EP0101758A1 - Vane pump or motor - Google Patents

Abstract

1. A vane pump or motor, comprising a housing containing the following components : a) a rotor (21), in which slots (22) and root spaces (23) are provided, b) double vanes, each comprising a front vane (24a) and a rear vane (24b) and guided in a corresponding slot (22), the front and rear vanes having outer head surfaces (25a, 25b), as well as vane roots (26a, 26b), and defining therebetween a central duct (27) which connects a root space (23) with an associated head space (25c) which is located between the outer head surfaces (25a, 25b), c) a cam ring (30), serving both to move the vanes radially, and to form - towards the rotor - at least one crescent-shaped displacement space (35), this space (35) exhibiting a region which becomes wider and another which becomes narrower, these regions being joined by transition zones and being subdivided, by the vanes (24a, 24b), into a plurality of cell spaces, d) at least one inlet opening (31), which communicates with that region of the displacement space which widens, and e) at least one outlet opening (33), which is connected to that region of the displacement space (35) which narrows, characterized in that f) each of the front vanes (24a) possesses a duct (27, 28) which opens onto the front surface, which is connected to the root space (23), and which is provided with a control edge, this edge co-operating with the surface of the rotor (21), the said vane (24a) normally being subjected to the same pressure on all sides, except that over the angular range (alpha) corresponding to the transition zone between the outlet opening (33) and the inlet opening (31), it is subjected to low pressure at its outer head surface (25a) and to high pressure at its other surfaces, and in that g) the rear part-vane (24b) posseses a rear duct (29) which begins at the vane head (25b) and terminates close to the vane root (26b), at a control edge (29a), this edge (29a) co-operating with the slot (22) in the rotor (21), the said part-vane (24b) being subjected to the same pressure on all sides, except that over the angular range (zeta) corresponding to the transition zone between the inlet opening (31) and the outlet opening (33), it is subjected to low pressure at its outer head surface (25b) and to high pressure at its other surfaces.

Description

The invention relates to a vane pump or motor with the features a to e of claim 1.

In such machines, smaller, kidney-shaped inlet and outlet openings leading to the footwell of the wings are provided, which are connected to the suction chamber and the pressure chamber. In the latter case, hydraulic pressure is exerted on the wings, which leads to increased friction of the wing head on the cam ring in the transition area between the suction and pressure kidneys, since the wing guided in its slot acts as a piston. Another disadvantage is that the contact pressure suddenly begins when the footwell in question comes into contact with the pressure chamber. This can lead to wing hammers. In the construction of the machine as a pump, the enclosed volume of a shrinking cell space leads to a pressure rise, which can cause the wing adjacent to a low-pressure room to lift off the stroke curve, which not only results in leakage losses, but also the subsequent re-fitting of the wing head Makes noise.

To combat these disadvantages, it is already known (DE-AS 26 46 635) to connect the footwell of each wing with an additional connecting channel guided through the rotor to the rear wing cell space and, if necessary, to apply pressure in this way beat, also to create a lockable groove on the front of each wing, which forms a delimited space together with a slot extension and the footwell. Each wing has a hook-like projection, which acts as a differential pressure piston, so that the contact pressures of the wings can be controlled in a certain way.

However, the disadvantages are the relatively complex construction and the fact that the pressure of the wings against the stroke curve in the area between the inlet and outlet, i.e. low pressure and high pressure, starts relatively late or a relatively large distance must remain between the kidney-shaped inlet opening and the assigned outlet opening, to get to the required pressure build-up.

The invention solves the problem that a vane pump or machine with the features a) to e) just develops the required contact pressure of the wing on the cam ring, with hydraulic support. takes place precisely at the points where a seal is required, while no such additional hydraulic contact pressure is developed at other points. In this way, the mechanical friction loss of the machine is reduced.

The solution to the problem arises from the main claim and is further developed and developed by the further claims.

Of particular advantage is the gradual increase in the hydraulic contact pressure of the wing in the intermediate area between the inlet and outlet opening, without the wing lifting and leakage losses due to backflow. Furthermore, wing bumps against the cam ring are avoided and the noise level is reduced.

• Fig. 1 einen Schnitt durch das Innere einer Flügelzellenpumpe für konstantes Fördervolumen,
• Fi^g. 2 eine Ansicht auf die Vorderseite eines Flügels,
• Fig. 3 einen Schnitt entlang der Linie III-III der Fig. 2,
• Fig. 4 eine Rückansicht des Flügels,
• Fig. 5 einen Schnitt durch das Innere einer Flügelzellenpumpe für variablen Förderstrom,
• Fig. 6 die Rückansicht eines Teilflügels,
• Fig. 7 einen Schnitt entlang der Linie VII-VII in Fig. 6,
• Fig. 8 eine Vorderansicht eines Teilflügels und
• Fig. 9 einen Schnitt entlang der Linie IX-IX in Fig. 8.

Two exemplary embodiments are described with reference to the drawings. It shows:

• 1 shows a section through the interior of a vane pump for constant delivery volume,
• Fi ^g . 2 shows a view of the front of a wing,
• 3 shows a section along the line III-III of FIG. 2,
• 4 is a rear view of the wing,
• 5 shows a section through the interior of a vane pump for variable flow,
• 6 shows the rear view of a partial wing,
• 7 shows a section along the line VII-VII in FIG. 6,
• 8 is a front view of a partial wing and
• 9 shows a section along the line IX-IX in FIG. 8.

1 shows the interior of a vane pump, while the housing and the drive have been omitted. The vane pump contains a rotor 1 with slots 2 and foot spaces 3, which merge into one another at a stage 3a. In the respective slots 2, one-piece wings 4 are guided, which have a wing head 5, a wing foot 6, further seen in the machine direction, a groove-shaped front channel 7 and a groove-shaped rear channel 9. The front channel 7. begins with a control edge 7a on the wing front and ends at the bottom of the wing root. The rear channel 9 begins at the wing head 5 and ends at a control edge 9a. The control edge 7a cooperates with the surface of the rotor 1 to open or close the channel 7 at about half the stroke of the wing. At approximately the same time, control edges 9a overlap with step 3a. The wing head 5 is asymmetrical, i.e. provided with a rounded wing tip, which can be arranged offset to the front, so that uneven head areas 5a, 5b are formed on both sides of the wing tip.

The drawing also shows the inner contours of a cam ring 10, two kidney-shaped inlet openings 11, 12 and two kidney-shaped outlet openings 13, 14 indicated that each lead to a suction chamber or pressure chamber, not shown. Between the rotor 1 and the cam ring 10, two crescent-shaped delivery spaces 15, 16 are arranged, which are divided by the wings 4 into a plurality of moving cell spaces, which expand in the vicinity of the inlet openings 11, 12 in the direction of rotation of the rotor 1 shown and narrow in the vicinity of the outlet openings 13, 14.

The operation of the vane pump will be explained using the different positions α, β, γ, δ, ε of the vanes 4.

In phase a, the rear channel 9 connects the footwell 3 to the inlet opening 11, so that when the rotor 1 rotates, the wing 4 in question can follow the lifting curve 10 under the action of the centrifugal force, the expanding footwell 3 via the channel 9 is filled with the inflowing hydraulic fluid. In the area of the inlet opening 11, the control edge 9a of stage 3a and the control edge 7a approach the surface of the rotor 1, so that the channel 9 is blocked and the channel 7 is opened. The footwell 3 is therefore still filled.

In phase β, the wing 4 has left the area of the inlet opening 11 and is approaching the outlet opening 13, ie a pressure builds up in the cell space 15 _β , which passes through the channel 7 into the foot space 3 and hydraulically counteracts the wing 4 urges the cam ring 10. The wing 4 acts as a differential pressure piston, since the wing foot underside 6 and the head surface 5a are at increasing pressure, while the head surface 5b remains connected to the low pressure of the inlet side. The hydraulic contact pressure of the wing 4 is calculated from the difference between the areas 6 minus 5a, multiplied by the increasing difference in the pressures in front of and behind the wing. The pressure side is therefore well sealed by the suction side, and the better the higher the difference in pressures, the better.

The pressure generated in the cell space 13b depends on the narrowing of the cell space and can reach peak values that are above the pressure in the outlet 13.

In phase γ the differential pressure lying on the top surface 5b can therefore predominate and force the wing 4 inwards more quickly than it corresponds to the stroke curve 10. In such a case, the wing head 5 lifts off a little from the stroke curve 10, as a result of which the cell space 15β is relieved. If one wants to avoid this lifting, relief grooves 13a can be provided in the side covers or pressure plates of the vane pump, which open into the outlet opening 13.

When passing the kidney-shaped outlet opening 13, the wing 4 is switched over again, i.e. the channel 7 is closed and the channel 9 is opened, as shown in the phase δ. The pressure is the same on both sides of the wing.

When the wing 4 approaches the second inlet opening 12, as shown in phase e, the head surface 5a comes to low pressure, while the differential surface 6 minus Sb remains at higher pressure, so that the wing is pressed against the stroke curve 10 hydraulically. The seal between the pressure area 13 and the suction area 12 is thus good.

The wing moves further into position α ', which corresponds to phase α and therefore does not need to be explained further.

The vane pump shown schematically in FIG. 5 is set up for a variable flow. A rotor 21 and a displaceable cam ring 30 are accommodated in a housing 20. The rotor 21 contains slots 22 and foot spaces 23 as well as blades composed of partial blades 24a and 24b. The partial wings 24a, 24b each have an asymmetrically designed head, the outer head surfaces of which are designated 25a and 25b, between which a head space 25c extends. A wing base 26a and 26b is also provided. The overall wing has a front channel 27, 28 and a rear channel 29. The front channel is formed by a continuous groove 27 between the foot space 23 and the head space and a control bore 28 which extends at half the wing stroke across the partial wing 24a. The rear channel 29 is formed by a groove in the partial wing 24b and has a control edge 29a.

The cam ring 30 has a circular-cylindrical inner contour, so that a crescent-shaped conveying space 35 is formed for the likewise circular-cylindrical outer contour of the rotor 21, which is divided by the wings into a plurality of cell spaces which migrate between a kidney-shaped inlet opening 31 and a likewise kidney-shaped outlet opening 33 and expand or contract in the process. The eccentricity of the cam ring 30 can be adjusted by means of two pistons 36, 37, the smaller piston 36 being constantly connected to pump pressure, while the cylinder space 38 of the larger piston 37, which may also be loaded with a spring 39, is controlled by a valve 40 becomes. In the exemplary embodiment shown, the valve 40 is designed as a pressure compensator, i.e. a slide piston 41 is provided which is exposed on the one hand to the pump pressure and on the other hand to the pressure of an adjustable spring 42. If the pump pressure is low, the cylinder 38 receives hydraulic fluid via a throttle 43, while if the pressure is too high, the cylinder chamber 38 is connected to a tank line 44 via the valve 40. With the circuit shown, a certain pump pressure is adjusted, the delivery rate fluctuating between a minimum and a maximum delivery rate in accordance with the eccentricity of the cam ring 30. It goes without saying that the pump can also be regulated according to other criteria.

• In der Phase a am Trennsteg zwischen Auslaßöffnung 33 und Einlaßöffnung 31 ist der Fußraum 23 über den Kanal 29 mit dem rückwärtigen Zellenraum verbunden, während der.Kanal 27, 28 gesperrt ist. Die an dem Flügel angrenzenden Zellenräume - auf der einen Seite Hochdruck und auf der anderen Seite Niedrigdruck - sind somit gegeneinander abgedichtet. Dabei wird die Flügelfußunterseite 26a, 26b, die äußere Flügelkopffläche 25b und der Flügelzwischenraum 25c vom Druck beaufschlagt, die äußere Flügelkopffläche 25a liegt jedoch auf niedrigem Druck, so daß der Teilflügel 24a mit einer geringen hydraulischen Kraft an den Hubring 30 angepreßt wird.

The operation of the vane pump is explained using the vane positions a to x:

• In phase a at the separating web between the outlet opening 33 and the inlet opening 31, the foot space 23 is connected to the rear cell space via the channel 29, while the channel 27, 28 is blocked. That attack on the wing zenden cell spaces - high pressure on one side and low pressure on the other - are thus sealed against each other. The wing base underside 26a, 26b, the outer wing head surface 25b and the wing space 25c are pressurized, but the outer wing head surface 25a is at a low pressure, so that the partial wing 24a is pressed against the cam ring 30 with a small hydraulic force.

By choosing the asymmetry of the partial wing 24 a. Size of this hydraulically generated contact pressure can be determined to meet the conflicting demands for good sealing and low friction loss.

In phase β, the wing has the same switching state as in phase a, but the two wing sides are connected to one another via inlet opening 31. There is therefore no hydraulic pressing of the wing. The same applies to the phase γ.

In the phase δ - approximately in the middle of the arc of the inlet 31 - the switching process between the channel 27, 28 and the channel 29 takes place, i.e. the control edge 29a enters the guide slot 22, while the control bore 28 emerges from the outline of the rotor 21 and establishes the connection to the footwell 23 via the centrally arranged groove 27.

In phase ε, the wing leaves the area of the kidney-shaped inlet opening 31.

In phase t - at the partition between inlet 31 and outlet 33 - the footwell 23 receives increasing hydraulic pressure via the channel 27, 28 from the front cell space, so that the surfaces 25a, 25c, 26a, 26b come to high pressure, while the outer Wing head surface 25b remains at low pressure and the partial wing 24b is thus pressed hydraulically against the lifting curve 30. The cell spaces adjacent to the wing, which are at different pressures, are thus well sealed from one another.

In phase _n , the wing enters the area of the outlet opening 33 so that both wing sides appear high pressure and the wing is no longer pressed hydraulically. The same applies during phases e and L, between which the switching of channels 27, 28 to 29 takes place. As can be seen, the control bore 28 is blocked and the channel 29 is released. This happens around the same time; however, a slight positive or negative opening coverage can also be maintained, ie a state in which both channels 27, 28 and 29 are open or blocked. The positive opening coverage is preferred since no pressure pulse then arises in the footwell 23.

In the phases x and λ, the wing moves further into the footwell 23 without any significant changes compared to the state in the phase.

The embodiment of the wing with the two partial wings 24a and 24b has the particular advantage of good conformability to the lifting curve 30 and the formation of two sealing areas on each wing. A wing designed in this way can also be used in the embodiment of the pump according to FIG. 1. The wing 4, which is simpler in itself, can also be used in the variable pump according to FIG. 5. Both types have in common the elimination of the additional inlet and outlet kidney to the footwell 23, which must be provided in known, marketable pump designs. This omission not only saves on manufacturing costs, but also the size of the leakage current is reduced, since the close proximity of the additional inlet and outlet kidneys to the footwells results in relatively high pump losses. In the invention, the foot spaces 23 are connected to the other hydraulic spaces via the channels 7 and 8 or 27, 28, 29, without this leakage loss occurring.

In the assembled wing, the partial wings 24a, 24b touch each other and are movable on the one hand, on the other hand, the lubricating film in the separating surface ensures a certain drag effect between the partial wings.

Claims (10)

1) Vane pump or motor, which contains the following components in a housing: a) a rotor (1; 21) with slots (2; 22) and foot wells (3; 23) made therein, b) wings (4; 24a, 24b) which are guided in the respective slot (2; 22) and have a wing head (5; 25a, 25b) and a wing base (6; 26a, 26b), c) a cam ring (10; 30) for the radial drive of the vanes and for the formation - towards the rotor - of at least one crescent-shaped delivery chamber (15, 16; 35) which is divided into a plurality of by the vanes (4; 24a, 24b) Cell spaces is divided, d) at least one inlet opening (11, 12; 31) which is connected to the expanding crescent-shaped conveying space (15, 16; 35) and the angularly assigned foot wells (3; 23) and e) at least one outlet opening (13, 14; 33), which is connected to the narrowing delivery chamber (15, 16; 35) and the angularly assigned foot wells (3; 23), characterized in that
that the wing (4; 24a, 24b) f) a channel opening at the front (7; 27, 28), which begins at the front of the wing at a control edge or bore (7a; 28) and ends at the underside of the wing (6; 26a), and g) has a rear channel (9; 29) which begins at the wing head (5; 25b) and ends at a control edge (9a; 29ä) in the vicinity of the wing root (6; 26b), and that h) the control edges or bores (7a, 9a; 28, 29a) depending on the position of the wing (4; 24a, 24b) alternately release or block the channels (7, 9; 27, 28, 29). 2) Vane pump or motor according to claim 1, characterized in that the wing (4) is in one piece, has a wing head (5) with a rounded wing tip and the channels (7, 9) extend as grooves on the wing surfaces. 3) Vane pump or motor according to claim 1, characterized in that the wings are in two parts (24a, 24b), each partial wing (24a, 24b) has a head (25a, 25b), between which and the cam ring (30) Each has a head space (25c) which is connected to the respective foot space (23) via a central channel (27). 4) Vane pump or motor according to claim 3, characterized in that the front opening channel (27, 28) is partially designed as a control bore (28) to the central channel (27). 5) vane pump or motor according to claim 2 or 3,
characterized in that the head (5; 25a, 25b) of each wing (4) or partial wing (24a, 24b) is asymmetrically formed at the edges. 6) vane pump or motor according to one of claims 1 to 5,
characterized in that the control edge or bore (7a; 28) of the front-facing channel (7; 27, 28) is provided at a point on the wing (4; 24a, 24b) which crosses the surface of the rotor (1) when the wing moves past the inlet and outlet openings (11, 12, 13, 14; 31, 33). 7) Vane pump or motor according to claim 6, characterized in that the control edge or bore (7a; 28) at approximately half the stroke of the vane (4; 24a, 24b) aligned with the surface of the rotor (1). 8) vane pump or motor according to one of claims 1 to 7,
characterized in that the control edge (9a; 29a) of the rear channel (9; 29) is attached at a location near the wing base (6; 26) which forms a step (3a, 23a) between the footwell (3 .; 23 ) and slot (2; 22) crosses when the wing moves past the inlet or outlet opening (11, 12, 13, 14; 31, 33). 9) vane pump or motor according to one of claims 1 to 8,
characterized in that an opening overlap is maintained when the channels (7, 9; 27, 28, 29) are released and blocked. 10) vane pump or motor according to one of claims 1 to 9,
characterized in that the foot spaces (3; 23) are connected to the suction areas (11, 12; 31) and pressure areas (13, 14; 33) of the machine solely via the channels (7, 9; 27, 28, 29).

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