EP0301230B1 - Axial or radial piston machine with a valve arrangement comprising a valve ring - Google Patents

Axial or radial piston machine with a valve arrangement comprising a valve ring Download PDF

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Publication number
EP0301230B1
EP0301230B1 EP88109856A EP88109856A EP0301230B1 EP 0301230 B1 EP0301230 B1 EP 0301230B1 EP 88109856 A EP88109856 A EP 88109856A EP 88109856 A EP88109856 A EP 88109856A EP 0301230 B1 EP0301230 B1 EP 0301230B1
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EP
European Patent Office
Prior art keywords
valve
piston
piston machine
machine according
valve ring
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EP88109856A
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German (de)
French (fr)
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EP0301230A3 (en
EP0301230A2 (en
Inventor
Manfred Lotter
Rainer Stölzer
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Hydromatik GmbH
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Hydromatik GmbH
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Publication of EP0301230A3 publication Critical patent/EP0301230A3/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/02—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis with wobble-plate

Definitions

  • the invention relates to a piston machine according to the preamble of claim 1.
  • Control valve arrangements with a valve ring and a valve seat in the form of an annular surface, on which a plurality of valve openings open are used, for example, in hydraulic power steering systems for motor vehicles.
  • FR-A-2193152 describes such a steering system, the control valve arrangement of which comprises two valve openings opening diametrically on the annular surface of a control body and a rigid, closed valve ring which loosely surrounds the control body and protects it from radial movements in order to close one and release the other Can perform valve opening; the valve ring lies against the control body or its ring surface with a comparatively small peripheral section in the region of the valve opening to be closed in each case.
  • the valve ring is fixed on the latter by means of a pin which is arranged offset by 90 ° with respect to both valve openings.
  • valve ring in this known control valve arrangement is not suitable for radial or axial piston machines because of its comparatively small circumferential section, which is available for contacting the control body, since more than two, generally seven to 9 valve openings each open out on the annular surfaces of their control valve arrangements each of which must be about half closed or open.
  • a valve ring is required, which with a correspondingly larger circumferential section can rest against the control body or its annular surface.
  • Such a Valve ring is known from DE-OS 3623797.
  • the valve ring surrounds the annular surface with radial movement play and it is made of a material, such as spring steel, which is not subject to any expansion deformation when the high pressure occurs and cannot be destroyed, for example pierced, by the high pressure due to the corresponding high strength.
  • the valve ring has a comparatively low bending stiffness, so that it can bend in its plane under the effect of the high pressure that occurs and consequently can assume different radii of curvature, with no stresses affecting the fatigue strength occurring.
  • valve openings due to high pressure will move the valve ring as a whole by releasing the valve openings to be opened by the amount of its radial play; then it is bent under the action of the high pressure in such a way that it conforms to the entire circumferential portion of the annular surface, on which the valve openings to be closed open and which is usually about 180 ° in axial piston machines.
  • the distance between the opposite circumferential section of the valve ring and the ring surface is increased somewhat, thereby creating the required flow cross section.
  • both the opening and the closing function of the valve ring are continuous, whereby it continuously lies against the ring surface in the circumferential direction and lifts again. There is no need to fix the valve ring in the circumferential direction, so that it can roll on the ring surface while avoiding wear.
  • the essential individual parts of the axial piston pump, generally designated 1 in FIG. 1, are a housing 4 consisting of a cup-shaped housing part 2 and a housing cover 3, a drive shaft 7 passing through the cup-shaped housing part 2 or the cavity 5 of the housing 4 along the central axis 6
  • a plurality, in the present case seven, of pistons 9 arranged on a pitch circle 8, correspondingly by means of a swash plate 11 arranged on the drive shaft 7 in a rotationally fixed manner dimensioned and assigned piston bores 12 of a cylinder block 13 arranged on the inside of the housing cover 3 are displaceable and generally designated 14 and 15 inlet and outlet valves for controlling the axial piston pump.
  • the swash plate 11 is mounted with its circumferential surface and with its end surface facing away from the cylinder block 13 in a radial and an axial slide bearing 16, 17.
  • the pistons 9 are held in contact with the slant surface 19 of the swash plate 11 by a retraction plate 18, the slant plate 11 being in contact through a ball head bearing 20 with a sleeve 21 arranged on the drive shaft 7, which - and thus also the retraction plate 18 - a spring 22 supported on the housing cover 3 is acted upon in the direction of the skew surface 19.
  • the pistons 9 have spherical piston heads with which they are mounted in an articulated but axially fixed manner in sliding shoes 23 which slide on the inclined surface 19.
  • the inlet valves 14 are formed by a channel connection running inside the piston 9 and emerging radially at a specific point on the piston jacket 24.
  • the arrangement is such that this point, designated 25, is exposed in the retracted position of the respective piston 9 to the cavity 5 of the housing 4, but is covered by the wall of the associated piston bore 12 in the advanced position of the respective piston 9.
  • the distance a of this point 25 from the edge 26 of the associated piston bore 12 in the retracted position of the piston 9 is to be adapted to the functional requirements of the axial piston pump 1 and is approximately 2 mm in the present exemplary embodiment.
  • the piston bore 12 is filled by negative pressure from the cavity 5 of the housing 4, which is filled with fluid during operation.
  • pistons 9 with a bore 27 (hollow piston) extending from their end face are used.
  • the opening to the cavity 5 is formed by at least one, preferably four radial bores 28.
  • the exhaust valves 15 have a common valve ring 31, which is arranged with radial movement play S 1 and lateral movement play S 2 in an annular groove 32 which, in the present exemplary embodiment, surrounds all existing piston bores 12 and - seen radially - is arranged in the region of the inner ends of the piston bores 12 .
  • the outlet valves 15 are further formed by delivery channels 33 with valve openings 34, starting from the piston bores 12 and opening radially into an annular groove 32, the diameter d of which is smaller than the width b of the valve ring 31.
  • a further delivery channel 35 extends radially outward from the annular groove 32 from which opens into a radial connection 36 for a delivery line, not shown.
  • the cylinder block 13 protrudes by the dimension denoted by c into the cylindrical section 37 of the cup-shaped housing 2, an annular body 41 being inserted between the outer lateral surface 38 of the cylinder block 13 and the cylindrical inner lateral surface 39 of the section 37 (see distance B) is axially fixed at its end facing the swash plate 11 to a shoulder 42 of the housing part 2 and at its other end to a shoulder 43 of the cylinder block 13, and the ring channel 32 limited on its side facing the swash plate 11.
  • the ring channel 32 is delimited by the housing cover 3 or its flange-shaped extension. The housing cover 3 is thus centered indirectly via the ring body 41 in the cylindrical recess of the housing part 2.
  • the ring body 41 fits with a fine fit on the cylinder block 13 and in the housing part 2.
  • O-rings 40 can be provided in ring grooves between the ring body 41 and adjoining parts (housing part 2) and the housing part 2 and the housing cover 3.
  • the housing cover 3 is fastened to the housing part 2 by screws 44.
  • the fluid is sucked through an indicated suction line, which can be connected to a radial line connection 45, and a flow channel 46, which connects to the line connection 45, into the cavity 5 of the housing 4 and further into the piston bores 12 as described above.
  • the pistons 9 are fed, in which essentially half of the number of pistons 9 present, in the present exemplary embodiment seven, participates, the fluid flows out of the piston bores 12 in the direction of the flow arrows designated 47 in FIG. 2 into the annular channel 32 and further pushed laterally through the gaps 48 between the valve ring 31 and the radial walls of the ring channel 32 past the valve ring 31, the fluid passing through the delivery channel 34 to the indicated delivery line.
  • the existing valve openings 34 are each opened or closed by a radial displacement of the valve ring 31, as can best be seen in FIG. 2.
  • the valve ring 31 is due to the the flow pressure of the fluid exiting through the valve openings 34 automatically moves him into the position in which he opens the valve openings 34 discharging the pressurized fluid (left side).
  • the diametrically opposed valve openings 34 (right side) are closed at the same time, the negative pressure contained in the associated piston bores 12 and possibly the pressure on this side of the valve ring 31, the tight contact of the valve ring 31 on the annular surface containing the valve openings 34 49 of the ring channel 32 causes.
  • the valve ring 31 is able to contact the ring surface 49 of the ring channel 32 by approximately 180 °, ie to deform or bend in such a way that it consists of a flexible, preferably elastically flexible material such as metal or plastic.
  • the size of the movement s1, s2 or column depends on the throughput or delivery volume of the axial piston pump 1. The arrangement must be such that the fluid can be conveyed out of the piston bores 12 without significant throttling losses.
  • the size of the movement s1, s2 or column 48 is thus also dependent on the number of pistons 9, because with a larger number of pistons 9, the delivery volume is also larger.
  • the movement play s 1, s 2 or the column 48 can be dimensioned relatively small.
  • the size of the movement s1, s2 or gap widths depend on the throughput or delivery volume of the axial piston machine 1. With a diameter of the valve ring 31 of about 50 mm, about 0.3 to 1 mm should be aimed for. In experiments, good results were achieved with a movement clearance or a gap width of approximately 0.5 mm. This makes it clear that the Elasticity of the valve ring can be relatively low.
  • the embodiment according to the invention can also be used for piston machines with an adjustable throughput quantity, since the above-described relationship allows deviations of certain sizes.
  • valve arrangement according to the invention in contrast to the previously described valve ring 31 as an outer ring, it is also possible to design the valve arrangement according to the invention with a valve ring as an inner ring.
  • configuration according to the invention can also be implemented on a radial piston machine (pump).

Description

Die Erfindung bezieht sich auf eine Kolbenmaschine nach dem Oberbegriff des Patentanspruchs 1.The invention relates to a piston machine according to the preamble of claim 1.

Steuerventilanordnungen mit einem Ventilring und einem Ventilsitz in Form einer Ringfläche, an der mehrere Ventilöffnungen ausmünden, werden beispielsweise in hydraulischen Servolenkungen für Kraftfahrzeuge verwendet. In der FR-A-2193152 ist eine derartige Lenkung beschrieben, deren Steuerventilanordnung zwei diametral an der Ringfläche eines Steuerkörpers ausmündende Ventilöffnungen und einen starren, geschlossenen Ventilring umfaßt, der den Steuerkörper lose umgibt und diesem gegenüber Radialbewegungen zum Verschließen jeweils einer und Freigeben der jeweils anderen Ventilöffnung durchführen kann; dabei legt sich der Ventilring mit einem vergleichsweise kleinen Umfangsabschnitt im Bereich der jeweils zu verschließenden Ventilöffnung an den Steuerkörper bzw. dessen Ringfläche an. Der Ventilring ist zur Vermeidung von Umfangsbewegungen gegenüber dem Steuerkörper an diesem mittels eines Zapfens festgelegt, der um 90° gegenüber beiden Ventilöffnungen versetzt angeordnet ist.Control valve arrangements with a valve ring and a valve seat in the form of an annular surface, on which a plurality of valve openings open, are used, for example, in hydraulic power steering systems for motor vehicles. FR-A-2193152 describes such a steering system, the control valve arrangement of which comprises two valve openings opening diametrically on the annular surface of a control body and a rigid, closed valve ring which loosely surrounds the control body and protects it from radial movements in order to close one and release the other Can perform valve opening; the valve ring lies against the control body or its ring surface with a comparatively small peripheral section in the region of the valve opening to be closed in each case. In order to avoid circumferential movements with respect to the control body, the valve ring is fixed on the latter by means of a pin which is arranged offset by 90 ° with respect to both valve openings.

Der Ventilring in dieser bekannten Steuerventilanordnung ist aufgrund seines vergleichsweise kleinen Umfangsabschnittes, der für die Anlage an den Steuerkörper zur Verfügung steht, nicht für Radial- oder Axialkolbenmaschinen geeignet, da an den Ringflächen deren Steuerventilanordnungen mehr als jeweils zwei, im allgemeinen sieben bis 9 Ventilöffnungen ausmünden, die jeweils etwa zur Hälfte geschlossen bzw. geöffnet sein müssen. Dazu ist ein Ventilring erforderlich, der sich mit einem entsprechend größeren Umfangsabschnitt an den Steuerkörper bzw. dessen Ringfläche anlegen kann. Ein solcher Ventilring ist aus der DE-OS 3623797 bekannt. Er liegt ohne radiales Spiel der die Auslaßventilöffnungen enthaltenden Ringfläche eines Zylinderblocks einer Radialkolbenmaschine abdichtend an und besteht aus elastisch dehnbarem Material, so daß er unter der Wirkung des Auslaßdrucks von den Auslaßöffnungen, diese freigebend, abgehoben werden kann. Die dabei auftretenden Beanspruchungen des Ventilrings verhindern, daß die bekannte Radialkolbenmaschine für Hochdruck eingesetzt werden kann. Bei einem solchen Einsatz besteht nämlich die Gefahr, daß der dehnbare Ventilring unter der Wirkung des Hochdrucks beschädigt oder zumindest über seine Elastizitätsgrenze hinaus gedehnt wird, so daß seine Funktion, insbesondere im Dauerbetrieb, beeinträchtigt wird. Bei der angesichts der erforderlichen Dehnbarkeit des Ventilringes realieierbaren, häufig unzureichenden Materialfestigkeit besteht sogar die Gefahr, daß der Hochdruck die Ventilringe im Bereich der zu verschließenden Ventilöffnungen durchdrückt.The valve ring in this known control valve arrangement is not suitable for radial or axial piston machines because of its comparatively small circumferential section, which is available for contacting the control body, since more than two, generally seven to 9 valve openings each open out on the annular surfaces of their control valve arrangements each of which must be about half closed or open. For this purpose, a valve ring is required, which with a correspondingly larger circumferential section can rest against the control body or its annular surface. Such a Valve ring is known from DE-OS 3623797. It rests without radial clearance of the annular surface of a cylinder block of a radial piston machine containing the outlet valve openings and is made of elastically stretchable material so that it can be lifted off from the outlet openings, releasing them, under the effect of the outlet pressure. The resulting stresses on the valve ring prevent the known radial piston machine from being used for high pressure. In such an application, there is a risk that the expandable valve ring will be damaged under the action of high pressure or at least be stretched beyond its elastic limit, so that its function, in particular in continuous operation, will be impaired. Given the often inadequate material strength that can be achieved in view of the required extensibility of the valve ring, there is even the risk that the high pressure will push through the valve rings in the area of the valve openings to be closed.

Es ist Aufgabe der Erfindung, eine Kolbenmaschine der eingangs genannten Art so weiterzubilden, daß sie sich auch für den Hochdruck eignet.It is an object of the invention to develop a piston machine of the type mentioned at the outset in such a way that it is also suitable for high pressure.

Diese Aufgabe wird durch die kennzeichnenden Merkmale des Patentanspruchs 1 gelöst.This object is achieved by the characterizing features of patent claim 1.

Erfindungsgemäß umgibt der Ventilring die Ringfläche mit radialem Bewegungsspiel und er besteht aus einem Material, wie etwa Federstahl, welches bei dem auftretenden Hochdruck keiner Dehnungs-Verformung unterliegt und aufgrund entsprechend hoher Festigkeit nicht vom Hochdruck zerstört, beispielsweise durchstoßen werden kann. Gleichzeitig weist der Ventilring eine vergleichsweise geringe Biegesteifigkeit auf, so daß er sich unter der Wirkung des auftretenden Hochdrucks in seiner Ebene verbiegen und folglich unterschiedliche Krümmungsradien annehmen kann, wobei keine die Dauerfestigkeit beeinträchtigenden Spannungen auftreten. Aufgrund des an den zu öffnenden Ventilöffnungen anstehenden Hochdrucks verlagert sich der Ventilring als Ganzes unter Freigabe der zu öffnenden Ventilöffnungen um das Maß seines radialen Bewegungsspiels; sodann wird er unter der Wirkung des Hochdrucks derart biegeverformt, daß er sich an den gesamten Umfangsabschnitt der Ringfläche anschmiegt, auf welchem die zu verschließenden Ventilöffnungen ausmünden und welcher bei Axialkolbenmaschinen üblicherweise etwa 180° beträgt. Dabei wird der Abstand zwischen dem gegenüberliegenden Umfangsabschnitt des Ventilrings und der Ringfläche noch etwas vergrößert, wodurch der erforderliche Strömungsquerschnitt geschaffen wird. Im Betrieb ist sowohl die Öffnungs- als auch die Schließfunktion des Ventilrings kontinuierlich, wobei er sich in Umfangsrichtung fortlaufend an die Ringfläche anlegt und wieder abhebt. Dabei bedarf es keiner Fixierung des Ventilringes in Umfangsrichtung, so daß er sich unter Vermeidung von Verschleiß auf der Ringfläche abwälzen kann.According to the invention, the valve ring surrounds the annular surface with radial movement play and it is made of a material, such as spring steel, which is not subject to any expansion deformation when the high pressure occurs and cannot be destroyed, for example pierced, by the high pressure due to the corresponding high strength. At the same time, the valve ring has a comparatively low bending stiffness, so that it can bend in its plane under the effect of the high pressure that occurs and consequently can assume different radii of curvature, with no stresses affecting the fatigue strength occurring. Because of the opening Valve openings due to high pressure will move the valve ring as a whole by releasing the valve openings to be opened by the amount of its radial play; then it is bent under the action of the high pressure in such a way that it conforms to the entire circumferential portion of the annular surface, on which the valve openings to be closed open and which is usually about 180 ° in axial piston machines. The distance between the opposite circumferential section of the valve ring and the ring surface is increased somewhat, thereby creating the required flow cross section. In operation, both the opening and the closing function of the valve ring are continuous, whereby it continuously lies against the ring surface in the circumferential direction and lifts again. There is no need to fix the valve ring in the circumferential direction, so that it can roll on the ring surface while avoiding wear.

In den Unteransprüchen sind vorteilhafte Weiterbildungen der Erfindung beschrieben. Durch die Ausgestaltung nach Anspruch 2 läßt sich die Abhebefunktion des Ventilrings verbessern. Als Werkstoff für den Ventilring eignet sich sowohl Metall als auch Kunststoff. Die in den Ansprüchen 4 bis 9 enthaltenen Merkmale sind aus baulichen Gründen von Vorteil, wobei sie eine einfache, funktionstüchtige und leistungsstarke Kolbenmaschine ergeben.Advantageous developments of the invention are described in the subclaims. The lifting function of the valve ring can be improved by the configuration according to claim 2. Both metal and plastic are suitable as the material for the valve ring. The features contained in claims 4 to 9 are advantageous for structural reasons, resulting in a simple, functional and powerful piston machine.

Erfindung die Erkenntnis aus, daß ein nicht dehnbarer Ventilring alle Ventilfunktionen gleichzeitig zu erfüllen vermag, wobei aufgrund der Biegsamkeit eine Abdichtung auf einem Umfangsabschnitt von etwa 180° erreicht wird. Einer Fixierung des Ventilrings in Umfangsrichtung bedarf es nicht.Invention based on the knowledge that a non-stretchable valve ring can perform all valve functions at the same time, a seal being achieved on a circumferential section of approximately 180 ° due to the flexibility. It is not necessary to fix the valve ring in the circumferential direction.

In den Unteransprüchen sind vorteilhafte Weiterbildungen der Erfindung beschrieben. Durch die Ausgestaltung nach Anspruch 2 läßt sich die Abhebefunktion des Ventilrings verbessern. Als Werkstoff für den Ventilring eignet sich sowohl Metall als auch Kunststoff. Die in den Ansprüchen 4 bis 9 enthaltenen Merkmale sind aus baulichen Gründen von Vorteil, wobei sie eine einfache, funktionstüchtige und leistungsstarke Kolbenmaschine ergeben.Advantageous developments of the invention are described in the subclaims. The lifting function of the valve ring can be improved by the configuration according to claim 2. Both metal and plastic are suitable as the material for the valve ring. The features contained in claims 4 to 9 are advantageous for structural reasons, resulting in a simple, functional and powerful piston machine.

Nachfolgend wird die Erfindung anhand eines in einer Zeichnung dargestellten bevorzugten Ausführungsbeispiels erläutert. Es zeigt:

Fig. 1
eine erfindungsgemäß ausgestaltete Axialkolbenpumpe im axialen Schnitt;
Fig. 2
den Schnitt II-II in Fig. 1.

The invention is explained below on the basis of a preferred exemplary embodiment illustrated in a drawing. It shows:
Fig. 1
an axial piston pump designed according to the invention in axial section;
Fig. 2
the section II-II in Fig. 1st

Die wesentlichen Einzelteile der in Fig. 1 allgemein mit 1 bezeichneten Axialkolbenpumpe sind ein aus einem topfförmigen Gehäuseteil 2 und einem Gehäusedeckel 3 bestehendes Gehäuse 4, eine das topfförmige Gehäuseteil 2 bzw. den Hohlraum 5 des Gehäuses 4 längs der Mittelachse 6 durchsetzende Antriebswelle 7, eine Mehrzahl, im vorliegenden Fall sieben, auf einem Teilkreis 8 angeordnete Kolben 9, die mittels einer auf der Antriebswelle 7 drehfest angeordneten Schiefscheibe 11 in entsprechend bemessenen und zugeordneten Kolbenbohrungen 12 eines innenseitig am Gehäusedeckel 3 angeordneten Zylinderblocks 13 verschiebbar sind und allgemein mit 14 und 15 bezeichnete Ein- und Auslaßventile zur Steuerung der Axialkolbenpumpe.The essential individual parts of the axial piston pump, generally designated 1 in FIG. 1, are a housing 4 consisting of a cup-shaped housing part 2 and a housing cover 3, a drive shaft 7 passing through the cup-shaped housing part 2 or the cavity 5 of the housing 4 along the central axis 6 A plurality, in the present case seven, of pistons 9 arranged on a pitch circle 8, correspondingly by means of a swash plate 11 arranged on the drive shaft 7 in a rotationally fixed manner dimensioned and assigned piston bores 12 of a cylinder block 13 arranged on the inside of the housing cover 3 are displaceable and generally designated 14 and 15 inlet and outlet valves for controlling the axial piston pump.

Beim vorliegenden Ausführungsbeispiel ist die Schiefscheibe 11 mit ihrer Umfangsfläche und mit ihrer dem Zylinderblock 13 abgewandten Stirnfläche in einem radialen und einem axialen Gleitlager 16, 17 gelagert. Die Kolben 9 werden durch eine Rückzugplatte 18 in Kontakt mit der Schieffläche 19 der Schiefscheibe 11 gehalten, wobei die Schiefscheibe 11 durch ein Kugelkopflager 20 mit einer auf der Antriebswelle 7 angeordneten Hülse 21 in Kontakt steht, die ― und somit auch die Rückzugplatte 18 ― durch eine am Gehäusedeckel 3 abgestützte Feder 22 in Richtung auf die Schieffläche 19 beaufschlagt ist. Die Kolben 9 weisen kugelförmige Kolbenköpfe auf, mit denen sie gelenkig, jedoch axial ortsfest in an der Schieffläche 19 gleitenden Gleitschuhen 23 gelagert sind.In the present exemplary embodiment, the swash plate 11 is mounted with its circumferential surface and with its end surface facing away from the cylinder block 13 in a radial and an axial slide bearing 16, 17. The pistons 9 are held in contact with the slant surface 19 of the swash plate 11 by a retraction plate 18, the slant plate 11 being in contact through a ball head bearing 20 with a sleeve 21 arranged on the drive shaft 7, which - and thus also the retraction plate 18 - a spring 22 supported on the housing cover 3 is acted upon in the direction of the skew surface 19. The pistons 9 have spherical piston heads with which they are mounted in an articulated but axially fixed manner in sliding shoes 23 which slide on the inclined surface 19.

Beim vorliegenden Ausführungsbeispiel werden die Einlaßventile 14 durch eine innerhalb des Kolbens 9 verlaufende und radial an einer bestimmten Stelle des Kolbenmantels 24 austretende Kanalverbindung gebildet. Die Anordnung ist so getroffen, daß diese mit 25 bezeichnete Stelle in der zurückgezogenen Position des jeweiligen Kolbens 9 zum Hohlraum 5 des Gehäuses 4 freiliegt, jedoch in der vorgeschobenen Position des jeweiligen Kolbens 9 von der Wand der zugehörigen Kolbenbohrung 12 abgedeckt ist. Der Abstand a dieser Stelle 25 vom Rand 26 der zugehörigen Kolbenbohrung 12 in der zurückgezogenen Stellung des Kolbens 9 ist an die funktionellen Anforderungen der Axialkolbenpumpe 1 anzupassen und beträgt beim vorliegenden Ausführungsbeispiel etwa 2 mm. In dieser zurückgezogenen Position des Kolbens 9 erfolgt das Füllen der Kolbenbohrung 12 durch Unterdruck aus dem Hohlraum 5 des Gehäuses 4, der im Betrieb mit Fluid gefüllt ist.In the present exemplary embodiment, the inlet valves 14 are formed by a channel connection running inside the piston 9 and emerging radially at a specific point on the piston jacket 24. The arrangement is such that this point, designated 25, is exposed in the retracted position of the respective piston 9 to the cavity 5 of the housing 4, but is covered by the wall of the associated piston bore 12 in the advanced position of the respective piston 9. The distance a of this point 25 from the edge 26 of the associated piston bore 12 in the retracted position of the piston 9 is to be adapted to the functional requirements of the axial piston pump 1 and is approximately 2 mm in the present exemplary embodiment. In this retracted position of the piston 9, the piston bore 12 is filled by negative pressure from the cavity 5 of the housing 4, which is filled with fluid during operation.

Beim vorliegenden Ausführungsbeispiel werden Kolben 9 mit einer von ihrer Stirnseite ausgehenden Bohrung 27 (Hohlkolben) eingesetzt. Die Öffnung zum Hohlraum 5 hin ist durch wenigstens eine, vorzugsweise vier radiale Bohrungen 28 gebildet.In the present exemplary embodiment, pistons 9 with a bore 27 (hollow piston) extending from their end face are used. The opening to the cavity 5 is formed by at least one, preferably four radial bores 28.

Die Auslaßventile 15 weisen einen gemeinsamen Ventilring 31 auf, der mit radialem Bewegungsspiel S₁ und seitlichem Bewegungsspiel S₂ in einer Ringnut 32 angeordnet ist, die beim vorliegenden Ausführungsbeispiel alle vorhandenen Kolbenbohrungen 12 umgibt und ― radial gesehen ― im Bereich der inneren Enden der Kolbenbohrungen 12 angeordnet ist. Die Auslaßventile 15 werden weiter durch von den Kolbenbohrungen 12 ausgehende und radial in eine Ringnut 32 ausmündende Förderkanäle 33 mit Ventilöffnungen 34 gebildet, deren Durchmesser d geringer ist, als die Breite b des Ventilrings 31. Von der Ringnut 32 geht radial auswärts ein weiterer Förderkanal 35 aus, der in einen radialen Anschluß 36 für eine nicht dargestellte Förderleitung mündet.The exhaust valves 15 have a common valve ring 31, which is arranged with radial movement play S 1 and lateral movement play S 2 in an annular groove 32 which, in the present exemplary embodiment, surrounds all existing piston bores 12 and - seen radially - is arranged in the region of the inner ends of the piston bores 12 . The outlet valves 15 are further formed by delivery channels 33 with valve openings 34, starting from the piston bores 12 and opening radially into an annular groove 32, the diameter d of which is smaller than the width b of the valve ring 31. A further delivery channel 35 extends radially outward from the annular groove 32 from which opens into a radial connection 36 for a delivery line, not shown.

Der Zylinderblock 13 ragt um das mit c bezeichnete Maß in den zylindrischen Abschnitt 37 des topfförmigen Gehäuses 2 hinein, wobei zwischen der Außenmantelfläche 38 des Zylinderblocks 13 und der zylindrischen Innenmantelfläche 39 des Abschnitts 37 (vgl. Abstand B) ein Ringkörper 41 eingesetzt ist, der an seinem der Schiefscheibe 11 zugewandte Ende an einer Schulter 42 des Gehäuseteils 2 und an seinem anderen Ende an einer Schulter 43 des Zylinderblocks 13 axial fixiert ist, und der den Ringkanal 32 auf seiner der Schiefscheibe 11 zugewandten Seite begrenzt. Auf der anderen Seite ist der Ringkanal 32 durch den Gehäusedeckel 3 bzw. dessen flanschförmige Erstreckung begrenzt. Der Gehäusedeckel 3 ist somit mittelbar über den Ringkörper 41 in der zylindrischen Ausnehmung des Gehäuseteils 2 zentriert. Es ist zu berücksichtigen, daß der Ringkörper 41 mit einer feinen Passung auf den Zylinderblock 13 und in das Gehäuseteil 2 paßt. Zur Abdichtung des Ringkanals 32 können O-Ringe 40 in Ringnuten zwischen dem Ringkörper 41 und anliegenden Teilen (Gehäuseteil 2) sowie dem Gehäuseteil 2 und dem Gehäusedeckel 3 vorgesehen sein. Die Befestigung des Gehäusedeckels 3 am Gehäuseteil 2 erfolgt durch Schrauben 44.The cylinder block 13 protrudes by the dimension denoted by c into the cylindrical section 37 of the cup-shaped housing 2, an annular body 41 being inserted between the outer lateral surface 38 of the cylinder block 13 and the cylindrical inner lateral surface 39 of the section 37 (see distance B) is axially fixed at its end facing the swash plate 11 to a shoulder 42 of the housing part 2 and at its other end to a shoulder 43 of the cylinder block 13, and the ring channel 32 limited on its side facing the swash plate 11. On the other hand, the ring channel 32 is delimited by the housing cover 3 or its flange-shaped extension. The housing cover 3 is thus centered indirectly via the ring body 41 in the cylindrical recess of the housing part 2. It must be taken into account that the ring body 41 fits with a fine fit on the cylinder block 13 and in the housing part 2. To seal the ring channel 32, O-rings 40 can be provided in ring grooves between the ring body 41 and adjoining parts (housing part 2) and the housing part 2 and the housing cover 3. The housing cover 3 is fastened to the housing part 2 by screws 44.

Im Betrieb der Axialkolbenpumpe 1 wird das Fluid durch eine andeutungsweise dargestellte, an einem radialen Leitungsanschluß 45 anschließbare Saugleitung und einen sich an den Leitungsanschluß 45 anschließenden Strömungskanal 46 in den Hohlraum 5 des Gehäuses 4 und weiter wie vorbeschrieben in die Kolbenbohrungen 12 gesaugt. Beim Vorschub der Kolben 9, an dem jeweils im wesentlichen die Hälfte der Anzahl der vorhandenen, beim vorliegenden Ausführungsbeispiel sieben Kolben 9 teilnimmt, wird das Fluid aus den Kolbenbohrungen 12 in Richtung der in Fig. 2 mit 47 bezeichneten Strömungspfeile in den Ringkanal 32 und weiter seitlich durch die zwischen dem Ventilring 31 und den radialen Wänden des Ringkanals 32 vorhandenen Spalte 48 am Ventilring 31 vorbeigedrückt, wobei das Fluid durch den Förderkanal 34 zur angedeuteten Förderleitung gelangt.In the operation of the axial piston pump 1, the fluid is sucked through an indicated suction line, which can be connected to a radial line connection 45, and a flow channel 46, which connects to the line connection 45, into the cavity 5 of the housing 4 and further into the piston bores 12 as described above. When the pistons 9 are fed, in which essentially half of the number of pistons 9 present, in the present exemplary embodiment seven, participates, the fluid flows out of the piston bores 12 in the direction of the flow arrows designated 47 in FIG. 2 into the annular channel 32 and further pushed laterally through the gaps 48 between the valve ring 31 and the radial walls of the ring channel 32 past the valve ring 31, the fluid passing through the delivery channel 34 to the indicated delivery line.

Die vorhandenen Ventilöffnungen 34 werden jeweils durch eine radiale Verlagerung des Ventilrings 31 geöffnet oder geschlossen, wie es am besten aus Fig. 2 ersichtlich ist. Dabei wird der Ventilring 31 aufgrund des auf ihn wirkenden Strömungsdrucks des durch die Ventilöffnungen 34 austretenden Fluids automatisch in die Lage bewegt, in der er die unter Druck stehendes Fluid auslassenden Ventilöffnungen 34 öffnet (linke Seite). Die diametral entgegengesetzt angeordneten Ventilöffnungen 34 (rechte Seite) werden dabei gleichzeitig geschlossen, wobei der in den zugehörigen Kolbenbohrungen 12 enthaltene Unterdruck und ggf. der auf dieser Seite auf den Ventilring 31 lastende Druck die dichte Anlage des Ventilrings 31 an der die Ventilöffnungen 34 enthaltenden Ringfläche 49 des Ringkanals 32 bewirkt. Der Ventilring 31 ist in der Lage, sich um ca. 180° an die Ringfläche 49 des Ringkanals 32 anzulegen, d.h. so zu verformen bzw. zu biegen, da er aus einem biegsamen, vorzugsweise elastisch biegsamen Material wie Metall oder Kunststoff besteht.The existing valve openings 34 are each opened or closed by a radial displacement of the valve ring 31, as can best be seen in FIG. 2. The valve ring 31 is due to the the flow pressure of the fluid exiting through the valve openings 34 automatically moves him into the position in which he opens the valve openings 34 discharging the pressurized fluid (left side). The diametrically opposed valve openings 34 (right side) are closed at the same time, the negative pressure contained in the associated piston bores 12 and possibly the pressure on this side of the valve ring 31, the tight contact of the valve ring 31 on the annular surface containing the valve openings 34 49 of the ring channel 32 causes. The valve ring 31 is able to contact the ring surface 49 of the ring channel 32 by approximately 180 °, ie to deform or bend in such a way that it consists of a flexible, preferably elastically flexible material such as metal or plastic.

Die Größe der Bewegungsspiele s₁, s₂ bzw. Spalte ist abhängig vom Durchsatz- bzw. Fördervolumen der Axialkolbenpumpe 1. Die Anordnung ist so zu treffen, daß das Fluid ohne wesentliche Drosselverluste aus den Kolbenbohrungen 12 herausgefördert werden kann. Die Größe des Bewegungsspiels s₁, s₂ bzw. der Spalte 48 ist somit auch abhängig von der Anzahl der Kolben 9, denn bei einer größeren Anzahl von Kolben 9 ist auch das Fördervolumen größer. Dagegen können beim Vorhandensein einer geringen Anzahl Kolben, d.h., einem verhältnismäßig geringem Fördervolumen, die Bewegungsspiele s₁, s₂ bzw. die Spalte 48 verhältnismäßig klein bemessen werden.The size of the movement s₁, s₂ or column depends on the throughput or delivery volume of the axial piston pump 1. The arrangement must be such that the fluid can be conveyed out of the piston bores 12 without significant throttling losses. The size of the movement s₁, s₂ or column 48 is thus also dependent on the number of pistons 9, because with a larger number of pistons 9, the delivery volume is also larger. On the other hand, if there is a small number of pistons, i.e. a relatively small delivery volume, the movement play s 1, s 2 or the column 48 can be dimensioned relatively small.

Die Größe der Bewegungsspiele s₁, s₂ bzw. Spaltweiten sind abhängig vom Durchsatz bzw. Fördervolumen der Axialkolbenmaschine 1. Bei einem Durchmesser des Ventilrings 31 von etwa 50 mm sollten etwa 0,3 bis 1 mm angestrebt werden. Bei Versuchen wurden gute Ergebnisse bei einem Bewegunngsspiel bzw. einer Spaltweite von etwa 0,5 mm erzielt. Hierdurch wird deutlich, daß die Elastizität des Ventilringes verhältnismäßig gering sein kann.The size of the movement s₁, s₂ or gap widths depend on the throughput or delivery volume of the axial piston machine 1. With a diameter of the valve ring 31 of about 50 mm, about 0.3 to 1 mm should be aimed for. In experiments, good results were achieved with a movement clearance or a gap width of approximately 0.5 mm. This makes it clear that the Elasticity of the valve ring can be relatively low.

Trotz der vorbeschriebenen Beziehung zwischen der Größe der Spalte 48 und dem Durchsatzvolumen ist die erfindungsgemäße Ausgestaltung auch für Kolbenmaschinen mit verstellbarer Durchsatzmenge einsetzbar, da die vorbeschriebene Beziehung Abweichungen bestimmter Größen erlaubt.Despite the above-described relationship between the size of the column 48 and the throughput volume, the embodiment according to the invention can also be used for piston machines with an adjustable throughput quantity, since the above-described relationship allows deviations of certain sizes.

Im Rahmen der Erfindung ist es im Gegensatz zum vorbeschriebenen Ventilring 31 als Außenring auch möglich, die erfindungsgemäße Ventilanordnung mit einem Ventilring als Innenring auszuführen. Außerdem ist erfindungsgemäße Ausgestaltung auch an einer Radialkolbenmaschine (Pumpe) zu verwirklichen.In the context of the invention, in contrast to the previously described valve ring 31 as an outer ring, it is also possible to design the valve arrangement according to the invention with a valve ring as an inner ring. In addition, the configuration according to the invention can also be implemented on a radial piston machine (pump).

Claims (9)

1. An axial or radial piston machine having a piston block with a plurality of piston bores each slidably housing a piston and opening through valve openings on to an annular surface that cooperates with a closed valve ring to form a control valve ring, characterised in that a radial clearance (s₁) is provided between the annular surface (49) and the valve ring (31) and that the bending strength of the valve ring (31) is such that under the hydraulic pressure obtaining at at least one valve opening (34) it adapts without deformation by stretching to the annular surface (49) in the neighbourhood of the respective other valve openings (34) to be closed.
2. A piston machine according to claim 1, characterised in that the valve ring (31) is elastically flexible.
3. A piston machine according to claim 1 or claim 2, characterised in that the valve ring (31) consists of steel or other metal or of plastics material.
4. A piston machine according to any one of claims 1 to 3, characterised in that the annular passage (32) is located in the region of the inner ends of the piston bores (12), preferably radially outwards of the piston bores (12).
5. A piston machine according to any one of claims 1 to 4, characterised in that in an axial piston machine the annular passage (32) is located between a cylinder block (13) fixed to the housing and a wall (37) of the housing (4) surrounding the block.
6. A piston machine according to claim 5, characterised in that an annular body (41) axially bounding the annular passage (32) is inserted between the outer cylindrical surface (38) of the cylinder block (13) and the wall (37).
7. A piston machine according to claim 6, characterised in that the annular body (41) is held axially between a shoulder (42) on the wall (37) of the housing (4) and a shoulder (43) on the cylinder block (13).
8. A piston machine according to any one of claims 5 to 7, characterised in that the cylinder block (13) is located on the inside of a flange-shaped housing cover (3) axially bounding the annular passage (32), preferably as an integral continuation thereof.
9. A piston machine according to any one of claims 1 to 8, characterised in that a radial delivery passage (46) leads from the annualar passage (32) to a preferably radial pipe connection (36).
EP88109856A 1987-07-28 1988-06-21 Axial or radial piston machine with a valve arrangement comprising a valve ring Expired - Lifetime EP0301230B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3724967 1987-07-28
DE19873724967 DE3724967A1 (en) 1987-07-28 1987-07-28 AXIAL OR RADIAL PISTON MACHINE WITH A VALVE RING CONTROL VALVE ARRANGEMENT

Publications (3)

Publication Number Publication Date
EP0301230A2 EP0301230A2 (en) 1989-02-01
EP0301230A3 EP0301230A3 (en) 1989-09-06
EP0301230B1 true EP0301230B1 (en) 1991-09-25

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EP88109856A Expired - Lifetime EP0301230B1 (en) 1987-07-28 1988-06-21 Axial or radial piston machine with a valve arrangement comprising a valve ring

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DE (2) DE3724967A1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3841382C1 (en) * 1988-12-08 1990-03-15 Hydromatik Gmbh, 7915 Elchingen, De
DE4238376A1 (en) * 1992-11-13 1993-12-02 Bosch Gmbh Robert Radial piston pump with elastic valve ring - uses fluid pressure from pistons to rotate valve ring and so distribute wear uniformly
DE19740436A1 (en) * 1997-09-15 1999-03-18 Schaeffler Waelzlager Ohg Swashplate bearing for plunger pump
DE102005060957B4 (en) * 2005-12-20 2012-08-23 Industriehansa Consulting & Engineering Gmbh High pressure pump with several pistons per cylinder

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB541295A (en) * 1940-02-09 1941-11-20 Browett Lindley 1931 Ltd J Improvements in and relating to air compressors
GB1431437A (en) * 1972-07-19 1976-04-07 Bendix Westinghouse Ltd Power assistance control device
DE3623797A1 (en) * 1985-07-24 1987-03-19 Barmag Barmer Maschf Radial piston pump

Also Published As

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DE3865140D1 (en) 1991-10-31
EP0301230A3 (en) 1989-09-06
EP0301230A2 (en) 1989-02-01
DE3724967A1 (en) 1989-02-09

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