WO2014154465A1 - Hydrostatic piston machine, in particular hydrostatic axial piston machine - Google Patents

Hydrostatic piston machine, in particular hydrostatic axial piston machine Download PDF

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Publication number
WO2014154465A1
WO2014154465A1 PCT/EP2014/054367 EP2014054367W WO2014154465A1 WO 2014154465 A1 WO2014154465 A1 WO 2014154465A1 EP 2014054367 W EP2014054367 W EP 2014054367W WO 2014154465 A1 WO2014154465 A1 WO 2014154465A1
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WO
WIPO (PCT)
Prior art keywords
hydrostatic
piston machine
cylinder drum
steel
cylinder
Prior art date
Application number
PCT/EP2014/054367
Other languages
German (de)
French (fr)
Inventor
David Breuer
Manuel Sell
Hendrik Friedrich
Original Assignee
Robert Bosch Gmbh
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Publication date
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Publication of WO2014154465A1 publication Critical patent/WO2014154465A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F04B1/122—Details or component parts, e.g. valves, sealings or lubrication means
    • F04B1/124—Pistons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
    • F03C1/00—Reciprocating-piston liquid engines
    • F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
    • F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
    • F03C1/0602—Component parts, details
    • F03C1/0605—Adaptations of pistons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
    • F03C1/00—Reciprocating-piston liquid engines
    • F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
    • F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
    • F03C1/061—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having stationary cylinders
    • F03C1/0623—Details, component parts
    • F03C1/0626—Cylinders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
    • F03C1/00—Reciprocating-piston liquid engines
    • F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
    • F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
    • F03C1/0636—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F03C1/0644—Component parts
    • F03C1/0652—Cylinders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F04B1/14—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having stationary cylinders
    • F04B1/141—Details or component parts
    • F04B1/143—Cylinders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F04B1/20—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F04B1/2014—Details or component parts
    • F04B1/2035—Cylinder barrels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/14—Pistons, piston-rods or piston-rod connections
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/16—Casings; Cylinders; Cylinder liners or heads; Fluid connections

Definitions

  • Hydrostatic piston machine in particular hydrostatic
  • the invention relates to a hydrostatic piston machine which can be used as a pump or as an engine and is designed in particular as a hydrostatic axial piston machine and which has a cylinder drum in which a plurality of cylinder bores is formed, in which axially movable
  • Displacer are arranged.
  • hydrostatic axial piston pump are known in which a cast cylinder drum and gas-nitrided pistons are used: For this combination works well, is on the surface of the cylinder bores of the cylinder drum by heat treatment, usually in a nitriding or in a
  • Nitrocarburizing a so-called compound layer (in the English compound zone or compound layer or white zone or white layer called), which is also briefly called VS, is located entirely outside and consists of iron nitrides, and underneath a so-called diffusion layer produced. After the heat treatment, the cylinder drums are checked for dimensional accuracy and, if necessary, reworked to ensure dimensional accuracy. If the connection layer is not present or if it is removed during post-processing, seizing between the displacer piston and the cylinder drum and thus failure of the hydrostatic piston machine can occur.
  • hydrostatic axial piston pumps in which a sintered cylinder drum and gas-nitrided and post-oxidized displacement pistons are used.
  • the functionability of the piston engine is ensured by an intake process.
  • the sintering cycle Cylinder drums are not heat treated and thus have no bonding layer in the cylinder bores.
  • Hydrostatic axial piston pumps are also known in which a steel cylinder drum hardened after processing by nitriding in its peripheral layers and nitrided and postoxidized displacement pistons are used. This heat-treated cylinder drum again has a bonding layer by nitriding in the cylinder bores.
  • the contact points between the displacement piston and the cylinder drum of a hydrostatic piston machine are tribologically complex contact points. Among other things, the largest mechanical hydraulic losses occur at these contact points in the corner drive. If these contact points are not functioning properly, this will soon lead to failure of the hydrostatic piston machine. For the contact points, so for the displacement piston and the cylinder drum any materials can be used if the function should be guaranteed.
  • the object of the invention is to provide a hydrostatic piston engine of the type mentioned with a well-functioning, cost-effective and low-friction pairing / combination of materials of displacement piston and cylinder drum. This object is achieved in that in a hydrostatic piston engine having the features of the preamble of claim 1, the cylinder drum made of a steel without a heat treatment following the production ment is made and that the displacement piston made of steel and have a hard edge layer.
  • the cylinder drum is made of a tempered, so relatively soft steel.
  • the displacers are heat treated. They can be nitrided, in particular gas-nitrided and post-oxidized.
  • the existing of a steel displacer are nitrided and post-oxidized, in particular nitrocarburized and post-oxidized.
  • displacers with a DLC (diamond-like carbon) layer (in German with a layer of diamond-like carbon).
  • the cylindrical drum made of a tempered steel can be used without further heat treatment and the creation of a hard surface layer on the surface of the cylinder bores.
  • Tempered steel is steel that is first hardened and then tempered at temperatures of 500 degrees Celsius and above. After such treatment, the risk of cracking and brittle fracture is greatly reduced. By tempering tempered steel, the hardness and strength generally decrease, and the deformability increases.
  • steel grade 42 CrMoS4 + QT is a grade of steel well suited to the cylinder barrel, with the abbreviation QT standing for "tempered".
  • Axial piston machines with the pairing of post-oxidized displacement piston and relatively soft steel cylinder drum have been tested without failure with high transit time.
  • the cylinder bores can be made very accurate and fast in terms of size and shape, as a distortion of the Zy- Linderbohronne is avoided by the non-consecutive heat treatment. Due to the accuracy of the cylinder bores in the dimensions and in the shape of a good mechanical-hydraulic efficiency of the hydrostatic piston machine is obtained. The run-in behavior is improved. By eliminating the heat treatment, the production costs are low. Finally, high pressures are possible by using steel for the cylinder drum.
  • the axial piston machine shown has a drive shaft 1, which is rotatably supported via two roller bearings 2 and 3 in a housing which consists essentially of a housing pot and a connecting plate closing the housing pot.
  • the drive shaft 1 has a first shaft portion, which is enclosed radially by a recess of a cylinder drum 4.
  • a second shaft section of the drive shaft 1 has an outer gear section 5, on which the cylinder drum 4 is arranged with an internal gear hole 6. About the teeth of the drive shaft 1 and the cylinder drum 4 are rotatably coupled together.
  • the cylinder drum 4 has a plurality of lying on a common pitch cylinder bores 7, in each of which a piston 8 is slidably guided. These pistons 8 define together with the cylinder bores 7 work spaces 9 whose volume changes with the stroke of the piston.
  • a the working space 9 remote ball joint 10 of each displacer 8 is pivotally connected to a Kolbengleitschuh 1 1.
  • This Kolbengleitschuh 1 1 is located on a pivotally mounted on the housing swash plate 12, called because of the pivoting and swivel cradle on.
  • the angle of attack of the support surface che 13, at which the Kolbengleitiana 1 1 in Appendix and can slide along, determines the one performed during a revolution of the cylinder drum 4 piston stroke and thus the delivery volume (pump operation) or displacement (engine operation) of the machine.
  • a retraction ball 18 is arranged, which acts on a retraction plate 19 in the direction of the pivoting cradle 12, wherein the retraction plate 19 in turn the Kolbengleit matter 1 1 in contact with the support surface 13 of
  • the cylinder drum 4 On the side facing away from the pivoting cradle 12, the cylinder drum 4 has an end wall 14 with which it is in abutment against a rotationally fixed control plate 15 supported on the housing, which has a pressure kidney 16 and a suction kidney 17 on the same pitch circle as the cylinder bores 7.
  • the pressure kidney 16 and the suction kidney 17 are in communication with the high-pressure channel or the low-pressure channel of a connection plate 21.
  • the pressure kidney and the suction kidney are shown on the control plate for better understanding. In itself they are in the section shown, which lies in a plane which is perpendicular to the pivot axis of the pivoting cradle and in which the axis of the drive shaft 1 is not visible.
  • the pivoting cradle 12 is adjustable by an adjusting device 20.
  • the cylinder drum 4 is made of a tempered steel.
  • steel grade 42 CrMoS4 + QT is a good type of steel suitable for the cylinder barrel, with the abbreviation QT (quenched and tempered) meaning "tempered.”
  • Displacers 8 are also made of steel gas nitrided, in particular gas nitrocarburized, and postoxidized, because of the postoxidation, the uppermost layer of the displacers is an oxide layer.
  • the surface of the displacers is enriched with nitrogen and carbon. This was done in a gas atmosphere, the ammonia and carbon donating additional gases at a treatment temperature of, for example, 570 ° C to 580 ° C.
  • the resulting Nitrocarburier für consists of a compound layer of, for example, about 20 ⁇ and an underlying diffusion layer.
  • the displacer are post-oxidized in an oxygen-releasing medium.
  • a Fe.sub.3O.sub.4 oxide layer having a thickness of from 1 to 4 ⁇ m, usually between 2 and 3 ⁇ m, is formed.
  • a hydrostatic axial piston machine according to the invention can be used with particular advantage as a component of a hydraulic hybrid drive in a motor vehicle, in particular in a passenger vehicle. In vehicles, it is particularly important to have a small footprint and low costs of the individual components at high power.

Abstract

The invention relates to a hydrostatic piston machine, which can be used as a pump or as a motor, is formed in particular as a hydrostatic axial piston machine and has a cylinder drum in which there are formed a multiplicity of cylinder bores, in which axially movable displacement pistons are arranged. Hydrostatic axial piston pumps with quite different material combinations of cylinder drum and displacement pistons are known. It is an object of the invention to provide a hydrostatic piston machine of the type mentioned in the introduction that has an inexpensive and low-friction pairing/combination of the materials of displacement pistons and cylinder drum which operates effectively. This object is achieved, according to the invention, by virtue of the fact that the cylinder drum is produced from steel without a heat treatment following production, and by virtue of the fact that the displacement pistons consist of steel and have a hard marginal layer, in particular are nitrocarburized and reoxidized. The cylinder drum, which is produced from a relatively soft steel, can be used without the cylinder bores being subjected to a further heat treatment.

Description

Beschreibung Titel  Description title
Hydrostatische Kolbenmaschine, insbesondere hydrostatische  Hydrostatic piston machine, in particular hydrostatic
Axialkolbenmaschine axial piston
Beschreibung description
Die Erfindung bezieht sich auf eine hydrostatische Kolbenmaschine, die als Pumpe oder als Motor verwendet werden kann und insbesondere als hydrostatische Axialkolbenmaschine ausgebildet ist und die eine Zylindertrommel aufweist, in der eine Vielzahl von Zylinderbohrungen ausgebildet ist, in denen axial bewegbare The invention relates to a hydrostatic piston machine which can be used as a pump or as an engine and is designed in particular as a hydrostatic axial piston machine and which has a cylinder drum in which a plurality of cylinder bores is formed, in which axially movable
Verdrängerkolben angeordnet sind. Es sind hydrostatische Axialkolbenpumpe bekannt, in denen eine Gusszylindertrommel und gasnitrierte Kolben verwendet werden: Damit diese Kombination gut funktioniert, wird an der Oberfläche der Zylinderbohrungen der Zylindertrommel durch Wärmebehandlung, die üblicherweise in einem Nitrieren oder in einem Displacer are arranged. There are hydrostatic axial piston pump are known in which a cast cylinder drum and gas-nitrided pistons are used: For this combination works well, is on the surface of the cylinder bores of the cylinder drum by heat treatment, usually in a nitriding or in a
Nitrocarburieren besteht, eine sogenannte Verbindungsschicht (im Englischen Compound zone oder Compound layer oder white zone oder white layer genannt), die kurz auch VS genannt wird, sich ganz außen befindet und aus Eisennitriden besteht, und darunterliegend eine sogenannte Diffusionsschicht erzeugt. Nach der Wärmebehandlung werden die Zylindertrommeln nach Maßhaltigkeit kontrolliert und gegebenenfalls nachbearbeitet, um die Maßhaltigkeit zu gewährleisten. Ist die Verbindungs- schicht nicht vorhanden oder wird diese bei der Nachbearbeitung entfernt, kann es zum Fressen zwischen den Verdrängerkolben und der Zylindertrommel und damit zum Ausfall der hydrostatischen Kolbenmaschine kommen. Nitrocarburizing, a so-called compound layer (in the English compound zone or compound layer or white zone or white layer called), which is also briefly called VS, is located entirely outside and consists of iron nitrides, and underneath a so-called diffusion layer produced. After the heat treatment, the cylinder drums are checked for dimensional accuracy and, if necessary, reworked to ensure dimensional accuracy. If the connection layer is not present or if it is removed during post-processing, seizing between the displacer piston and the cylinder drum and thus failure of the hydrostatic piston machine can occur.
Bekannt sind auch hydrostatische Axialkolbenpumpen, in denen eine Sinterzylinder- trommel und gasnitrierte und nachoxidierte Verdrängerkolben eingesetzt werden. Durch die Verwendung der nachoxidierten Verdrängerkolben wird durch einen Ein- laufprozess die Funktionsfähigkeit der Kolbenmaschine sichergestellt. Die Sinterzy- lindertrommeln werden nicht wärmebehandelt und besitzen somit keine Verbindungsschicht in den Zylinderbohrungen. Also known are hydrostatic axial piston pumps in which a sintered cylinder drum and gas-nitrided and post-oxidized displacement pistons are used. Through the use of the post-oxidized displacement pistons, the functionability of the piston engine is ensured by an intake process. The sintering cycle Cylinder drums are not heat treated and thus have no bonding layer in the cylinder bores.
Es sind auch hydrostatische Axialkolbenpumpen bekannt, in denen eine nach der Bearbeitung durch Nitrieren in ihren Randschichten gehärtete Stahlzylindertrommel und nitrierte und nachoxidierte Verdrängerkolben eingesetzt werden. Diese wärmebehandelte Zylindertrommel weist durch das Nitrieren in den Zylinderbohrungen wieder eine Verbindungsschicht auf. Die Kontaktstellen zwischen den Verdrängerkolben und der Zylindertrommel einer hydrostatischen Kolbenmaschine sind tribologisch komplexe Kontaktstellen. An diesen Kontaktstellen entstehen in der Eckleistung unter anderem auch die größten mechanisch hydraulischen Verluste. Wenn diese Kontaktstellen nicht einwandfrei funktionieren, führt diese schon sehr bald zum Ausfall der hydrostatischen Kolbenmaschi- ne. Für die Kontaktstellen, also für die Verdrängerkolben und die Zylindertrommel können beliebige Materialien verwendet werden, wenn die Funktion gewährleistet sein soll. Hydrostatic axial piston pumps are also known in which a steel cylinder drum hardened after processing by nitriding in its peripheral layers and nitrided and postoxidized displacement pistons are used. This heat-treated cylinder drum again has a bonding layer by nitriding in the cylinder bores. The contact points between the displacement piston and the cylinder drum of a hydrostatic piston machine are tribologically complex contact points. Among other things, the largest mechanical hydraulic losses occur at these contact points in the corner drive. If these contact points are not functioning properly, this will soon lead to failure of the hydrostatic piston machine. For the contact points, so for the displacement piston and the cylinder drum any materials can be used if the function should be guaranteed.
Andererseits werden von den Anwendern immer höhere Betriebsdrücke gefordert, um bei gegebenem Bauraum hydrostatische Kolbenmaschine mit höherer Leistung zu haben. Ab bestimmten Betriebsdrücken können aktuell eingesetzte Werkstoffe wie Eisenguss oder Sintereisen nicht mehr verwendet werden, da die Werkstoffe die hohen Belastungen nicht mehr aufnehmen können und versagen. Aufgabe der Erfindung ist es, eine hydrostatische Kolbenmaschine der eingangs genannten Art mit einer gut funktionierenden, kostengünstigen und reibungsarmen Paarung/Kombination der Materialien von Verdrängerkolben und Zylindertrommel zu schaffen. Diese Aufgabe wird erfindungsgemäß dadurch gelöst, dass bei einer hydrostatischen Kolbenmaschine mit den Merkmalen aus dem Oberbegriff des Patentanspruchs 1 die Zylindertrommel aus einem Stahl ohne eine der Fertigung folgende Wärmebehand- lung gefertigt ist und dass die Verdrängerkolben aus Stahl bestehen und eine harte Randschicht aufweisen. On the other hand, users are demanding ever higher operating pressures in order to have a hydrostatic piston engine with a higher output in a given space. From certain operating pressures, currently used materials such as cast iron or sintered iron can no longer be used as the materials can no longer absorb the high loads and fail. The object of the invention is to provide a hydrostatic piston engine of the type mentioned with a well-functioning, cost-effective and low-friction pairing / combination of materials of displacement piston and cylinder drum. This object is achieved in that in a hydrostatic piston engine having the features of the preamble of claim 1, the cylinder drum made of a steel without a heat treatment following the production ment is made and that the displacement piston made of steel and have a hard edge layer.
Bevorzugt ist die Zylindertrommel aus einem vergüteten, also relativ weichen Stahl gefertigt. Preferably, the cylinder drum is made of a tempered, so relatively soft steel.
Vorteilhafterweise sind die Verdrängerkolben wärmebehandelt. Sie können nitriert, insbesondere gasnitriert und nachoxidiert sein. Bevorzugt sind die aus einem Stahl bestehenden Verdrängerkolben nitriert und nachoxidiert, insbesondere nitrocarburiert und nachoxidiert. Advantageously, the displacers are heat treated. They can be nitrided, in particular gas-nitrided and post-oxidized. Preferably, the existing of a steel displacer are nitrided and post-oxidized, in particular nitrocarburized and post-oxidized.
Möglich ist auch, die Verdrängerkolben mit einer DLC-Schicht (Diamond-like Carbon Schicht) (in Deutsch: mit einer Schicht aus diamantähnlichem Kohlenstoff) zu verse- hen. It is also possible to provide the displacers with a DLC (diamond-like carbon) layer (in German with a layer of diamond-like carbon).
Die aus einem vergüteten Stahl gefertigte Zylindertrommel kann ohne weitere Wärmebehandlung und die Erzeugung einer harten Randschicht an der Oberfläche der Zylinderbohrungen verwendet werden. Vergüteter Stahl ist solcher Stahl, der zu- nächst gehärtet und dann bei Temperaturen von 500 Grad Celsius und mehr angelassen wird. Nach einer derartigen Behandlung ist das Risiko der Rissbildung und eines spröden Bruchs stark verringert. Durch das Anlassen von gehärtetem Stahl nehmen im Allgemeinen die Härte und Festigkeit ab und das Formänderungsvermögen nimmt zu. The cylindrical drum made of a tempered steel can be used without further heat treatment and the creation of a hard surface layer on the surface of the cylinder bores. Tempered steel is steel that is first hardened and then tempered at temperatures of 500 degrees Celsius and above. After such treatment, the risk of cracking and brittle fracture is greatly reduced. By tempering tempered steel, the hardness and strength generally decrease, and the deformability increases.
Eine für die Zylindertrommel gut geeignete Stahlsorte ist zum Beispiel der Stahl 42 CrMoS4+QT, wobei die Abkürzung QT für„vergütet" steht. For example, steel grade 42 CrMoS4 + QT is a grade of steel well suited to the cylinder barrel, with the abbreviation QT standing for "tempered".
Axialkolbenmaschinen mit der Paarung von nachoxidierten Verdrängerkolben und relativ weicher Stahlzylindertrommel sind ohne Ausfall mit hoher Laufzeit getestet worden. Mit der erfinderischen Paarung können die Zylinderbohrungen hinsichtlich Maß und Form sehr genau und schnell hergestellt werden, da ein Verziehen der Zy- linderbohrungen durch die nicht nachfolgende Wärmebehandlung vermieden ist. Aufgrund der Genauigkeit der Zylinderbohrungen in den Maßen und in der Form wird ein guter mechanisch-hydraulische Wirkungsgrad der hydrostatischen Kolbenmaschine erhalten. Das Einlaufverhalten ist verbessert. Durch den Entfall der Wärme- behandlung sind die Herstellkosten gering. Schließlich sind durch die Verwendung von Stahl für die Zylindertrommel hohe Drücke möglich. Axial piston machines with the pairing of post-oxidized displacement piston and relatively soft steel cylinder drum have been tested without failure with high transit time. With the inventive mating the cylinder bores can be made very accurate and fast in terms of size and shape, as a distortion of the Zy- Linderbohrungen is avoided by the non-consecutive heat treatment. Due to the accuracy of the cylinder bores in the dimensions and in the shape of a good mechanical-hydraulic efficiency of the hydrostatic piston machine is obtained. The run-in behavior is improved. By eliminating the heat treatment, the production costs are low. Finally, high pressures are possible by using steel for the cylinder drum.
Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt und wird im Folgenden näher beschrieben. Die einzige Figur der Zeichnung zeigt einen Längs- schnitt durch eine verstellbare hydrostatische Axialkolbenmaschine in Schrägscheibenbauweise. An embodiment of the invention is illustrated in the drawing and will be described in more detail below. The sole figure of the drawing shows a longitudinal section through an adjustable hydrostatic axial piston machine in swash plate design.
Die dargestellte Axialkolbenmaschine besitzt eine Triebwelle 1 , die über zwei Wälzlager 2 und 3 in einem Gehäuse, das im Wesentlichen aus einem Gehäusetopf und eine den Gehäusetopf verschließende Anschlussplatte besteht, drehbar gelagert ist. Die Triebwelle 1 hat einen ersten Wellenabschnitt, der radial von einer Ausnehmung einer Zylindertrommel 4 umschlossen ist. The axial piston machine shown has a drive shaft 1, which is rotatably supported via two roller bearings 2 and 3 in a housing which consists essentially of a housing pot and a connecting plate closing the housing pot. The drive shaft 1 has a first shaft portion, which is enclosed radially by a recess of a cylinder drum 4.
Ein zweiter Wellenabschnitt der Triebwelle 1 weist einen Außenverzahnungsbereich 5 auf, auf dem die Zylindertrommel 4 mit einer Innenverzahnungsbohrung 6 angeordnet ist. Über die Verzahnungen sind die Triebwelle 1 und die Zylindertrommel 4 drehfest miteinander gekoppelt. A second shaft section of the drive shaft 1 has an outer gear section 5, on which the cylinder drum 4 is arranged with an internal gear hole 6. About the teeth of the drive shaft 1 and the cylinder drum 4 are rotatably coupled together.
Die Zylindertrommel 4 besitzt eine Mehrzahl von auf einem gemeinsamen Teilkreis liegenden Zylinderbohrungen 7, in denen jeweils ein Kolben 8 verschiebbar geführt ist. Diese Kolben 8 begrenzen gemeinsam mit den Zylinderbohrungen 7 Arbeitsräume 9, deren Volumen sich mit dem Hub der Kolben ändert. The cylinder drum 4 has a plurality of lying on a common pitch cylinder bores 7, in each of which a piston 8 is slidably guided. These pistons 8 define together with the cylinder bores 7 work spaces 9 whose volume changes with the stroke of the piston.
Eine dem Arbeitsraum 9 entfernte Gelenkkugel 10 eines jeden Verdrängerkolbens 8 ist gelenkig mit einem Kolbengleitschuh 1 1 verbunden. Dieser Kolbengleitschuh 1 1 liegt an einer verschwenkbar am Gehäuse gelagerten Schrägscheibe 12, wegen der Verschwenkbarkeit auch Schwenkwiege genannt, an. Der Anstellwinkel der Stützflä- che 13, an der die Kolbengleitschuhe 1 1 in Anlage sind und entlanggleiten können, bestimmt den bei einer Umdrehung der Zylindertrommel 4 vollführten Kolbenhub und damit das Fördervolumen (Pumpenbetrieb) beziehungsweise Schluckvolumen (Motorbetrieb) der Maschine. A the working space 9 remote ball joint 10 of each displacer 8 is pivotally connected to a Kolbengleitschuh 1 1. This Kolbengleitschuh 1 1 is located on a pivotally mounted on the housing swash plate 12, called because of the pivoting and swivel cradle on. The angle of attack of the support surface che 13, at which the Kolbengleitschuhe 1 1 in Appendix and can slide along, determines the one performed during a revolution of the cylinder drum 4 piston stroke and thus the delivery volume (pump operation) or displacement (engine operation) of the machine.
Auf der Antriebswelle 1 ist eine Rückzugkugel 18 angeordnet, die eine Rückzugplatte 19 in Richtung auf die Schwenkwiege 12 zu beaufschlagt, wobei die Rückzugplatte 19 wiederum die Kolbengleitschuhe 1 1 in Anlage an der Stützfläche 13 der On the drive shaft 1, a retraction ball 18 is arranged, which acts on a retraction plate 19 in the direction of the pivoting cradle 12, wherein the retraction plate 19 in turn the Kolbengleitschuhe 1 1 in contact with the support surface 13 of
Schwenkwiege 12 hält. Pivoting cradle 12 stops.
Auf der der Schwenkwiege 12 abgewandten Seite besitzt die Zylindertrommel 4 eine Stirnwandung 14, mit der sie an einer am Gehäuse abgestützten, drehfesten Steuerplatte 15 in Anlage ist, die eine Druckniere 16 und eine Saugniere 17 auf demselben Teilkreis wie die Zylinderbohrungen 7 aufweist. Die Druckniere 16 und die Saugniere 17 stehen mit dem Hochdruckkanal beziehungsweise dem Niederdruckkanal einer Anschlussplatte 21 in Verbindung. In der Figur sind die Druckniere und die Saugniere an der Steuerplatte zum besseren Verständnis eingezeichnet. An sich sind sie in dem gezeigten Schnitt, der in einer Ebene liegt, die senkrecht auf der Schwenkachse der Schwenkwiege steht und in der die Achse der Triebwelle 1 liegt nicht sichtbar. On the side facing away from the pivoting cradle 12, the cylinder drum 4 has an end wall 14 with which it is in abutment against a rotationally fixed control plate 15 supported on the housing, which has a pressure kidney 16 and a suction kidney 17 on the same pitch circle as the cylinder bores 7. The pressure kidney 16 and the suction kidney 17 are in communication with the high-pressure channel or the low-pressure channel of a connection plate 21. In the figure, the pressure kidney and the suction kidney are shown on the control plate for better understanding. In itself they are in the section shown, which lies in a plane which is perpendicular to the pivot axis of the pivoting cradle and in which the axis of the drive shaft 1 is not visible.
Die Schwenkwiege 12 ist durch eine Versteilvorrichtung 20 einstellbar. The pivoting cradle 12 is adjustable by an adjusting device 20.
Erfindungsgemäß ist die Zylindertrommel 4 aus einem vergüteten Stahl gefertigt. Eine für die Zylindertrommel gut geeignete Stahlsorte ist zum Beispiel der Stahl 42 CrMoS4+QT, wobei die Abkürzung QT (quenched and tempered) für„vergütet" steht. Auch die Verdrängerkolben 8 sind aus einem Stahl gefertigt. Die Verdrängerkolben werden nach der fertigen mechanischen Bearbeitung gasnitriert, insbesondere gasnitrocarburiert, und nachoxidiert. Aufgrund des Nachoxidierens ist die oberste Schicht der Verdrängerkolben eine Oxidschicht. According to the invention, the cylinder drum 4 is made of a tempered steel. For example, steel grade 42 CrMoS4 + QT is a good type of steel suitable for the cylinder barrel, with the abbreviation QT (quenched and tempered) meaning "tempered." Displacers 8 are also made of steel gas nitrided, in particular gas nitrocarburized, and postoxidized, because of the postoxidation, the uppermost layer of the displacers is an oxide layer.
Beim Gasnitrocarburieren wird die Oberfläche der Verdrängerkolben mit Stickstoff und Kohlenstoff angereichert. Dies erfolgte in einer Gasatmosphäre, die Ammoniak und kohlenstoffabgebenden Zusatzgase enthält, bei einer Behandlungstemperatur von zum Beispiel 570°C bis 580°C. In gas nitrocarburizing, the surface of the displacers is enriched with nitrogen and carbon. This was done in a gas atmosphere, the ammonia and carbon donating additional gases at a treatment temperature of, for example, 570 ° C to 580 ° C.
Die dabei entstehende Nitrocarburierschicht besteht aus einer Verbindungsschicht von zum Beispiel etwa 20 μιτι und einer darunter liegenden Diffusionsschicht. The resulting Nitrocarburierschicht consists of a compound layer of, for example, about 20 μιτι and an underlying diffusion layer.
Danach werden die Verdrängerkolben in einem Sauerstoff abgebenden Medium nachoxidiert. Dabei wird im äußeren Bereich der Verbindungsschicht eine Fe3O4°- Oxidschicht von einer Dicke von 1 bis 4 μιτι, meist zwischen 2 und 3 μιτι, gebildet. Thereafter, the displacer are post-oxidized in an oxygen-releasing medium. In this case, in the outer region of the connecting layer, a Fe.sub.3O.sub.4 oxide layer having a thickness of from 1 to 4 μm, usually between 2 and 3 μm, is formed.
Eine erfindungsgemäße hydrostatische Axialkolbenmaschine ist mit besonderem Vorteil als Komponente eines hydraulischen Hybridantriebs in einem Kraftfahrzeug, insbesondere in einem Personenkraftfahrzeug verwendbar. In Fahrzeugen kommt es in besonderer Weise auf einen geringen Platzbedarf und niedrige Kosten der einzel- nen Komponenten bei hoher Leistung an. A hydrostatic axial piston machine according to the invention can be used with particular advantage as a component of a hydraulic hybrid drive in a motor vehicle, in particular in a passenger vehicle. In vehicles, it is particularly important to have a small footprint and low costs of the individual components at high power.

Claims

Patentansprüche claims
1 . Hydrostatische Kolbenmaschine, insbesondere hydrostatische Axialkolben- maschine mit einer Zylindertrommel(4), in der eine Vielzahl von Zylinderbohrungen (7) ausgebildet ist, in denen axial bewegbare Verdrängerkolben (8) angeordnet sind, dadurch gekennzeichnet, dass die Zylindertrommel (4) aus einem Stahl ohne eine der Fertigung folgende Wärmebehandlung gefertigt ist und dass die 1 . Hydrostatic piston machine, in particular hydrostatic axial piston machine with a cylinder drum (4), in which a plurality of cylinder bores (7) is formed, in which axially movable displacement piston (8) are arranged, characterized in that the cylinder drum (4) made of a steel without any of the manufacturing following heat treatment is made and that the
Verdrängerkolben (8) aus Stahl bestehen und eine harte Randschicht aufweisen. Displacement piston (8) made of steel and have a hard edge layer.
2. Hydrostatische Kolbenmaschine nach Patentanspruch 1 , dadurch gekennzeichnet, dass die Zylindertrommel (4) aus einem vergüteten Stahl gefertigt ist. 2. Hydrostatic piston engine according to claim 1, characterized in that the cylinder drum (4) is made of a tempered steel.
3. Hydrostatische Kolbenmaschine nach Patentanspruch 1 oder 2, dadurch gekennzeichnet, dass die Verdrängerkolben (8) wärmebehandelt sind, insbesondere nitriert und nachoxidiert sind. 3. Hydrostatic piston engine according to claim 1 or 2, characterized in that the displacement piston (8) are heat-treated, in particular nitrided and post-oxidized.
4. Hydrostatische Kolbenmaschine nach Patentanspruch 1 oder 2, dadurch gekennzeichnet, dass die Verdrängerkolben (8) nitrocarburiert und nachoxidiert sind. 4. Hydrostatic piston machine according to claim 1 or 2, characterized in that the displacement piston (8) are nitrocarburized and post-oxidized.
5. Hydrostatische Kolbenmaschine nach einem vorhergehenden Patentanspruch, dadurch gekennzeichnet, dass sie eine Axialkolbenmaschine in Schrägscheibenbauweise ist. 5. Hydrostatic piston engine according to any preceding claim, characterized in that it is an axial piston machine in swash plate design.
PCT/EP2014/054367 2013-03-27 2014-03-06 Hydrostatic piston machine, in particular hydrostatic axial piston machine WO2014154465A1 (en)

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DE201310205375 DE102013205375A1 (en) 2013-03-27 2013-03-27 Hydrostatic piston machine, in particular hydrostatic axial piston machine

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1159428A (en) * 1955-11-08 1958-06-27 Daimler Benz Ag Piston, in particular axial piston unit blocks of hydrostatic control mechanisms
DE1963769A1 (en) * 1969-12-19 1971-06-24 Rauch Fa Constantin Cylinder drum control plate combination for axial piston machines
US4799419A (en) * 1978-03-22 1989-01-24 Linde Aktiengesellschaft Multi-cylinder hydraulic piston device, a cylinder therefor, and its method of making
EP1310577A1 (en) * 2001-11-12 2003-05-14 Hitachi, Ltd. Fuel pump and direct fuel injection engine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1159428A (en) * 1955-11-08 1958-06-27 Daimler Benz Ag Piston, in particular axial piston unit blocks of hydrostatic control mechanisms
DE1963769A1 (en) * 1969-12-19 1971-06-24 Rauch Fa Constantin Cylinder drum control plate combination for axial piston machines
US4799419A (en) * 1978-03-22 1989-01-24 Linde Aktiengesellschaft Multi-cylinder hydraulic piston device, a cylinder therefor, and its method of making
EP1310577A1 (en) * 2001-11-12 2003-05-14 Hitachi, Ltd. Fuel pump and direct fuel injection engine

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