Vane cell pump/motor

Abstract

A vane pump or motor has structural features for ensuring a substantially constant relationship between rotor vanes (30) and a surrounding wall 44) of a rotor chamber (15) of a stator (16). This is done by changing shapes of either the surrounding wall or the guide tracks to be out of round such that, during a full rotation, the arrangement of the rotor vanes (30) to the surrounding wall (44) remains the same. That is, a diameter (b) of the rotor chamber (15) in an axial plane (a-a), defined by maximum and minimum radial movement of a rotor vane (30), is greater than a diameter (c) perpendicular thereto, or a diameter (d) of the guide tracks (59) perpendicular to the axial plane is greater than a diameter (e) lying in the axial plane (a-a) of the guide tracks (59). An intake and an exhaust are provided in one of two symmetrical sections of the rotor chamber (15) defined by the axial plane (a-a). Elastic guide rings, rotatable with the rotor, can also be used.

Description

BACKGROUND OF THE INVENTION

[0001] This invention concerns a vane cell pump and/or motor (referred to herein as a cell pump/motor since the same structure can be used as either a pump or as a motor) having a stator and a rotor with the rotor being linked to a drive shaft, wherein: the rotor is mounted eccentrically in a cylindrical rotor chamber of the stator, the chamber has an intake and an exhaust, the rotor has angularly-spaced radially-movable plate-like rotor vanes mounted thereon, and a portion of each vane in the rotor chamber facing away from a surrounding wall of the rotor chamber engages a guide track that is coaxial to the rotor chamber for moving the vanes to defined radial positions.

[0002] German patent document De 37 39 078 discloses a vane cell pump, also referred to herein simply as a vane pump, having a pump construction as set forth in the introductory paragraph above in which plate-like vanes guided to be radially movable in a pump rotor are moved to their pumping positions by ring shaped guide tracks mounted in the rotor chamber to end walls forming the chamber to be coaxial with the chamber.

[0003] The guide tracks define ring surfaces of ring grooves, into which tab-like protrusions from vane edges of the vanes engage with radial play.

[0004] During rotation of the pump rotor, surfaces of enlarged portions of the tab-like protrusions of the rotor vanes which face a surrounding wall of the rotor chamber, press radially-outwardly against a groove-forming wall of the ring groove of the guide track due to centrifugal force such that outer vane edges do not come into contact with the surrounding wall of the rotor chamber during rotor rotation, and thereby remain friction-heat free.

[0005] Although in this described structure the ring-shaped guide tracks allow a beneficial movement of the outer length-wise edges of the rotor vanes relative to the surrounding wall of the rotor chamber, this solution does not guarantee optimal satisfaction for pumping gas or liquid mediums, even at the start of rotor rotation.

[0006] The reason for this is the eccentric bearing mount of the pump rotor in the circular-cylindrical rotor chamber; that is, because of a resulting radial movement of the rotor vanes through a rotation angle of 180°, they successively move further away from and closer to the surrounding chamber wall, with the rotor vanes only being in a position of the smallest gap from the surrounding wall of the rotor chamber in a rotor defined axial plane at the maximum and minimum vane radially-outward movement.

[0007] It is therefore an object of this invention to provide a vane motor/pump of the type set forth in the introductory paragraph above which is improved such that, through a rotation angle of 360°, a relative arrangement of the length edge of the rotor vane to the surrounding wall of the rotor chamber remains substantially constant.

SUMMARY OF THE INVENTION

[0008] According to principles of this invention, elements of the pump/motor of the type set forth in the opening paragraph above are modified to produce a substantially constant gap between the rotor vanes and the surrounding wall of the rotor chamber.

[0009] In a first embodiment, the surrounding wall of the rotor chamber deviates from a circularly shaped cylinder. In this regard, it has its largest diameter in a rotor-axial plane passing through maximum and minimum radial-movement positions of the rotor vanes and, accordingly the rotor chamber has a slightly oval shape, elongated in the direction of this axial plane.

[0010] This results in the rotor vanes, which cooperate with circular cylindrical guide tracks, maintaining a more exact desired guide-track-defined position relative to the chamber surrounding wall, in every rotational position.

[0011] In a second embodiment, there is a special structuring of the guide track to have a slightly larger diameter perpendicular to the axial plane described above than is its diameter in the axial plane, with the rotor chamber having a circular cylindrical surrounding shape.

[0012] In each embodiment, a respective intake and exhaust of the rotor chamber are provided in one of two symmetrical segments of the rotor chamber, which are on opposite side of, or defined by, the above described axial plane in which the axis lies.

[0013] A further embodiment follows therefrom. In a pump/motor structure of this embodiment, steering rings for the rotor vanes, at least on their outer surfaces, are structured to be radially elastic so that the rotor vanes are held in continuous snug contact with the surrounding wall of the rotor chamber throughout 360° rotation of the rotor.

[0014] In this regard, the steering ring can be made with an elastic-material surrounding cover, or hoop, or an entire ring body of the steering ring can be springy elastic material.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Further benefits, characteristics and details of the invention are explained in more detail below using embodiments shown in the drawings. The described and drawn features, can be used individually or in preferred combinations in other embodiments of the invention. The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of the preferred embodiment of the invention, as illustrated in the accompanying drawings in which reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the invention in a clear manner.

[0016] FIG. 1 is a schematic width-wise cross-sectional view of a prior art vane pump/motor illustrating the problem solved by this invention;

[0017] FIGS. 2 and 3 are schematic cross-sectional views similar to FIG. 1 of vane pumps/motors of first and second embodiments of this invention;

[0018] FIG. 4 is an exploded isometric view of a third-embodiment vane pump/motor of this invention;

[0019] FIG. 5 is length-wise cross-sectional view of the vane pump/motor of FIG. 4; and

[0020] FIG. 6 is an end view of the vane pump/motor of FIGS. 4 and 5.

DETAILED DESCRIPTION OF THE INVENTION

[0021] A rotor 10 is coupled to a drive shaft 12 to be thereby driven. The rotor 10 is arranged within a rotor chamber 15, which is connected to an intake and an exhaust (not shown), of a stator 16, in whose end walls the drive shaft 12 is rotationally mounted.

[0022] Four only, for example, rotor vanes 30 extend radially outwardly from the rotor 10 at uniform angular spacing from one another and are elongated in a rotor-axial direction, and, in a normal manner, sealingly form with end edges thereof, together with adjacent opposite end surfaces defining the rotor chamber 15 sealed contacts to form sealed drive cells which are further defined by adjacent rotor vanes 30 and a surrounding wall 44 of the rotor chamber 15.

[0023] As shown in FIG. 1, each slat-like rotor vane 30 is radially, moveably guided in the rotor 10 such that, which cannot be seen in the drawing because of the view used, during its rotation, its outer vane edge 50 preferably remains spaced a defined radial gap from the chamber surrounding wall 44 of the rotor chamber 15, and therefore preferably not in touch therewith.

[0024] This radial vane positioning is carried out by a vane-guide apparatus, which includes a circular cylindrical guide track 59 on each opposite end surface defining the rotor chamber 15, the circular cylindrical guide tracks 59 being arranged to be coaxial to an axis 60 of the rotor chamber 15. These guide tracks 59 forcibly move the rotor vanes 30 in both radial directions, they being formed, for example, to have grooves in which edge protrusions of the rotor vanes 30 ride. This cannot be seen from the simplified depiction of FIG. 1, however such guide tracks are disclosed in German patent publication DE 37 39 078 A1.

[0025] In this known pump structure it is disadvantageous that the radial gaps of the outer vane edges 50 of the rotor vanes 30, during a rotor turn angle of 180°, in a driven direction of the rotor 10, are first enlarged and then correspondingly made smaller over a sector of 90° of the rotor chamber 15, because of kinetic conditions dictated by the eccentricity of the rotor 10. Dashed lines in FIG. 1 indicate this change in the radial vane gap.

[0026] FIG. 2 depicts how this enlargement of the radial gap of the outer vane edge 50 from the surrounding wall 44 of the rotor chamber 15 can be avoided in a first embodiment of this invention.

[0027] To do this, the rotor chamber 15 has, in a movement of a rotor vane 30 between a maximum and a minimum outward radial position, a diameter b in a rotor 10 defined axial plane a-a which is larger than its diameter c that is perpendicular to the diameter b. Of course this diameter difference lies in a range of a few hundredths of a millimeter.

[0028] In an embodiment of a vane pump according to FIG. 3, an enlargement of the radial gap of the outer vane edge 50 from the surrounding wall 44 of the rotor chamber 15 is avoided by the surrounding wall 44 being circular-cylindrical and by a diameter d of the guide tracks, perpendicular to the axial plane a-a defined by the maximum and minimum outward radial movement (or position) of the rotor vane 30 in the rotor 10, being correspondingly larger than a diameter e lying in the axial plane a-a.

[0029] In an embodiment of the vane pump shown in FIGS. 4 and 5, parts are identified by the same numbers as are used in the above described pump structures for the same or similar parts.

[0030] In this structure, the guide tracks 59 (see FIG. 5) for the rotor vanes 30 are formed as outer surrounding surfaces of two steering rings 66 and 68. These are inter-engaged, with radial play, by the drive shaft 12, each preferably engaging in an end depression of the rotor 10 such that it is not in contact with the end wall of a pump-containing housing 20. Vane lower edges 70 (FIG. 5) of the rotor vanes 30 rest, at respective opposite vane end portions, on the steering rings 66 or 68, which rotate with rotation of the rotor 10.

[0031] Each steering ring 66 and 68 has, as per FIG. 6, for example, a ring body 72 of metal or resinous plastic which is provided with a shell or tightening hoop 73 of an elastic material, such as an appropriate plastic or rubber, or the ring body can be made completely of radially-springy elastic. The ring outer diameter and the dimension of the rotor vane 30 in the radial direction relative to the drive shaft 12 are, in this case, preferably designed so that the rotor vane 30 is pressed into constant contact with the surrounding wall 52 of the rotor chamber 15 by an appropriate radial bias, that is snug. This vane pump has an intake 74 and an exhaust 76.

[0032] All of the above-described structures can also be arranged such that when there is a constant rotor rpm, fluid-volume flow of a driven or circulated fluid can be made to change. In this regard, a bearing of the drive shaft 12 can be made to be decoupled from the stator 16 and to be radially adjustable relative to the rotor 10 in a bearing housing. This can be carried out manually, or it can be rpm, pressure or flow volume dependent.

Claims

1. A vane pump/motor having a stator (16) and a rotor (10) linked to a drive shaft (12), said rotor being mounted eccentrically in a cylindrical rotor chamber (15) of the stator (16), said chamber having an intake and an exhaust, with the rotor having angularly-spaced radially-movable plate-like rotor vanes mounted thereon, with a portion of each vane within the rotor chamber (15) facing away from a surrounding wall (44) of the rotor chamber (15) engaging with a circular guide track (59) that is coaxial to the rotor chamber (15) and which moves the vanes to defined radial positions, wherein:

a diameter (b) of the rotor chamber (15) in a defined axial plane (a-a) extending through maximum and minimum radial movement position of the rotor vanes (30) in the rotor (10) is larger than a diameter (c) of the rotor chamber perpendicular to the diameter (b), with the intake and exhaust being in one of symmetrical segments of the rotor chamber defined by the axial plane (a-a).

2. A vane pump/motor having a stator (16) and a rotor (10) linked to a drive shaft (12), said rotor being mounted eccentrically in a cylindrical rotor chamber (15) of the stator (16), said chamber having an intake and an exhaust, with the rotor having angularly-spaced radially-movable plate-like rotor vanes mounted thereon, with a portion of each vane within the rotor chamber (15) facing away from a surrounding wall (44) of the rotor chamber (15) engaging a guide track (59) that is coaxial to the rotor chamber (15) and which moves the vanes to defined radial positions, wherein:

A diameter (d) of the guide track (59) taken perpendicular to a defined axial plane (a-a) through maximum and minimum radial movement positions of the rotor vanes (30) in the rotor (10) is larger than a diameter (e) of the guide track (59) lying in the axial plane (a-a), and wherein the intake and exhaust are provided in one of symmetrical segments of the rotor chamber defined by the axial plane (a-a).

3. A vane pump/motor having a stator (16) and a rotor (10) linked to a drive shaft (12), said rotor being mounted eccentrically in a circular-cylindrical rotor chamber (15) of the stator (16), said chamber having an intake (74) and an exhaust (76), with said rotor having angularly-spaced radially-movable plate-like rotor vanes mounted thereon, with a portion of each vane within the rotor chamber (15) facing away from a surrounding wall (44) of the rotor chamber (15) engaging an outer surrounding surfaces (59) of cylindrical steering rings (66, 68) which are engaged, with radial play, with the rotor drive shaft (12) by being respectively loosely placed in depressions in the rotor, wherein:

at least outer surfaces of the steering rings (66, 68) are structured to have radial spring elasticity and the rotor vane (30) is held by a predetermined spring bias between the outer surfaces of the steering rings and a cylindrical surrounding wall (52).

4. The vane pump/motor of

claim 3 wherein the steering ring (66, 68) has a shell (73) of a material having spring elasticity.

5. The vane pump/motor of

claim 3 wherein an entire ring body (72) forming each steering ring (66, 68) is radially elastic.