DE102020203450A1 - Axial piston machine with controlled cylinder pressure and control panel adjusted by means of a regulator - Google Patents

Abstract

The invention relates to an axial piston machine (10) with a cylinder drum (60) which can be rotated with respect to an axis of rotation (30) and has an end face (63) pointing in the direction of the axis of rotation (30), the end face (63) in the direction of the axis of rotation (30) ) can be pressed by a piston-cylinder unit (80) against a control surface (54), the piston-cylinder unit (80) being able to be acted upon with a control pressure for this purpose, wherein the control surface (54) can be arranged in a rotationally fixed manner.
According to the invention, the control pressure (85) is provided via an adjustable control valve (90), the control valve (90) being connected to a control device (92) in such a way that it can be adjusted by the control device (92), the control device (92) having a Controller (100) implemented, the manipulated variable (101) of which influences the setting of the control valve (90).

Description

The invention relates to an axial piston machine according to the preamble of claim 1.

From the DE 39 04 782 A1 an axial piston machine in swash plate design is known. A piston-cylinder unit is arranged between the drive shaft and the cylinder drum, with which an end face of the cylinder drum can be pressed against a control surface. The control pressure in the piston-cylinder unit is taken from the control recess in which the high pressure is applied.

One advantage of the present axial piston machine is that the leakages occurring between the end face and the control surface are minimal under all operating conditions. The axial piston machine can be operated at particularly high speeds and at particularly high pressure.

According to claim 1, it is proposed that the control pressure is provided via an adjustable control valve, the control valve being connected to a control device in such a way that it can be adjusted by the control device, the control device implementing a regulator whose manipulated variable influences the setting of the control valve. The axial piston machine is preferably designed in a swash plate design, the piston-cylinder unit being supported on the drive shaft. The axial piston machine can also have a bent axis design. The control valve is preferably electrically adjustable. The control device preferably comprises a digital computer, the controller being implemented digitally. The controller is preferably a continuous, linear controller which is most preferably calculated in a time-discrete manner. The controller is preferably a PI controller.

Advantageous developments and improvements of the invention are specified in the dependent claims.

It can be provided that the control pressure is connected to a first pressure sensor, the first pressure sensor being connected to the control device, an actual variable of said controller being a measured value of the first pressure sensor, a target variable of the controller at least depending on a high pressure of the axial piston machine can be selected. It would also be conceivable that the actual size is determined with a sensor which directly measures the thickness of the hydrostatic lubricating film between the end face and the control surface. Ultimately, it is precisely this thickness that should have a defined value, so that with the least possible leakage there is still an essentially complete hydraulic relief between the end face and control surface. However, such a fluid film thickness sensor is extremely expensive. With the proposed first pressure sensor, which is significantly more cost-effective, a comparable result can be achieved if the assigned target value is selected as proposed.

Complete hydraulic relief should be understood to mean a state in which there is no mechanical contact whatsoever between the end face and the control surface, the pressure force there being transmitted hydrostatically via the pressure fluid used in the axial piston machine. The pressure fluid is preferably a liquid and most preferably hydraulic oil. The axial piston machine preferably has a first and a second working connection, a rotation of the cylinder drum being accompanied by a fluid flow between the first and the second working connection. The axial piston machine can be 4-quadrant capable, i.e. it can be operated with two opposite directions of rotation of the cylinder drum and in each direction of rotation with two opposite flow directions, regardless of the pressures applied to the first and second working port. The high pressure is the higher pressure from the pressure at the first working connection and the pressure at the second working connection. The high pressure is preferably connected to a second pressure sensor. The second pressure sensor is preferably connected to the control device.

Provision can be made for at least one first characteristic diagram to be stored in the control device which has at least the high pressure as an input variable, it having the setpoint variable of the controller as an output variable. The first and / or the second characteristic diagram discussed further below can be implemented in the form of a table of values. It is also possible to implement the first and / or the second characteristic diagram using mathematical interpolation formulas. Mixed forms of these two types of implementation are also conceivable. It is conceivable that the first and the second characteristic diagram explained further below are determined experimentally using the fluid film thickness sensor mentioned above in such a way that the desired ratios result. It is also conceivable that the first and / or the second characteristic diagram are determined by computer simulation.

It can be provided that the first characteristic map has a speed of the cylinder drum and / or a pivot angle of the axial piston machine and / or a viscosity of the pressure fluid as a further input variable. The axial piston machine preferably has an adjustable displacement volume. In the case of a swashplate machine, the swivel angle describes the pivoting of the swivel cradle required for this. In the case of a bent axis machine, the swivel angle describes the angle between the axis of rotation of the drive shaft and the axis of rotation of the cylinder drum. The viscosity of the printing fluid is preferably determined using a temperature sensor, the viscosity of which is determined from the corresponding measured value and a temperature-viscosity characteristic curve of the printing fluid.

A fluid source can be provided via which the control valve is supplied with pressurized fluid. The fluid source is preferably formed by the first and / or the second working connection. The first and the second working connection can be connected on the inlet side to a shuttle valve, the control valve being connected on the outlet side to the shuttle valve. The fluid source can also be formed by a separate control oil pump.

It can be provided that the control valve comprises a single, continuously adjustable control panel, an opening cross-section of the control panel being adjustable by means of the control device. There is preferably a time-invariant relationship between the corresponding actuating signal at the control valve and the opening cross-section of the control panel. In particular, the relationship mentioned is not defined by other, subordinate control loops. For example, the actuating current at the control valve is approximately proportional to the opening cross-section of the control orifice. The control valve is preferably a 2/2-way proportional directional valve, which is most preferably designed to be directly controlled. It is also conceivable to use a 3/2-way proportional directional valve which is additionally connected to a fluid sink, for example the essentially pressureless interior of the housing or to a tank. It is also conceivable to use a pressure reducing valve as the control valve, so that the control pressure is regulated hydraulically. With the previously proposed very simple control valve, however, the following improvements can be made to the control method, which significantly improve the stability of the overall system without increasing the hardware expenditure as a result.

It can be provided that a setting of the control valve is determined from the manipulated variable of the controller and a pilot control variable, the pilot control variable at least depending on the high pressure of the axial piston machine. In this way, the period of time until a regulated state is reached can be minimized. The stability of the control is also improved. The setting of the control valve is preferably determined by adding up the manipulated variable of the controller and the pilot control variable.

It can be provided that at least one second characteristic map, which is different from the first, is stored in the control device, the second characteristic map having at least the high pressure of the axial piston machine as an input variable, wherein it has the pilot control variable as an output variable. The first and the second characteristic diagram can be combined to form a multi-dimensional characteristic diagram, that is to say to form a characteristic diagram that has several output variables. In contrast, the first and / or the second characteristic diagram preferably has only a single output variable.

It can be provided that the second characteristic diagram has a speed of the cylinder drum and / or a pivot angle of the axial piston machine and / or a viscosity of the pressure fluid as a further input variable. This allows the pilot control variable to be flexibly adapted to the different operating conditions of the axial piston machine.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or on their own, without departing from the scope of the present invention.

• 1 einen Längsschnitt einer erfindungsgemäßen Axialkolbenmaschine;
• 2 einen hydraulischen Schaltplan der Axialkolbenmaschine nach 1;
• 3 einen Ausschnitt von 1 im Bereich der Kolben-Zylinder-Einheit;
• 4 einen Längsschnitt der Zylindertrommel;
• 5 eine Seitenansicht der Zylindertrommel nach 4;
• 6 eine perspektivische Ansicht der Steuerplatte; und
• 7 einen Schaltplan der Regelung der Axialkolbenmaschine nach 1.

The invention is explained in more detail below with reference to the accompanying drawings. It shows:

• 1 a longitudinal section of an axial piston machine according to the invention;
• 2 a hydraulic circuit diagram of the axial piston machine 1 ;
• 3 a section of 1 in the area of the piston-cylinder unit;
• 4th a longitudinal section of the cylinder drum;
• 5 a side view of the cylinder drum according to 4th ;
• 6th a perspective view of the control plate; and
• 7th a circuit diagram of the control of the axial piston machine according to 1 .

1 shows a longitudinal section of an axial piston machine according to the invention 10 . The axial piston machine 10 includes a housing 40 , which in the present case consists of a first and a second housing part 41 ; 42 is composed. The first housing part 41 is designed like a pot, with the open side of the plate-like second housing part 42 is covered, so that there is a closed interior. In the case 40 is a drive shaft 33 with a first and a second pivot bearing 31 ; 32 with respect to an axis of rotation 30th rotatably mounted. The first and the second Pivot bearing 31 ; 32 are designed here as tapered roller bearings. The drive shaft 33 protrudes with a tenon 34 out of the case 40 out, which is provided with a spline in the present case.

Inside the case 40 is the drive shaft 33 from a cylinder drum 60 surrounded by splines (no.66 in 4th ) with respect to the axis of rotation 30th non-rotatably with the drive shaft 33 connected is. The cylinder drum 60 has one in the direction of the axis of rotation 30th pointing face 63 with which they are at a control surface 54 is present. The frontal area 63 is in the present case flat and perpendicular to the axis of rotation 30th arranged. But it can also be one with respect to the axis of rotation 30th rotationally symmetrical face 63 be used, which is curved, for example, concave. The latter is common, for example, in an axial piston machine with a bent axis design. In the cylinder drum 60 are several linearly movable working pistons 13th added, which is preferably evenly distributed around the axis of rotation 30th are arranged around. An axis of movement of the working piston 13th is in the present case slightly inclined to the axis of rotation 30th arranged.

The control surface 54 is present on a separate control plate 50 arranged, and they are also directly on the housing 40 can be arranged. The control panel 50 is with respect to the axis of rotation 30th non-rotatably with the housing 40 connected, taking them in the direction of the axis of rotation 30th on the housing 40 is supported. Accordingly, there is between the end face 63 and the control surface 54 when operating the axial piston machine 10 a relative rotation, whereby a hydrostatic lubricating film is formed there. One advantage of the invention is that the leakages caused by this lubricating film are minimal under all operating conditions, with minimal wear being observed at the same time. The axial piston machine 10 can in particular be operated at high pressures and / or high speeds.

The present axial piston machine 10 is designed in swash plate design, the present invention can also be used for axial piston machines in bent axis design. The swivel cradle 15th is pivotable with respect to a pivot axis which is perpendicular to the axis of rotation 30th is arranged. In the present case, the pivot axis intersects the axis of rotation 30th , whereby they are also at a distance from the axis of rotation 30th can be arranged. The working piston 13th are each over a sliding shoe 14th on a flat surface of the swivel cradle 15th supported, the corresponding contact surfaces are preferably hydraulically relieved. The swivel angle of the swivel cradle is in the present case by means of a first and a second adjusting cylinder 16 ; 17th , which are each designed as a single-acting cylinder, adjustable. The present axial piston machine 10 can be adjusted above zero, ie the direction of flow can be adjusted simply by swiveling the swivel cradle 15th reverse without changing the direction of rotation of the cylinder drum. However, the present invention can also be used for axial piston machines which, starting from the displacement volume of zero, can only be adjusted in one direction, or for axial piston machines whose displacement volume is constant.

The piston-cylinder unit should also be pointed out 80 with which the cylinder drum 60 to the control surface 54 can be hydraulically pressed in a defined manner, with further details referring to the explanations 3 is referred.

2 shows a hydraulic circuit diagram of the axial piston machine 10 after 1 . The axial piston machine 10 has a first and a second working connection 11 ; 12th , which in the present case is attached to the second housing part (no. 42 in 1 ) are arranged. The axial piston machine 10 is 4-quadrant-capable in the present case, ie it can be operated with two opposite directions of rotation of the drive shaft, with two opposite flow directions being possible in both cases. The pressure at the first and second working port 11 ; 12th can be largely arbitrary. As a result, the axial piston machine 10 work alternately as a pump and as a motor. The drive shaft of the axial piston machine 10 stands with an engine 12th in rotary drive connection, which can be designed as an electric motor or an internal combustion engine. The drive shaft rotates with a fluid flow between the first and the second working port 11 ; 12th as long as the set displacement is different from zero.

The set swivel angle, and indirectly the displacement volume, is present with a swivel angle sensor 113 measurable. The temperature of the pressure fluid, and indirectly its viscosity, is present with a temperature sensor 115 measurable which at the first or the second working connection 11 ; 12th can be connected. The speed of the drive shaft or the cylinder drum is preferably provided with a speed sensor 114 measurable.

The first and the second working port 11 ; 12th are on the inlet side of a shuttle valve 22nd connected. The higher pressure from the pressure at the first working connection is therefore at its output 11 and the pressure at the second working connection 12th at. This pressure is referred to as letterpress in the context of the present application 20th designated. In the present case, it serves as a fluid source 21 for the supply of the control valve 90 with pressure fluid. It should be noted here that a separate control oil pump can also be used as the fluid source. Of the High pressure 20th is present with a second pressure sensor 112 measured.

The high pressure 20th is via a control valve 90 to the two transfer recesses 55 in the control panel 50 routed in parallel to the control valve 90 are connected. The control valve 90 includes a continuously adjustable control panel 91 whose opening cross-section is adjustable from zero to a predetermined maximum value. The adjustment is preferably done electrically, most preferably by means of an electromagnet 94 whose actuating force acts directly on the valve slide or the valve cone of the control valve 90 acts. The control valve 90 is present by means of a spring 93 biased to the locked position. In the present case, it is designed as a 2/2-way proportional valve. The one downstream of the control panel 91 applied pressure is called control pressure 85 designated. The control pressure 85 is present by means of a first pressure sensor 111 measured. Alone 2 sensors shown 111 ; 112 ; 113 ; 114 ; 115 are to a control device 92 connected, with the electromagnet there as well 94 of the control valve 90 is connected so that the control valve 90 by the control device 92 is adjustable. The control device 92 implements those below with reference to 7th described scheme. It preferably comprises a programmable digital computer.

3 shows a section of 1 in the area of the piston-cylinder unit 80 . The piston-cylinder unit 80 comprises a first and a second annular piston 81 ; 82 , each between the drive shaft 33 and the cylinder drum 60 are included. The corresponding, preferably with respect to the axis of rotation 30th circular cylindrical, contact gaps are each with a sealing ring 86 , in particular an O-ring, sealed in a substantially fluid-tight manner. The first ring piston 81 is in the direction of the axis of rotation 30th from the control surface (No. 54 in 1 ) away from a shoulder on the drive shaft 33 positively supported. The second ring piston 82 is in the direction of the axis of rotation 30th on the control surface (No. 54 in 1 ) to via a locking ring 87 on the cylinder drum 60 supported. The cylinder drum 60 , the drive shaft 33 and the first and second annular pistons 81 ; 82 together delimit a fluid space 84 , which except for the fluid channels 65 is essentially closed in a fluid-tight manner. The cylinder drum 60 is in the direction of the axis of rotation 30th minimal mobility in relation to the drive shaft 33 so that the one in the fluid space 84 pending control pressure 85 the cylinder drum 60 against the control surface (No. 54 in 1 ) presses. The corresponding counterforce is generated via the drive shaft 33 on the first pivot bearing (No. 31 in 1 ) supported. The installation position of the corresponding tapered roller bearing is selected accordingly so that the two tapered roller bearings form an O-arrangement.

The appendix should also be pointed out 83 on the first and on the second annular piston 81 ; 82 . These are initially arranged so that the first and the second annular piston 81 ; 82 the mouth openings 68 the fluid channels can not cover. Next is the corresponding surface on which the first and the second annular piston 81 ; 82 can come to rest, small compared to the entire end face of the first or the second annular piston 81 ; 82 executed. The annular piston is thus in every position 81 ; 82 ensures that the control pressure 85 a sufficiently high pressure of the cylinder drum 60 on the control surface (No. 54 in 1 ) causes.

4th shows a longitudinal section of the cylinder drum 60 . A cylinder bore can be seen 64 , with all cylinder bores 64 are executed identically. The cylinder bore 64 has a circular cylindrical section 67 , in which the assigned working piston (No. 13 in 1 ) is accommodated in a linearly movable and essentially fluid-tight manner. The circular cylindrical section can be formed by a separate liner made of a plain bearing material such as bronze. The cylinder bore 64 opens with a first mouth opening 61 on the face 63 the end. The cross-sectional area of the first orifice 61 can be equal to the cross-sectional area of the circular cylindrical section 67 or be a little smaller. In the latter case, it is solely due to the hydraulic forces in the cylinder bore 64 a pressing of the cylinder drum 60 to the control surface (No. 54 in 1 ) causes. In the context of the present invention, this force should be compared to that with the piston-cylinder unit (No. 80 in 3 ) achievable force should not be too great, so that a meaningful control of the corresponding contact force is possible. The present invention enables particularly large first mouth openings 61 so that the axial piston machine even at very high speeds of the cylinder drum 60 not cavitated in the suction area.

Between two adjacent cylinder bores 64 is each a fluid channel 65 arranged, which so inclined to the axis of rotation 30th runs that it on the one hand with a second mouth opening 62 on the face 63 opens out, with a third mouth opening at the opposite end 68 into the fluid space (No. 84 in 3 ) flows out. All fluid channels 65 are designed to be identical to one another. They are straight, and in the present case they are designed as circular cylindrical stepped bores. The section that has the second orifice 62 forms, has a smaller diameter than the other section. This is intended to minimize the area of the assigned transfer recesses (No. 55 in 6th ) can be achieved so that the hydraulic force acting there is small compared to the force of the piston-cylinder unit.

The cylinder drum 60 is formed in one piece in the present case. In particular in the area of the circular cylindrical section 67 and the face 63 it can be surface-hardened, for example nitrocarburized. The cylinder drum 60 consists for example of steel or cast iron.

5 shows a side view of the cylinder drum 60 after 4th . The shape of the first mouth openings, which deviates from the circular shape, can be seen 61 . Their width in the radial direction is in particular made smaller than their length in the circumferential direction. The first muzzle openings 61 are as close as possible to the splines 66 arranged so that there particularly low centrifugal forces act on the pressure fluid. This measure allows the maximum permissible speed of the cylinder drum 60 can be increased. The first muzzle openings 61 define a reference circle 70 whose center is the axis of rotation 30th is. The radially outermost point of each first orifice 61 lies on this reference circle 70 . The second mouth openings 62 are all radially outside the reference circle 70 arranged. This means that the cylinder drum does not exist in any position 60 a direct fluid connection between the cylinder bores 64 and the control pressure (No. 85 in 2 ). Instead, this always runs via the adjustable control panel (No. 91 in 2 ).

There are a total of nine cylinder bores 64 provided, which are uniformly distributed around the axis of rotation 30th are arranged around. Between all cylinder bores 64 is in the present case in each case a fluid channel with a corresponding second mouth opening 62 arranged. The spacing (No. 71 in 4th ) of all second mouth openings to the axis of rotation 30th is executed the same. In principle, it is conceivable only between some of the cylinder bores 64 to provide a fluid channel. Then the transfer recesses (No. 55 in 6th ) extend over a larger section of the circumference, so that there are greater hydraulic forces, which is undesirable.

6th Figure 3 shows a perspective view of the control plate 50 from the control surface 54 here. The control panel 50 is essentially designed as a flat plate with a constant thickness. Your in 6th the invisible back is completely flat. The control surface 54 is on the other hand with an inner ring recess 57 , an annular groove 56 and an outer ring recess 58 Mistake. The inner ring recess 57 and the ring groove 56 defines the surface with which the control surface 54 in the area of the first and the second control recess 51 ; 52 rests against the end face of the cylinder drum. This area defines the leakages that occur there. It is designed in such a way that under all operating conditions a hydrostatic lubricating film is formed that is so thick that the end face is essentially completely removed from the control surface 54 is separated. However, the lubricating film mentioned should not be thicker.

The first and the second control recess 51 , 52 are each designed as circular curved elongated holes, the corresponding circle center from the axis of rotation 30th is defined. They are aligned with the first mouth openings (No. 61 in 6th ) of the cylinder drum. In the circumferential direction they can have notches at both ends 53 be provided with which pressure peaks during operation of the axial piston machine are minimized. The first and the second control recess 51 ; 52 enforce the control plate 50 in the direction of the axis of rotation 30th . They are designed to be mirror-symmetrical, since the present axial piston machine is 4-quadrant capable.

Between the ring groove 56 and the outer ring recess 58 are the two transfer recesses 55 arranged. These enforce the control plate 50 in the direction of the axis of rotation 30th . They are each designed as a circularly curved elongated hole, the corresponding center point of the circle from the axis of rotation 30th is defined. Its width in the radial direction is equal to the corresponding width (No. 72 in 4th ) of the second mouth openings, whereby they are arranged in alignment with these. Their length in the circumferential direction is chosen so that in each rotational position of the cylinder drum at least one second mouth opening above a transfer recess 55 stands. Their length is slightly greater than half of the in 5 visible spacing of the second mouth openings. The two transfer recesses 55 are arranged in mirror image to each other. It goes without saying that any number of transfer recesses 55 can be used as long as their length is designed accordingly in the circumferential direction.

The ring groove 56 is at the bottom of the groove with a second breakthrough 132 provided which the control plate 50 in the direction of the axis of rotation 30th interspersed. There they will be in the ring groove 56 accumulating leakage is diverted to the interior of the housing, in order to be passed from there via a leakage connection on the housing into a tank. The first breakthrough 131 in the center of the control plate 50 is driven by the drive shaft (No. 33 in 1 ) interspersed.

7th shows a circuit diagram of the control of the axial piston machine 1 . The corresponding controller 100 is preferably a continuous, linear controller, whereby it is designed, for example, as a PI controller. The control deviation 105 is the difference between a target size 103 and an actual size 102 educated. The actual size is that of the first pressure sensor 111 measured control pressure. The target size 102 is by means of a first map 121 determined. Its input variable is that with the second pressure sensor 112 measured high pressure, the readings of the speed sensor 114 and / or the swivel angle sensor 113 and / or the temperature sensor 115 can be used as further input variables. The first map 121 is designed so that the regulation results in an essentially constant thickness of the hydrostatic lubricating film between the end face of the cylinder drum and the control surface.

The manipulated variable 101 of the controller acts on the control valve 90 . The control valve 90 can use a single adjustable control panel 91 as the inevitable leaks result in a constant drop in the control pressure (No. 85 in 2 ) if this effect is not achieved by opening the control panel accordingly 91 is counteracted.

It has been shown that this particularly simple control enables particularly stable system behavior to be achieved.

The regulator 100 can be supplemented by a feedforward control. The corresponding input tax figure 104 is preferably used as the manipulated variable 101 of the controller 100 added. The manipulated variable 104 can by means of a second map 122 be determined. The input variables of the second map 122 can read the measured values of the second pressure sensor 112 and / or the speed sensor 114 and / or the swivel angle sensor 113 and / or the temperature sensor 115 be. The second map 112 can be determined, for example, by operating a system without pilot control with constant measured values at the sensors mentioned until a constant manipulated variable is obtained 101 levels off. This manipulated variable is then used as a pre-control variable. This measure can shorten the period of time until a regulated state is reached.

List of reference symbols

n

Speed of the cylinder drum

T

Temperature of the pressure fluid

α

Swivel angle

10

Axial piston machine

11

first working connection

12th

second working connection

13th

Working piston

14th

Sliding shoe

15th

Swivel cradle

16

first adjusting cylinder

17th

second adjusting cylinder

20th

High pressure

21

Fluid source

22nd

Shuttle valve

23

engine

30th

Axis of rotation

31

first pivot bearing

32

second pivot bearing

33

Drive shaft

34

Cones

40

casing

41

first housing part

42

second housing part

50

Control plate

51

first tax recess

52

second control recess

53

score

54

Control surface

55

Transfer recess

56

Ring groove

57

inner ring recess

58

outer ring recess

60

Cylinder drum

61

first mouth opening

62

second mouth opening

63

Face

64

Cylinder bore

65

Fluid channel

66

Splines

67

circular cylindrical section of the cylinder bore

68

third mouth opening

70

Reference circle

71

radial distance of a second mouth opening to the axis of rotation

72

Diameter of the second mouth opening measured in the radial direction

80

Piston-cylinder unit

81

first annular piston

82

second ring piston

83

Appendix

84

Fluid space

85

Control pressure

86

Sealing ring

87

Circlip

90

Control valve

91

Control panel

92

Control device

93

feather

94

Electromagnet

100

Regulator

101

Manipulated variable

102

Actual size

103

Target size

104

Input tax quantity

105

Control deviation

111

first pressure sensor

112

second pressure sensor

113

Swivel angle sensor

114

Speed sensor

115

Temperature sensor

121

first map

122

second map

131

first breakthrough

132

second breakthrough

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 3904782 A1 [0002]

Claims (9)

Axial piston machine (10) with a cylinder drum (60) which can be rotated with respect to an axis of rotation (30) and has an end face (63) pointing in the direction of the axis of rotation (30), the end face (63) in the direction of the axis of rotation (30) by a piston -Cylinder unit (80) can be pressed against a control surface (54), wherein the piston-cylinder unit (80) can be acted upon with a control pressure (85) for this purpose, wherein the control surface (54) can be arranged non-rotatably, characterized in that the control pressure (85) is provided via an adjustable control valve (90), the control valve (90) being connected to a control device (92) in such a way that it can be adjusted by the control device (92), the control device (92) being a regulator (100) implemented, the manipulated variable (101) of which influences the setting of the control valve (90). Axial piston machine according to Claim 1 , the control pressure (85) being connected to a first pressure sensor (111), the first pressure sensor (111) being connected to the control device (92), an actual variable (102) of said controller (100) being a measured value of the first pressure sensor (111), a setpoint value (103) of the controller (100) being selectable at least as a function of a high pressure (20) of the axial piston machine (10). Axial piston machine according to one of the preceding claims, wherein in the control device (92) at least one first map (121) is stored, which has at least the high pressure (20) as an input variable, it being the target variable (103) of the controller (100) as Has output size. Axial piston machine according to one of the preceding claims, wherein the first map (121) has a speed (n) of the cylinder drum (60) and / or a pivot angle (α) of the axial piston machine (10) and / or a viscosity of the pressure fluid as a further input variable. Axial piston machine according to one of the preceding claims, wherein a fluid source (21) is provided, via which the control valve (90) is supplied with pressure fluid. Axial piston machine according to one of the preceding claims, wherein the control valve (90) comprises a single, continuously adjustable control panel (91), an opening cross-section of the control panel (91) being adjustable by the control device (92). Axial piston machine according to one of the preceding claims, wherein a setting of the control valve (90) is determined from the manipulated variable (101) of the controller (100) and a pilot control variable (104), the pilot control variable (104) at least from the high pressure (20) of the axial piston machine (10) depends. Axial piston machine according to one of the Claims 3 until 7th , wherein in the control device (92) at least one second map (122) different from the first (121) is stored, the second map (122) having at least the high pressure (20) of the axial piston machine (10) as an input variable, it being the pilot control variable (104) as the output variable. Axial piston machine according to Claim 8 , the second characteristic map (122) having a speed (n) of the cylinder drum (60) and / or a pivot angle (a) of the axial piston machine (10) and / or a viscosity of the pressure fluid as a further input variable.

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