CN111164311B

CN111164311B - Rotary piston pump for fluid

Info

Publication number: CN111164311B
Application number: CN201880062365.3A
Authority: CN
Inventors: 康拉德·尼克尔; 弗朗茨·帕维勒克
Original assignee: Nidec GPM GmbH
Current assignee: Nidec GPM GmbH
Priority date: 2017-09-28
Filing date: 2018-07-16
Publication date: 2021-12-14
Anticipated expiration: 2038-07-16
Also published as: DE102017122611B3; BR112020004076A2; EP3688309A1; CN111164311A; WO2019063159A1; US20200217314A1

Abstract

The invention relates to an oscillating piston pump for liquid and gaseous fluids, comprising: a pump housing (1) having at least two sector-shaped working chambers (10) which are diametrically opposed with respect to a pivot axis (12) arranged therein; an oscillating piston (2) having at least two displacement portions (20) extending radially with respect to the pivot axis (12), each displacement portion being pivotably accommodated in one working chamber (10); an electric drive (3) which moves the oscillating piston (2) alternately by a pivoting movement between two turning points defined in the working chamber (10); a set of outlet valves (4) ensuring the volume displaced from the working chamber (10) to be displaced to the pump outlet (14); and a set of inlet valves (5) ensuring that the volume flowing in from the pump inlet (15) enters the working chamber (10). The set of outlet valves (4) or the set of inlet valves (5) is arranged on both sides of each working chamber (10) and communicates with the pump outlet (14) or the pump inlet (15) via the pump housing (1). The other set of inlet valve (5) or outlet valve (4) is arranged in the oscillating piston (2) and communicates (14) with the pump inlet (15) or pump outlet through a cavity (25) in the oscillating piston (2).

Description

Rotary piston pump for fluid

The present invention relates to an electric rotary piston pump for liquid and gaseous fluids, which can be universally applied in different applications, for example as an oil pump or compressor.

For this reason, the main rotary displacement pumps known in the prior art, such as vane pumps or rotary vane pumps, are widely used for liquid as well as gaseous fluids. During production, due to its construction, a large number of components, such as vanes, springs and seals, must be installed on such vane pumps. Furthermore, in order to ensure long durability, many fittings related to sliding or sealing must be manufactured with high dimensional accuracy at the vanes, sliding slit grooves, etc., since incidental tolerance deviations may limit functionality.

In addition, non-rotary displacement pumps with oscillating pump parts are known from other applications, such as rotary piston pumps or pendulum piston pumps, for example, oil-free vacuum pumps, which can be operated without a supply of lubrication using air, the piston of the pendulum running against an air cushion on a fixed chamber wall. The pump assembly of such a rotary piston pump may comprise relatively few components, namely a piston or pendulum that can be swung, and a pump chamber with a valve, more precisely.

Patent application DE 102016119985.0 (unpublished at the filing date of the international application) of the same applicant describes, in an exemplary application, a pendulum piston pump which is used as an oil-free vacuum pump in a brake booster for vehicles.

The pendulum piston pump includes a pendulum, a pump housing, a plurality of check valves, an intake port, and an eccentric drive mechanism. The pendulum is pivotable about a pivot axis point and has two pistons. The pump housing has two scalloped pump chamber sections and a side lift surface that respectively limit the outermost position of the pendulum's pivotal movement on each piston. The check valve releases the obstruction of the connection with the outside when receiving the pressure from the pump chamber section. During the pivoting movement of the pendulum, the inlet port of the inlet closes against the pump chamber section due to the overlap with the respective piston. As they pass through the outermost position of the piston, they are unobstructed in the area of rotation. An eccentric drive mechanism is arranged between the pendulum bob and the motor.

Such a pendulum or rotary piston pump is relatively compact and powerful, and is simple to assemble, with few separate pump assemblies. However, they are limited to the supply of gas, i.e. compressible media.

It is an object of the invention to provide a compact pump with economical components, which is also suitable for supplying fluids or liquid media.

According to the invention, this object is achieved by a rotary piston pump for liquid and gaseous fluids having the features of claim 1.

An electric rotary piston pump, comprising, among other elements: a rotary piston having a displacement portion extending in a diameter direction and accommodated in a sector-shaped working chamber of a pump housing; and a set of inlet or outlet valves provided on either side of the working chamber, the electric rotary piston pump being characterized in particular in that a further set of inlet or outlet valves is arranged in the rotary pistons and communicates with the pump inlet or pump outlet via a cavity in the rotary pistons.

The invention therefore provides for the first time a rotary piston pump whose inlet guide or outlet guide opens into the working chamber on the one hand via the pump housing and on the other hand via the rotary piston.

In conventional assemblies, the inlet guide as well as the outlet guide open into the working chamber through the pump housing, the aperture of which is usually one of the inlet guides, being covered by the piston and only temporarily opened. Thus, the charge exchange with the working chamber is only performed during a part of the piston stroke. In order to effectively configure the volumetrically efficient working path of the piston to facilitate displacement of each piston stroke, the corresponding ability to charge the exchange extends only to the turning region of the piston. Such rotary piston pumps or pendulum piston pumps are suitable only for efficient operation of compressible gaseous media, because of the short available time for filling or sucking in the pumping medium in the empty working chamber.

With the assembly according to the invention, the orifice of the inlet guide and the orifice of the outlet guide can ensure a continuous charge exchange throughout the piston stroke, which allows a volumetrically efficient operation to be achieved using, in addition to a compressible gaseous medium, an incompressible liquid medium or a fluid with any gas phase compared to liquid.

The rotary piston pump according to the invention achieves an improved performance to size ratio compared to rotary displacement pumps (e.g. vane pumps) suitable for supplying liquid media.

In addition, the assembly of the rotary piston pump according to the invention comprises fewer components and fewer sliding contact surfaces than a vane pump, so that it can be produced more economically in terms of assembly work and material selection.

Advantageous further embodiments of the rotary piston pump according to the invention are the object of the dependent claims.

According to an aspect of the invention, the cavity of the rotary piston is open towards an axial side with respect to the pivot axis, and an orifice facing the pump inlet or the pump outlet of the rotary piston may be formed in the pump housing so as to overlap with the open cross-section of the cavity.

Since the inlet guide or the outlet guide intersects the respective end face between the housing wall and the moving piston, a flow connection can be achieved by means of a gap seal or the like without interfering with the movement of the piston. In contrast to flexible channels or the like, a fatigue-free flow connection is thus provided.

According to an aspect of the invention, the open cross section of the cavity may extend annularly about the pivot axis, and the aperture of the pump inlet or pump outlet may be centrally disposed with respect to the pivot axis.

This configuration achieves a regular flow cross-section at the intersection point between the pump housing and the rotary piston throughout the pivoting movement.

According to one aspect of the invention, the cavity takes the form of a hollow space matching the outer contour of the rotary piston.

Due to this construction, the flow cross-section is maximized in the rotary piston. At the same time, the oscillating mass of the rotary piston and the necessary material usage are minimized, which reduces the drive power and material costs.

According to one aspect of the invention, the rotary piston may be manufactured as a molded plastic part having an overmolded steel shaft as a pivot shaft.

This material selection further contributes to the goal of achieving low wobble mass and economically realizing the rotary piston as a molded part.

According to one aspect of the invention, the outlet valve may be formed by a flexible locking blade that releases the outlet side of the valve opening.

Due to this configuration, the valve of the pump is provided as an economical bent sheet metal part or other flexible material as a single part, e.g. stamped, formed and inserted in the receptacle of the pump housing in the shape of a strut or the like.

According to one aspect of the invention, the inlet valves are each formed by an arrangement of prisms having a triangular cross section, which prisms can be flexibly moved relative to one another, the apex edges of the cross sections of which prisms are arranged to face the flow direction and the lateral faces of the cross sections of which are arranged to face perpendicularly to the closing direction.

Thanks to this configuration, the valve of the pump is manufactured by selecting a material with suitable elasticity as the moulding or even integrally with the moulding of the rotary piston. The shape and alignment of the effective flow of such flexible, prismatic valve elements results in their automatic spreading or pressing together depending on the flow direction. In the application shown, as an inlet valve on a rotary piston, the mass inertia of the flexible valve element additionally supports both the closing and opening functions during the oscillatory acceleration of the piston.

According to one aspect of the invention, the electric drive can be configured as a rotary solenoid drive, the armature of which can be electromagnetically pivoted about a pivot axis between two operating points and which is non-rotatably fixed with the rotary piston.

The driving concept of a rotary solenoid driver is well suited for the pendulum displacement piston mode of operation, since the torque generated and the required torque order are not constant, but increase equally towards the working point of the rotary solenoid or the turning point of the rotary piston.

In addition, the direct drive connection may be constructed by a shaft without eccentric motion or the like. In addition, more economical control electronics can be implemented as a general purpose ECU for a brushless dc motor in the related art.

According to one aspect of the invention, the electric drive may be configured as a rotary electric motor coupled to the rotary piston by an eccentric actuator mechanism.

In the case of this alternative, drives of various economic standards can be used, at least with respect to the electric motor.

The invention will be explained in detail below on the basis of an exemplary embodiment with reference to the drawings. Wherein the drawings are as follows:

fig. 1 is a sectional view of a rotary piston pump according to the invention, in which a plan view of the rotary piston, the working chamber and the valves is shown.

Fig. 2 is a perspective view of a rotary piston pump according to the invention with a central inlet port and a pressure bore.

Fig. 3 is a longitudinal sectional view of a rotary piston pump according to the invention with a rotary solenoid drive.

First, the structure of an exemplary embodiment of a rotary piston pump according to the invention, which is designed for use as an oil pump in a low-pressure lubricant system, for example for supplying lubricating oil to gears in a transmission, will be described with reference to fig. 1.

In fig. 1, above and to the right of the pivot axis 12, two sector-shaped working chambers 10 are shown, diametrically opposite one another, which extend in a plane in the pump housing 1 in response to the pivoting movement of the rotary piston 2. The side of the working chamber 10 forms a run-up surface for the rotary piston 2.

Above and to the right and below the pivot axis 12, two regions of the pump outlet 14, which are shown connected via arcuate channels in the pump housing 1, are arranged between the working chambers 10. Between the working chamber 10 and the pump outlet 14, a valve opening is formed in the climbing surface of the working chamber 10. These valve openings together with the hook-shaped flexible locking blades 40, which cover the side of the valve openings located on the outside with respect to the working chamber 10, respectively, form the outlet valve 4 of the rotary piston pump.

The rotary piston 2 is fixed on a pivot shaft 12, which pivot shaft 12 is at the same time the drive shaft of the electric drive 3. The rotary piston 2 comprises two displacement portions 20 which are alternately rotated through approximately 90 ° in the working chamber 10, as indicated by the double arrow. Between the displacement portions 20, the rotary piston 2 has a circular outer contour. The interior of the rotary piston 2 is a hollow portion and is open to the observer side of the figure, thereby forming a cavity 25. The cavity 25 surrounds the accommodation space of the pivot shaft 12 and extends into the displacement portion 20.

The inlet valve 5 of the rotary piston pump is arranged in the side of the displacement section 20 which is pivoted towards the climbing surface of the working chamber 10. The inlet valve 5 is formed by the prism portion 50 and the opening in the region of the wall of the rotary piston 2 lying therebetween. The prism portion 50 has a triangular cross section and is formed integrally with the rotary piston 2 at one end. Due to the fact that in the exemplary embodiment the inlet valve 5 allows an aspirated delivery flow from the cavity 25 into the working chamber 10 and should be blocked in the opposite direction, all triangular cross sections are arranged in an efficient flow manner such that their apex points towards the cavity 25 and the surface or hypotenuse of the triangle points towards the pump chamber 10.

The prism part 50 has a free end facing the open side of the cavity 25, so that when a sufficiently elastic material, in particular a plastic material, is selected, the prism part 50 can be tilted on the free end like a cantilever clamped on one side. Thus, when the pumping medium flows through, the prism 50 will tilt flexibly, either spreading out at the free end or pressing together, depending on the direction of flow, due to the different flow resistances of the triangular cross-section. Thus, the channel function and the blocking function result in opposite flow directions.

In an exemplary embodiment of a rotary piston pump configured for use as a lubricating oil pump (i.e. for pumping higher viscosity media), it is already possible to achieve a sufficient valve function by means of the illustrated arrangement of three prism portions 50 with a central larger cross section and two offset smaller cross sections, the blocking function being improved by the choice of different cross-sectional dimensions.

In fig. 2, the outside of the pump cover 11 of the rotary piston pump is shown, on which the inlet opening of the pump inlet 15 and the pressure opening of the pump outlet 14 are clearly shown. The inlet opening of the pump inlet 15 is arranged centrally in the pump cover 11 with respect to the pivot axis 12, so that it opens directly into the cavity 25 within the circular outer contour of the rotary piston 2, regardless of its position. As is evident from fig. 1 and 2, the pressure opening of the pump outlet 14 leads to the region of the pump outlet 14 shown in the lower left hand corner of the pivot axis 12.

As shown in fig. 3, the pump housing 1 further comprises a flange portion in which the electric drive 3 is accommodated oriented in the direction of the working chamber 10. On the right side of the pump housing 1, a further flange portion closed by a cover 13 is provided, in which flange portion a control circuit 34 of the electric drive 3 is accommodated. The lead terminals of the solenoid 30 facing the electric drive 3 are led out of the pump housing 1 through a hole shown upwards.

In the embodiment shown, the electric drive 3 is provided by a so-called bi-stable rotary solenoid comprising two solenoids 30 and an armature 32. The solenoids 30 are axially separated from each other and are in contact with two pole rings 31 and a coaxial ferrite core 33, the two pole rings 31 also being axially separated. The armature 32 is pivotable on the pivot axis 12 and has two armature bodies, each having a circumferentially longer diametrical extension and a circumferentially shorter diametrical extension offset by 90 °, i.e. for example a circular region with two ring segments which are recessed on the inner sides opposite one another. The armature bodies are respectively received and mounted in central recesses of the pole rings 31. Each groove of the pole ring 31 has two opposing pole shoes.

When one of the solenoids 30 is energized, the armature 32 pivots by means of the reluctance force to a position in which the respective armature body extends with its longer diameter aligned between the pole shoes of the recess of the respective pole ring 31 in order to reduce the air gap and thereby reduce the reluctance in the magnetic circuit through the solenoid 30, the ferrite core 33, the pole ring 31 and the armature body.

The pole shoes of the two pole rings 31 or the two armature bodies of the armature bodies 32 are offset from one another by 90 °. Thus, when the two solenoids 30 are alternately supplied with current by the control circuit 34, the pivot axis 12 produces an alternating pivoting movement of 90 °.

Hereinafter, the function of the rotary piston pump will be explained.

When the rotary piston 2 moves in the counterclockwise direction from the initial position shown in fig. 1, a volume of pumped medium is displaced in front of the rotary piston 2 or discharged from the working chamber 10. Thereby, the flexible locking blade 40 of the outlet valve 4 is pushed outwards on the pressure side of the rotary piston 2 in the pump housing 1 and opens the valve opening. The prism 50 of the inlet valve 5 on the front pressure side of the rotary piston 2 presses against each other at the free end and blocks the passage to the cavity 25.

At the same time, a negative pressure is generated in the portion of the working chamber 10 on the rear side of the rotary piston 2, so that a certain amount of the pumped medium sucked in through the pump inlet 15 follows and flows into the working chamber 10. Thus, on the rear intake side of the rotary piston 2, the prism portion 50 of the inlet valve 5 is scattered at the free end by the sucked-in transport flow and is open for flow from the cavity 25 into the working chamber 10. The flexible locking blades 40 of the outlet valve 4 are pulled towards the valve opening in the pump housing 1 on the inlet side of the rotary piston 2 and block the outlet valve 4.

The same function is provided in the reverse pivoting movement to return to the initial position of the rotary piston 2 in fig. 1. The rotary piston pump is thus a two-stroke pump.

Claims

1. A rotary piston pump for liquid and gaseous fluids comprising:

a pump housing (1) having at least two sector-shaped working chambers (10), the two working chambers (10) being diametrically opposed to each other with respect to a pivot axis (12) located therebetween;

a rotary piston (2) having at least two displacement portions (20), the two displacement portions (20) extending radially relative to the pivot axis (12) and being respectively rotatably accommodated in one of the working chambers (10);

an electric drive (3) that moves the rotary piston (2) alternately between two turning points with a pivoting motion contained in the working chamber (10);

a set of outlet valves (4) allowing the volume displaced from the working chamber (10) to flow to a pump outlet (14); and a set of inlet valves (5) allowing the volume flowing into the working chamber (10) to enter from a pump inlet (15); wherein

One of the set of outlet valves (4) and the set of inlet valves (5) is arranged on both sides of each of the working chambers (10) and communicates with the pump outlet (14) or the pump inlet (15) through the pump housing (1);

is characterized in that:

the other of the set of inlet valves (5) or the set of outlet valves (4) is arranged in the rotary piston (2) and communicates with the pump inlet (15) or the pump outlet (14) via a cavity (25) in the rotary piston (2).

2. The rotary piston pump of claim 1 wherein:

the cavity (25) of the rotary piston (2) is open towards an axial side relative to the pivot axis (12), and an aperture of the pump inlet (15) or pump outlet (14) facing the rotary piston (2) is formed in the pump housing (1) to overlap with the open cross-section of the cavity (25).

3. The rotary piston pump of claim 2, wherein:

the open cross section of the cavity (25) extends annularly about the pivot axis (12), and the orifice of the pump inlet (15) or pump outlet (14) is centrally disposed with respect to the pivot axis (12).

4. A rotary piston pump according to any one of claims 1 to 3, wherein:

the cavity (25) takes the form of a hollow space which is matched to the outer contour of the rotary piston (2).

5. A rotary piston pump according to any one of claims 1 to 3, wherein:

the rotary piston (2) is made as a molded plastic part with an overmoulded steel shaft as the pivot axis (12).

6. A rotary piston pump according to any one of claims 1 to 3, wherein:

the outlet valve (4) is formed by a flexible locking blade (40), the flexible locking blade (40) releasing the outlet side of the valve opening.

7. A rotary piston pump according to any one of claims 1 to 3, wherein:

the inlet valves (5) are each formed by an arrangement of prisms (50) having a triangular cross section, the prisms (50) being flexibly movable relative to one another, the apex edges of the cross sections of the prisms (50) being arranged facing the flow direction and the sides of the cross sections of the prisms (50) being arranged perpendicularly facing the closing direction.

8. A rotary piston pump according to any one of claims 1 to 3, wherein:

the electric drive (3) is configured as a rotary solenoid drive, the armature (30) of which can be electromagnetically pivoted about the pivot axis (12) between two operating points and is fixed non-pivotably to the rotary piston (2).

9. A rotary piston pump according to any one of claims 1 to 3, wherein:

the electric drive (3) is configured as an electric rotary motor which is coupled to the rotary piston (2) by means of an eccentric actuator mechanism.

10. Use of a rotary piston pump according to any of claims 1 to 9 for pumping liquid and/or gaseous fluids.

11. Use of a rotary piston pump according to any of claims 1 to 9 as a lubricating oil pump for a transmission.