EP3688309A1

EP3688309A1 - Oscillating piston pump for fluids

Info

Publication number: EP3688309A1
Application number: EP18740840.6A
Authority: EP
Inventors: Conrad Nickel; Franz Pawellek
Original assignee: Nidec GPM GmbH
Current assignee: Nidec GPM GmbH
Priority date: 2017-09-28
Filing date: 2018-07-16
Publication date: 2020-08-05
Also published as: WO2019063159A1; US20200217314A1; BR112020004076A2; CN111164311B; DE102017122611B3; CN111164311A

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 relative to a pivot axis (12) arranged in-between; an oscillating piston (2), having at least two displacement portions (20) which extend diametrically relative to the pivot axis (12) and are each received pivotably in one of the working chambers (10); an electric drive (3), which moves the oscillating piston (2) alternately on a pivot movement between two turning points delimited within the working chambers (10); a group of outlet valves (4), which ensure the discharge of a volume displaced from the working chambers (10) to a pump outlet (14); and a group of inlet valves (5), which ensure the entry of a volume flowing into the working chambers (10) from a pump inlet (15). The group of outlet valves (4) or inlet valves (5) is arranged on both sides of each working chamber (10) and communicates through the pump housing (1) with the pump outlet (14) or the pump inlet (15). The other group of inlet valves (5) or outlet valves (4) is arranged in the oscillating piston (2) and communicates via a cavity (25) in the oscillating piston (2) with the pump inlet (15) or the pump outlet (14).

Description

description

Swivel piston pump for fluids

The present invention relates to an electric rotary piston pump for liquid and gaseous fluids which are universally used for various applications, e.g. can be used as an oil pump or compressor.

In the prior art here / u predominantly circumferential positive displacement pumps, such as vane pumps or rotary vane pumps are known, which are widely used both for liquid and gaseous fluids. On such vane pumps are by design a large number of parts such as wings, springs and seals to mount in the production. Furthermore, to ensure a long service life numerous sliding and sealing relevant fits to wings, Gleitschlitztaschen and the like must be made with high dimensional accuracy, since isolated Toleranzabwei tions limit the functionality.

From other applications, such as Oil-free running vacuum pumps are also known non-rotating positive displacement pumps with oscillating pump components such as oscillating piston pumps or oscillating piston pumps, which operate with gases without a lubricant supply during operation, the pistons of the pendulum against an air cushion on a fixed chamber wall start. The pump assembly of such rotary piston pumps may comprise relatively few components, i. strictly speaking, a pivotable piston or pendulum and a pump chamber with valves.

A patent application DE 10 2016 1 19 985.0 of the same Applicant, unpublished at the filing date of the present patent application, describes a pendulum piston pump for exemplary use as an oil-free vacuum pump on a brake booster of a vehicle. This reciprocating pump includes a pendulum, a pump housing, a plurality of check valves, suction ports and an eccentric drive mechanism. The pendulum is pivotable about a pivot point and has two pistons. The Pumpengehäusc has two sector-shaped Pumpcnkammersegmente and lateral contact surfaces, which limit the respective outermost positions of the pivotal movement of the pendulum on each piston. Non-return valves release a connection to the outside of the pump chamber segments under pressure. Intake ports of the inlet are closed during the pivoting movement of the pendulum by an overlap with the respective piston to the pump chamber segments. They are released in a reverse region when passing through the outermost position of the pistons. Between the pendulum and an electric motor, an eccentric drive mechanism is arranged.

Such reciprocating piston pumps or swivel piston pumps are relatively compact and powerful and have a simple structure with a few individual pump components. However, they are based on the promotion of gases, i. limited to compressible media.

The present invention has for its object to provide a once again compact pump with cost-effective design, which is also suitable for the promotion of fluids or liquid media.

This object is achieved according to the invention by a rotary piston pump for liquid and gaseous fluids with the features of claim 1.

The electrically driven rotary piston pump, which includes, inter alia, a rotary piston with diametrically extending displacement sections, which are accommodated in sectoral working chambers of a pump housing, as well as a group of inlet valves or outlet valves, which are arranged on both sides of the working chambers, are in particular characterized in that the another group of intake valves or exhaust valves is disposed in the rotary piston and over a cavity in the rotary piston communicates with the pump inlet and the pumping outlet, respectively.

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

In conventional constructions in which both the inlet guide and the outlet guide open into the working chamber through the pump housing, a mouth, i.d.R. that of the inlet guide, overflowed by the piston and released only temporarily. Thus, however, a charge exchange with the working chamber can take place only during part of the piston stroke. In order to efficiently design a volumetrically effective working distance of the piston in favor of the displacement volume per piston stroke, a corresponding release for charge exchange extends only within a turning region of the piston. Due to the short available time window for filling or sucking a pumped medium into an emptied working chamber, such Schwenkkol benpumpen or pendulum pumps are only for efficient operation with kompressiblcn, gaseous media.

Due to the construction according to the invention, the mouth of the inlet guide and the outlet of the Auslassiuhrung over the entire piston stroke away a continuous charge exchange, which is why in addition to compressible gaseous media and a volumetrically efficient operation with incompressible, liquid media or a fluid with any ratio of gas phase to liquid phase can be realized.

Compared to rotary positive displacement pumps, such as vane pumps, which are suitable for conveying liquid media, the oscillating piston pump according to the invention achieves a better power-to-size ratio. In addition, the structure of the rotary piston pump according to the invention comprises fewer components and fewer sliding contact surfaces compared to vane pumps, so that it is cheaper to produce in terms of installation effort and material.

Advantageous developments of the rotary piston pump according to the invention are the subject of the dependent claims.

According to one aspect of the invention, the cavity of the rotary piston may be open to an axial side with respect to the pivot axis, and a muzzle of the pump inlet or pump outlet in the pump housing facing the rotary piston may be formed in overlap with an opening cross section of the cavity.

By means of a corresponding front-side interface of the inlet guide or the outlet guide between the housing wall and the moving piston, a flow connection without impairing the piston movement can be realized by means of a gap seal or the like. In comparison to a flexible line or the like, a fatigue-free flow connection is thus created. According to one aspect of the invention, the opening cross-section of the cavity may extend annularly about the pivot axis, and the mouth of the pump inlet and the pump outlet, respectively, may be disposed centrally of the pivot axis. As a result of this embodiment, a uniform flow cross section at the interface between the pump housing and the oscillating piston is achieved over the entire pivoting movement.

According to one aspect of the invention, the cavity may take the form of a cavity corresponding to the outer contour of the pivoting piston. By this configuration, the flow cross-section is maximized in the rotary piston. At the same time, the oscillating mass of the oscillating piston and the required material use are minimized, whereby a drive power and material costs are reduced.

According to one aspect of the invention, the swivel piston can be manufactured in the form of a plastic casting 1 with an overmolded steel shaft as the swivel axis.

Through this choice of material, the objectives of a low oscillating mass and a cost-effective design of the oscillating piston as a molded part are further favored.

According to one aspect of the invention, the exhaust valves can be formed by flexible locking wings, which release an output side of a valve opening.

By virtue of this configuration, the valves of the pump are provided in one piece as cost-effective bending web parts or of other flexible materials, which are e.g. punched in the form of a clip or the like, molded and inserted into a receptacle of the pump housing.

According to one aspect of the invention, the inlet valves can each be formed by an arrangement of flexibly movable prisms having a triangular cross section, which are opposite to a vertex edge of the cross section of a passage direction and are arranged perpendicularly opposite to a side surface of the cross section to a reverse direction.

As a result of this embodiment, the valves of the pump are produced by selecting a material of suitable elasticity as a cast body or even integrally with the cast body of the oscillating piston. The flow-effective geometry and orientation of such flexible prismatic valve elements causes an automatic spreading or squeezing thereof depending on the flow direction. In the illustrated application as intake valves on a Swivel piston, the functionality of a closing and opening is still supported in an advantageous manner by the inertia of the flexible valve elements in the oscillating acceleration sequence of the piston in addition simultaneously. According to one aspect of the invention, the electric drive can be used as a rotary magnet

Be formed drive whose armature between two operating points about the pivot axis is electromagnetically pivotable, and is fixed in rotation with the Schwenkkolbcn. The drive concept of a rotary magnet drive is ideal for the operating principle of an oscillating displacement piston, since the torque generated and the torque required are not constant, but increase in the same sense to the operating points of the rotary magnet or to the turning points of the rotary piston.

Moreover, a direct drive connection can be established via a shaft without eccentric kinematics or the like. In addition, less expensive control electronics can be used as a conventional brushless DC motor ECU in the prior art.

According to one aspect of the invention, the electric drive may be formed as an electrically rotating motor, which is coupled via an eccentric actuating mechanism with the pivot piston. In the case of this alternative, an available variety of inexpensive standard drives can be resorted to, at least with regard to the electric motor.

The invention will now be described in detail with reference to an exemplary embodiment with reference to the drawings. In these show:

1 shows a cross section through the rotary piston pump according to the invention with a plan view of the rotary piston, the working chambers and the valves. FIG. 2 is a perspective view of the rotary piston pump according to the invention with a central suction opening and a discharge nozzle; FIG. Fig. 3 is a longitudinal section through the rotary piston pump according to the invention with a rotary magnet drive.

Referring first to Fig. 1, there will be described the construction of an exemplary embodiment of the rotary piston pump of the present invention which is suitable for use as an oil pump in a low pressure lubricant system, such as an oil pump. is designed for a lubricating oil supply of gears in a transmission.

In Fig. 1, two diametrically opposed, sector-shaped working chambers 10 are shown from a pivot axis 12 from top left and bottom right, which extend in the pump housing 1 in a plane for pivotal movement of the rotary piston 2. The flanks of Arbeitskammem 10 form contact surfaces for the rotary piston. 2

Shown from the pivot axis 12 from the top right and bottom left, two areas of a pump outlet 14 are arranged between the Arbeitskammem 10, which are connected via an arcuate channel i the pump housing 1. Between the working chambers 10 and the pump outlet 14 10 valve openings are formed in the contact surfaces of the working chambers. The valve openings, together with clasp-shaped elastic blocking vanes 40, which each cover a side of the valve openings lying outside the working chamber 10, are exhaust valves 4 of the oscillating piston pump.

The pivoting piston 2 is fixed on the pivot axis 12, which is at the same time a drive shaft of the electric drive 3. The Schwenkkolbcn 2 comprises two Verdrängerabschnitte 20, which are mutually pivoted in the Arbeitskammem 10 over a rotation angle of about 90 °, as shown by the double arrow. Between the displacer sections 20, the swivel piston 2 has a circular Outer contour on. Inside, the rotary piston 2 is excluded as a hollow body and opened to the viewer's side of the representation, resulting in a cavity 25 results. The cavity 25 surrounds a receptacle of the pivot axis 12 and extends into the displacement sections 20.

In the flanks of the displacement sections 20, which are pivoted to the contact surfaces of the working chambers 10, inlet valves 5 of the Schwenkkolbenpumpc are arranged. The inlet valves 5 are formed by prismatic sections 50 and intermediate openings in the region of the wall of the rotary piston 2. The prismatic portions 50 have a triangular cross-section and are formed integrally with the swinging piston 2 at one end. Since in the exemplary embodiment are intake valves 5, which allow a sucked flow from the cavity 25 in a working chamber 10 to pass, and to lock in the opposite direction, all triangular cross-sections are flow-effectively aligned so that they to the cavity 25 with a vertex and point to the pump chamber 10 with a surface or hypotenuse of the triangle.

To the open side of the cavity 25, the prismatic sections 50 have a free end, so that they can tilt at the free end by selecting a material with sufficient elasticity, in particular a plastic, in the sense of cantilevered bending beam. With a flow through the pumped medium, the prismatic sections 50 are thus inclined in a flexible manner, wherein they are either spread apart or pushed together, depending on the flow direction, due to the different flow resistance of the triangular cross section at the free end. Thus, in opposite flow directions, a pass function and a lock function result.

In the exemplary embodiment of the rotary piston pump, which is designed for use as a lubricating oil pump, that is for fluids of higher viscosity, a sufficient valve function can already by the illustrated arrangement of three prismatic sections 50 with a medium larger cross section and two offset to smaller cross-sections can be achieved, the blocking function is improved by the choice of different cross-sectional sizes.

In Fig. 2, an outer side of a pump cover 11 of the Schwenkkolbenpumpc is shown, on which a suction port of the pump inlet 15 and a discharge nozzle of the Punpenauslasses 14 can be seen. The suction opening of the pump inlet 15 is arranged centrally to the pivot axis 12 in the pump cover 1 1, so that it opens within the circular outer contour of the rotary piston 2, regardless of its position directly into the cavity 25. As can be seen from FIGS. 1 and 2, the discharge nozzle of the pump outlet 14 opens into the region of the pumping outlet 14 shown at the bottom left of the pivot axis 12.

As shown in Fig. 3, the Pumpengehäusc 1 further comprises a directed towards the working chambers 10 flange portion in which an electric drive 3 is received. On a side of the pump housing 1 shown on the right, a further flange section closed off by a cover 13 is formed, in which a control circuit 34 of the electric drive 3 is accommodated. Supply connections, which lead to El ektromagneten 30 of the electric drive 3, pass out of the pump housing 1 through a nozzle shown directed upward.

In the illustrated embodiment, the electric drive 3 is provided by a so-called bistable rotary magnet, which comprises two electromagnets 30 and an armature 32. The electromagnets 30 are axially separated from each other and are in contact with two equally axially spaced pole rings 31 and a coaxial ferrite core 33. The armature 32 is pivotable on the pivot axis 12 and has two anchor body, each having a diametrically longer, and offset by 90 ° to have a diametrically shorter extent of the circumference, ie, for example, a circular area with two opposite inwardly recessed circular arc segments. The anchor body are each received in a central recess of a pole ring 31 stored. Each recess of the pole rings 31 has two opposite pole shoes. When one of the electromagnets 30 is energized, the armature 32 pivots by a reluctance force into a position in which the corresponding anchor body aligns with its longer diametrical extent between the pole pieces of the recess of the corresponding pole ring 31 to the air gap and thus the magnetic To reduce resistance in a magnetic circuit, which passes through the electromagnet 30, the ferrite core 33, the pole ring 31 and the anchor body.

The pole shoes of the two pole rings 31 or the two anchor body of the armature 32 are offset by 90 ° to each other. When the two electromagnets 30 are alternately supplied with power by the control circuit 34, a mutual pivoting movement of the pivot axis 12 is thus generated by 90 °.

The operation of the rotary piston pump will be explained below.

When the oscillating piston 2 moves counterclockwise from the starting position shown in FIG. 1, a volume of the conveying medium is displaced in front of the oscillating piston 2 or pushed out of the working chambers 10. Here, the flexible blocking vanes 40 of the exhaust valves 4 are urged on the pressure side of the rotary piston 2 in the pump housing 1 to the outside and release the valve openings. The prismatic portions 50 of the inlet valves 5 on the front pressure side of the rotary piston 2 are urged against each other at the free ends and block an opening to the cavity 25.

At the same time arises in the portion of the working chamber 10 on the rear side of the rotary piston 2, a negative pressure, so that a volume of the pumped medium, which is sucked through the pump inlet 15, flows into the working chamber 10. Here, prismatic portions 50 of the intake valves 5 are spread apart on the rear suction side of the Schwcnkkolbens 2 by the intake flow at the free ends and open for a flow from the cavity 25 into the working chamber 10. The flexible blocking vanes 40 of the exhaust valves 4 are on the Suction side of the swing piston 2 pulled against the valve openings in the pump housing 1 and lock the exhaust valves. 4 In a reverse pivotal movement back to the starting position of the rotary piston 2 in Fig. 1, the same operation. The rotary piston pump is thus a type of double stroke pump.

Claims

claims

A rotary piston pump for liquid and gaseous fluids, comprising: a pump housing (1) having at least two sector-shaped working chambers (10) diametrically opposed to an intermediate pivot axis (12); a swivel piston (2) which has at least two displacer sections (20) extending diametrically to the pivot axis (12) and which are each pivotably received in one of the working chambers (10); an electric drive (3) which mutually moves the pivoting piston (2) on a pivoting movement between two turning points limited within the working chambers (10); a group of exhaust valves (4) providing discharge to a pump outlet (14) of a volume displaced from the working chambers (10); and a group of inlet valves (5) providing inlet from a pump inlet (15) to a volume flowing into the working chambers (10); wherein the group of exhaust valves (4) or intake valves (5) is disposed on either side of each working chamber (10) and communicates through the pump housing (1) with the pump outlet (14) and the pump inlet (15), respectively; characterized in that the other group of intake valves (5) or exhaust valves (4) is arranged in the swivel piston (2) and via a cavity (25) in the swivel piston (2) to the pump inlet (15) or the pump outlet ( 14) communicates.

A rotary piston pump according to claim 1, wherein the cavity (25) of the rotary piston (2) is open to an axial side with respect to the pivot axis (12), and an orifice of the pump inlet (15) or the pump outlet (15) facing the pivot piston (2). 14) is formed in the pump housing (1) in overlap with an opening cross-section of the cavity (25).

Rotary piston pump according to claim 1 or 2, wherein the opening cross-section of the cavity (25) extends annularly around the pivot axis (12), and the mouth, the pump inlet (15) and the pump outlet (14) is arranged centrally to the pivot axis (12).

Rotary piston pump according to one of claims 1 to 3, wherein the cavity (25) takes the form of a the outer contour of the pivot piston (2) corresponding cavity.

Swivel piston pump according to one of claims 1 to 4, wherein the swivel piston (2) is made as a plastic casting with an overmolded steel shaft as a pivot axis (12).

Rotary piston pump according to one of claims 1 to 5, wherein the outlet valves (4) are formed by flexible blocking vanes (40) which release an outlet side of a valve opening.

7. The rotary piston pump according to any one of claims 1 to 6, wherein the inlet valves (5) are each formed by an array of flexibly movable prisms (50) having a triangular cross-section, with a vertex edge of the cross section of a passage direction opposite and with a side surface of the cross section a locking direction are arranged directed perpendicularly opposite.

8. Rotary piston pump according to one of claims 1 to 7, wherein the electric drive (3) is designed as a rotary magnet drive whose armature (30) between two operating points about the pivot axis (12) el ektromagneti is pivotally sch, and with the oscillating piston ( 2) rotation is firmly fixed.

9. Rotary piston pump according to one of claims 1 to 7, wherein the electric drive (3) is designed as an electrically rotating motor which is coupled via an eccentric actuating mechanism with the pivot piston (2).

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

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