DE102018212042A1 - Hydraulic machine with regulated displacement - Google Patents

Abstract

Disclosed is a hydraulic machine with an adjustable stroke volume, and with an actuator element, of which a hydrostatic signal pressure space is limited in sections, an actuator element being articulated directly or indirectly from the position of which the stroke volume is dependent, at least for supplying the signal pressure space with signal pressure medium Directional control valve is provided, which has a valve body coupled to the actuator element, which is movable as a function of an actuating force acting on it and a coupling force, and of which a first throttle cross section, which is continuously adjustable as a function of this movement, is limited in sections, via which a pressure medium source is also fluidly connected the signal pressure space is connectable.

Description

The invention relates to a hydraulic machine according to the preamble of patent claim 1.

Depending on the requirements, hydraulic machines, in particular hydraulic pumps, are subject to a variety of strategies for regulating the pressure, a pressure difference above a load pressure, a cut-off pressure and even performance. If the hydraulic machine is designed with an adjustable displacement volume, the displacement volume can be used as the manipulated variable. The regulators used are of a hydromechanical design and influence a pressure or a pressure medium volume flow of a signal pressure medium with which an adjusting device of the hydraulic machine is acted upon. The controllers are designed as directional valves, the valve body of which is acted upon on the one hand by a setpoint value and on the other hand by a feedback actual value.

In order to regulate the displacement volume, so-called electro-proportional adjustment of the displacement volume is known from data sheet RE 92703 / 10.2014 by the applicant. A control pressure chamber of an adjustment cylinder, which is coupled to a swash plate of the hydraulic machine, is supplied with control pressure medium via the control valve. The control valve is actuated electromagnetically in accordance with a setpoint, the electromagnetic actuating force acting on the valve piston in accordance with the setpoint. To counteract this, the position of the swivel cradle is coupled back to the valve body in a force-coupled manner. Depending on an equilibrium of forces on the valve body, signal pressure medium is then either fed into the signal pressure space or released from it. The displacement volume increases upon discharge, whereas it decreases when pressurized. Generic hydraulic machines are in the patent DE 103 60 452 B3 and in the published application DE 10 2013 224 112 A1 described by the applicant.

If the signal pressure medium leaks out of the signal pressure space in the direction of a pressure medium sink, the adjustment piston is initially displaced in the direction of a reduction in the signal pressure space. If the nominal value remains the same, that is to say the actuating force acting on the valve piston of the regulator remains constant, this adjustment also leads to its adjustment by coupling the force with the valve body. As a result, signal pressure medium flows from the high pressure into the signal pressure chamber via a control edge and an associated throttle cross section of the controller. In this way, the leakage volume is replaced by means of the regulating action of the controller. The volume flow over the control edge causes a flow force that shifts on the valve body and thus closes the throttle cross section again. The greater the pressure loss across the control edge, the greater this. The equilibrium of forces on the piston is restored when the compression of the spring arranged between the actuating piston and the valve piston, caused by the flow force, compensates for the flow force. The described relationship between leakage, control intervention, flow force and increased coupling force of the spring leads to an unexpected and undesired drift of the actual value towards a larger displacement volume for a given setpoint.

In contrast, the invention has for its object to provide a hydraulic machine with less drift of the displacement volume.

This object is achieved by a hydraulic machine with the features of patent claim 1.

Advantageous developments of the hydraulic machine are described in claims 2 to 14.

A hydraulic machine has an adjustable stroke volume and an actuator element, of which a hydrostatic signal pressure space is limited in sections, an actuator element of the hydraulic machine being articulated directly or indirectly by the actuator element, the position of which depends on the stroke volume. At least to supply the control pressure chamber with control pressure medium, a control valve, in particular a directional control valve, is provided, which has a valve body coupled to the actuator element. This is movable, in particular linearly movable, as a function of an actuating force acting on it and a coupling force that results, in particular, from a position of the actuating element relative to the valve body. A first throttle cross section, which is continuously adjustable as a function of this movement, is limited in sections by the valve body, in particular in cooperation with a cylinder bore in which it is guided. Via the first throttle cross section, a pressure medium source can be fluidly connected to the signal pressure chamber for supplying it with pressure medium. According to the invention, a second throttle cross section is provided, via which the control pressure chamber can be acted upon or acted upon by pressure medium.

As a result, a leakage volume flow from the signal pressure space can be at least partially replaced or adjusted via the second throttle cross section, in addition to the first throttle cross section. As a result, the valve body experiences less or no deflection based on leakage, so that for a given setpoint, the drift of the displacement volume with the pressure before or the pressure difference over the first throttle cross-section is reduced, which improves the repeatability of the control.

In a further development, the hydraulic machine is a hydraulic pump, in particular an axial piston pump in a swashplate design. The hydraulic machine is preferably designed with a low-pressure and a pressure or high-pressure connection. It is preferably set up such that pressure medium can be conveyed from the low-pressure connection to the high-pressure connection.

The hydraulic machine is preferably designed in such a way that an enlargement of the signal pressure space causes a reduction in the stroke volume.

The pressure medium source is preferably the high-pressure connection or another high-pressure chamber of the hydraulic machine.

The actuator element is in particular an actuating piston of a hydrostatic actuating cylinder of the hydraulic machine.

The actuating force is dependent in particular on a setpoint signal for the stroke volume or a swivel angle, in particular proportional thereto. The actuating force can be generated electromagnetically, for example. For this purpose, the HM preferably has an electromagnet which - according to the setpoint signal - can be controlled with a control or excitation current, which is in particular continuously variable.

The actuating force acts on the valve body in particular in the direction of a reduction in the first throttle cross section.

The coupling is preferably a force coupling, in particular a path-dependent force coupling. This is implemented, for example, via an elastic element or an elastic unit, in particular a spring or a spring assembly. This is particularly preferably a feedback spring that is elastic in the pushing and / or pulling direction.

The actuator element and the valve body are preferably coupled via the spring in such a way that a reduction in the signal pressure space brings the actuator element closer to the valve body and / or acts in the direction of compression of the spring.

The spring is preferably arranged between the actuator element or a section connected to it and the valve body, in particular supported on both.

The directional control valve is also provided for releasing the control pressure medium from the control pressure chamber. For this purpose, a third throttle cross-section is limited in sections by the valve body, depending on its movement, and adjustable in the opposite direction to the first throttle cross-section. A pressure medium sink, in particular the low-pressure connection or a low-pressure container / tank of the hydraulic machine, can be fluidly connected to the control pressure chamber via this.

The actuating force acts on the valve body in particular in the direction of an enlargement of the third throttle cross section. This enlargement acts by increasing the pressure medium connection of the signal pressure chamber with the pressure medium sink in the direction of a reduction of the signal pressure chamber and thus an increase in the stroke volume.

The respective throttle cross section is preferably designed as an orifice. An adjustable throttle cross-section, in particular the first and third, is preferably provided with at least one control notch.

The second throttle cross section is preferably designed in such a way that an operational leakage flow out of the signal pressure chamber, in particular in the direction of the pressure medium sink, can be at least partially compensated via it, in particular by a pressure medium inflow via the second throttle cross section.

The second throttle cross section is preferably decoupled from the valve body and / or from its movement.

A further development in terms of device technology and control technology is simple, in which the second throttle cross section is fixed. The second throttle cross section can be used more flexibly, in particular due to lower drift over larger pressure or pressure difference ranges, if it is designed to be adjustable.

In a further development, the second throttle cross section is therefore designed to be adjustable as a function of a pressure of the pressure medium source and / or a pressure difference of the pressure medium source from the control pressure chamber and / or a position of the valve body.

A further development in which the signal pressure space is fluidly connected or connectable to the same pressure medium source as via the first throttle cross section via the second throttle cross section is device-technically simple and can be designed more simply with regard to the compensation volume flow that arises.

For this purpose, the first throttle cross section and the second throttle cross section are preferably connected fluidically in parallel.
The actuator element preferably has a housing with a cylinder bore, in which it is accommodated in a movable, in particular linearly movable manner, and by which the control pressure space is limited in sections.

A housing of the directional control valve, in which the valve body, in particular in a cylinder bore, is accommodated movably, in particular linearly movably, has a pressure connection which is or can be connected to the pressure medium source.

From this, a pressure medium flow path preferably branches off to the signal pressure chamber in which the second throttle cross section is arranged.

The directional control valve is arranged in a space-saving and robust manner if a housing of the directional control valve is designed in a cartridge construction and is inserted at least in sections into a larger housing or a larger housing section of the hydraulic machine.

The pressure connection of the directional control valve is preferably formed by an outer circumferential groove or an outer circumferential groove section formed on the housing of the directional control valve.

The directional control valve, the actuator element and the control pressure chamber are particularly compact if the latter is delimited at least in sections by the housing of the directional control valve, in particular from its end face, and the pressure medium flow path has an opening into the control pressure chamber.

In one development, the housing of the directional control valve and the actuator element are firmly connected and / or they are formed in one piece with one another.

Hydraulic machine according to one of the preceding claims, wherein the valve body and the actuator element, in particular the two housings in which they are each accommodated, are aligned at least in sections in the direction of movement of the valve body. In particular, their central axes are aligned.

Two exemplary embodiments of a hydraulic machine according to the invention are shown in the drawings. The invention will now be explained with reference to the figures of these drawings.

• 1 einen hydraulischen Schaltplan einer erfindungsgemäßen Hydromaschine gemäß einem ersten Ausführungsbeispiel,
• 2 ein Druck-Schwenkwinkeldiagramm einer Hydromaschine gemäß dem Stand der Technik,
• 3 ein Schwenkwinkel-Ansteuerstromdiagramm der Hydromaschine gemäß dem Stand der Technik,
• 4 ein Druck- Schwenkwinkeldiagramm der Hydromaschine gemäß 1,
• 5 ein Schwenkwinke-Ansteuerstromdiagramm der Hydromaschine gemäß 1,
• 6 eine erfindungsgemäße Hydromaschine gemäß einem zweiten Ausführungsbeispiel, und
• 7 ein Regelventil der Hydromaschine gemäß 6 in einem Längsschnitt.

Show it:

• 1 2 shows a hydraulic circuit diagram of a hydraulic machine according to the invention in accordance with a first exemplary embodiment,
• 2 2 shows a pressure swivel angle diagram of a hydraulic machine according to the prior art,
• 3 2 shows a swivel angle drive current diagram of the hydraulic machine according to the prior art,
• 4 a pressure swivel angle diagram of the hydraulic machine according to 1 .
• 5 a swivel angle drive current diagram of the hydraulic machine according to 1 .
• 6 a hydraulic machine according to the invention according to a second embodiment, and
• 7 a control valve according to the hydraulic machine 6 in a longitudinal section.

According to 1 is a first embodiment of a hydraulic machine 1 designed with adjustable displacement. It is designed as a swash plate type axial piston pump. Except for the aspects according to the invention and described later, it largely corresponds, for example, to the hydraulic machine as described in the published patent application DE 10 2013 224 112 A1 the applicant is described. A detailed description of aspects known from the prior art is omitted. The hydromachine 1 has a low pressure connection 2 , through which it can suck in pressure medium from a tank T in pump operation. It also has a pressure or high pressure connection 4 , via which they go into a pressure or high pressure line 6 promotes. Due to the design with swiveling swashplate 8th is the displacement volume on the hydraulic machine 1 proportional to the swivel angle α the swashplate. In the exemplary embodiment shown, this is between a swivel angle α = 0 and a maximum swivel angle α _max pivotable. An adjustment of the swivel angle α from 0 to α _max , corresponds to an increase in the displacement volume and a so-called swiveling to the maximum. The swashplate 8th is with an adjusting device in the form of an actuating cylinder 10 coupled. This has an actuating piston 12 , of which the swash plate 8th is articulated. Via a coupling linkage 14 is on the control piston 12 a feedback spring 16 indirectly supported. The support is such that the feedback spring 16 Compressive forces on the coupling linkage 14 can transmit.

The actuator cylinder 10 has a signal pressure space 18 , which can be loaded with signal pressure medium. A pressure in the signal pressure room 18 results in an actuating pressure force in the direction of a reduction in the swivel angle α and reducing the displacement volume acts. The actuating pressure counteracts the actuating piston 12 a return spring 20 , The actuating piston 12 is on a cylinder bore 22 of the actuating cylinder 10 recorded linearly movable.

To control the swivel angle α and the dependent stroke volume is a hydromechanical controller 27 designed in the form of a continuously adjustable 3/2-way valve. The regulator 27 has a valve body 28 that can be moved linearly in a cylinder bore 30 is recorded. It has a first throttle cross section 32 in the form of a first orifice, over which the signal pressure space 18 with the pressure line 6 is fluidly connectable. According to the invention is a second throttle cross section 34 provided over which the signal pressure space 18 with the pressure line 6 , parallel to the first throttle cross section 32 and regardless of the valve body 28 and its position is fluidly connectable. The second throttle cross section 34 is formed by an aperture with a fixed cross section. The valve body 28 is pressure balanced by using signal lines on both of its faces 36 the pressure in the signal pressure space 18 overloaded.

The regulator 27 still has a third throttle cross section 38 over which the signal pressure space 18 is fluidly connectable to the tank T. According to 1 has the controller 27 also an electromagnet 40 over which the valve body 28 with an operating force according to a target value of the swivel angle α is acted upon. The setpoint is specified via a signal line 42 and the control of the electromagnet 40 with a drive current I _S , On the valve body 28 act because of the constructive design of the controller 27 at least the actuating force of the electromagnet 40 on the one hand, and the coupling force of the feedback spring 16 on the other hand.

In regular operation, a swivel angle setpoint value α _{S is} generated by energizing the drive current I _S specified. This results in the actuation force on the valve body 28 that in the direction of the control of the third throttle cross section 38 is effective. As a result, the signal pressure space 18 over the increasingly large third throttle cross section 38 connected to the tank T. Due to the force of the return spring 20 becomes the actuating piston 12 in the direction of a reduction in the signal pressure space 18 shifted and signal pressure medium is over the third throttle cross section 38 discharged to tank T. With the displacement of the control piston 12 goes a compression of the feedback spring 16 hand in hand, causing the from her to the valve body 28 impressed coupling force in the direction of the opening of the first throttle cross section 32 increases. In the exemplary embodiment shown is the valve body 28 with reference to its throttle cross sections 32 . 38 and the cylinder bore 30 designed with a negative overlap so that both throttle cross-sections are in a balance of forces between the coupling force and the actuating force 32 . 38 are somewhat open.

Now, for example, a smaller swivel angle α control current is required I _S lowered, which reduces the actuation force and the valve body 28 in 1 to the right and thus in the direction of an increasing opening of the first throttle cross section 32 is moved. Accordingly, pressure medium flows increasingly from the pressure line 6 over the first throttle cross section 32 in the signal pressure space 18 , causing the piston 12 in the direction of increasing the signal pressure space 18 is shifted until the balance of forces is restored.

When the swivel angle is increased α however, increase the drive current I _S , the actuating force and the displacement of the valve body 28 in the direction of increasing opening of the third throttle cross section.

In normal operation emerges from the signal pressure space 18 and the signal lines 36 a leakage volume flow, resulting in a slight displacement of the actuating piston 12 in the direction of reducing the signal pressure space 18 results. As already shown, the control current remains the same I _S and constant actuation force of the electromagnet 40 the feedback spring 16 over the paddock stand 14 compressed so that the coupling force increases. The regulator 27 thus reacts to the displacement of the actuating piston 12 due to leakage and the first throttle cross section 32 is increasingly opened, so that pressure medium in the signal pressure space 18 can flow and the leakage-related adjustment of the control piston 12 is ultimately compensated. However, due to the flow dynamics occur at the first throttle cross section 32 Flow forces on the valve body 28 towards closing the first throttle cross section 32 are effective. In the state of equilibrium of forces on the valve piston 28 is therefore the coupling force of the feedback spring 16 higher than without this leak. Accordingly, it is due to the drive current I _S adjusting swivel angle α larger than the expected swivel angle α without leakage, what is called drift.

It should be emphasized that the previous description only describes the problem of the generic hydraulic machine. According to the invention, this problem is solved by providing the second throttle cross section 34 ; 134 between the pressure connection 4 and the signal pressure space 18 the hydromachine 1 ; 101 solved or at least reduced.

The 2 and 3 describe this problem. According to 2 it can be seen that, for example, with a given swivel angle α with increasing pressure p , and thus increasing pressure difference between the pressure p in the pressure line 6 and the signal pressure p _S in the signal pressure room 18 , the swivel angle α increases as described. This is shown as an example for an initial swivel angle of 20, 40, 60, 80 and 95% of the maximum possible swivel angle α _max ,

3 shows another representation of the problem, being about the drive current I _S the swivel angle α is plotted in percent. The two upper curves correspond to a swinging out and swiveling in with hysteresis at a higher pressure and the two lower curves correspond to the same process at a lower pressure. It is easy to see that for a given control current I _S the swivel angle α increases (drifts), the greater the pressure p is. There is therefore no longer the advantageous and desired proportional relationship between the control current I _S and the swivel angle α (Displacement volume).

To alleviate this effect is according to 1 the second throttle cross section 34 provided that is parallel to the first throttle cross section 32 the signal pressure space 18 with the pressure medium source (pressure line 6 ) can fluidly connect. According to the second throttle cross section 34 formed by an orifice, the throttle cross section of which is completely independent of the valve body 28 is. In the exemplary embodiment shown, it is fixed and has an opening cross section of 0.5 mm.

The second throttle cross section is preferably between 0.3 and 0.8 mm, it preferably referring to an operationally relevant pressure difference between pressure p and signal pressure p _S or is optimized for an operationally relevant interval of this pressure difference.

The second throttle cross-section enables normal operation 34 the compensation of the leakage flow mentioned above, so that it no longer or not completely over the first throttle point 32 must be balanced and the undesirable effect of shifting the balance of forces on the valve body 28 is at least mitigated.

4 and 5 show the effect of the second throttle cross section according to the invention 34 , The representation also applies qualitatively to the second exemplary embodiment described below. Here is in 4 analogous to the representation according to 2 (Prior art) the pressure p about the swivel angle α applied. Starting from a swivel angle α of, for example, 40% and low pressure p it can be clearly seen that according to the curve on the right the swivel angle α with increasing pressure p drifts towards larger values. In 4 these curves are shown on the left for a second throttle cross-section of 0.5 mm and 0.6 mm. It can be seen that the second throttle cross section 34 can lead to a reversal or decrease of the mentioned drift or shift. A vertical course of the curve (indicated by dashed lines) would be desirable here, starting from the exemplary swivel angle α = 40%, ie a pressure independence. With a cross-section smaller than 0.5 mm, this vertical course is theoretically obtainable. Analogous to 3 (State of the art) is in 5 the relationship between the swivel angle α in percent and the control current I _S with existing, second throttle cross section 34 outlined. The second throttle point 34 a diameter of 0.6mm. Noticeable compared to 3 is that the hysteresis curve for lower pressure is now above that for higher pressure. In addition, the two hysteresis curves are compared to those according to 3 , moved closer together. In other words, according to the invention, given a drive current I _S with variation of the pressure p not so large deviations in the swivel angle a ,

According to 6 has a second embodiment of a hydraulic machine according to the invention 101 additional control functions. Firstly, this is a pressure difference or flow controller 44 over which the print p the pressure line 6 is regulated to a value consisting of a sum of a reported load pressure p _LS and one at the pressure difference controller 44 set value of a pressure difference. This ensures that hydraulic consumers supplied with metering orifices always have a pressure that is sufficiently high above the load pressure. Furthermore, the hydro machine 101 a pressure or pressure cut-off regulator 46 , which only intervenes when the pressure p in the pressure line 6 one on the pressure regulator 46 set setpoint is reached or exceeded. In principle, the supreme authority of all controllers 44 . 46 and 127 He thus intervenes to limit pressure before a pressure relief valve (not shown) limits the pressure by blowing off pressure medium, thereby avoiding this form of energy loss. The two controllers 44 and 46 correspond to the state of the art, which is why no further explanations are required.

In addition to the additional controls 44 . 46 gives way to the hydromachine 101 in their construction, in particular the controller according to the invention 127 regarding from. First you notice that a valve body 128 (its central axis) of the controller 127 , with the actuating piston 12 (whose central axis) is aligned. actuating piston 12 and valve body 128 are therefore extremely compactly arranged in a row. This also makes it possible for the feedback spring 16 as shown within the signal pressure space 118 is arranged.

Because of the controller structure mentioned with the controllers 44 . 46 is also the valve body 128 configured differently from that of the first embodiment. It is about the construction of the valve body 128 the fluidic connection between the controllers 44 . 46 with the signal pressure space 118 ensured. For this purpose, the valve body 128 a longitudinal bore 48 on. This is through a radial bore 29 in permanent pressure medium connection with a regulator connection 52 , via the two controllers connected in series 44 . 46 with the controller 127 are connected to pressure medium. The controller connection 52 is about the controller 44 . 46 both with the pressure line 6 , as well as fluidically connectable to the tank T. Furthermore, the controller has 128 a pressure connection P and a signal pressure connection Ps. The pressure connection P is with the pressure line 6 and the signal pressure connection P _S with the signal pressure space 118 fluid-connected. The valve body too 128 is over the signal line 36 designed to be pressure balanced.

The valve body 128 is due to the action of the electromagnet 40 , as already described in the first embodiment, between two positions a and b continuously adjustable. As in the first embodiment is in a first or control position a the pressure connection can be connected or connected to the signal pressure connection Ps via the first throttle cross section. In the position b is the pressure connection P shut off and the controller connection 52 is connected to the signal pressure port Ps. The controller connection is in all positions of the valve body, including a and b 52 over the radial bore 29 and the longitudinal bore 48 with one towards the signal pressure room 118 opening check valve 54 connected. This can be used by the controller 44 or 46 at the controller connection 52 provided pressure at the check valve 54 against that of the controller 127 are adjusted according to the setpoint signal pressure, taking into account that on the check valve 54 burdening feedback spring 16 the correspondingly greater than the signal pressure in the signal pressure space 118 interspersed.

7 shows the controller 127 according to 6 , including the control piston 12 , The regulator 127 is designed as a 3/2-way valve in cartridge design. This means that a housing 56 in which the valve body 128 is guided in a linearly movable manner, is provided with an essentially cylindrical outer circumference, and into a main housing of the hydraulic machine 101 screwable / screwed in. To the case 56 is the electromagnet 40 screwed. The electromagnet 40 opposite, at an end portion of the housing 56 , is the cylinder bore 22 in which the actuating piston 12 is linearly movable, pot-shaped. The valve body 128 and the actuating piston 12 align with their central axes. From the cylinder bore 22 and the hollow actuating piston 12 is the signal pressure space 118 limited. The longitudinal hole is clearly visible 48 of the valve body 128 that on a the electromagnet 40 facing end section in the radial bore 29 empties. The housing 56 has three circumferential grooves on the outside, each with the connection P (Connection to the pressure line 6 ), Ps (connection to the signal pressure chamber 118 ) and the controller connection 52 communicate. Starting from the circumferential grooves mentioned, star bores extend radially inward towards the cylinder bore 30 of the housing 56 and to the valve body 128 ,

The valve body 128 has a central control collar on which towards the star holes of the pressure connection P a first control edge is formed, which together with a first control edge of the cylinder bore 30 the first throttle cross section 132 formed. The same control collar is in the direction of the star holes of the controller connection 52 a third control edge formed together with a third control edge of the cylinder bore 30 the third throttle cross section 138 formed.

The pressure connection P , or its star holes, are from the signal pressure space 118 separated by a case back. A through hole is formed in this, which according to 6 the second throttle cross section 134 formed. This serves to compensate for the leakage from the signal pressure space that has already been discussed, according to the invention 118 ,

Disclosed is a hydraulic machine with a displacement volume controlled by a control valve, wherein a leakage volume flow of the actuating pressure medium used for adjustment can be replaced via a throttle cross section of the hydraulic machine that is independent of the control valve.

LIST OF REFERENCE NUMBERS

1; 101

hydromachine

2

Low pressure port

4

pressure connection

6

pressure line

8th

swash plate

10

actuating cylinder

12

actuating piston

14

coupling linkage

16

Feedback spring

18; 118

Adjusting pressure chamber

20

Return spring

22

bore

26

tank line

27; 127

regulator

28; 128

valve body

29

radial bore

30

bore

32; 132

first throttle cross section

34; 134

second throttle cross section

36

signal line

38; 138

third throttle cross section

40

electromagnet

42

signal line

44

Flow control

46

pressure regulator

48

Through Hole

50

regulator connection

52

regulator connection

54

check valve

56

casing

P

pressure connection

P _S

Loading Connection

α

swivel angle

α _max

maximum swivel angle

p

print

p _S

actuating pressure

I _S

driving

a, b

position

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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 10360452 B3 [0003]
• DE 102013224112 A1 [0003, 0037]

Claims (14)

Hydraulic machine with adjustable stroke volume, and with an actuator element (12), of which a hydrostatic signal pressure chamber (18; 118) is limited in sections, an actuator element (8) being articulated directly or indirectly from the actuator element, the position of which determines the stroke volume At least for supplying the control pressure chamber (18; 118) with control pressure medium, a directional valve (27; 127) is provided, which has a valve body (28; 128) coupled to the actuator element (12) which, depending on an actuating force acting on it and a coupling force is movable and by which a first throttle cross-section (32; 132), which is continuously adjustable as a function of this movement, is limited in sections, via which a pressure medium source (6) can be fluidly connected to the control pressure chamber (18; 118), characterized in that that a second throttle cross-section (34; 134) is provided, via which the control pressure chamber (18; 118) is pressurized or pressurized is beatable. Hydro machine after Claim 1 , wherein the second throttle cross section (34; 134) is designed such that a leakage flow out of the signal pressure chamber (18; 118) can be at least partially compensated for via it. Hydro machine after Claim 1 or 2 , wherein the second throttle cross section (34; 134) is decoupled from the valve body (28; 128) and / or from its movement. Hydro machine according to one of the Claims 1 to 3 , wherein the second throttle cross section (34; 134) is fixed, or wherein the second throttle cross section is adjustable. Hydro machine after Claim 4 , wherein the second throttle cross-section is adjustable depending on a pressure of the pressure medium source and / or a pressure difference of the pressure medium source to the control pressure chamber and / or a position of the valve body. Hydraulic machine according to one of the preceding claims, wherein the signal pressure chamber (18; 118) via the second throttle cross section (34; 134) is fluidly connected or connectable to the same pressure medium source (6) as via the first throttle cross section (32; 132). Hydro machine according to one of the preceding claims, wherein the first throttle cross-section (32; 132) and the second throttle cross-section (34; 134) are connected fluidically in parallel. Hydraulic machine according to one of the preceding claims, wherein a housing of the actuator element (12) has a cylinder bore (22) in which the actuator element (12) is movably received and by which the control pressure chamber (18; 118) is limited in sections. Hydro machine according to one of the preceding claims, wherein a housing (56) of the directional control valve (127), in which the valve body (128) is movably received, has a pressure connection (P) which is connected or can be connected to the pressure medium source (6), and from which a pressure medium flow path branches off to the signal pressure chamber (118), in which the second throttle cross section (134) is arranged. Hydro machine according to one of the preceding claims, wherein the directional control valve (127) or at least one housing (56) of the directional control valve (127) is designed in a cartridge design and is inserted into a housing or housing section of the hydraulic machine (101). Hydro machine at least after Claim 9 and 10 , wherein the pressure connection (P) is formed by an outer circumferential groove or an outer circumferential groove section formed on the housing (56) of the directional valve (127). Hydro machine according to one of the Claims 9 to 11 , the control pressure chamber (118) being delimited in sections by the housing (56) of the directional control valve (127), and the pressure medium flow path having an opening into the control pressure chamber (118). Hydro machine at least after Claim 8 and 9 , wherein the housing (56) of the directional control valve (127) and the actuator element (12) are firmly connected and / or are formed in one piece with one another. Hydro machine according to one of the preceding claims, wherein the valve body (128) and the actuator element (12) in the direction of movement of the valve body (128) are arranged at least in sections in alignment.

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