Automotive fluid pendulum vane pump The invention is directed to an automotive fluid pendulum vane pump, in particular to an automotive pendulum vane pump for providing lubricant within a lubrication system of an internal combustion engine.

A state-of-the-art pendulum vane pump comprises a rotor hub being provided with a plurality of vane slots and a rotor ring, which is eccentrically arranged with respect to the rotor hub and which is co-rotatably connected to the rotor hub via several pendulum vanes. The pendulum vanes are pivotably hinged at the rotor ring and are slidably guided within the vane slots of the rotor hub in a fluid-tight manner, so that the pendulum vanes define and fluidically separate several pumping compartments within the pumping chamber. By driving the rotor hub, the driving torque is transferred to the rotor ring via the pendulum vanes. Alternatively, the rotor ring can be driven, so that the driving torque is transferred from the rotor ring to the rotor hub. Due to the eccentricity of the rotor ring, the pendulum vanes perform a stroke-type movement within the vane slots, wherein the pendulum foot is linearly guided within the vane slots and the pendulum stem is pivoting with respect to the vane slot within one rotation of the rotor hub. For providing the torque transfer between the rotor hub and the rotor ring via the pendulum vane, the pendulum stem contacts a rounded opening edge of the vane slot for a defined contact angle. This supporting surface defines a force transferring section so that the driving force is transferred by a defined section of the pendulum vane at the pendulum stem. As a result, the mechanical load is transferred within a specific contact angle. The force transferring contact between the pendulum vane and the supporting surface at the rotor hub is engaged within the contact angle. This contact angle corresponds approximately to the compartment angle defining the angle between two adjacent pendulum vanes. WO 2018/153468 A1 discloses an example of such a pendulum vane pump. The shape of the pendulum stem and in particular the shape of the pendulum stem contact surface is the result of a topology optimisation software. As one section of the pendulum vane at the foot-sided end of the pendulum stem contact surface is transversally protruding, the vane slot contact wall is provided with a diving recess, in which the protruding section is diving during the pivoting of the pendulum stem. As a result, the contact angle describing the rotation angle over which the rounded opening edge supports the pendulum stem within one rotation, could be marginally increased in relation to earlier state-of-the-art embodiments. Thereby, more than one single pendulum vane is simultaneously in a force transferring contact with the rotor hub, so that the driving force transfer could be distributed to at least two adjacent pendulum vanes.

The sliding movement of the pendulum foot requires a plane vane slot sidewall for an effective guiding of the pendulum vane and for guaranteeing a fluid-tight sealing of the pumping compartments. The diving recess is located proximally next to the rounded opening edge of the vane slot and defines a non-plane section of the sidewall, so that the stroke length of the pendulum vane is restricted by the diving recess. As a result, a rotor hub with a relatively large diameter is required to allow a sufficient stroke of the pendulum foot within the recess-free section of the vane slot.

It is an object of the invention to provide an automotive fluid pendulum vane pump with improved compactness.

This object is achieved by an automotive fluid pendulum vane pump according to the invention with the features of main claim 1. An automotive fluid pendulum vane pump according to the invention comprises a static pump housing, a rotatable rotor ring and a rotatable and non-shiftable rotor hub with numerous substantially radial vane slots. The automotive fluid pendulum vane pump further comprises a plurality of pendulum vanes which fluidically separate a plurality of pumping compartments within the pumping chamber and which mechanically connect the rotor ring and the rotor hub. Preferably, the rotor hub is mechanically driven, for example, by an internal combustion engine Alternatively, it can be advantageous to drive the rotor ring. Due to the mechanical and co-rotatable connection between the rotor hub and the rotor ring via the pendulum vanes, the rotor ring is driven by the rotor hub. The displacement of the pump is caused by the eccentricity of the rotor ring with respect to the rotor hub. This eccentricity can be static or variable.

Each pendulum vane comprises an articular pendulum head which defines a pendulum articulation together with a corresponding articular pendulum cavity within the rotor ring. The pendulum articulation allows a pivoting movement of the pendulum vane. Each pendulum vane further comprises a pendulum foot which is arranged radially slidable and pivotable within its corresponding vane slot. The pendulum foot is slidably guided within the vane slot by two substantially parallel vane slot sidewalls. The pendulum foot and the pendulum head are connected by a pendulum stem. The pendulum vane is preferably substantially T-shaped.

Every vane slot comprises a vane slot sidewall which is provided with a protruding contact nose. The contact nose is located in the opening region of the vane slot and is preferably circularly rounded. Adjacent to the protruding contact nose, the vane slot sidewall is provided with a substantially plane and completely recess-free vane slot sidewall contact section. The vane slot sidewall contact section is preferably parallel to a opposite contact wall at the other transversal side of the vane slot. The contact nose protrudes transversally referring to the vane slot sidewall contact section and extends towards the inside of the vane slot. Thereby a substantially radial and constant vane slot undercut is defined. Seen from the radial outside of the vane slot, the vane slot sidewall contact section is transversally offset referring to the protruding contact nose so that the vane slot is transversally wider radially inwardly of the contact nose. If the rotor hub is driving the rotor ring, both the protruding contact nose and the vane slot sidewall contact section are arranged at the lagging vane slot sidewall. The lagging vane slot sidewall is the vane slot sidewall which is, seen in rotational direction, the following vane slot sidewall of one vane slot. For example, if the rotor hub drives the rotor ring and rotates counter clock- wisely, the lagging vane slot sidewall is the right-sided vane slot sidewall.

The pendulum foot is slidably guided within the vane slot. As the rotor ring is eccentrically arranged with respect to the rotor hub, the pendulum foot performs a linear stroke within the vane slot during one rotation of the pendulum vane pump. Further, the pendulum vane moves in a tilting or pivoting manner so that the pendulum foot is accordingly pivoting within the vane slot. During the stroke movement, the pendulum vane is sliding over the vane slot sidewall contact section. The stroke length depends on the eccentricity of the rotor ring. For guaranteeing an effective guiding of the pendulum foot, it is required that the vane slot sidewall contact section is substantially plane and recess-free and is substantially parallel to the opposite vane slot sidewall. The recess-free vane slot sidewall contact section allows a relatively large radial stroke of the pendulum foot with no or a minimum safety distance to the contact nose and accordingly allows a relatively large eccentricity of the rotor ring for providing a relatively large displacement volume within a relatively compact pendulum vane pump. The effective radial vane slot sidewall contact section length guiding the pendulum foot is preferably at least 75% of the geometric radial vane slot contact wall section length. Compared to the effective radial vane slot sidewall contact section length, the geometric radial vane slot contact wall section length additionally includes the safety distance which avoids a contact between the pendulum foot and the protruding contact nose. The relatively large stroke of the pendulum foot allows a reduction of the vane slot length and thereby allows a reduction of the rotor hub diameter in relation to a state-of-the-art pendulum vane pump with a recess in the vane slot sidewall, so that the diameter of the pumping chamber and, as a result, the size of the complete pendulum vane pump can be reduced while not decreasing the effective displacement volume. For transferring the torque from the driven rotor component to the dragged rotor component, the driving force is transferred via the pendulum vane which mechanically connects the rotor hub and the rotor ring. The force transfer between the rotor hub and the pendulum vane is mainly provided by the form-locked connection between the pendulum stem and the rotor hub. The pendulum vane, in particular the pendulum stem is provided with a contact path comprising a contact path surface. This contact path surface is sectorally in contact with the contact nose, preferably is in a sliding contact with the contact nose for a defined contact angle. Via the contact path surface, the pendulum vane is supported at the contact nose in a force- transferring manner. The contact path surface is shaped such that, despite the stroke movement of the pendulum foot and the pivoting movement of the pendulum stem, the contact path surface is permanently in contact with the contact nose for a defined contact angle. Depending on the angular position of the rotor, the supporting contact point moves along the preferably circular surface of the protruding contact nose and also moves along the preferably concave contact path surface of the pendulum stem so that a constant and uniform force transfer over the complete contact angle is ensured. The radial inner end of the contact path surface at the pendulum stem defines an inner tangential pendulum stem lobe which is protruding transversally referring to the pendulum stem. This pendulum stem lobe is defined as a result of the preferably concave shape of the contact path surface with a waisted middle section and an embossed end section. The length of the contact path surface and accordingly the position of the pendulum stem lobe at the pendulum stem mainly depends on the stroke length of the pendulum vane and, as a result, depends on the eccentricity of the rotor ring. Preferably the length of the contact path surface is at least 60% of the pendulum stem length, which is the length between the pendulum foot and the pendulum head. During the rotation of the rotor, the pendulum vane performs a stroking and pivoting movement in relation to the rotor hub. Resulting from this movement pattern, the pendulum stem lobe temporarily dives into the vane slot undercut. The vane slot undercut ensures a relatively large movement space for the pendulum vane and avoids a contact of the pendulum stem lobe with the vane slot sidewall contact section. Thereby the supportive contact between the contact path surface and the protruding contact nose extends over a relatively large contact angle, preferably over a contact angle which is 110% of the compartment angle. A contact angle which is larger than the compartment angle results at least temporarily in a simultaneous engaging of at least two adjacent pendulum vanes, so that the transfer of the rotational force is at least temporarily provided by more than one single pendulum vane. Depending on the design of the pump and the number of the pendulums, a simultaneous engaging of more than two adjacent pendulums is also possible. The distribution of the rotational forces to more than one pendulum vane reduces the surface pressure at each supporting contact surface and generally reduces the total mechanical loads of the pendulum vanes, respectively, compared to a pump with a contact angle being equal to or less than the compartment angle. The reduction of the mechanical loads reduces the wear, so that the reliability and the life endurance of a pump according to the invention is significantly increased compared to a state-of-the-art pendulum vane pump. In addition, the relatively low mechanical loads allow a relatively compact design with light weight components.

Preferably, the pendulum stem lobe dives into the vane slot undercut within the contact angle, so that the tangential height of the protruding contact nose is significant for the maximum eccentricity of the pump. The tangential height of the protruding contact nose is at least 0.1 mm referring to the vane slot sidewall contact section. In a preferred embodiment according to the invention, the radial outer end of the contact path surface defines an outer tangential pendulum lobe. For example, the outer tangential pendulum lobe defines the radial outer end of the preferably concave contact path surface. The rotor ring is provided with radial recesses being adjacent to the articular pendulum cavity. The radial recesses correspond to the respective outer tangential pendulum lobe at each pendulum vane, so that the outer tangential pendulum lobe temporarily dives into the corresponding radial recess during one full rotation of the rotor. Similar to the vane slot undercuts which avoid a contact between the inner tangential pendulum lobe and the vane slot sidewall contact section, the radial recesses avoid a contact between the outer tangential pendulum lobe and the rotor ring at the radial outer end of the pendulum vane.

In a preferred embodiment of the invention, wherein either the rotor hub or the rotor ring is mechanically driven by an external engine, the automotive fluid pendulum vane pump is provided with a shiftable and non- rotatable control ring. The control ring is shiftable with respect to the rotor hub between a minimum and maximum eccentricity position, so that the displacement volume of the pumping chamber is variable. The rotor ring is rotatably and co-shiftably supported by the control ring. Accordingly, the eccentricity of the rotor ring can be varied with respect to the rotor hub. In particular for an automotive fluid pendulum vane pump being driven by an internal combustion engine, the variability of the eccentricity is significant for providing a pendulum vane pump with a non-speed-dependent flow rate.

As in non-variable automotive fluid pendulum vane pumps, wherein the pendulum stem lobe dives into the vane slot undercut at a maximum eccentricity position of the rotor ring, the pendulum stem lobe preferably dives into the vane slot undercut at a maximum eccentricity position of the control ring. This allows a relatively large maximum eccentricity of the rotor ring providing a relatively high displacement ratio within the pumping chamber and, as a result, a relatively high outlet pressure and therefore a relatively high pump efficiency.

One embodiment of the invention is described with reference to the enclosed drawings, wherein figure 1 shows a top view of an opened automotive fluid pendulum vane pump according to the invention, and figure 2 shows an enlarged view of figure 1, showing a pendulum vane being in force-transferring contact within the contact angle.

Fig. 1 shows an embodiment of an automotive fluid pendulum vane pump 10 for providing pressurised lubricant within a lubrication system of an internal combustion engine. The automotive fluid pendulum vane pump 10 comprises a static pump housing 12, a rotatable rotor ring 16 and a rotatable and non-shiftable rotor hub 14. The rotor ring 16 and the rotor hub 14 define a pumping chamber 19. The rotor ring 16 rotates with in a shiftable control ring 18, which is arranged linearly slidable within the pump housing 12 for varying the eccentricity of the rotor ring 16 with respect to the rotor hub 14. The shiftable control ring 18 allows a variation of the displacement volume of the automotive fluid pendulum vane pump 10 depending on its rotational speed. The rotor hub 14 is provided with seven radial vane slots 50 for slidably guiding seven pendulum vanes 30. The pendulum vanes 30 are pivotably hinged at the radial inside of the rotor ring 16. Each pendulum vane 30 comprises an articular and cylindrically- shaped pendulum head 32 which defines a pendulum articulation 33 together with a corresponding articular and cylindrically-shaped pendulum cavity 31 at the rotor ring 16. Each pendulum vane 30 further comprises a substantially cuboid pendulum foot 34. The pendulum foot 34 and the pendulum head 32 are connected by an elongated pendulum stem 35, so that the pendulum vane 30 is substantially T-shaped. During one rotation of the automotive fluid pendulum vane pump 10, the pendulum vane 30 performs both a stroke-type movement and a pivoting movement resulting from the geometrical and mechanical constraints of the pendulum vanes 30. Each vane slot 50 is provided with two parallel and radially oriented plane sidewalls 54 which are in a slidable and fluid-tight contact with the pendulum foot 34. Thereby, the seven pendulum vanes 30 fluidically separate seven pumping compartments 60 within the pumping chamber 19. According to the stroke-type movement of the pendulum vane 30, the pendulum foot 34 linearly slides within the vane slot 50. As the pendulum vane 30 is in addition to the stroke-type movement pivoting, the pendulum foot 34 slightly rotates within the vane slot 50. For that reason, the transversal sliding surfaces 53 of the pendulum foot 34 are arc-shaped, wherein both sliding surfaces 53 define a segment of one and the same circle, so that both sliding surfaces 53 have the same rotational centre point C and the same radius R. The radius R of the circle corresponds to the width W of the vane slot 50, so that the arc-shaped sliding surfaces 53 are permanently in a fluid-tight contact with the parallel vane slot sidewalls 54, shown in fig. 2.

One vane slot sidewall 54 is provided with a protruding circularly-shaped contact nose 58 which is located in the opening region of the vane slot 50. As the rotor hub 14 is driving the rotor ring 16 and rotates counter clockwise, the protruding contact nose 58 is arranged at the opening edge of the vane slot 50 at the right vane slot sidewall 54. The vane slot sidewall 54 is further provided with a plane and completely recess-free vane slot sidewall contact section 55, which is arranged proximally adjacent to the protruding contact nose 58. The vane slot sidewall contact section 55 is provided with two length specifications. The effective length el_ of the vane slot sidewall contact section 55 defines the effective sliding section being in a sliding and fluid-tight contact with the sliding surfaces 53 of the pendulum foot 34 during its movement. The geometric length gl_ defines the real length of the vane slot sidewall contact section 55. The effective length el_ is about 90 % of the geometric length gl_, so that a small safety distance between the pendulum foot 34 and the protruding contact nose 58 is guaranteed, if the pendulum foot 34 is in the radial outer dead centre position.

The protruding contact nose 58 protrudes transversally towards the inside of the vane slot 50. The height h of the protruding contact nose with respect to the vane slot sidewall contact section 55 is about 2.0 mm. Thereby, a vane slot undercut 56 of 2.0 mm depth is defined. The pendulum stem 35 is at one side provided with a contact path 36 comprising a contact path surface 36'. This contact path 36 is convex shaped and is provided at one side of the pendulum stem 35, namely the right side which is facing the protruding contact nose 58, so that the contact path surface 36' contacts the protruding contact nose for a defined contact angle CS. This contact angle CS is about 1.75 times larger than a compartment angle CA which is defined by the angle between two adjacent pendulum vanes 30 and which defines the angle of one pumping compartment 60. According to the total number of seven pumping compartments 60, the compartment angle CA is 51.4°, so that the contact angle CS is about 90°. The convex and arc shaped contact path 36 is shaped such that the contact path surface 36' is in a permanent tangential and force transferring contact with the contact nose 58 over the complete contact angle CS. For achieving the above- mentioned contact angle CS, the contact path length pL is about 80% of the pendulum stem length sL. Depending on the relative position between this waisted pendulum vane 30 and the contact nose 58, the supporting contact point B moves nearly along the complete contact path surface 36 and along a defined circumferential section of the protruding nose 58. As the contact angle CS is larger than the compartment angle CA, the driving force resulting from the driving torque initiated by the rotor hub 14 is continuously transferred to the rotor ring 16 by two adjacent pendulum vanes 30 simultaneously. The mechanical load at each contact path 36 is thereby halved.

The radial inner end of the contact path surface 36' defines an inner tangential pendulum stem lobe 40, which is protruding transversally to the outside of the pendulum stem 35. For guaranteeing a relatively large contact angle CS between the contact path 36 and the contact nose 58, the pendulum stem lobe 40 temporarily dives into the vane slot undercut 56. Thereby, the vane slot undercut 56 avoids a physical contact between the pendulum stem lobe 40 and the vane slot sidewall contact section 55, in particular at a maximum eccentricity position of the control ring 18. Compared to a state-of-the-art pendulum vane pump, the automotive fluid pendulum vane pump 10 thereby provides a relatively large contact angle CA in combination with a relatively large stroke of the pendulum foot. In addition, the mechanical loads at all force transferring components are relatively low. This results in a relatively compact automotive fluid pendulum vane pump 10 with a relatively large eccentricity and, as a result, with a relatively high pump efficiency. The radial outer end of the contact path surface 36' defines an outer tangential pendulum lobe 38, which is protruding transversally with respect to the pendulum stem 35. The rotor ring 16 is adjacent to the articular pendulum cavity 31 provided with a radial recess 17 which is corresponding to the outer pendulum lobe 38. Depending on the relative position between the rotor ring 16 and the pendulum vane 30, the outer tangential pendulum stem lobe 38 dives into the radial recess 17 of the rotor ring 16 to avoid a physical contact between the outer tangential pendulum lobe 38 and the rotor ring 16.