its valve opening, so that the connection channel is at discharge pressure. The moment for opening the pressure adaption valve depends only on the angular extent and the angular position of the valve opening of the following compartment and of the connection channel. When the valve opening of the following pumping compartment arrives at the opening edge of the connection channel, the pressure adaption valve opens and thereby pre-opens a fluidic connection between the leading compartment and the following compartment. This fluidic connection is open until the valve opening passes the closing edge of the connection channel. Irrespective of the actively open fluidic connection of the pressure adaption valve itself, the effective pressure adaption functionality of the pressure adaption valve is only active until the pendulum vane separating the leading and the following compartment passes the opening edge of the discharge opening. In either case, the angular extent of the connection channel is larger than the angular extent of the valve opening pair. The effective valve opening angle depends on the angular position and the angular extent of the connection channel with respect to the discharge opening edge and on the angular extent and the circumferential position of the valve openings in relation to the pendulum vane between the following pre-openable pumping compartment and the adjacent leading pumping compartment.

Generally, a pre-opening angle defines the angular extent from the pre-opening point of the fluidic connection between the pre-openable pumping compartment and the discharge opening to the opening of the actual fluidic connection between the pumping compartment and the discharge opening for the discharging process. Accordingly, the pre-opening angle substantially defines the effective valve opening angle. The pre-opening angle is significantly defined by the angle between the opening edge of the connection channel and the opening edge of the discharge opening, i.e. the theoretical circumferential overlap between these two opening edges. This pre-opening angle is preferably 0.5-25.0°.

In a preferred embodiment of the invention, the valve opening is defined by a valve opening groove at an axial front surface of the rotor ring. The groove has a very low depth of preferably 0.1-5.0 mm to provide the said throttling effect. In a preferred embodiment of the invention the valve openings of each valve opening pair are arranged adjacent to the pendulum hinge, so that the fluidic connecting length between the adjacent pumping compartments is relatively short. The short connecting length allows a short but effective opening interval of the valve, which is needed especially at higher rotational speed.

In a particularly preferred embodiment of the automotive pendulum-slider pump according to the invention, the rotor housing is defined by a non-rotatable and radially shiftable control ring. The control ring is radially shiftable to vary the eccentricity between the rotor ring and the rotor hub. With this variable eccentricity, the displacement volume of the pumping compartments rotating within the pumping chamber is variable and, for example, adjustable to the lubrication requirements of the internal combustion engine, so that the pump flow rate is not depending on the rotational speed of the pump. Preferably, the valve openings are arranged such that the opening and closing of the fluidic connection is independent of the eccentricity of the control ring, so that the switching functionality of the pressure adaption valve is effective at any eccentricity position of the control ring.

In a preferred embodiment of the invention, the connection channel is defined by a connection groove at an axial front surface of the rotor housing at the same axial end of the pumping chamber as the valve opening groove provided in the rotor ring. Similar to the valve opening groove, the connection groove is also provided with a very low depth of 0.1-5.0 mm to provide a throttling effect of the pressure adaption valve for reducing the pump efficiency losses over the valve openings. It can be advantageous to provide both axial front surfaces with valve opening grooves and with corresponding connection grooves to provide two fluidically parallel pressure adaption valves at each pre-openable pumping compartment. An embodiment of the invention is described with reference to the enclosed drawings, wherein figure 1 shows a first embodiment of an automotive pendulum-slider pump according to the invention with a switching pressure adaption valve which provides an indirect fluidic connection of the pre-openable pumping compartment with the discharge opening via a leading pumping compartment in a schematic cross-sectional view, and figure 2 shows a second alternative embodiment of an automotive pendulum-slider pump according to the invention with a switching pressure adaption valve which provides a direct fluidic connection of the pre-openable pumping compartment with the discharge opening in a schematic cross-sectional view.

Figure 1 and figure 2 show an automotive pendulum-slider pump 10,10' for pumping a liquid lubricant within a lubrication system of an internal combustion engine. The automotive pendulum-slider pump 10,10' comprises a rotor housing 12 defined by a radially shiftable control ring 15 being pivotably hinged at a pivotable control ring articulation 70 within a static pump housing 11. The pump 10,10' comprises a rotatable rotor ring 20,20' rotating within the control ring 15 and enclosing a pumping chamber 25. The automotive pendulum-slider pump 10,10' further comprises a rotatable rotor hub 35, which is co-rotatably connected with the rotor ring 20,20', and comprises seven pendulum vanes 30, which are pivotably hinged at the rotor ring 20,20'. Each pendulum vane 30 is pivotably hinged by a separate pendulum hinge 32 to fluidically separate the pumping chamber 25 into seven pumping compartments 40. One axial sidewall 28 of the pumping chamber 25 is defined by the static pump housing 11. The other axial sidewall is defined by a housing cover (not shown). The axial sidewall 28 has a crescent-shaped suction opening 18 for sucking lubricant into the pumping chamber 25 and a crescent-shaped effective discharge opening 19 for discharging the lubricant.

The pivoting control ring 15 varies the eccentricity of the rotor ring 20,20' with respect to the rotor hub 35 to thereby vary the specific displacement volume of the pumping compartments 40, so that the pump flow rate can be regulated independently of the rotational speed of the mechanical pendulum-slider pump 10,10'.

In the embodiment of figure 1, two adjacent pumping compartments 40 are fluidically connected by a pressure adaption valve 50 comprising a valve opening pair 51, with two separate valve openings 52,53 defined by radially oriented valve opening grooves 56,57 at an axial front surface 22 of the rotor ring 20. A first valve opening 52 at a leading non-pre-openable pumping compartment 40A and a second valve opening 53 at a following pre-openable pumping compartment 40B. The valve opening grooves 56,57 extent from the inner cylinder surface 24 of the rotor ring 20 to the outer cylinder surface 23 of the rotor ring 20 and are arranged adjacent to the pendulum hinge 32. The depth of the valve opening grooves 56,57 is 0.1-5.0 mm. The valve openings 52,53 are fluidically connected by a connection channel 55 bypassing the pendulum hinge 32 and thereby fluidically connecting the leading non-pre-openable pumping compartment 40A and the following pre-openable pumping compartment 40B.

The connection channel 55 is defined by a connection groove 59 at an axial front surface 16 of the control ring 15 at the same corresponding axial end of the pumping chamber 25 as the valve opening groove 56,57 at the rotor ring 20. The connection groove 59 is arranged in theoretical circumferential overlap with the opening edge 17 of the discharge opening 19, and extends in both circumferential directions at the inner cylinder surface 29 of the control ring 15 referring to the opening edge 17. The axial depth of the connection groove 59 is 0.1-5.0 mm. With this connection groove 59, a gap at the inner cylinder surface 29 of the control ring 15 is opened, so that the connection groove 59 is fluidically opened to the passing-by radially oriented valve openings 52,53 in the rotor ring 20.

The angular extent of the connection groove 59 defines a connection channel angle R. of 20°, which is larger than the angular extent of the valve opening pairs 51. The angular extent of the valve opening pairs 51 is defined by the angle being spanned between the extreme valve opening edges of each valve opening pair 51. The effective fluidic valve opening angle substantially depends on the pre-opening angle P which is defined by the angular extent between the circumferential opening edge of the connection groove 59 and the opening edge 17 of the discharge opening 19. As the opening edge 53' of the valve opening 53 of the pre-openable pumping compartment 40B is circumferentially centrically arranged with respect to the pendulum hinge 32, the effective fluidic valve opening angle is significantly defined by the pre-opening angle P. This pre-opening angle P is about 5°.

The pressure adaption valve is an automatically switching valve, so that the connection groove 59 intermittently fluidically connects the two valve openings 52,53 and thereby fluidically connects the leading non-pre-openable pumping compartment 40A and the following pre-openable pumping compartment 40B. The connection groove 59 is arranged such that a fluidic connection between the leading pumping compartment 40A and the following pumping compartment 40B is provided right before the following pumping compartment 40B has arrived at the discharge opening 19. Therefore, when the first valve opening 52 of the leading pumping compartment 40A overlaps with the connection groove 59, the connection groove 59 is pre-filled with lubricant from the leading pumping compartment 40A, so that the connection groove 59 is at discharge pressure. After that, when the second valve opening 53 of the following pumping compartment 40B overlaps with the connection groove 59, i.e. if both valve openings 52,53 simultaneously overlap with the connection groove 59, the pressure adaption valve 50 pre-opens a fluidic connection between the leading non-pre-openable pumping compartment 40A and the following pre-openable pumping compartment 40B. As a result, the following pumping compartment 40B is indirectly fluidically connected to the discharge opening 19 via the leading pumping compartment 40A until the pendulum vane 30' between the leading pumping compartment 40A and the following pumping compartment 40B passes the discharge opening edge 17. The pressure of the following pumping compartment 40B is thereby adapted to the discharge pressure for lowering the pressure difference before opening the actual direct fluidic connection between the following pumping compartment 40B and the discharge opening 19. The lower pressure difference results in a reduction of the pressure pulsations caused by the abrupt pressure equalization of the following pumping compartment 40B with the discharge opening 19.

The rotor ring 20 is provided with a defined number of valve opening pairs 51 depending on the number of pendulum vanes 30 separating the pumping chamber 25. In this configuration, the pendulum-slider pump 10 is provided with an odd number of seven pendulum vanes 30. The number of pre-openable pumping compartments 40B is smaller than the number of pendulum vanes 30 divided by two, so that a pendulum-slider pump 10 with seven pendulum vanes 30 is provided with three valve opening pairs 51, each at one pre-openable pumping compartment 40B. The valve opening grooves 56,57 are arranged adjacent to and on both sides of the pendulum hinge 32. The arrangement of the valve opening pairs 51 over the circumference is asymmetrical. Every second pendulum hinge 32 is provided with a valve opening pair 51. Because of the odd number of pendulum vanes 30, one single pumping compartment 40C is not fluidically connected to any of its adjacent pumping compartments 40. As a result, an asymmetrical arrangement of the pre-openable pumping compartments 40B is provided. The thereby asymmetrically arranged pressure adaption valves 50 cause a spreading of the pressure pulsation frequency spectrum. Additionally, the acoustic opening noise is reduced at three pendulum vanes 30, which further reduces the noise emissions of the pendulum-slider pump 10.

In the embodiment of figure 2 the pendulum-slider pump 10' is also provided with three pre-openable pumping compartments 40B. Each of the pre-openable pumping compartments 40B is provided with a valve opening 53 being defined by a radially oriented valve opening groove 57 at an axial front surface 22' of the rotor ring 20'. Compared to the first embodiment of figure 1, only the pre-openable pumping compartments 40B are provided with a valve opening 53. The pendulum slider pump 10' is provided with an alternative connection channel 55' which is defined by a connection groove 59' at an axial front surface 16' at the same axial end of the pumping chamber 25 as the valve opening groove 57 provided in the rotor ring 20'.

Compared to the first embodiment of figure 1, the angular extent R' of the connection groove 59' is increased such that the connection groove 59' extends into the discharge opening area 19'. A connection channel opening 60 defined by a radially oriented connection channel opening groove 61 fluidically connects the connection groove 59' with the discharge opening 19, so that the connection groove 59' is permanently in a direct fluidic connection with the discharge opening 19. The angular extent R' of the connection groove 59' is about 40°. In comparison to the first embodiment, the connection groove 59' is at the same axial end of the pumping chamber 25 as the discharge opening 19 to provide a direct fluidic connection to the discharge opening 19. Due to this permanent fluidic connection to the discharge opening 19, the connection groove 59' is permanently at discharge pressure. If the valve opening groove 57 defining the valve opening 53 of the pre-openable pumping compartments arrives at the connection groove 59', the valve opening groove 57 and the connection groove 59' overlap, so that a fluidic connection between the pre-openable pumping compartment 40B and the discharge opening 19 is provided. As a result, the pre-openable pumping compartment 40B is directly fluidically connected to the discharge opening 19 via the connection channel 55' until a, seen in rotational direction, leading pendulum vane 30' of the pre-openable pumping compartment 40B passes the discharge opening edge 17. As a result, the same pressure equalization effect as described in the embodiment of figure 1 is provided. As the position of the opening edge of the valve opening 53 at the pre-openable pumping compartment 40B and the pre-opening angle P is identical to the pendulum-slider pump 10 of the first embodiment, the effective fluidic valve opening angle is also identical.

The circumferential arrangement of the pre-openable pumping compartments 40B is identical to the asymmetric arrangement of the pre-openable pumping compartments 40B of figure 1 and achieves the same results regarding the spreading of the pressure pulsation frequency spectrum and the reduction of the acoustic opening noise.

Claims

C L A I M S Automotive pendulum-slider pump (10,10') for providing pressurized lubricant, comprising a non-rotatable rotor housing (12), a rotatable rotor ring (20,20') rotating within the rotor housing (12) and enclosing a pumping chamber (25) with a suction opening (18) and a discharge opening (19), a rotatable rotor hub (35) being co-rotatably connected with the rotor ring (20,20'), and a plurality of pendulum vanes (30) being arranged over the circumference of the rotor ring (20,20') and each vane (30) being pivotably hinged by a separate pendulum hinge (32) at the rotor ring (20,20'), the pendulum vanes (30) fluidically separating the pumping chamber (25) into a plurality of pumping compartments (40), wherein the pumping chamber (25) is provided with an automatically switching pressure adaption valve (50,50') for pre-opening a fluidic connection between at least one pre-openable pumping compartment (40B) and the discharge opening (19) right before the pumping compartment (40B) has arrived at the discharge opening (19). Automotive pendulum-slider pump (10,10') according to claim 1, wherein some but not all pumping compartments (40) are pre-openable by the pressure adaption valve (50,50'). Automotive pendulum-slider pump (10) according to one of the preceding claims, wherein the pressure adaption valve (50) fluidically connects two adjacent pumping compartments (40), so that the following pre-openable pumping compartment (40B) being not directly fluidically connected to the discharge opening (19) is indirectly fluidically connected to the discharge opening (19) via a leading pumping compartment (40A) being already in a direct fluidic connection with the discharge opening (19).

4. Automotive pendulum-slider pump (10') according to one of the preceding claims, wherein the pre-openable pumping compartments (40B) are provided with at least one valve opening (53) at the rotor ring (20).

5. Automotive pendulum-slider pump (10) according to claim 3, wherein both the pre-openable pumping compartments (40B) and their adjacent leading pumping compartments (40A) are provided with at least one valve opening (52,53) at the rotor ring (20').

6. Automotive pendulum-slider pump (10') according to claim 4, wherein one single static connection channel (55') is provided at the rotor housing (12) to intermittently open and close the fluidic connection between the valve opening (53) of the pre-openable pumping compartments (40B) and the discharge opening (19)

7. Automotive pendulum-slider pump (10) according to claim 5, wherein one single static connection channel (55) is provided at the rotor housing (12) to intermittently open and close the fluidic connection between the valve opening (53) of the pre-openable pumping compartment (40B) and the valve opening (52) of the adjacent leading pumping compartment (40A).

8. Automotive pendulum-slider pump (10,10') according to one of the preceding claims, wherein the number of pendulum vanes (30) is preferably odd. 19

9. Automotive pendulum-slider pump (10,10') according to claim 8, wherein the number of pre-openable pumping compartments (40B) is less than the number of pendulum vanes (30) divided by two.

10. Automotive pendulum-slider pump (10,10') according to one of the claims 4-9, wherein the valve opening (52,53) is defined by a valve opening groove (56,57) at an axial front surface (22,22') of the rotor ring (20,20').

11. Automotive pendulum-slider pump (10,10') according to one of the claims 4-10, wherein the valve openings (52,53) are arranged adjacent to the pendulum hinge (32).

12. Automotive pendulum-slider pump (10,10') according to one of the preceding claims, wherein the rotor housing (12) is defined by a non-rotatable and radially shiftable control ring (15) to vary the eccentricity of the rotor ring (20,20') with respect to the rotor hub (35).

13. Automotive pendulum-slider pump (10) according to one of the claims 6-12, wherein the connection channel (55,55') is defined by a connection groove (59,59') at an axial front surface (16,16') of the rotor housing (12) at the same axial end of the pumping chamber (25) as the groove (56,57) provided in the rotor ring (20).

14. Automotive pendulum-slider pump (10) to claim 10, wherein the depth of the groove (56,57) within the rotor ring (20,20') is 0.1-5.0 mm.

15. Automotive pendulum-slider pump (10) according to claim 13, wherein the depth of the groove (59,59') within the rotor housing (12) is 0.1-5.0 mm.