CN215256630U - Displacement volume setting device and hydrostatic variable displacement axial piston machine - Google Patents

Abstract

A displacement volume setting device for a hydrostatic variable displacement axial piston machine is disclosed, including an input device for providing a displacement command. The displacement volume adjustment device sets the inclination angle of the displacement element in accordance with the displacement command. The link member includes: an input coupling element connected to the input device, an output coupling element connected to the displacement volume adjusting device, and a connecting element. The input coupling element and the output coupling element are connected by a connecting element which is elastically deformable if the force which is generated by the high pressure level present at the hydrostatic axial piston machine and acts on the output coupling element exceeds a predetermined threshold value. A hydrostatic variable displacement axial piston machine is also disclosed.

Description

Displacement volume setting device and hydrostatic variable displacement axial piston machine

Technical Field

The utility model relates to a quiet hydraulic variable displacement axial piston machine. More particularly, the present invention relates to a displacement volume setting device for a hydrostatic variable displacement axial piston machine.

Background

Hydraulic work vehicles are usually equipped with a hydrostatic variable displacement axial piston machine which is driven by an internal combustion engine in order to generate hydraulic pressure which can be converted, for example, by a hydraulic motor into the propulsion force of the vehicle. In most cases, the displacement volume of a hydrostatic motor that propels a vehicle or actuates a work device (work function) is constant. The speed of the hydraulic motor and/or the (auxiliary) working devices are controlled by controlling the displacement volume of the hydrostatic axial piston machine. It follows, therefore, that the angle of inclination of the displacement element of a hydrostatic variable displacement axial piston machine must be adjustable.

The angle of inclination of the displacement element is adjusted in accordance with an input command from the vehicle operator, which is transmitted to the displacement element of the hydrostatic variable displacement axial piston machine via some interface (interface), such as a pedal or lever, by providing a rigid mechanical connection element. Hydrostatic variable displacement axial piston machines equipped with rigid link elements are commonly referred to as direct displacement control units.

Because the linkage between the axial displacement unit and the operator input device is rigid, the load acting on the displacement unit may increase the force required to hold the linkage in place and may also provide an undesirable mechanical feedback signal to the input device.

If the vehicle operator increases the force on the input command device, the hydraulic power generated by the hydrostatic variable displacement axial piston machine should also increase. If the angle of inclination of the displacement element is unable to adapt to the new load situation (as is the case with the normal behavior of a hydrostatic variable displacement unit), the rotational speed of the internal combustion engine is forced to decrease, which may lead to engine stall, particularly if the operator's input commands prevent the hydrostatic variable displacement unit from adapting to the increasing load on the work vehicle. The internal combustion engine is then required to provide more power to the hydrostatic axial piston machine, and therefore the internal combustion engine is forced to run at a different torque-to-speed ratio, which in turn deviates from the designed torque/speed ratio. At such different torque-to-speed ratios, the efficiency of the internal combustion engine is worse than when operating in the target operating state. System overload may occur because the internal combustion engine may not be able to provide sufficient power for the deviating system conditions. This not only leads to an increase in fuel consumption; it may also cause the engine to stall if the required torque exceeds the torque that the internal combustion engine can provide.

SUMMERY OF THE UTILITY MODEL

It is therefore an object of the present invention to provide a displacement volume setting device capable of providing a direct mechanical connection between an operator input device and a displacement element of a hydrostatic variable displacement axial piston machine, wherein the displacement volume setting device is configured to invalidate operator input commands if necessary to maintain a target operating state or to avoid stalling of an internal combustion engine.

This object is solved by a displacement volume setting device according to an embodiment of the invention and by a hydrostatic variable displacement axial piston machine according to an embodiment of the invention.

According to the present invention, a displacement volume setting device for a hydrostatic variable displacement axial piston machine includes an input device for providing a displacement command. Preferably, the input device is a mechanical device that is moved to adjust the displacement volume and consequent volume flow of the axial piston machine. The input device may be disposed remotely from the hydrostatic variable displacement axial piston machine, such as in an operator cab of the work vehicle.

According to the utility model discloses a displacement volume setting means still includes displacement volume adjusting device, and this displacement volume adjusting device is used for setting for the inclination of displacement element according to the displacement command that provides via input device. According to the utility model discloses, the motion of discharge capacity volume adjustment device leads to the change of the inclination of discharge capacity component to finally lead to the change of the discharge capacity volume of axial piston machine. Preferably, the displacement volume adjusting means is further arranged as a mechanical device attached to the displacement element and capable of transferring a force acting on the displacement volume adjusting means to the displacement element and vice versa from the displacement element towards the input means. The displacement volume adjusting means may be, for example, a control rod or lever connected to a displacement element, which may be, for example, a swash plate or yoke (yoke).

According to the utility model discloses, discharge capacity volume setting device includes the link element, and this link element has: an input coupling element connected to the input device, an output coupling element connected to the displacement volume adjusting device, and a connecting element connecting the input coupling element with the output coupling element. The connecting element transmits a displacement command from the input device, which is transmitted via the input coupling element, to the output coupling element and, in turn, to the displacement volume adjustment device via the output coupling element. The connecting element typically exhibits inelastic behavior, but is elastically deformable if the force generated by the high pressure levels present at/in the hydrostatic variable displacement axial piston machine exceeds a predetermined threshold.

The hydrostatic variable displacement axial piston machine may be, for example, a hydrostatic pump, which is connected to a hydraulic consumer (e.g., a hydraulic motor) via a high-pressure line. If the load counteracting the force/movement of the hydraulic consumer increases, the pressure level in the high pressure line increases, increasing the pressure difference that must be created by the hydrostatic variable displacement axial piston pump between its inlet and outlet. This may occur if a vehicle hydraulically propelled by a hydraulic motor is traveling uphill or is traveling/pushing/pulling against an obstacle. In response to an increasing load on the high pressure side, the displacement element of the axial piston machine tilts towards a smaller displacement volume, thereby reducing the volume flow through the pump and increasing the pressure difference between the inlet and outlet of the pump, e.g. if the speed of the work vehicle is to be maintained in such a situation, the input command must be adjusted. In the case of a direct displacement controlled hydraulic pump, this can only be done by commanding the displacement element to obtain a larger tilting angle, but a larger tilting angle will result in a larger torque being provided by the drive motor, with the negative consequences already mentioned above.

For a command to increase displacement volume that produces a relatively small pressure change at the high pressure side of the hydrostatic axial piston machine, the displacement command is directly and rigidly transferred to the displacement volume adjusting element, and load feedback is directly and rigidly transferred from the displacement volume adjusting device back to the input device in the opposite manner.

The connecting element according to the invention decouples the input coupling element from the output coupling element by elastic deformation if the force generated by the higher pressure level acting on the displacement element of the hydrostatic axial piston machine (and on the output coupling element) is greater than a predetermined threshold value. Thus, the inclination angle of the displacement element is no longer directly controlled by the input means. This elastic deformation allows the output coupling element to move relative to the input coupling element and avoids overloading of the drive engine by enabling the displacement volume adjusting element to retract such that the displacement element can rotate back to a lower angle of inclination.

This elastic deformation limits the force generated by the high pressure side of the hydraulic axial piston machine to a predetermined threshold value. The magnitude of the load acting on the hydraulic axial piston machine below a predetermined threshold allows the drive engine to maintain an economical operating state range and/or prevents the engine from suffering damage. Furthermore, a direct feedback of the load acting on the displacement element may be relayed to the input device. On the other hand, if the tilt angle needs to be adapted due to the external load representative value being above the threshold, a mechanical feedback-free behavior is provided.

The predetermined threshold value can be set by a pretension force on the connecting element. If the force exerted on the connecting element is smaller than the pretensioning force, the pretensioned connecting element will play a rigid role in the transmission of the load from the input coupling element to the output coupling element (and vice versa). Thus, it can be derived: if the pretensioned connecting element is elastically deformable, it can be set such that it deforms, for example, if the load acting on the hydraulic axial piston machine is greater than a threshold value set by the pretension force.

According to the invention, the pretensioning force of the connecting element can be adjusted. The magnitude of the pretension affects the behavior of the hydraulic work machine (vehicle). If the pretension force is high, a rigid feedback is provided between the input coupling element and the output coupling element even when the external load is high. If the pretension force, and thus the threshold value, is low, the displacement volume setting means will react more smoothly to external loads and displacement commands provided via the input means, if it would result in a high pressure level above the threshold value.

To achieve this, the connecting element may comprise a spring or another type of elastically deformable element. The choice of material for the resiliently deformable member may be wide, including but not limited to metal, plastic or reinforced plastic. The elastically deformable element may thus have any form, such as an extension spring, a compression spring, a torsion spring or any other type of spring. The connecting element can also be designed as a spring washer, lock washer, rupture disk, screw or bolt or similar.

Contemplated within the scope of the present invention is to provide a partially elastic element, the partially elastic element comprising: a component that is rigid in any operating condition: and an elastically deformable component that deforms when a force generated by the high pressure level and acting on the output coupling element exceeds a predetermined threshold set by a pretension force of the elastically deformable element.

The elastically deformable elements can also be designed as pre-tensioned ropes, cables, rods or columns with a small diameter, so that they are elastically deformable if the forces acting on them exceed a predetermined threshold value. Depending on the design of the link elements, the elastic connection elements may be able to transmit tensile and/or compressive forces. As described, the connecting element may also comprise a combination of said components.

Furthermore, the link element may comprise an end stop limiting the elastic deformation of the link element, wherein the damping element may be arranged at the end stop. By providing an end stop, a force range for the elastic behavior of the connecting element is defined. The lower end of the range is defined by the amplitude of the predetermined threshold value and the upper end of the range is defined by the position of the upper end stop and the corresponding maximum elastic deformation force therewith. The connecting element acts elastically if the force acting on the output coupling element is within this force range. If the force is outside the force range, the connecting element acts as a rigid force transmission means. If the force is less than the pretensioning force, a rigid transmission is provided without causing an elastic deformation of the connecting element. If the force is greater than the pretension force, the link element elastically transmits the displacement command until the end stop is contacted.

Damping elements, such as shock absorbers, crane bumpers, foam rubber or similar elements, can smoothly transition the elastic behavior of the connecting element to the rigid behavior of the connecting element. In addition, the damping element may dampen vibrations, thereby providing a more comfortable load feedback to an operator of the variable displacement axial piston machine.

The input device for providing the displacement command may be a joystick, lever, pedal or similar device for providing a mechanical input command. Preferably, the movement of the input means is transferred to the displacement element via a mechanical transmission (e.g. a link element) defining a movement/transmission ratio, so that a comfortable/economical operation of the axial piston machine may be achieved.

The displacement command may also be an electrical signal or hydraulic pressure that is mechanically translated to the input coupling element via a solenoid or servo. As described, the mechanical movement of the input coupling element can thus be transferred to the displacement element. The load feedback acting on the high pressure side of the hydrostatic axial piston machine is transmitted via the link element to the input device where it can be used as feedback to a system operator or a system control unit, for example to adapt the engine drive speed.

As mentioned before, the link element may transmit linear and/or rotational movements. It is also within the spirit of the present invention that the linkage elements transmit a combination of linear and/or rotational motion.

The hydrostatic variable displacement piston machine may be of the swash plate or bent-shaft type. It is common knowledge of the person skilled in the art that in the first case the displacement element is a tiltable swash plate, also called rotary element, and in the second case the displacement element is a yoke.

Although the inventive concept has been described with a hydraulic axial plunger pump, any hydrostatic axial plunger machine may be equipped with a displacement volume setting device according to the invention. Thus, a hydrostatic axial piston machine equipped with a displacement volume setting device according to the invention may be a hydrostatic motor, a hydrostatic pump and/or be part of a hydrostatic transmission.

Drawings

In the following figures, exemplary embodiments of a displacement volume setting device of a hydrostatic variable displacement axial piston machine according to the present invention are shown. The proposed embodiments can be combined with each other without departing from the spirit of the inventive concept. Combinations and substitutions of embodiments not shown in the drawings or in the foregoing description, but within the knowledge of one skilled in the art, are also covered by the spirit of the invention. The proposed embodiments do not limit the scope of the invention. The following figures show:

fig. 1 shows a first embodiment of a displacement volume setting device according to the invention in a side view;

FIG. 2 shows the embodiment of FIG. 1 in a cross-sectional view;

fig. 3 shows a second embodiment of a displacement volume setting device according to the invention in a side view;

FIG. 4 shows the embodiment of FIG. 3 in cross-section;

fig. 5 shows a third embodiment of a displacement volume setting device according to the invention in a cross-sectional view.

Although the following drawings illustrate different embodiments of the present invention, the same reference numerals are used for equivalent parts, regardless of the specific embodiments.

Detailed Description

Fig. 1 shows a side view of a first embodiment of a link element 10 of a displacement volume setting device 1 according to the invention. The linkage element 10 comprises an input coupling element 15 and an output coupling element 20, both the input coupling element 15 and the output coupling element 20 being provided as separate components. The input coupling element 15 and the output coupling element 20 are rotatable relative to each other about a pivot axis 28, wherein both the input coupling element 15 and the output coupling element 20 are connected to a pivot pin 25 serving as a common center of rotation. The input coupling element 15 is connected to the input device 6 and the output coupling element 20 is connected to the displacement volume adjusting device 8. Relative rotation between the output coupling element 20 and the input coupling element 15 is limited by a connecting element 30, which connecting element 30 is arranged in the path of the force between the input coupling element 15 and the output coupling element 20.

The connecting element 30, which is shown in more detail in fig. 2, comprises a guide rod 32, on which guide rod 32 a spring 38 is movably arranged. Spring 38 bears on one side against spring seat 40 and on the other side against washer 34, washer 34 being held in place by nut 36. The guide rod 32 is inserted into openings 48 formed in the input coupling element 15 and the output coupling element 20. A lever end pin 42 is fixed to the end of the guide lever 32 opposite the spring 38 and projecting through the opening 48, so that the relative position of the input coupling element 15 and the output coupling element 20 is limited in one direction by the lever end pin 42. In the other direction, the movability of the pin 32 is limited by the spring seat 40. As in this embodiment, the convex surfaces on the spring seat 40 and the rod end pin 42 may be received by concave grooves also formed in the input coupling member 15 and the output coupling member 20. The paired arrangement of the convex and concave surfaces ensures that the guide bar axis 26 can remain stationary as the input coupling element 15 and/or the output coupling element 20 rotate about the pivot pin 25. As shown in the embodiment of fig. 2, the guide rod 32 is threaded such that the nut 36 can be threaded onto the guide rod 32 and held in place by the threads. By tightening nut 36 toward spring seat 40, a compressive force is applied to spring 38 via washer 34, which results in a force that presses spring seat 40 against input coupling member 15 and output coupling member 20. The compression force may be set according to a threshold value selected for an allowable high pressure level acting on the displacement element of the hydrostatic variable displacement axial piston machine.

The displacement volume setting device 1 in the embodiment of fig. 1 and 2 can be mounted to a variable displacement axial piston machine. Before starting the operation of the variable displacement axial piston machine, the spring 38 can be pretensioned by adjusting the position of the nut 36 on the guide rod 32. The pretension of spring 38 increases if nut 36 is threaded toward spring seat 40, and decreases if nut 36 is threaded in the opposite direction.

In the nominal operating state, an input command is provided, for example a movement of an input lever, which is set via the input device 6. The input command causes the input coupling element 15 to rotate, which is indicated by the double-headed arrow 60. The rotational input command is transmitted to the spring seat 40 or the rod end pin 42 via the input coupling element 15 (depending on the rotational direction of the input coupling element 15). If the force applied to the spring seat 40 or the rod end pin 42 by the rotational movement of the input coupling element 15 is less than the pretension force of the spring 38, the rotation of the input coupling element 15 will be inelastically transferred towards the output coupling element 20, which output coupling element 20 rotates about the pivot pin 25 in the same direction as the input coupling element 15 and transfers this rotation to the displacement volume adjusting device 8, resulting in a change of the inclination angle of the displacement element of the axial piston machine (not shown).

The principle described in the preceding paragraph applies in reverse if the direction of the force is reversed, i.e. if a force is exerted by the displacement volume adjusting device 8 on the output coupling element 20 such that the output coupling element 20 rotates about the pivot pin 25 as the centre of rotation (see double arrow 65). If the force exerted by the rotation of the output coupling element 20 on the spring seat 40 or the rod end pin 42 is less than the pre-tension force of the spring 38 (which represents a predetermined threshold value of the high pressure level), the connecting element 30 exhibits a rigid behavior and transmits the rotation of the output coupling element 20 directly to the input coupling element 15. The input coupling element 15 is connected to the input device 6 so as to provide direct (mechanical) feedback of the load acting on the displacement volume adjusting device 8 to the input device 6.

This means that the operator of the hydrostatic variable displacement axial piston machine can feel the load on the work machine (vehicle) transmitted via the displacement volume adjusting device 8. For example, if an obstacle occurs in the travel path of a vehicle propelled by the axial piston machine according to the invention, the operator, after feeling an increase in the load at the input device 6, can react to the increased load, if necessary.

However, if the load acting on the displacement volume adjusting device 8 exceeds the magnitude of the threshold set by the pretensioning force of the spring 38, the rotation of the output coupling element 20 results in a force on the rod end pin 42 or the spring seat 40 that is greater than the pretensioning force of the spring 38. This means that the spring 38 is compressed and that relative rotation between the input coupling element 15 and the output coupling element 20 is allowed, since the connecting element 30 exhibits a resilient behavior.

The elastic behavior of the connecting element 30 enables decoupling of the movement of the input coupling element 15 and the input device 6 from the movement of the output coupling element 20 and the displacement volume adjustment device 8 connected to the output coupling element 20. Thus, the hydraulic unit controlled by the input device 6 can adjust its tilt angle independently of the input command. Thereby, a stable and efficient operating point may be maintained for the internal combustion engine, and the internal combustion engine will not be operated in a torque range where there is a risk of very low efficiency or stalling the engine. According to the present invention, if the high load present on the high pressure side of the hydrostatic variable displacement axial piston machine exceeds a threshold value, the displacement element will tilt back and reduce the displacement, the displacement volume adjustment device 8 transmits the reduction of the tilt angle to the output coupling element 20. As the displacement volume decreases, the torque required by the internal combustion engine also decreases.

Those skilled in the art know many devices comparable to spring 38 and may be pre-tensioned in a similar manner. For example, tension springs, torsion springs, or any other type of spring or other elastically deformable device and/or material may be employed. Furthermore, a different means for pre-tensioning the elastically deformable means compared to the nut 36 incorporating the washer 34 may be provided by, for example, a clip or latching means. The present invention also covers the transformation of the concept shown in the embodiment of fig. 1 and 2 from a range of mainly rotational motion to a range of linear motion.

Fig. 3 and 4 show a second embodiment of a link element 10 of a displacement volume setting device 1 of a hydrostatic variable displacement axial piston machine, which link element 10 is adapted to transmit relative rotational movement between an input device 6 and a displacement volume adjusting element 8. The input device 6 is connected to an input coupling element designed as a first pin 15. The displacement volume adjusting device 8 is connected to a further second pin 20 which serves as an output coupling element. The first pin 15 and the second pin 20 are connected by a rotary spring 38 serving as the connecting element 30. The spring 38, the input device 6 and the displacement volume adjusting element 8 share a common centre of rotation 39, which centre of rotation 39 is defined by the guide rod (shaft) 32. The input device 6 and the displacement volume adjusting device 8 are movably arranged (at least in the direction of rotation) on the shaft 32.

In the embodiment according to fig. 3 and 4, the rotational movement and the corresponding torque acting on the displacement volume adjustment device 8 are transmitted via the second pin 20 to the connecting element 30, which connecting element 30 acts rigidly when the force balance between the input coupling element 15 and the output coupling element 20 is smaller than its pretension. The torque of the displacement volume adjusting device 8 is then rigidly transmitted to the input device 6 and vice versa. If the force balance between the input coupling element 15 and the output coupling element 20 is above a pretension force (a predetermined threshold), the connecting element 30 is elastic and thus the torque of the displacement volume adjusting device 8 is decoupled from the input device 6, allowing the axial piston machine to react load-dependent.

Fig. 5 shows a cross-sectional view of a link element 10 applying the principle of linear motion. The link element 10 comprises a guide rod 32 which is part of the connecting element 30. The guide rod 32 is actuated on its free end by the input coupling element 15. On the opposite end of the guide rod 32 in the embodiment according to fig. 5, a spring 38 is movably arranged and fixed between the first washer 34 and the second washer 35. First and second washers 34 and 35 are disposed between first and second nuts 36 and 37 and are held in place by first and second nuts 36 and 37, respectively. The washers 34, 35 abut on the side facing away from the spring against a first shoulder 46 and a second shoulder 47 of the housing 20 serving as output coupling element. The housing 20 includes a first opening 48 and a second opening 49 and circumferentially surrounds the spring assembly. The guide rod 32 projects from the first opening 48 towards the input coupling element 15. The second opening 49 of the output coupling element 20 is closed by an end stop 44 provided as an end cap.

The pretension of the spring 38 can be adjusted by screwing the nuts 36, 37 on the guide rod 32 and thereby changing the distance between the first and second nuts 36, 37 and the two respective washers 34, 35. If the distance between the first nut 36 and the second nut 37 is greater than the distance between the shoulders 46, 47, the washers 34, 35 will be pressed against the shoulders 46, 47 by the force of the spring 38. In case the distance between the two nuts 36, 37 is smaller than the distance between the two shoulders 46, 47, the washers 34, 35 are arranged with clearance from the shoulders 46, 47 and are free to move at least a distance on the rod 32. Preferably, in the starting position, the distance between nuts 36, 37 and between shoulders 46, 47 is substantially the same, so that washers 34, 35 simultaneously abut nuts 36, 37 and against shoulders 46, 47.

If the force balance between the force exerted by the input coupling element 15 towards the housing 20 (representing the output coupling element) and the force exerted by the displacement volume adjusting element on the housing 20 in the opposite direction is smaller than the pretensioning force of the spring 38, the connecting element 30 acts inelastically and transfers the force from the housing 20 (the output coupling element) directly to the input coupling element 15 and vice versa, wherein the force is transferred via the first shoulder 46 to the first washer 34, to the spring 38, to the second washer 35, to the nut 37 on the guide rod 32 and vice versa.

If the difference between the forces at the input coupling element 15 and the output coupling element 20 is greater than a threshold value predetermined by the pretension force, the spring 38 is compressed, so that a relative movement between the output coupling element 20 (housing 20) and the input coupling element 15 is possible. For example, if the output coupling element 20 is pushed towards the input coupling element 15 held in place, and the displacement force at the output coupling element 20 is greater than the pretension force of the spring 38, the spring 38 compresses towards the input coupling element 15 and the distance between the output coupling element 20 and the input coupling element 15 decreases. If spring 38 includes a linear characteristic, the distance between input coupling element 15 and output coupling element 20 is proportional to the displacement force.

An end stop 44 is provided which limits the relative movement between the output coupling element 20 and the input coupling element 15 in the event of very high displacement forces. If the end stop 44 is in contact with the first nut 36, the force of the output coupling element 20 is transmitted directly towards the input coupling element 15, compared to the non-elastic case. Thus, the connecting element 30 does exhibit elastic behavior when the displacement force is greater than a first threshold defined by the pretension force and less than a predetermined second threshold defined by the force required for the end stop 44 to contact the first nut 36.

From the above disclosure as well as the drawings and claims, it will be appreciated that the displacement volume setting device according to the invention and the hydrostatic variable displacement axial piston machine according to the invention provide many possibilities and advantages compared to the prior art. Those skilled in the art will further recognize that further modifications and variations may be made to the displacement volume setting device and hydrostatic variable displacement axial piston machine according to the present invention without departing from the spirit and scope of the invention. Accordingly, such modifications and variations are within the scope and covered by the following claims. It is further understood that the examples in the embodiments described above are for illustrative purposes only and that various modifications, changes, or combinations thereof that will occur to those skilled in the art are intended to be included within the spirit and scope of the present application.

List of reference numerals

1 displacement volume setting device

6 input device

8-displacement volume adjusting device

10 connecting rod element

15 input coupling element/first pin

20 output coupling element/second pin/housing

25 pivot pin

26 guide rod axis

28 pivot axis

30 connecting element

32 guide rod

34 washer/first washer

35 second gasket

36 nut/first nut

37 second nut

38 spring

39 center of rotation

40 spring seat

42 bar end pin

44 end stop/end cap

46 first shoulder

47 second shoulder

48 first opening

49 second opening

60 double arrow

65 double arrow

Claims (11)

1. A displacement volume setting device (1) of a hydrostatic variable displacement axial piston machine, characterized in that the displacement volume setting device (1) comprises:

-an input device (6), said input device (6) being adapted to provide a displacement command,

-displacement volume adjusting means (8), said displacement volume adjusting means (8) being for setting an inclination angle of a displacement element in dependence of said displacement command,

-a link element (10), the link element (10) having:

i) an input coupling element (15), the input coupling element (15) being connected to the input device (6),

ii) an output coupling element (20), the output coupling element (20) being connected to the displacement volume adjusting device (8), and

iii) a connecting element (30), which connecting element (30) connects the input coupling element (15) with the output coupling element (20), wherein the connecting element (30) is elastically deformable when a force acting on the output coupling element (20) resulting from a high pressure level prevailing on the hydrostatic axial piston machine exceeds a predetermined threshold value.

2. A displacement volume setting device according to claim 1, wherein the predetermined threshold value is set by a pretension force on the connecting element (30).

3. A displacement volume setting device according to claim 2, wherein the pretension on the connecting element is adjustable.

4. A displacement volume setting device according to any of claims 1-3, wherein the connecting element comprises a spring (38) or an elastically deformable element.

5. A displacement volume setting device according to claim 4, wherein the spring (38) is an extension spring, a compression spring, a torsion spring or any other type of spring.

6. A displacement volume setting device according to any of claims 1-3, characterized in that the link element (10) comprises an end stop (44), the end stop (44) limiting the elastic deformation of the connection element (30), wherein a damping element is arrangeable at the end stop (44).

7. A displacement volume setting device according to any of claims 1-3, wherein the input device (6) is a joystick, a lever or a pedal.

8. A displacement volume setting device according to any of claims 1-3, wherein the displacement command is an electrical signal or hydraulic pressure mechanically translated to the input coupling element (15) via a solenoid or a servo.

9. A displacement volume setting device according to any of claims 1-3, characterized in that the link element (10) transmits linear and/or rotational motion.

10. A hydrostatic variable displacement axial piston machine, characterized in that it is equipped with a displacement volume setting device (1) according to any one of claims 1 to 9, wherein it is of the swash plate or bent-axle type.

11. The hydrostatic variable displacement axial piston machine of claim 10, wherein the hydrostatic variable displacement axial piston machine is a hydrostatic motor, a hydrostatic pump, and/or is part of a hydrostatic transmission.

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