DE102020109134A1 - Axial piston machine - Google Patents

Abstract

An axial piston machine comprising a drive shaft, a drive unit connected to it in a rotationally fixed manner with one or more drive unit pistons, the piston stroke of which is adjustable by a swash plate, at least one return spring acting on the swash plate and an actuating piston being supported on the swash plate, the axial piston machine at least one control or Control valve or at least one control or regulator unit, characterized in that an actuating piston is guided in the connection plate and an actuating lever acts as a coupling element between the actuating piston and the swashplate and the actuating piston axis and the actuating lever axis are on a plane E1, in particular on a from the drive shaft axis M outgoing half-plane E1 * are located.

Description

The invention relates to an axial piston machine in swash plate design with at least one control or regulating valve for setting the angle of inclination of the swash plate.

The term “axial piston machine” includes both an axial piston pump and an axial piston motor. A special type of axial piston machine is the swash plate machine, which comprises an engine in the form of an engine drum in which several engine pistons are axially displaceably mounted in corresponding cylinder bores of the engine. The drive unit is non-rotatably connected to the drive shaft of the axial piston machine, which is set in rotation by mechanical work, for example in the pump mode. In pump operation, from a certain starting position, the pistons perform a stroke movement parallel to the axis of rotation during half a revolution, in order to suck in hydraulic fluid from the low-pressure side, referred to in the following text as hydraulic oil for better readability, whereas the remaining half revolution of a full rotation around the axis of rotation is a lowering movement execute and thereby have brought the hydraulic oil previously sucked in to the high pressure level and the work output, ie to the high pressure side. In the motor operating mode, the operating principle is reversed in that a controlled pressure actuation of the engine piston generates a rotational movement of the drive unit. The stroke of the engine pistons is determined by the swivel angle of the swash plate, also known as the swivel cradle. When the drive shaft rotates, the engine pistons performing the lifting movement are constantly aligned parallel to the latter and are each pulled or pushed against the movement specified by the swash plate and the retraction plate with the aid of a sliding shoe that is hinged to the piston. The swash plate does not follow the rotary movement of the drive shaft, so that the sliding shoes attached to the piston perform a sliding movement on the surface of the swash plate facing the sliding shoes. The stroke of the engine pistons used can thus be adjusted via the swivel angle of the swashplate. The maximum stroke of the engine piston results from the maximum possible swivel angle of the swash plate. The minimum stroke of the engine piston results from the minimum possible swivel angle of the swash plate.

There are also axial piston machines in which the so-called swiveling of the swash plate through the neutral position, the so-called mooring operation, is provided. There are also axial piston machines that can work in four-quadrant operation. At this point it should be pointed out that the invention can also be applied to such axial piston machines.

The desired / required value of the swivel angle of the swash plate, which is determined by the control or by a regulation, is achieved by means of a mechanical force transmission through the actuating unit acting on the swash plate. The force develops through an oil pressure, the so-called control pressure, which acts on the control piston belonging to the control unit. The pressure level of the set pressure is specified via a control valve hydraulically connected upstream of the setting unit or a hydraulic regulating valve connected hydraulically upstream of the setting unit. There is an oil connection between the control pressure output, which is also referred to as the working connection, of the control valve and the so-called control chamber. In the actuating chamber, the actuating piston is acted upon by the hydraulic oil that is under actuating pressure.

Furthermore, in addition to the control valve, further purely hydraulic or mechatronic components can be provided which are used to control or regulate the axial piston machine. An example of a purely hydraulic component is a pressure cut-off which can be used, for example, to limit the output pressure of an axial piston machine operating in pump mode. An example of a mechatronic component is an electrically controllable pressure reduction unit. The output pressure of such a pressure reduction unit can, for example, be fed to the valve piston of the control valve which specifies the control pressure and which has a control pressure connection and a corresponding control surface provided for this purpose.

Since there is a desire here for a construction that is as compact as possible, the object of the present invention is to provide a suitable solution for the arrangement and integration of corresponding hydraulic components in or on the axial piston machine.

This object is achieved by an axial piston machine according to the features of claim 1. Advantageous refinements of the axial piston machine are the subject matter of the dependent claims.

The axial piston machine according to the invention comprises a drive shaft and a drive unit connected to it in a rotationally fixed manner with one or more drive unit pistons, the piston stroke of which can be adjusted by a swash plate. At least one return spring acts on the swash plate and an actuating piston is supported on the swash plate. Furthermore, the axial piston machine has at least one control or control valve or at least one control or regulating unit. According to the invention it is now proposed that the actuating piston be guided in the connection plate and an actuating lever acts as a coupling element between the actuating piston and swash plate. It is essential that the actuating piston axis and the actuating lever axis are on the same plane E1 are located. The actuating piston axis and the actuating lever axis are preferably located on a half-plane extending from the drive shaft axis M E1 * .

The actuating piston axis can run parallel to the drive shaft axis, the actuating lever axis being in the plane E1 , in particular in a half-plane extending from the drive shaft axis M E1 * is located. It is conceivable that the actuating lever enables approximately parallel functional positions to the drive shaft axis and / or approximately coaxial functional positions to the actuating piston axis. Approximately preferably means an angular deviation from the respective axis of less than 3 °, particularly preferably of less than 2 ° and ideally of less than 1 °.

Starting from the generic axial piston machine, it can be advantageous for certain types of open-loop or closed-loop control if the control or regulating valve which specifies the control pressure is located within the connection plate of the axial piston machine.

It is particularly advantageous if the control and / or regulating valve can be inserted into the connection plate from the outside, for example can be screwed into a corresponding bore in the connection plate from the outside. For this purpose, the relevant control or regulating valve is preferably provided with a cartridge-shaped housing. This allows a simple change. Different types of valves or controllers can be used without any problems, depending on the application. The corresponding control or regulating valve is already integrated in the axial piston machine. However, an exchange is possible without opening the axial piston machine and the axial piston machine remains identical. For example, a structure for volume flow control of the axial piston machine can be represented by appropriate installation of a volume flow control valve, or a structure for power control of the axial piston machine can be represented by appropriate installation of a power regulator.

Furthermore, it is provided according to the invention that one or more further hydraulic components, in particular valves or regulators, for controlling the control or regulating valve and / or for controlling or regulating the axial piston machine are stacked on a section of the connecting plate surface, in particular on a section of the connecting plate in Area of the control or regulating valve housed there. This enables very short connection paths for the hydraulic connection of the individual hydraulic components. Furthermore, the axial piston machine can be equipped with the desired hydraulic components quickly and easily. The proposed construction also allows the construction of a particularly compact unit that can be integrated into a higher-level machine in a space-saving manner.

A particular advantage of the axial piston machine arises when, according to a preferred embodiment of the invention, at least one controller axis of the stacked hydraulic components is perpendicular to the drive mechanism axis of the axial piston machine. Ideally, all controller axes of the stacked hydraulic components are perpendicular to the engine axis.

The control or regulating valve acts preferably hydraulically on a mechanical adjustment unit, which mechanically triggers a pivoting of the swash plate as a function of the control pressure of the control valve. For this purpose, the adjusting device preferably comprises an adjusting lever which is mechanically connected to the swash plate on the one hand and is pressurized by the generated adjusting pressure of the control valve on the other hand via an adjusting piston attached at the end. A parallel course of the longitudinal axes of the adjusting lever and / or adjusting piston and / or control piston of the control or regulating valve is advantageous here. It is particularly advantageous if the central longitudinal sections of the adjusting lever, the adjusting piston and the control or regulating valve and the engine itself lie in a common plane. The same can optionally also apply to the return spring of the swash plate and other components of the axial piston machine.

The hydraulic pilot control of the control or regulating valve for setting the desired inclined angle of the swash plate and thus the volume that can be conveyed in pump operation or the power in motor operation is carried out according to one possible embodiment of the invention by means of a pressure reduction unit, the pressure output of which is connected to the control input of the control valve. It is possible for the pressure reduction unit to be electromagnetically piloted in order to be able to set the outgoing control pressure that is applied to the control valve accordingly. The pressure reduction unit is mounted on the intended mounting section on the connecting plate surface, possibly stacked there with additional hydraulic components.

Further hydraulic components for controlling / regulating the axial piston machine can can also be placed on the lateral surface of the connection plate, for example placed in a sandwich-like manner on the aforementioned pressure reduction unit. It applies here that at least one controller axis of the stacked hydraulic components, ideally all controller axes, run parallel to one another and are oriented perpendicular to the longitudinal axis of the drive shaft.

Further hydraulic components are understood to be one or more valves for implementing control types. In particular, such valves for pressure control, volume control, power control or a combination thereof. Mechanical-hydraulic controllers or electric-hydraulic controllers are conceivable.

A specific example of these additional hydraulic components is, for example, a pressure cut-off, in particular in combination with a load-sensing stage. The load-sensing stage with pressure cut-off can be accommodated compactly within a twin housing that sits on the housing of the pressure reduction unit.

With the chosen structure it is advantageous if the longitudinal axes of the pressure reduction unit on the one hand and load sensing and pressure separation on the other hand run parallel to one another, but do not lie in the same vertical sectional plane. Specifically, the central longitudinal axis of the pressure reduction unit is offset from the common central longitudinal sectional plane of the load sensing stage and pressure cut-off.

In a further advantageous embodiment of the invention, the axial piston machine is designed as a modular kit with at least two connection plates. The at least two available connection plates allow an uncomplicated and quick adaptation of the axial piston machine to the desired type of application. In particular, the connection plate can also be exchanged by the customer without specialist knowledge.

A decisive advantage of such a kit is that, for example, at least one connection plate is kept ready for each direction of rotation of the drive shaft. By changing the connection plate, the axial piston machine can be quickly and flexibly converted to the desired direction of rotation in pump and / or motor operation. In the ideal case, the at least two connection plates only differ in the position of the hydraulic connections, i.e. the positioning of the high or low pressure connection (suction connection in pump operation), these are only arranged in a reversed position for the respective direction of rotation. Usually, the low-pressure and high-pressure connections on axial piston machines differ in terms of diameter.

The advantageous modular concept allows additional variations of the connection plate, so the high and low pressure connection in a connection plate can be at the rear end of the axial piston machine in the axial direction, while a further connection plate has pressure connections positioned laterally. Likewise, the available connection plates can be equipped with or without a shaft drive for connecting a downstream machine, in particular an axial piston machine. If the connection plate includes a corresponding through drive, a detachable arrangement of a flange adapter is useful in order to enable flexible connection of different flange types.

• 1: einen Längsschnitt entlang der Triebwelle durch die erfindungsgemäße Axialkolbenmaschine,
• 2: eine schematische Abbildung der Axialkolbenmaschine entsprechend dem Längsschnitt der 1,
• 3: eine weitere schematische Ansicht der Axialkolbenmaschine in einer Draufsicht,
• 4: eine vereinfachte Darstellung der 3 mit eingezeichneten Reglerachsen,

Further advantages and properties of the invention are to be explained in more detail below using an exemplary embodiment shown in the figures. Show it:

• 1 : a longitudinal section along the drive shaft through the axial piston machine according to the invention,
• 2 : a schematic illustration of the axial piston machine according to the longitudinal section of the 1 ,
• 3 : Another schematic view of the axial piston machine in a plan view,
• 4th : a simplified representation of the 3 with indicated controller axes,

1 shows an axial longitudinal section through the axial piston machine according to the invention. The invention is described below using an axial piston pump, but it is explicitly pointed out that the features of the invention according to the invention can also be used in an axial piston motor without restriction. It is also pointed out that the features according to the invention can also be used for an axial piston machine which can work in a multi-quadrant operation.

On the drive shaft 1 is a non-rotating engine drum 2 arranged, in the drum revolver-like several engine pistons 3 in cylinder bores 4th are used. The engine pistons 3 are each supported by a sliding shoe 5 on the swashplate 6th from. The swash plate is via a compression spring 7th on the main body 8th supported. When the drive shaft rotates 1 slide the engine pistons 3 by means of their sliding shoes 5 over the sliding surface of the swashplate 6th and it depends on the swivel angle of the swash plate 6th to a stroke movement of the engine pistons 3 . Depending on the operating mode of the axial piston machine, i.e. pump or Motor operation, this generates hydraulic energy or mechanical power.

A retaining device ensures that the running surfaces of the sliding shoes 5 the engine piston 3 contact with the sliding surface of the swash plate even during its suction phase 6th not lose. The restraint device consists of a retraction plate 10 as well as the coaxial on the drive shaft 1 seated retraction ball 9 . The latter is made by feather 12 in the drawing plane (plane E1 ) and in the illustrated embodiment in a half-plane extending from the drive shaft axis E1 * to the left in the direction of the swashplate 6th and is supported on the retraction plate 10 from. This causes the retraction plate to stand 10 in constant contact with the sliding shoes 5 and presses their running surfaces onto the swash plate 6th . The engine drum 2 is made by the central spring 12 towards the control plate 13 pressed.

The stroke of the engine pistons 3 is determined by the swivel angle of the swashplate 6th specified, which can be changed via an adjustment device during operation.

The lever 21st has a spherical end region on both sides, with one side of the adjusting lever 21st with the swash plate 6th and the other side with the actuating piston 22nd each forms a ball joint connection. The lever 21st can be rotationally symmetrical with respect to its longitudinal axis and / or mirror-symmetrical with respect to a vertical axis. The lever 21st extends in the axial direction from the swash plate 6th via the control panel 13 out into a blind hole 11a reaching inside the connection plate 11 and in which the actuating piston 22nd is led.

Inside the connection plate 11 can be a control or regulating valve 30th be housed.

That of the swashplate 6th The opposite spherical end of the adjusting lever forms with the spherical recess in the adjusting piston 22nd a ball joint connection. The adjusting piston 22nd is inside the blind hole 11a the connection plate 11 axially displaceable. The actuating piston shown in the exemplary embodiment has on its end face opposite the spherical recess 22nd a small cylindrical extension 23 on which there is a compression spring of the control or regulating valve 30th can support. With such a structure, the position of the actuating piston matters 22nd a force on this compression spring, which is then also referred to as a feedback spring. As a result, the open-loop or closed-loop control in which the control or regulating valve participates is established through the position of the actuating piston 22nd influences what is desired, for example, for volume flow control.

For limiting the adjustment movement for the swashplate 6th two stops ensure the setting piston 22nd in the area of the blind hole 11a . A first stop to limit the maximum pivot angle is through the bottom of the blind hole 11a formed, so that here the maximum insertion path of the setting lever 21st into the blind hole 11a is limited into it. A second stop for the actuating piston 22nd To limit the minimum swivel angle, the machine housing protrudes over a large area 8th in the area of the blind hole 11a educated.

The arrangement described enables the overall length of the connection plate to be used 11 for accommodating the control or regulating valve 30th . This can be inserted into the connection plate from the outside 11 inserted or screwed in, so that a simple exchange of the valve 30th is possible.

In the schematic representation of the 2 the axial piston machine is now with several attached hydraulic components 50 , 51 , 52 shown, the sandwich-like stacked and on the housing side on the connection plate 11 are attached. Such a hydraulic component is also a control valve or a regulating valve. For a better differentiation from a control or regulating valve 30th , which is built into the connection plate, becomes one on the outer surface of the connection plate 11 attached hydraulic component referred to as control or regulator unit. There can also be several control units on the outer surface of the connection plate 11 be attached. Likewise, several control units can be placed on the outer surface of the connection plate 11 be attached. In the same way, one control unit or several control units can have one control unit or with several control units in the corresponding position like the units 50 , 51 , 52 on the connection plate 11 be attached.

These said units mounted on the sub-base 50 , 51 , 52 are in close proximity to the position where, in the event of the presence of a control or regulating valve 30th in the connection plate 11 can be screwed in. This compact arrangement offers the advantage of short oil connections, which also run in the solid valve or controller housings and the connection plate. This results in a robust construction, which is clearly advantageous in the application for mobile work machines, where particularly high and frequently occurring shock and vibration loads are present.

• Die direkt auf der Anschlussplatte befestigte Einheit 50 kann eine elektrisch ansteuerbare Druckreduzierungseinheit sein. Über eine elektrische Ansteuerung wird am dortigen Druckausgang der gewünschte Steuerdruck erzeugt, der auf den Ventilkolben des Steuerventils 30 einwirkt. Steuerventil 30 kann ein Volumenstrom-Steuerventil sein. Bei den über der Druckreduzierungseinheit 50 befestigten Einheiten kann es sich um eine Druckabschneidung 51 und eine Load-Sensing-Einheit 52 handeln.

A specific application example of the schematic embodiment shown can be the following arrangement:

• The unit attached directly to the connection plate 50 can be an electrically controllable pressure reduction unit. The desired control pressure is generated at the pressure output there via an electrical control, which is applied to the valve piston of the control valve 30th acts. Control valve 30th can be a volume flow control valve. For those above the pressure reduction unit 50 attached units may be a pressure cutoff 51 and a load sensing unit 52 act.

The sandwich-like stacked units 50 , 51 , 52 are also in the plan view of the 3 recognizable. The 4th shows again the top view of 3 , but with the control or regulator axes shown in dashed lines 50a , 51a , 52a the control or regulating units 50 , 51 , 52 and the central longitudinal axis of the drive shaft, also shown in dashed lines 1 . It can be clearly seen that all said axes 50a , 51a , 52a of the units 50 , 51 , 52 perpendicular to the longitudinal axis of the drive shaft 2 stand. It can also be clearly seen that in the exemplary embodiment the respective longitudinal axes of the drive shaft 1 , the control lever 21st , the actuating piston 22nd and the control valve all on a common half plane E1 * lie. The half plane E1 * is limited by the longitudinal axis of the drive shaft. Regardless of the position of the setting piston, it is always the same half-plane E1 * .

In addition, the 4th infer that all control or regulator axes 52a , 51a , 50a of the units 52 , 51 , 50 run in pairs parallel to each other.

The control or regulator units 50 , 51 , 52 can be used regardless of the direction of rotation of the drive shaft or that of the engine. If the direction of rotation is changed, these units only need to be rotated by 180 ° in relation to their longitudinal direction.

• Durch die geringe Winkeländerung des Stellhebels 21 zur Mittelachse des Stellkolbens 22 wird eine nahezu querkraftfreie Kraftübertragung im Bereich des Stellkolbens 22 erreicht. Dazu trägt auch das Eintauchen des kugeligen Bereiches des Stellhebels 21 in den inneren Bereich des Stellkolbens 22 bei.

Further advantages of the structural arrangement which relate to the axial piston machine according to the invention:

• Due to the slight change in the angle of the adjusting lever 21st to the central axis of the actuating piston 22nd there is almost no transverse force transmission in the area of the setting piston 22nd reached. The immersion of the spherical area of the adjusting lever also contributes to this 21st in the inner area of the actuating piston 22nd at.

The even load on the swash plate bearing is particularly advantageous 40 by the forces from the adjustment device introduced centrally to the bearing points.

The arrangement of the control and regulating valves as well as the control and regulation units ensures that the installation space required for tandem operation of several axial piston machines is not blocked by them.

List of reference symbols

1

Drive shaft

2

Engine drum

3

Engine pistons

4th

Cylinder bores

5

Sliding shoe

6th

Swashplate

7th

Compression spring 7th

8th

Main body

9

Retraction ball

10

Retraction plate

11

Connection plate

11a

Blind hole

12

feather

13

Control plate

21st

Control lever

22nd

Control piston 22nd

23

cylindrical extension

30th

Control or regulating valve

40

Swashplate bearing

50

Pressure reduction unit

50a

Control or regulator axis

51

Pressure cut-off

51a

Control or regulator axis

52

Load sensing unit

52a

Control or regulator axes

E1a

level

E1 *

Half plane

Claims (9)

Axial piston machine comprising a drive shaft (1), a drive unit (20) connected to it in a rotationally fixed manner with one or more drive unit pistons (3), the piston stroke of which is adjustable by a swash plate (6), with at least one return spring (7) acting on the swash plate (6) and an adjusting piston (22) supported on the swash plate (6), the axial piston machine having at least one control or regulating valve (30) or at least one control or regulator unit, characterized in that an actuating piston (22) is guided in the connection plate (11) and an actuating lever ( 21) acts as a coupling element between actuating piston (22) and swash plate (6) and the actuating piston axis and the actuating lever axis are located on a plane E1, in particular on a half-plane E1 * starting from the drive shaft axis M. Axial piston machine according to Claim 1 , characterized in that the actuating piston axis runs parallel to the drive shaft axis M and the actuating lever axis is located in the plane E1 and in particular in a half-plane E1 * extending from the drive shaft axis M. Axial piston machine according to Claim 1 or 2 characterized in that the actuating lever (21) enables approximately parallel functional positions to the drive shaft axis M and / or approximately coaxial functional positions to the actuating piston axis, preferably an angular deviation from the respective axis of less than 3 °, preferably less than 2 ° and is particularly preferably made possible by less than 1 °. Axial piston machine according to Claim 2 or 3 , characterized in that the central axis course of the at least one return spring (7) is in the plane E1 and in particular in a half-plane E1 * starting from the drive shaft axis M. Axial piston machine according to Claim 4 , characterized in that the plane E1 and in particular the half-plane E1 * emanating from the drive shaft axis M runs centrally or almost centrally to the swash plate bearing (40). Axial piston machine according to one of the preceding claims, characterized in that a control or regulator valve (30) is in the connection plate (11), the axis of this control or regulating valve (30) being on the half-plane E1 * and preferably the axis this control or regulating valve (30) is arranged parallel to the drive shaft (1). Axial piston machine according to one of the Claims 1 to 5 or 6th , characterized in that at least one control or regulator unit (50, 51, 52) is arranged on the connection plate (11), the axis (50a, 51a, 52a) of the control or regulator unit (50, 51, 52) being approximately at right angles and preferably at right angles to the half-plane E1 *. Axial piston machine according to Claim 7 , characterized in that several units (50, 51, 52) for control and / or regulation are arranged on the connection plate (11), each axis (50a, 51a, 52a) of such a control or regulating unit (50, 51, 52) either runs approximately at right angles and preferably at right angles to the half plane E1 * or runs approximately parallel and preferably at right angles to the half plane E1 *. Axial piston machine according to Claim 6 , characterized in that each axis of the control or regulator valves (30) built into the connection plate (11) is approximately at right angles and preferably at right angles to at least one axis (50a, 51a, 52a) of a control or regulator unit arranged on the connection plate (11) (50, 51, 52) is aligned.

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