EP0767864B1 - Axial piston engine with a cooling circuit for the cylinders and pistons - Google Patents

Axial piston engine with a cooling circuit for the cylinders and pistons Download PDF

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Publication number
EP0767864B1
EP0767864B1 EP95921838A EP95921838A EP0767864B1 EP 0767864 B1 EP0767864 B1 EP 0767864B1 EP 95921838 A EP95921838 A EP 95921838A EP 95921838 A EP95921838 A EP 95921838A EP 0767864 B1 EP0767864 B1 EP 0767864B1
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EP
European Patent Office
Prior art keywords
axial piston
cooling
piston machine
cylinders
machine according
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Expired - Lifetime
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EP95921838A
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German (de)
French (fr)
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EP0767864A1 (en
Inventor
Heinz Berthold
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Brueninghaus Hydromatik GmbH
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Brueninghaus Hydromatik GmbH
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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
    • F01B3/0032—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F01B3/0044—Component parts, details, e.g. valves, sealings, lubrication
    • F01B3/0052—Cylinder barrel

Definitions

  • the invention relates to an axial piston machine according to the preamble of Claim 1.
  • Such axial piston machines are known from practice. Especially at Swashplate machines contain the piston that supports each piston on the swashplate Normal force a radial component that acts like one in the cylinder drum clamped beam acts on the piston and this within the cylinder canted. This leads in particular to the lack of piston lubrication, such as occurs during the start-up phase, for metallic contact between the piston and Cylinder wall with the result of corresponding heating by the occurring Frictional forces and risk of piston seizure.
  • GB-A-1 029 910 an axial piston machine according to the preamble of Claim 1 out.
  • the subject of this document is a lubrication device for hydraulic pumps and motors. Some are aligned in the radial direction Inlet and outlet channels provided to the lubricating oil for lubricating the pistons and to promote the storage of the cylinder drum. A connection between the am Outer circumference of the cylinder drum formed with the leak inside the Leakage fluid receiving space provided in the cylinder drum does not exist, so that none closed but an open lubrication circuit is present.
  • the solution according to the invention is based on the principle of cooling the piston critical points of metallic contact between the piston and cylinder and can thus not only in oil-operated axial piston machines, but also in those are used, which are intended for operation with a non-lubricating fluid are.
  • This cooling takes place by means of a cooling circuit which is connected to the leakage space connected, that is, completely separate from the working circuit of the axial piston machine is and in this way does not affect their efficiency.
  • the leakage fluid in the Leakage has its strongest cooling effect in the start-up phase, if so Risk of piston seizure is greatest because in this phase its temperature is roughly corresponds to the ambient room temperature.
  • This cooling device can be in the form of a another leakage fluid receiving space in a pressure and attached to the housing Suction channel of the connecting block containing the axial piston machine.
  • the cooling areas are preferably designed as annular spaces that the cylinders with surrounded by a small radial distance.
  • the cooling areas are advantageous to use as annular grooves in the cylinder walls form, so that the leak oil not only for cooling, but also for additional lubrication of the pistons.
  • the arrangement and number of Annular spaces or annular grooves can depend on the respective conditions of use Axial piston machine can be matched. So it can with axial piston machines low performance, each cylinder has a single cooling area, preferably in the end region of the cylinder drum facing the lifting disk, assign.
  • At least preferably an upper and a lower cooling area are provided, which are separated by a distribution channel or a distributor groove can be connected to each other.
  • the Leakage oil flow through an inlet channel and into one of the cooling areas maintain a discharge channel opening out of the respective other cooling area will.
  • suction channel of the axial piston machine Connect the cooling circuit via a dossel.
  • the one forced over the throttle Forced flow improves the cooling properties because relatively cool oil from the Inflow channel flows.
  • the axial piston machine shown in Figures 1 to 4 is in Swashplate design with adjustable displacement and one Current direction executed and includes in a known manner as essential components hollow cylindrical housing 1 with an open end (upper end in Figure 1) attached to the housing 1, the open end closing Terminal block 2, a lifting or swash plate 3, a control body 4, a Drive shaft 5, a cylinder drum 6 and a cooling circuit 7.1 according to the invention until 7.4.
  • the swash plate 3 is a so-called swivel cradle with a semi-cylindrical one Cross-section (see Figure 5) formed and supported with two, with mutual Distance parallel to the swivel direction bearing surfaces under hydrostatic Relief on two appropriately shaped bearing shells 8, which on the inner surface the housing end wall 9 opposite the connection block 2 are fastened.
  • the hydrostatic discharge takes place in a known manner via pressure pockets 10, which in the Bearing shells 8 are formed and supplied with pressure medium via connections 11 will.
  • actuator 13 engages in the direction of Terminal block 2 extending arm 14 of the swash plate 3 and is used for Swiveling the same about a swivel axis perpendicular to the swivel direction.
  • the control body 4 is on the inner surface of the housing interior facing the Terminal blocks 2 attached and with two through openings 15 in the form of kidney-shaped control slots which are connected via a pressure channel 16D or Suction channel 16S in the connection block 2 to a pressure and suction line, not shown are connected.
  • the pressure channel 16D has a smaller flow cross section than the suction channel 16S.
  • the spherical facing the interior of the housing Trained control surface of the control body 4 serves as a bearing surface for the Cylinder drum 6.
  • the drive shaft 5 protrudes through a through hole in the housing end wall 9 in the housing 1 and is in this through hole by means of a bearing 17 and by means of a further bearing 18 in a narrower bore section blind bore 19 at the end in the connection block 2 and one closer to it Bore section adjacent region of a central through hole 20 in Control body 4 rotatably mounted.
  • the drive shaft 5 penetrates inside the Housing also a central through hole 21 in the swash plate 3, whose diameter corresponds to the largest swash deflection of the swash plate 3 is dimensioned, as well as a central through bore in the cylinder drum 6 two hole sections.
  • One of these bore sections is formed on a cylinder drum 6, projecting beyond the end face 22 facing the swash plate 3 sleeve-shaped extension 23, via which the cylinder drum 6 by means of a keyway connection 24 is rotatably connected to the drive shaft 5.
  • the remaining bore section is conical; it tapers based on its cross section of largest diameter close to the first Bore section up to its cross section of smallest diameter close to the Control body 4 adjacent end face or bearing surface of the cylinder drum 6.
  • the of the Drive shaft 5 and this conical bore section is defined annular space designated by the reference numeral 25.
  • the cylinder drum 6 has generally axially extending, stepped Cylinder bores 26 which are even on a coaxial to the drive shaft axis Pitch circle are arranged on the cylinder drum end face 22 directly and on the Control body 4 facing cylinder drum bearing surface via outlet channels 27 open out in the same pitch circle as the control slots.
  • a bushing 28 is used in the on the Cylinder drum end face 22 directly opening cylinder bore sections a larger diameter.
  • the cylinder bores 26 including the bushings 28 are referred to here as cylinders.
  • Within this Cylinders 26, 28 are displaceably arranged pistons 29 on their swash plate 3 facing ends with ball heads 30 which are mounted in sliding shoes 31 and via this to an annular slide disk 32 fastened to the swash plate 5 are stored hydrostatically.
  • Each slide shoe 31 is on its slide plate 32 facing sliding surface with a pressure pocket, not shown, which over a through hole 33 in the shoe 31 to a stepped axial Through channel 34 connected in the piston 29 and in this way with the Piston 29 in the cylinder bore 26 delimited working space of the cylinder connected is.
  • a stepped axial Through channel 34 connected in the piston 29 and in this way with the Piston 29 in the cylinder bore 26 delimited working space of the cylinder connected is.
  • In each axial through channel 34 is in the area of the associated Ball head 30 formed a throttle.
  • the one in the interior of the housing of the components 3 to 6 etc. contained therein The space taken up serves as a leakage space 37 which is used in the operation of the Axial piston machine through all gaps, such as between the Cylinders 26, 28 and the piston 29, the control body 4 and the cylinder drum 6, the swash plate 3 and the sliding plate 32 and the bearing shells 8, etc., emerging Leakage fluid picks up.
  • the axial piston machine is designed for operation with oil as a fluid.
  • the cylinder drum 6 together with the piston 29 is rotated. If the swash plate 3 in a by actuating the actuator 13 Inclination (see FIG. 5) is pivoted relative to the cylinder drum 6, so all pistons perform 29 strokes; when rotating the Cylinder drum 6 through 360 °, each piston 29 passes through a suction and one Compression stroke, whereby corresponding oil flows are generated, their inflow and Dissipation via the mouth channels 27, the control slots 15 and the pressure and Suction channel 16D, 16S.
  • the swash plate 3 exerts a normal force F n on each slide shoe 31, which is perpendicular to the swash plate 3 with negligible friction.
  • This normal force is broken down into a piston force F k and a radial or transverse force F q in the spherical piston 30.
  • the transverse force F q acts in the ball head 30 on the piston 29 as on a beam clamped in the cylinder drum 6, which causes the axial reaction forces F r shown in FIG.
  • the piston 29 comes into metallic contact with the liner 28, and very high surface pressures can occur, which are the cause of correspondingly high frictional forces and thus heating at the contact points.
  • the cooling circuit 7.1 to 7.4 is connected to the leakage space 37 and includes the conical annulus 25 (so-called leakage fluid receiving space), the Through hole 20 in the control body 4, the blind hole 19 (so-called further Leakage fluid receiving space), a connecting this with the leakage space 37 Connection line 38, which is in a circumferential groove 39 in the inner surface of the Terminal block 2 opens out, as well as the cylinders 26, 28 all around Cooling areas connected to the conical annular space 25 via inlet channels 40 are and via drainage channels 41 on the cylindrical boundary surface 42 of the Open cylinder drum 6 into leakage space 37. All inlet channels 40 open in the conical annular space 25 at its cross-section of the largest diameter and Like all drainage channels 41, they run essentially radially through the Cylinder drum 6.
  • each cylinder 26, 28 is in the form of a cooling area an annular space 43 assigned as a circumferential groove in the wall of the Cylinder bore section of larger diameter and formed by the Liner 28 is covered.
  • the annular space 43 extends from near Mouth area of the cylinder bore 26 over about two thirds of the length the same in the direction of the mouth channels 27 and thus represents one of the upper Dead center position of the piston 29 associated upper cooling area.
  • One each Inlet channel 40 and an outlet channel 41 open approximately centrally in the annular space 43 and run coaxially with each other.
  • the heating leakage oil in the leakage space 37 is cooled as it flows through the blind bore 19 in the connection block 2, since this is exposed to the room temperature and is therefore cooler than the leakage oil in the leakage space 37.
  • the leakage oil in the cooling circuit 7.1 can be kept at correspondingly low temperatures by appropriately designing the connection block 2 and the blind bore 19 and, if appropriate, additionally cooling them by means of a separate coolant.
  • the cooling circuit 7.1 serves only as a cooling circuit due to the lack of connection to the cylinders 26, 28 (due to the closed annular spaces 43).
  • the cooling circuit 7.1 can additionally assume a lubricating function if, for example, the annular spaces 43 are connected to the cylinders 26, 28 via corresponding bores through the bushings 28.
  • the axial piston machine equipped with the cooling circuit 7.1 is designed for medium outputs due to the arrangement of the annular spaces 43 in the mouth area of the cylinders 26, 28.
  • the cooling circuit 7.2 according to FIG. 2 differs in otherwise the same Construction and cooling function of that of Figure 1 in that its Cooling areas have the shape of annular grooves 44 which are in the bushings 28 formed and open to the interior of the cylinders 26, 28.
  • the one with the Cooling circuit 7.2 equipped axial piston machine is due to the compared to the annular spaces 43 smaller axial width of the annular grooves 44 for smaller Services designed and performed as the axial piston machine according to Figure 1 at the same time additional lubrication of the pistons 29.
  • the cooling circuit 7.3 according to FIG. 3 differs in otherwise the same Construction and function of that of Figure 2 in that each Annular groove 44 is connected to a distributor groove 45 which is in the bushing 28 spirally surrounding, is formed and on the end face 22 of the cylinder drum 6 flows out.
  • the area of action of the ring grooves 44 with regard to cooling and Lubrication is made from them via the distributor grooves 45 into the leakage space 37 flowing leakage oil up to the mouth of the cylinders 26, 28 expanded.
  • the cooling circuit 7.4 according to FIG. 4 comprises the one in FIG. 1 for each cylinder 26, 28 shown upper annular space 43, but with a smaller axial width, and one another, lower annular space 46 of the same dimensions, which in the lower end region of the Liner 28, that is in the region of the cylinder 26, 28 above the Piston base 47 is formed at the bottom dead center position of the piston 29.
  • To the upper annular space 43 is an inlet channel 40 and to the lower annular space 46 Drain channel 41 connected.
  • a Distribution channel 48 is provided, which connects the two annular spaces 43, 46 together.
  • the cooling circuit 7.4 according to FIG. 4 like that according to FIG. 1, is not shown in FIG Connection with the cylinders 26, 28 and thus has only the function of a Cooling.
  • the cooling circuit 7.4 is very high performance for axial piston machines intended.
  • This cooling circuit can be used for high performance axial piston machines Find use when the annular spaces 43, 46 and possibly the Distribution channel 48 through corresponding holes through the bushings 28 with the Cylinders 26, 28 are connected. The same effect is achieved if the Annuli 43, 46, the distribution channel 48 and the holes mentioned Ring grooves and distributor grooves according to Figure 3 are replaced.
  • FIG. 6 shows the cooling circuit 7.1 already shown in FIG. 1.
  • the embodiment shown in Figure 6 differs from that Figure 1 in that between the suction channel 16S and the blind bore 19 a Through bore 51 is provided, the suction channel 16S of the axial piston machine connects to the cooling circuit 7.1.
  • the bore 51 is an anti-pulsation throttle 50 arranged in the bore 51. This flows under pre-compression via the anti-pulsation throttle 50 standing fluid of the suction channel 16S in the cooling circuit 7.1, causing leakage be balanced. The fluid flowing in via the throttle 50 causes a certain forced flow in the cooling circuit 7.1 reached, whereby the cooling properties of the cooling circuit can be improved.
  • the inflow from the suction channel 16S can at various points in the Axial piston machine can be arranged and in different areas of the cooling circuit flow into.
  • the arrangement of the throttle 50 in the is particularly advantageous Terminal block 2, where it between the blind bore 19 and the suction channel 16S in can be easily integrated.
  • the invention can also be implemented in inclined axis machines, since here too radial forces that jam the pistons in the cylinders can occur due to an inclined position of the pistons or piston rods as a result of Deviations between the part circle of the spherical seats in the Drive pulley and the pitch circle of the cylinder.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)

Abstract

The invention relates to an axial piston engine with a casing (1), the inside of which contains a leakage chamber (37) and an eccentric disc (3) and a rotatably fitted cylinder drum (6) with cylinders (26,28) and pistons (29) reciprocating therein, the ends of which projecting from the cylinders (26, 28) are supported on the eccentric disc (3). To prevent the cylinders from seizing while maintaining the efficiency of the axial piston engine, the invention provides for a cooling circuit (7.1 to 7.4) which comprises a leakage fluid catchment chamber (25) connected to the leakage chamber (37) and formed in the part of the cylinder drum (6) surrounded by the cylinders (26, 28); inlet and outlet channels (40, 41), at least one radial component of which runs through the cylinder drum (6); and cooling regions (43, 44, 46) running around the cylinders (26, 28), which are connected to the leakage fluid catchment chamber (25) and open via the outlet channels (41) into the leakage chamber (37) at an outer limiting surface (42) of the cylinder drum (6).

Description

Die Erfindung betrifft eine Axialkolbenmaschine nach dem Oberbegriff des Anspruches 1.The invention relates to an axial piston machine according to the preamble of Claim 1.

Derartige Axialkolbenmaschinen sind aus der Praxis bekannt. Insbesondere bei Schrägscheibenmaschinen enthält die jeden Kolben an der Schrägscheibe abstützende Normalkraft eine Radialkomponente, die wie auf einen in der Zylindertrommel eingespannten Balken auf den Kolben wirkt und diesen innerhalb des Zylinders verkantet. Dies führt insbesondere bei fehlender Kolbenschmierung, wie sie etwa während der Anlaufphase auftritt, zur metallischen Berührung zwischen Kolben und Zylinderwandung mit der Folge entsprechender Erwärmung durch die auftretenden Reibkräfte und Gefahr des Fressens der Kolben.Such axial piston machines are known from practice. Especially at Swashplate machines contain the piston that supports each piston on the swashplate Normal force a radial component that acts like one in the cylinder drum clamped beam acts on the piston and this within the cylinder canted. This leads in particular to the lack of piston lubrication, such as occurs during the start-up phase, for metallic contact between the piston and Cylinder wall with the result of corresponding heating by the occurring Frictional forces and risk of piston seizure.

Aus der DE-OS 14 03 754 ist eine Axialkolbenmaschine bekannt, bei der zum Zweck des Vermeidens der metallischen Berührung zwischen Kolben und Zylinder am Umfang jedes Zylinders oder des zugeordneten Kolbens Drucktaschen symmetrisch ausgebildet und über je eine Drossel sowie eine axiale Durchgangsbohrung im Kolben mit dem Arbeitsraum des Zylinders verbunden sind. Der Kolben wird durch das während des Kompressionshubs vom Arbeitsraum den Drucktaschen zuströmende, unter Hochdruck stehende Öl geschmiert und hydrostatisch entlastet und auf diese Weise zentrisch ohne Gefahr des Verkantens im Zylinder geführt. Die für diese hydrostatische Entlastung erforderliche Ölmenge fehlt im Arbeitskreislauf der Axialkolbenmaschine und führt somit zu einer Verringerung des Wirkungsgrades derselben.From DE-OS 14 03 754 an axial piston machine is known, for the purpose avoiding metallic contact between the piston and cylinder on the circumference each cylinder or the associated piston pressure pockets formed symmetrically and each with a throttle and an axial through hole in the piston with the Working space of the cylinder are connected. The piston is replaced by the during the Compression strokes from the work area to the pressure pockets, under high pressure Standing oil lubricated and hydrostatically relieved and thus centric without Risk of canting in the cylinder. The one for this hydrostatic relief required amount of oil is missing in the working circuit of the axial piston machine and leads thus reducing their efficiency.

Die gleichen Vorteile und Nachteile weist der in der DE-OS 18 04 529 beschriebene Axialkolbenmotor auf, bei dem in der Wandung jedes Zylinders eine umlaufende Nut ausgebildet ist, die über Anschlußkanäle in der Zylindertrommel und im Anschlußblock an die Hochdruckleitung einer diesen Axialkolbenmotor antreibenden Axialkolbenpumpe angeschlossen ist. The same advantages and disadvantages are described in DE-OS 18 04 529 Axial piston motor with a circumferential groove in the wall of each cylinder is formed, the connection channels in the cylinder drum and in the connection block to the high pressure line of a drive this axial piston motor Axial piston pump is connected.

Aus der GB-A-1 029 910 geht eine Axialkolbenmaschine nach dem Oberbegriff des Anspruchs 1 hervor. Gegenstand dieser Druckschrift ist eine Schmiervorrichtung für hydraulische Pumpen und Motoren. Dabei sind teilweise in radialer Richtung ausgerichtete Zulauf- und Ablaufkanäle vorgesehen, um das Schmieröl zum Schmieren der Kolben und der Lagerung der Zylindertrommel zu fördern. Eine Verbindung zwischen dem am Außenumfang der Zylindertrommel gebildeten Leckraum mit dem im Inneren der Zylindertrommel vorgesehenen Leckfluid-Aufnahmeraum besteht nicht, so daß kein geschlossener sondern ein offener Schmierkreislauf vorliegt.From GB-A-1 029 910 an axial piston machine according to the preamble of Claim 1 out. The subject of this document is a lubrication device for hydraulic pumps and motors. Some are aligned in the radial direction Inlet and outlet channels provided to the lubricating oil for lubricating the pistons and to promote the storage of the cylinder drum. A connection between the am Outer circumference of the cylinder drum formed with the leak inside the Leakage fluid receiving space provided in the cylinder drum does not exist, so that none closed but an open lubrication circuit is present.

Aus der EP-A-0 041 312 geht eine ähnliche Axialkolbenmaschine hervor. Zu Kühlzwecken ist eine Ejektorpumpe zusätzlich vorgesehen.A similar axial piston machine emerges from EP-A-0 041 312. To An ejector is also provided for cooling purposes.

Es ist die Aufgabe der Erfindung, eine Axialkolbenmaschine nach dem Oberbegriff des Anspruchs 1 so weiterzubilden, daß bei Aufrechterhaltung ihres Wirkungsgrades das Fressen der Kolben in den Zylindern verhindert wird. It is the object of the invention to provide an axial piston machine according to the preamble of Claim 1 to be further developed so that while maintaining its efficiency This prevents the pistons from seizing in the cylinders.

Diese Aufgabe wird durch die kennzeichnenden Merkmale des Anspruches 1 in Verbindung mit dessen gattungsbildenden Merkmalen gelöst.This object is achieved by the characterizing features of claim 1 Released with its generic characteristics.

Statt des Prinzips der aus dem Stand der Technik bekannten hydrostatischen Entlastung und Schmierung der Kolben basiert die erfindungsgemäße Lösung auf dem Prinzip der Kühlung der kritischen Stellen metallischer Berührung zwischen Kolben und Zylinder und kann somit nicht nur in ölbetriebenen Axialkolbenmaschinen, sondern auch in denjenigen eingesetzt werden, die für den Betrieb mit einem nichtschmierenden Fluid vorgesehen sind. Diese Kühlung erfolgt mittels eines Kühlkreislaufes, der an den Leckraum angeschlossen, das heißt völlig getrennt vom Arbeitskreislauf der Axialkolbenmaschine ist und auf diese Weise deren Wirkungsgrad nicht beeinträchtigt. Das Leckfluid im Leckraum weist seinen stärksten Kühleffekt in der Anlaufphase auf, wenn also die Gefahr der Kolbenfresser am größten ist, weil in dieser Phase seine Temperatur in etwa der umgebenden Raumtemperatur entspricht. Obwohl bei fortdauerndem Betrieb der Axialkolbenmaschine das Leckfluid im Leckraum auf höhere Temperaturen erwärmt wird, reicht sein Kühleffekt aufgrund des dem Druckunterschied entsprechenden Temperaturunterschiedes gegenüber dem im Arbeitskreislauf unter Hochdruck stehenden Fluid aus, der durch die inzwischen eingesetzte Kolbenschmierung erheblich verringerten Gefahr der Kolbenfresser zu begegnen.Instead of the principle of known hydrostatic relief and lubrication of the prior art The solution according to the invention is based on the principle of cooling the piston critical points of metallic contact between the piston and cylinder and can thus not only in oil-operated axial piston machines, but also in those are used, which are intended for operation with a non-lubricating fluid are. This cooling takes place by means of a cooling circuit which is connected to the leakage space connected, that is, completely separate from the working circuit of the axial piston machine is and in this way does not affect their efficiency. The leakage fluid in the Leakage has its strongest cooling effect in the start-up phase, if so Risk of piston seizure is greatest because in this phase its temperature is roughly corresponds to the ambient room temperature. Although continued operation of the Axial piston machine heats the leakage fluid in the leakage space to higher temperatures its cooling effect is sufficient due to the pressure difference Temperature difference compared to that in the working circuit under high pressure outstanding fluid, which is considerable due to the piston lubrication used in the meantime counter the reduced risk of piston seizures.

In diesem Zusammenhang ist es möglich, eine Kühleinrichtung zum Kühlen des Leckfluids im Kühlkreislauf vorzusehen. Diese Kühleinrichtung kann in Form eines weiteren Leckfluid-Aufnahmeraums in einem an das Gehäuse angesetzten, Druck- und Saugkanal der Axialkolbenmaschine enthaltenden Anschlußblock ausgebildet sein.In this context, it is possible to use a cooling device for cooling the Provide leakage fluids in the cooling circuit. This cooling device can be in the form of a another leakage fluid receiving space in a pressure and attached to the housing Suction channel of the connecting block containing the axial piston machine.

Die Kühlbereiche sind vorzugsweise als Ringräume ausgebildet, die die Zylinder mit geringem radialen Abstand umgeben. Bei Axialkolbenmaschinen, die mit Öl betrieben werden, ist es vorteilhaft, die Kühlbereiche als Ringnuten in den Zylinderwandungen auszubilden, so daß das Lecköl nicht nur zur Kühlung, sondern gleichzeitig auch zur zusätzlichen Schmierung der Kolben dient. Die Anordnung und die Anzahl der Ringräume bzw. Ringnuten kann auf die jeweiligen Einsatzbedingungen der Axialkolbenmaschine abgestimmt werden. So kann es bei Axialkolbenmaschinen mit geringer Leistung ausreichend sein, jedem Zylinder einen einzigen Kühlbereich, vorzugsweise in dem der Hubscheibe zugewandten Endbereich der Zylindertrommel, zuzuordnen. An diesen oberen Kühlbereich kann im Falle des Ringkanals ein Verteilerkanal und im Falle der Ringnut eine Verteilernut angeschlossen sein, die den zugeordneten Zylinder im wesentlichen spiralförmig umgibt und an der der Hubscheibe zugewandten Stirnseite der Zylindertrommel ausmündet. Statt des erwähnten oberen Kühlbereichs kann auch ein unterer Kühlbereich verwendet werden, der im Bereich der Zylindertrommel oberhalb des Kolbenbodens bei unterer Totpunktlage des Kolbens ausgebildet ist.The cooling areas are preferably designed as annular spaces that the cylinders with surrounded by a small radial distance. For axial piston machines that run on oil it is advantageous to use the cooling areas as annular grooves in the cylinder walls form, so that the leak oil not only for cooling, but also for additional lubrication of the pistons. The arrangement and number of Annular spaces or annular grooves can depend on the respective conditions of use Axial piston machine can be matched. So it can with axial piston machines low performance, each cylinder has a single cooling area, preferably in the end region of the cylinder drum facing the lifting disk, assign. In the case of the ring channel, one can access this upper cooling area Distribution channel and in the case of the annular groove, a distributor groove connected to the associated cylinder surrounds substantially in a spiral and on the of the lifting disc facing end of the cylinder drum opens out. Instead of the above A lower cooling area can also be used, which is in the area of the cooling area Cylinder drum above the piston crown with the piston at the bottom dead center is trained.

Bei Axialkolbenmaschinen höherer und höchster Leistung sind vorzugsweise wenigstens ein oberer und ein unterer Kühlbereich vorgesehen, die durch einen Verteilerkanal bzw. einer Verteilernut miteinander verbunden sein können. In diesem Fall kann die Leckölströmung durch einen in einen der Kühlbereiche einmündenden Zulaufkanal und einen aus dem jeweils anderen Kühlbereich ausmündenden Ablaufkanal aufrechterhalten werden.In the case of axial piston machines of higher and highest performance, at least preferably an upper and a lower cooling area are provided, which are separated by a distribution channel or a distributor groove can be connected to each other. In this case, the Leakage oil flow through an inlet channel and into one of the cooling areas maintain a discharge channel opening out of the respective other cooling area will.

Weiterhin ist es vorteilhaft, den Saugkanal der Axialkolbenmaschine mit dem Kühlkreislauf über eine Dossel zu verbinden. Der über die Drossel erzwungene Zwangsfluß verbessert die Kühleigenschaften, da stets relativ kühles Öl aus dem Saugkanal nachströmt. Darüberhinaus ergibt sich eine Reduzierung der Druckpulsation im Saugraum und dadurch eine Verminderung der Betriebsgeräusche.It is also advantageous to use the suction channel of the axial piston machine Connect the cooling circuit via a dossel. The one forced over the throttle Forced flow improves the cooling properties because relatively cool oil from the Inflow channel flows. In addition, there is a reduction in pressure pulsation in the suction chamber and thereby a reduction in operating noise.

Weitere Vorteile und Merkmale der Erfindung ergeben sich aus den verbleibenden Unteransprüchen.Further advantages and features of the invention result from the remaining ones Subclaims.

Nachstehend ist die Erfindung anhand von vier Ausführungsbeispielen unter Bezugnahme auf die Zeichnung näher beschrieben. Es zeigen:

Figur 1
als erstes Ausführungsbeispiel eine Axialkolbenmaschine im Axialschnitt mit einem Kühlkreislauf zur Kühlung der Zylinder und Kolben in einer ersten Ausgestaltung;
Figur 2
als zweites Ausführungsbeispiel die Axialkolbenmaschine nach Figur 1 im Axialschnitt mit einem Kühlkreislauf in einer zweiten Ausgestaltung;
Figur 3
als drittes Ausführungsbeispiel die Axialkolbenmaschine nach Figur 1 im Axialschnitt mit einem Kühlkreislauf in einer dritten Ausgestaltung;
Figur 4
als viertes Ausführungsbeispiel die Axialkolbenmaschine nach Figur 1 im Axialschnitt mit einem Kühlkreislauf in einer vierten Ausgestaltung;
Figur 5
einen Axialschnitt in schematischer Darstellung entlang der Linie V - V in Figur 4, der die an den Kolben der Axialkolbenmaschine nach den Figuren 1 bis 4 wirkenden Kräfte zeigt;
Figur 6
als fünftes Ausführungsbeispiel die Axialkolbenmaschine nach Figur 1 im Axialschnitt mit einem Kühlkreislauf, der mittels einer Drossel mit dem Saugkanal verbunden ist.
The invention is described in more detail below using four exemplary embodiments with reference to the drawing. Show it:
Figure 1
as a first embodiment, an axial piston machine in axial section with a cooling circuit for cooling the cylinders and pistons in a first embodiment;
Figure 2
as a second embodiment, the axial piston machine according to Figure 1 in axial section with a cooling circuit in a second embodiment;
Figure 3
as a third embodiment, the axial piston machine according to Figure 1 in axial section with a cooling circuit in a third embodiment;
Figure 4
as a fourth embodiment, the axial piston machine according to FIG. 1 in axial section with a cooling circuit in a fourth embodiment;
Figure 5
an axial section in a schematic representation along the line V - V in Figure 4, showing the forces acting on the piston of the axial piston machine according to Figures 1 to 4;
Figure 6
as a fifth exemplary embodiment, the axial piston machine according to FIG. 1 in axial section with a cooling circuit which is connected to the suction channel by means of a throttle.

Die in den Figuren 1 bis 4 dargestellte Axialkolbenmaschine ist in Schrägscheibenbauweise mit verstellbarem Verdrängungsvolumen und einer Stromrichtung ausgeführt und umfaßt in bekannter Weise als wesentliche Bauteile ein hohlzylindrisches Gehäuse 1 mit einem stirnseitig offenen Ende (oberes Ende in Figur 1) einen am Gehäuse 1 befestigten, dessen offenes Ende verschließenden Anschlußblock 2, eine Hub- oder Schrägscheibe 3, einen Steuerkörper 4, eine Triebwelle 5, eine Zylindertrommel 6 und einen erfindungsgemäßen Kühlkreislauf 7.1 bis 7.4.The axial piston machine shown in Figures 1 to 4 is in Swashplate design with adjustable displacement and one Current direction executed and includes in a known manner as essential components hollow cylindrical housing 1 with an open end (upper end in Figure 1) attached to the housing 1, the open end closing Terminal block 2, a lifting or swash plate 3, a control body 4, a Drive shaft 5, a cylinder drum 6 and a cooling circuit 7.1 according to the invention until 7.4.

Die Schrägscheibe 3 ist als sogenannte Schwenkwiege mit halbzylindrischem Querschnitt (vergleiche Figur 5) ausgebildet und stützt sich mit zwei, mit gegenseitigem Abstand parallel zur Schwenkrichtung verlaufenden Lagerflächen unter hydrostatischer Entlastung an zwei entsprechend geformten Lagerschalen 8 ab, die an der Innenfläche der dem Anschlußblock 2 gegenüberliegenden Gehäuse-Stirnwand 9 befestigt sind. Die hydrostatische Entlastung erfolgt in bekannter Weise über Drucktaschen 10, die in den Lagerschalen 8 ausgebildet sind und über Anschlüsse 11 mit Druckmittel versorgt werden. Eine in einer Ausbuchtung der zylindrischen Gehäusewandung 12 untergebrachte Stelleinrichtung 13 greift über einen sich in Richtung des Anschlußblocks 2 erstreckenden Arm 14 der Schrägscheibe 3 an und dient zum Verschwenken derselben um eine zur Schwenkrichtung senkrechte Schwenkachse.The swash plate 3 is a so-called swivel cradle with a semi-cylindrical one Cross-section (see Figure 5) formed and supported with two, with mutual Distance parallel to the swivel direction bearing surfaces under hydrostatic Relief on two appropriately shaped bearing shells 8, which on the inner surface the housing end wall 9 opposite the connection block 2 are fastened. The hydrostatic discharge takes place in a known manner via pressure pockets 10, which in the Bearing shells 8 are formed and supplied with pressure medium via connections 11 will. One in a bulge in the cylindrical housing wall 12 accommodated actuator 13 engages in the direction of Terminal block 2 extending arm 14 of the swash plate 3 and is used for Swiveling the same about a swivel axis perpendicular to the swivel direction.

Der Steuerkörper 4 ist an der dem Gehäuse-Innenraum zugewandten Innenfläche des Anschlußblocks 2 befestigt und mit zwei durchgehenden Öffnungen 15 in Form von nierenförmigen Steuerschlitzen versehen, die über einen Druckkanal 16D bzw. Saugkanal 16S im Anschlußblock 2 an eine nicht gezeigte Druck- und Saugleitung angeschlossen sind. Der Druckkanal 16D weist einen kleineren Strömungsquerschnitt als der Saugkanal 16S auf. Die dem Gehäuse-Innenraum zugewandte und sphärisch ausgebildete Steuerfläche des Steuerkörpers 4 dient als Lagerfläche für die Zylindertrommel 6.The control body 4 is on the inner surface of the housing interior facing the Terminal blocks 2 attached and with two through openings 15 in the form of kidney-shaped control slots which are connected via a pressure channel 16D or Suction channel 16S in the connection block 2 to a pressure and suction line, not shown are connected. The pressure channel 16D has a smaller flow cross section than the suction channel 16S. The spherical facing the interior of the housing Trained control surface of the control body 4 serves as a bearing surface for the Cylinder drum 6.

Die Triebwelle 5 ragt durch eine Durchgangsbohrung in der Gehäuse-Stirnwand 9 in das Gehäuse 1 hinein und ist mittels eines Lagers 17 in dieser Durchgangsbohrung sowie mittels eines weiteren Lagers 18 in einem engeren Bohrungsabschnitt einer endseitig erweiterten Sackbohrung 19 im Anschlußblock 2 und einem an diesen engeren Bohrungsabschnitt angrenzenden Bereich einer zentrischen Durchgangsbohrung 20 im Steuerkörper 4 drehbar gelagert. Die Triebwelle 5 durchsetzt im Inneren des Gehäuses weiterhin eine zentrische Durchgangsbohrung 21 in der Schrägscheibe 3, deren Durchmesser entsprechend dem größten Schwenkausschlag der Schrägscheibe 3 bemessen ist, sowie eine zentrische Durchgangsbohrung in der Zylindertrommel 6 mit zwei Bohrungsabschnitten.The drive shaft 5 protrudes through a through hole in the housing end wall 9 in the housing 1 and is in this through hole by means of a bearing 17 and by means of a further bearing 18 in a narrower bore section blind bore 19 at the end in the connection block 2 and one closer to it Bore section adjacent region of a central through hole 20 in Control body 4 rotatably mounted. The drive shaft 5 penetrates inside the Housing also a central through hole 21 in the swash plate 3, whose diameter corresponds to the largest swash deflection of the swash plate 3 is dimensioned, as well as a central through bore in the cylinder drum 6 two hole sections.

Einer dieser Bohrungsabschnitte ist in einer an der Zylindertrommel 6 angeformten, über deren der Schrägscheibe 3 zugewandte Stirnseite 22 hinausragenden hülsenförmigen Verlängerung 23 ausgebildet, über die die Zylindertrommel 6 mittels einer Keilnut-Verbindung 24 drehfest mit der Triebwelle 5 verbunden ist. Der verbleibende Bohrungsabschnitt ist mit konischem Verlauf ausgebildet; er verjüngt sich ausgehend von seinem Querschnitt größten Durchmessers nahe dem ersten Bohrungsabschnitt bis zu seinem Querschnitt kleinstem Durchmessers nahe der am Steuerkörper 4 anliegenden Stirn- oder Lagerfläche der Zylindertrommel 6. Der von der Triebwelle 5 und diesem konischen Bohrungsabschnitt definierte ringförmige Raum ist mit dem Bezugszeichen 25 bezeichnet.One of these bore sections is formed on a cylinder drum 6, projecting beyond the end face 22 facing the swash plate 3 sleeve-shaped extension 23, via which the cylinder drum 6 by means of a keyway connection 24 is rotatably connected to the drive shaft 5. Of the remaining bore section is conical; it tapers based on its cross section of largest diameter close to the first Bore section up to its cross section of smallest diameter close to the Control body 4 adjacent end face or bearing surface of the cylinder drum 6. The of the Drive shaft 5 and this conical bore section is defined annular space designated by the reference numeral 25.

Die Zylindertrommel 6 weist allgemein axial verlaufende, abgestufte Zylinderbohrungen 26 auf, die gleichmäßig auf einem zur Triebwellenachse koaxialen Teilkreis angeordnet sind, an der Zylindertrommel-Stirnseite 22 direkt und an der dem Steuerkörper 4 zugewandten Zylindertrommel-Lagerfläche über Mündungskanäle 27 auf dem gleichen Teilkreis wie die Steuerschlitze ausmünden. In die an der Zylindertrommel-Stirnseite 22 direkt ausmündenden Zylinderbohrungsabschnitte größeren Durchmessers ist je eine Laufbuchse 28 eingesetzt. Die Zylinderbohrungen 26 einschließlich der Laufbuchsen 28 sind hier als Zylinder bezeichnet. Innerhalb dieser Zylinder 26, 28 verschiebbar angeordnete Kolben 29 sind an ihren der Schrägscheibe 3 zugewandten Enden mit Kugelköpfen 30 versehen, die in Gleitschuhen 31 gelagert und über diese an einer an der Schrägscheibe 5 befestigten ringförmigen Gleitscheibe 32 hydrostatisch gelagert sind. Jeder Gleitschuh 31 ist an seiner der Gleitscheibe 32 zugewandten Gleitfläche mit je einer nicht gezeigten Drucktasche versehen, die über einer Durchgangsbohrung 33 im Gleitschuh 31 an einen abgestuften axialen Durchgangskanal 34 im Kolben 29 angeschlossen und auf diese Weise mit dem vom Kolben 29 in der Zylinderbohrung 26 abgegrenzten Arbeitsraum des Zylinders verbunden ist. In jedem axialen Durchgangskanal 34 ist im Bereich des zugeordneten Kugelkopfes 30 eine Drossel ausgebildet. Ein mittels der Keilnut-Verbindung 24 axial verschiebbar auf der Triebwelle 5 angeordneter und durch eine Feder 35 in Richtung der Schrägscheibe 3 beaufschlagter Niederhalter 36 hält die Gleitschuhe 31 in Anlage an die Gleitscheibe 32.The cylinder drum 6 has generally axially extending, stepped Cylinder bores 26 which are even on a coaxial to the drive shaft axis Pitch circle are arranged on the cylinder drum end face 22 directly and on the Control body 4 facing cylinder drum bearing surface via outlet channels 27 open out in the same pitch circle as the control slots. In the on the Cylinder drum end face 22 directly opening cylinder bore sections a larger diameter, a bushing 28 is used. The cylinder bores 26 including the bushings 28 are referred to here as cylinders. Within this Cylinders 26, 28 are displaceably arranged pistons 29 on their swash plate 3 facing ends with ball heads 30 which are mounted in sliding shoes 31 and via this to an annular slide disk 32 fastened to the swash plate 5 are stored hydrostatically. Each slide shoe 31 is on its slide plate 32 facing sliding surface with a pressure pocket, not shown, which over a through hole 33 in the shoe 31 to a stepped axial Through channel 34 connected in the piston 29 and in this way with the Piston 29 in the cylinder bore 26 delimited working space of the cylinder connected is. In each axial through channel 34 is in the area of the associated Ball head 30 formed a throttle. One axially by means of the keyway connection 24 slidably arranged on the drive shaft 5 and by a spring 35 in the direction the swash plate 3 pressurized hold-down 36 stops the sliding shoes 31 in contact the sliding washer 32.

Der im Gehäuse-Innenraum von den darin aufgenommenen Bauteilen 3 bis 6 etc. nicht eingenommene Raum dient als Leckraum 37, der das im Betrieb der Axialkolbenmaschine durch sämtliche Spalte, wie zum Beispiel zwischen den Zylindern 26, 28 und den Kolben 29, dem Steuerkörper 4 und der Zylindertrommel 6, der Schrägscheibe 3 und der Gleitscheibe 32 sowie den Lagerschalen 8 etc., austretende Leckfluid aufnimmt.The one in the interior of the housing of the components 3 to 6 etc. contained therein The space taken up serves as a leakage space 37 which is used in the operation of the Axial piston machine through all gaps, such as between the Cylinders 26, 28 and the piston 29, the control body 4 and the cylinder drum 6, the swash plate 3 and the sliding plate 32 and the bearing shells 8, etc., emerging Leakage fluid picks up.

Die Funktion der vorstehend beschriebenen Axialkolbenmaschine ist allgemein bekannt und in nachstehender Beschreibung bei Einsatz als Pumpe auf das wesentliche beschränkt.The function of the axial piston machine described above is generally known and in the description below when used as a pump to the essentials limited.

Die Axialkolbenmaschine ist für den Betrieb mit Öl als Fluid vorgesehen. Über die Triebwelle 5 wird die Zylindertrommel 6 mitsamt den Kolben 29 in Drehung versetzt. Wenn durch Betätigung der Stelleinrichtung 13 die Schrägscheibe 3 in eine Schrägstellung (vergleiche Figur 5) gegenüber der Zylindertrommel 6 verschwenkt ist, so vollführen sämtliche Kolben 29 Hubbewegungen; bei Drehung der Zylindertrommel 6 um 360° durchläuft jeder Kolben 29 einen Saug- und einen Kompressionshub, wobei entsprechende Ölströme erzeugt werden, deren Zu- und Abführung über die Mündungskanäle 27, die Steuerschlitze 15 und den Druck- und Saugkanal 16D, 16S erfolgen. Dabei läuft während des Kompressionshubs jedes Kolbens 29 Drucköl von dem betreffenden Zylinder 26, 28 über den axialen Durchgangskanal 34 und die Durchgangsbohrung 33 im zugeordneten Gleitschuh 31 in dessen Drucktasche und baut ein Druckfeld zwischen der Gleitscheibe 32 und dem jeweiligen Gleitschuh 31 auf, das als hydrostatisches Lager für letzteren dient. Ferner wird Drucköl über die Anschlüsse 11 den Drucktaschen 10 in den Lagerschalen 8 zur hydrostatischen Abstützung der Schrägscheibe 3 zugeführt. The axial piston machine is designed for operation with oil as a fluid. About the Drive shaft 5, the cylinder drum 6 together with the piston 29 is rotated. If the swash plate 3 in a by actuating the actuator 13 Inclination (see FIG. 5) is pivoted relative to the cylinder drum 6, so all pistons perform 29 strokes; when rotating the Cylinder drum 6 through 360 °, each piston 29 passes through a suction and one Compression stroke, whereby corresponding oil flows are generated, their inflow and Dissipation via the mouth channels 27, the control slots 15 and the pressure and Suction channel 16D, 16S. Each runs during the compression stroke Piston 29 pressure oil from the relevant cylinder 26, 28 via the axial Through channel 34 and the through hole 33 in the associated slide shoe 31 in whose pressure pocket and builds a pressure field between the sliding washer 32 and the respective slide shoe 31, which serves as a hydrostatic bearing for the latter. Further is pressure oil via the connections 11 to the pressure pockets 10 in the bearing shells 8 hydrostatic support of the swash plate 3 supplied.

Während des Kompressionshubs wird von der Schrägscheibe 3 auf jeden Gleitschuh 31 eine Normalkraft Fn ausgeübt, die bei vernachlässigbare Reibung auf der Schrägscheibe 3 senkrecht steht. Diese Normalkraft wird im Kugelkolben 30 in eine Kolbenkraft Fk und eine Radial- oder Querkraft Fq zerlegt. Die Querkraft Fq wirkt im Kugelkopf 30 auf den Kolben 29 wie auf einen in der Zylindertrommel 6 eingespannten Balken, was die in Figur 5 eingezeichneten, mit entsprechendem Wirkabstand entgegengesetzt gerichteten axialen Reaktionskräfte Fr hervorruft. Dadurch gelangt der Kolben 29 in metallische Berührung mit der Laufbuchse 28, wobei sehr hohe Flächenpressungen auftreten können, die die Ursache für entsprechend hohe Reibkräfte und damit Erwärmung an den Berührungsstellen sind. Dies kann bei herkömmlichen Axialkolbenmaschinen ohne den erfindungsgemäßen Kühlkreislauf 7.1 1 bis 7.4 insbesondere während der Anlaufphase, bei der noch keine ausreichende Kolbenschmierung durch das Drucköl in den Zylindern 26, 28 vorhanden ist, zum Fressen der Kolben 29 und damit zu entsprechenden Beschädigungen derselben und der Zylinder 26, 28 führen.During the compression stroke, the swash plate 3 exerts a normal force F n on each slide shoe 31, which is perpendicular to the swash plate 3 with negligible friction. This normal force is broken down into a piston force F k and a radial or transverse force F q in the spherical piston 30. The transverse force F q acts in the ball head 30 on the piston 29 as on a beam clamped in the cylinder drum 6, which causes the axial reaction forces F r shown in FIG. As a result, the piston 29 comes into metallic contact with the liner 28, and very high surface pressures can occur, which are the cause of correspondingly high frictional forces and thus heating at the contact points. In conventional axial piston machines without the cooling circuit 7.1 1 to 7.4 according to the invention, in particular during the start-up phase, in which there is still insufficient piston lubrication by the pressure oil in the cylinders 26, 28, to eat the pistons 29 and thus to damage them and the cylinders 26, 28 lead.

Der erfindungsgemäße Kühlkreislauf 7.1 bis 7.4 ist an den Leckraum 37 angeschlossen und umfaßt den konischen Ringraum 25 (sogenannter Leckfluid-Aufnahmeraum), die Durchgangsbohrung 20 im Steuerkörper 4, die Sackbohrung 19 (sogenannter weiterer Leckfluid-Aufnahmeraum), eine diesen mit dem Leckraum 37 verbindende Anschlußleitung 38, die in einer umlaufenden Rinne 39 in der Innenfläche des Anschlußblocks 2 ausmündet, sowie den Zylindern 26, 28 umlaufend zugeordnete Kühlbereiche, die über Zulaufkanäle 40 an den konischen Ringraum 25 angeschlossen sind und über Ablaufkanäle 41 an der zylindrischen Begrenzungsfläche 42 der Zylindertrommel 6 in den Leckraum 37 ausmünden. Sämtliche Zulaufkanäle 40 münden in den konischen Ringraum 25 an dessen Querschnitt größten Durchmessers ein und verlaufen ebenso wie sämtliche Ablaufkanäle 41 im wesentlichen radial durch die Zylindertrommel 6.The cooling circuit 7.1 to 7.4 according to the invention is connected to the leakage space 37 and includes the conical annulus 25 (so-called leakage fluid receiving space), the Through hole 20 in the control body 4, the blind hole 19 (so-called further Leakage fluid receiving space), a connecting this with the leakage space 37 Connection line 38, which is in a circumferential groove 39 in the inner surface of the Terminal block 2 opens out, as well as the cylinders 26, 28 all around Cooling areas connected to the conical annular space 25 via inlet channels 40 are and via drainage channels 41 on the cylindrical boundary surface 42 of the Open cylinder drum 6 into leakage space 37. All inlet channels 40 open in the conical annular space 25 at its cross-section of the largest diameter and Like all drainage channels 41, they run essentially radially through the Cylinder drum 6.

In der Ausgestaltung nach Figur 1 ist jedem Zylinder 26, 28 ein Kühlbereich in Form eines Ringraumes 43 zugeordnet, der als umlaufende Nut in der Wandung des Zylinderbohrungs-Abschnitts größeren Durchmessers ausgebildet und von der Laufbuchse28 abgedeckt ist. Der Ringraum 43 erstreckt sich von nahe dem Ausmündungsbereich der Zylinderbohrung 26 über etwa zwei Drittel der Länge derselben in Richtung der Mündungskanäle27 und stellt somit einen der oberen Totpunktlage des Kolbens 29 zugeordneten oberen Kühlbereich dar. Je ein Zulaufkanal 40 und ein Ablaufkanal 41 münden etwa mittig in den Ringraum 43 ein und verlaufen koaxial zueinander.In the embodiment according to FIG. 1, each cylinder 26, 28 is in the form of a cooling area an annular space 43 assigned as a circumferential groove in the wall of the Cylinder bore section of larger diameter and formed by the Liner 28 is covered. The annular space 43 extends from near Mouth area of the cylinder bore 26 over about two thirds of the length the same in the direction of the mouth channels 27 and thus represents one of the upper Dead center position of the piston 29 associated upper cooling area. One each Inlet channel 40 and an outlet channel 41 open approximately centrally in the annular space 43 and run coaxially with each other.

Die im Betrieb der Axialkolbenmaschine bei Drehung der Triebwelle 5 und der Zylindertrommel 6 auftretenden Zentrifugalkräfte setzen das im Ringraum 25 befindliche Lecköl unter einen geringen Überdruck, der eine Leckölströmung über die Zulaufkanäle 40, die Ringräume 43 und die Ablaufkanäle 41 zum Leckraum 37 und von diesem aus über die Anschlußleitung 38, die Sackbohrung 19 und die Durchgangsbohrung 20 zurück in den Ringraum 25 verursacht. Dabei wird die Geschwindigkeitsenergie des strömenden Lecköls in dem sich in Strömungsrichtung erweiternden und dadurch eine Diffusorwirkung aufweisenden Ringraum 25 in Druck umgewandelt, die die Strömungsgeschwindigkeit im Kühlkreislauf 7.1 erhöht. Die insbesondere beim Ausschwenken der Axialkolbenpumpe auf größtes Fördervolumen (entsprechend der größten Schrägstellung der Schrägscheibe 3) durch die entsprechend hohen Reaktionskräfte Fr erzeugte Wärme wird zum erheblichen Teil durch das in den Ringräumen 43 um die Laufbuchsen 28 strömende Lecköl in den Leckraum 37 abtransportiert. Da dem Druckunterschied von maximal nahezu 400 bar zwischen dem von der Axialkolbenmaschine geförderten, unter Hochdruck stehenden Drucköl und dem Lecköl im Leckraum 37 ein Temperaturunterschied von etwa 7°C pro 100 bar 1 entspricht, werden die kritischen Stellen der metallischen Berührung zwischen den Kolben 29 und den Laufbuchsen 28 effektiv gekühlt und somit das Fressen der Kolben 29 verhindert. Bei fortdauerndem Betrieb der Axialkolbenmaschine wird das sich erwärmende Lecköl im Leckraum 37 beim Durchströmen der Sackbohrung 19 im Anschlußblock 2 gekühlt, da dieser der Raumtemperatur ausgesetzt und somit kühler als das Lecköl im Leckraum 37 ist. Durch entsprechende Ausbildung des Anschlußblocks 2 und der Sackbohrung 19 sowie gegebenenfalls zusätzliche Kühlung derselben durch ein separates Kühlmittel kann das Lecköl im Kühlkreislauf 7.1 auf entsprechend niedrigen Temperaturen gehalten werden. Der Kühlkreislauf 7.1 dient wegen fehlender Verbindung mit den Zylindern 26, 28 (aufgrund der geschlossenen Ringräume 43) ausschließlich als Kühlkreislauf. Da die vorbeschriebene Axialkolbenmaschine für den Betrieb mit Öl vorgesehen ist, kann der Kühlkreislauf 7.1 zusätzlich eine Schmierfunktion übernehmen, wenn beispielsweise die Ringräume 43 über entsprechende Bohrungen durch die Laufbuchsen 28 mit den Zylindern 26, 28 in Verbindung stehen. Die mit dem Kühlkreislauf 7.1 ausgerüstete Axialkolbenmaschine ist aufgrund der Anordnung der Ringräume 43 im Ausmündungsbereich der Zylinder 26, 28 für mittlere Leistungen ausgelegt. The centrifugal forces that occur during operation of the axial piston machine when the drive shaft 5 and the cylinder drum 6 rotate place the leakage oil in the annular space 25 under a slight overpressure, which causes a leakage oil flow via the inlet channels 40, the annular spaces 43 and the outlet channels 41 to the leakage space 37 and from there caused via the connecting line 38, the blind hole 19 and the through hole 20 back into the annular space 25. The speed energy of the flowing leakage oil is converted into pressure in the annular space 25, which widens in the direction of flow and thereby has a diffuser effect, which increases the flow speed in the cooling circuit 7.1. The heat generated in particular when the axial piston pump is swung out to the largest delivery volume (corresponding to the largest inclined position of the swash plate 3) by the correspondingly high reaction forces F r is largely transported into the leakage space 37 by the leakage oil flowing in the annular spaces 43 around the bushings 28. Since the pressure difference of a maximum of almost 400 bar between the high-pressure oil delivered by the axial piston machine and the leak oil in the leakage space 37 corresponds to a temperature difference of about 7 ° C per 100 bar 1, the critical points of the metallic contact between the pistons 29 and the bushings 28 effectively cooled and thus prevents the pistons 29 from seizing. During continuous operation of the axial piston machine, the heating leakage oil in the leakage space 37 is cooled as it flows through the blind bore 19 in the connection block 2, since this is exposed to the room temperature and is therefore cooler than the leakage oil in the leakage space 37. The leakage oil in the cooling circuit 7.1 can be kept at correspondingly low temperatures by appropriately designing the connection block 2 and the blind bore 19 and, if appropriate, additionally cooling them by means of a separate coolant. The cooling circuit 7.1 serves only as a cooling circuit due to the lack of connection to the cylinders 26, 28 (due to the closed annular spaces 43). Since the above-described axial piston machine is intended for operation with oil, the cooling circuit 7.1 can additionally assume a lubricating function if, for example, the annular spaces 43 are connected to the cylinders 26, 28 via corresponding bores through the bushings 28. The axial piston machine equipped with the cooling circuit 7.1 is designed for medium outputs due to the arrangement of the annular spaces 43 in the mouth area of the cylinders 26, 28.

Der Kühlkreislauf 7.2 nach Figur 2 unterscheidet sich bei ansonsten gleicher Konstruktion und Kühlfunktion von demjenigen nach Figur 1 dadurch, daß seine Kühlbereiche die Form von Ringnuten 44 aufweisen, die in den Laufbuchsen 28 ausgebildet und zum Inneren der Zylinder 26, 28 hin offen sind. Die mit dem Kühlkreislauf 7.2 ausgerüstete Axialkolbenmaschine ist aufgrund der im Vergleich zu den Ringräumen 43 geringeren axialen Breite der Ringnuten 44 für geringere Leistungen als die Axialkolbenmaschine nach Figur 1 ausgelegt und übernimmt gleichzeitig eine zusätzliche Schmierung der Kolben 29.The cooling circuit 7.2 according to FIG. 2 differs in otherwise the same Construction and cooling function of that of Figure 1 in that its Cooling areas have the shape of annular grooves 44 which are in the bushings 28 formed and open to the interior of the cylinders 26, 28. The one with the Cooling circuit 7.2 equipped axial piston machine is due to the compared to the annular spaces 43 smaller axial width of the annular grooves 44 for smaller Services designed and performed as the axial piston machine according to Figure 1 at the same time additional lubrication of the pistons 29.

Der Kühlkreislauf 7.3 nach Figur 3 unterscheidet sich bei ansonsten gleicher Konstruktion und Funktion von demjenigen nach Figur 2 dadurch, daß an jede Ringnut 44 eine Verteilernut 45 angeschlossen ist, die in der Laufbuchse28, diese spiralförmig umgebend, ausgebildet ist und an der Stirnseite 22 der Zylindertrommel 6 ausmündet. Der Wirkungsbereich der Ringnuten 44 hinsichtlich der Kühlung und Schmierung wird durch das aus ihnen über die Verteilernuten 45 in den Leckraum 37 strömende Lecköl bis zur Ausmündung der Zylinder 26, 28 erweitert.The cooling circuit 7.3 according to FIG. 3 differs in otherwise the same Construction and function of that of Figure 2 in that each Annular groove 44 is connected to a distributor groove 45 which is in the bushing 28 spirally surrounding, is formed and on the end face 22 of the cylinder drum 6 flows out. The area of action of the ring grooves 44 with regard to cooling and Lubrication is made from them via the distributor grooves 45 into the leakage space 37 flowing leakage oil up to the mouth of the cylinders 26, 28 expanded.

Der Kühlkreislauf 7.4 nach Figur4 umfaßt je Zylinder 26, 28 den in Figur 1 dargestellten oberen Ringraum 43, allerdings mit geringerer axialer Breite, und einen weiteren, unteren Ringraum 46 gleicher Abmessungen, der im unteren Endbereich der Laufbuchse 28, das heißt im Bereich des Zylinders 26, 28 oberhalb des Kolbenbodens 47 bei unterer Totpunktlage des Kolbens 29 ausgebildet ist. An den oberen Ringraum 43 ist ein Zulaufkanal 40 und an den unteren Ringraum 46 ein Ablaufkanal 41 angeschlossen. Zur Aufrechterhaltung der Leckölströmung ist ein Verteilerkanal 48 vorgesehen, der die beiden Ringräume 43, 46 miteinander verbindet. Der Kühlkreislauf 7.4 nach Figur 4 steht ebenso wie derjenige nach Figur 1 nicht in Verbindung mit den Zylindern 26, 28 und hat somit lediglich die Funktion einer Kühlung. Da diese Kühlung an den beiden kritischen Stellen metallischer Berührung zwischen Kolben 29 und Laufbuchse28 sowie dem dazwischenliegenden Bereich erfolgt, ist der Kühlkreislauf 7.4 für Axialkolbenmaschinen sehr hoher Leistung vorgesehen. Dieser Kühlkreislauf kann für Axialkolbenmaschinen höchster Leistung Verwendung finden, wenn die Ringräume 43, 46 und gegebenenfalls der Verteilerkanal 48 über entsprechende Bohrungen durch die Laufbuchsen 28 mit den Zylindern 26, 28 in Verbindung stehen. Der gleiche Effekt wird erzielt, wenn die Ringräume 43, 46, der Verteilerkanal 48 und die genannten Bohrungen durch Ringnuten und Verteilernuten nach Figur 3 ersetzt werden. The cooling circuit 7.4 according to FIG. 4 comprises the one in FIG. 1 for each cylinder 26, 28 shown upper annular space 43, but with a smaller axial width, and one another, lower annular space 46 of the same dimensions, which in the lower end region of the Liner 28, that is in the region of the cylinder 26, 28 above the Piston base 47 is formed at the bottom dead center position of the piston 29. To the upper annular space 43 is an inlet channel 40 and to the lower annular space 46 Drain channel 41 connected. To maintain the leakage oil flow is a Distribution channel 48 is provided, which connects the two annular spaces 43, 46 together. The cooling circuit 7.4 according to FIG. 4, like that according to FIG. 1, is not shown in FIG Connection with the cylinders 26, 28 and thus has only the function of a Cooling. Because this cooling at the two critical points of metallic contact between piston 29 and bushing 28 and the area in between takes place, the cooling circuit 7.4 is very high performance for axial piston machines intended. This cooling circuit can be used for high performance axial piston machines Find use when the annular spaces 43, 46 and possibly the Distribution channel 48 through corresponding holes through the bushings 28 with the Cylinders 26, 28 are connected. The same effect is achieved if the Annuli 43, 46, the distribution channel 48 and the holes mentioned Ring grooves and distributor grooves according to Figure 3 are replaced.

Figur 6 zeigt den bereits in Figur 1 dargestellten Kühlkreislauf 7.1. Jedoch unterscheidet sich das in Figur 6 dargestellte Ausführungsbeispiel von demjenigen nach Figur 1 dadurch, daß zwischen dem Saugkanal 16S und der Sackbohrung 19 eine Durchgangsbohrung 51 vorgesehen ist, die den Saugkanal 16S der Axialkolbenmaschine mit dem Kühlkreislauf 7.1 verbindet. In der Bohrung 51 ist eine Antipulsationsdrossel 50 angeordnet. Über die Antipulsationsdrossel 50 fließt das unter einer Vorkompression stehende Fluid des Saugkanals 16S in den Kühlkreislauf 7.1 ein, wodurch Leckverluste ausgeglichen werden. Durch das über die Drossel 50 nachströmende Fluid wird ein gewisser Zwangsfluß in dem Kühlkreislauf 7.1 erreicht, wodurch die Kühleigenschaften des Kühlkreislaufes verbessert werden. Darüberhinaus wird durch den Zufluß des niedriger temperierten Fluids aus dem Saugkanal 16S eine effektive Kühlung des im Kühlkreislauf 7.1 umgewälzten Fluids erreicht. Als weiterer Vorteil ergibt sich durch den Einsatz der Antipulsationsdrossel 50 eine Reduzierung der Druckpulsation im Saugkanal 16S, was zu einer erheblichen Verminderung der Betriebsgeräusche führt.FIG. 6 shows the cooling circuit 7.1 already shown in FIG. 1. However the embodiment shown in Figure 6 differs from that Figure 1 in that between the suction channel 16S and the blind bore 19 a Through bore 51 is provided, the suction channel 16S of the axial piston machine connects to the cooling circuit 7.1. In the bore 51 is an anti-pulsation throttle 50 arranged. This flows under pre-compression via the anti-pulsation throttle 50 standing fluid of the suction channel 16S in the cooling circuit 7.1, causing leakage be balanced. The fluid flowing in via the throttle 50 causes a certain forced flow in the cooling circuit 7.1 reached, whereby the cooling properties of the cooling circuit can be improved. In addition, the inflow of lower temperature fluids from the suction channel 16S effective cooling of the im Cooling circuit 7.1 circulated fluid reached. Another advantage results from the use of the anti-pulsation throttle 50 reduces the pressure pulsation in the Suction channel 16S, which leads to a significant reduction in operating noise.

Der Zufluß aus dem Saugkanal 16S kann an verschiedenen Stellen der Axialkolbenmaschine angeordnet sein und in verschiedene Bereiche des Kühlkreislaufes einmünden. Besonderes vorteilhaft ist jedoch die Anordnung der Drossel 50 in dem Anschlußblock 2, wo sie zwischen der Sackbohrung 19 und dem Saugkanal 16S in einfacher Weise integriert werden kann.The inflow from the suction channel 16S can at various points in the Axial piston machine can be arranged and in different areas of the cooling circuit flow into. However, the arrangement of the throttle 50 in the is particularly advantageous Terminal block 2, where it between the blind bore 19 and the suction channel 16S in can be easily integrated.

Selbstverständlich kann die in Figur 6 dargestellte Antipulsationsdrossel 50 auch bei den anhand der Figuren 2 bis 4 vorstehend beschriebenen Ausführungsbeispielen ohne weiteres zum Einsatz kommen.Of course, the anti-pulsation throttle 50 shown in FIG based on Figures 2 to 4 embodiments described above without more are used.

Die vorgenannten Ausgestaltungen der Kühlbereiche sind beispielhaft und können in Anpassung an die jeweiligen Einsatzbedingungen geändert werden. So ist es beispielsweise möglich, im Kühlkreislauf nach Figur 4 beide Ringräume bzw. Ringnuten an je einen Zulaufkanal und einen Ablaufkanal anzuschließen und den Verteilerkanal bzw. die Verteilernut wegzulassen.The aforementioned configurations of the cooling areas are exemplary and can be seen in Adaptation to the respective operating conditions can be changed. That's the way it is for example possible, in the cooling circuit according to FIG. 4, both annular spaces or To connect ring grooves to an inlet channel and an outlet channel each and the Omit the distributor channel or the distributor groove.

Die Erfindung kann auch in Schrägachsenmaschinen verwirklicht werden, da auch hier die Kolben in den Zylindern verkantende Radialkräfte auftreten können, und zwar aufgrund einer Schrägstellung der Kolben bzw. Kolbenstangen als Folge von Abweichungen zwischen dem als Ellipse erscheinenden Teilkreis der Kugelsitze in der Triebscheibe und dem Teilkreis der Zylinder.The invention can also be implemented in inclined axis machines, since here too radial forces that jam the pistons in the cylinders can occur due to an inclined position of the pistons or piston rods as a result of Deviations between the part circle of the spherical seats in the Drive pulley and the pitch circle of the cylinder.

Claims (15)

  1. Axial piston machine having a housing (1) the interior housing chamber of which includes a leakage chamber (37) and accommodates a swash plate (3) and a rotatably mounted cylinder drum (6) having cylinders (26, 28) and pistons (29) reciprocally movable in the cylinders, the ends of which pistons projecting out of the cylinders (26, 28) bear on the swash plate (3), a leakage fluid receiving chamber (25) being formed in the part of the cylinder drum (6) surrounded by the cylinders (26, 28), and there being formed in the cylinder drum (6) supply and discharge channels (40, 41) which run through the cylinder drum (6) with at least a radial component,
    characterised by
    a connection line (38) connecting the leakage fluid receiving chamber (25) with the leakage chamber (37) to form a cooling circuit (7.1 to 7.4),
    cooling regions (43, 44, 46) associated to surround the cylinders (26, 28) for cooling the cylinders, which cooling regions are connected via the supply channels (40) belonging to the cooling circuit (7.1 to 7.4) to the leakage fluid receiving chamber (25) and open out via the discharge channels (41) belonging to the cooling circuit (7.1 to 7.4) at an outer bounding surface (42) of the cylinder drum (6) into the leakage chamber (37), and
    a cooling device (19) for cooling the leakage fluid in the cooling circuit (7.1 to 7.4).
  2. Axial piston machine according to claim 1, characterized in that the leakage fluid receiving chamber (25) widens in the manner of a diffusor in the flow direction up to the opening region of the supply channels (40) to the cooling regions (43, 44, 46).
  3. Axial piston machine according to claim 2, characterized in that the cooling device (19) is configured in the form of a further leakage fluid receiving chamber in a connection block (2) placed on the housing (1) and containing pressure and suction channels (16D, 16S) of the axial piston machine.
  4. Axial piston machine according to claim 2 or 3, characterized in that both leakage fluid receiving chambers (19, 25) run coaxially of one another and are connected with one another, and in that the cylinder drum (6) is arranged on a drive shaft (5) for rotation therewith, which drive shaft penetrates at least the leakage fluid receiving chamber (25) in the cylinder drum (6).
  5. Axial piston machine according to any preceding claim, characterized in that the cooling regions are formed as annular chambers (43, 36) which surround the cylinders (26, 28) with a slight radial spacing.
  6. Axial piston machine according to any preceding claim, characterized in that the cooling regions are formed as annular grooves (44) in the walls of the cylinders (26, 28).
  7. Axial piston machine according to any preceding claim, characterized in that there is connected to each cooling region (44) a distributor groove (45) or a distributor channel which encircles the associated cylinder (26, 28) in substance in a spiral manner and opens out at the end face (22) of the cylinder drum (6) towards the stroke disc (3).
  8. Axial piston machine according to any preceding claim, characterized in that there is associated with each cylinder at least an upper cooling region (43) in the end region of the cylinder drum (6) towards the stroke disc (3) and/or there is associated therewith a lower cooling region (46) in the region thereof above the piston floor (47) when in the lower dead centre position of the piston (29).
  9. Axial piston machine according to claim 8, characterized in that a further distributor channel (48) or a further distributor groove connects the lower and the upper cooling regions (43, 46) with one another.
  10. Axial piston machine according to claim 9, characterized in that there is associated with one of the two cooling regions (43) at least a supply channel (40) and with the other cooling region (46) at least a discharge channel (41).
  11. Axial piston machine according to any of claims 1 to 10, characterized in that there is associated with each cooling region (43, 44) at least one supply channel (40) and one discharge channel (41).
  12. Axial piston machine according to any preceding claim, characterized in that the supply channels (40) and the discharge channels (41) run substantially radially.
  13. Axial piston machine according to any preceding claim, characterized in that the cooling circuit (7.1 to 7.4) is connected with the suction channel (16S) of the axial piston machine via a choke (50).
  14. Axial piston machine according to claim 13, characterized in that the choke (50) opens into the cooling circuit (7.1 to 7.4) in a region between the leakage chamber (37) and the leakage fluid receiving chamber (25).
  15. Axial piston machine according to claim 13 or 14, characterized in that the choke (50) is formed in a connection block (2) placed on the housing (1) and containing the pressure and suction channels (16D, 16S) of the axial piston machine.
EP95921838A 1994-06-30 1995-06-07 Axial piston engine with a cooling circuit for the cylinders and pistons Expired - Lifetime EP0767864B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4423023 1994-06-30
DE4423023A DE4423023C2 (en) 1994-06-30 1994-06-30 Axial piston machine with a cooling circuit for the cylinders and pistons
PCT/EP1995/002180 WO1996000838A1 (en) 1994-06-30 1995-06-07 Axial piston engine with a cooling circuit for the cylinders and pistons

Publications (2)

Publication Number Publication Date
EP0767864A1 EP0767864A1 (en) 1997-04-16
EP0767864B1 true EP0767864B1 (en) 1998-08-12

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EP95921838A Expired - Lifetime EP0767864B1 (en) 1994-06-30 1995-06-07 Axial piston engine with a cooling circuit for the cylinders and pistons

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US (1) US5971717A (en)
EP (1) EP0767864B1 (en)
JP (1) JP3570517B2 (en)
DE (2) DE4423023C2 (en)
WO (1) WO1996000838A1 (en)

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Also Published As

Publication number Publication date
DE4423023C2 (en) 1998-07-09
JP3570517B2 (en) 2004-09-29
WO1996000838A1 (en) 1996-01-11
DE4423023A1 (en) 1996-01-04
DE59503183D1 (en) 1998-09-17
US5971717A (en) 1999-10-26
JPH10502148A (en) 1998-02-24
EP0767864A1 (en) 1997-04-16

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