Axial piston hydraulic machine

Abstract

The present disclosure relates to an axial piston hydraulic machine (10). The axial piston hydraulic machine (10) includes a swash plate (22), a first fluid port (28), and a second fluid port (30). A fluid bypass (80) may be provided that fluidly connects the first fluid port (28) with the second fluid port (30), and an angle of inclination of the swash plate (22) may be self-adjusted according to a flow cross-section of the fluid bypass (80).

Description

Technical Field

[0001] The present disclosure relates to an axial piston hydraulic machine, and more particularly, to a swash plate axial piston hydraulic machine, which is referred to as a swash plate motor or a swash plate pump in the technical field. Background Art

[0002] A hydraulic press may be configured as a device that converts the kinetic energy of a fluid into mechanical energy. In this case, the hydraulic press may represent a hydraulic engine, and the mechanical energy may drive an output shaft. Conversely, a hydraulic press may convert mechanical energy provided by a (e.g., input) shaft into the kinetic energy of a fluid. In this case, they may be referred to as hydraulic pumps.

[0003] A conventional swash plate axial piston hydraulic machine (i.e., engine or pump) comprises a transmission shaft rotatable about a first axis of rotation also referred to as the transmission axis. The machine can pressurize a working fluid (for a pump) or distribute mechanical work (for an engine) produced by the pressure of the working fluid.

[0004] Such conventional axial piston hydraulic machines typically include a cylinder body that can rotate around the same first axis of rotation according to the rotation of the transmission shaft. The cylinder body typically includes a plurality of cylinders and cooperating pistons, which can be arranged circumferentially around the axis of rotation of the cylinder body. Typically, each piston is received in one of the cylinders, thereby forming a piston-cylinder arrangement. The piston can move axially in the cylinder between an upper stroke limit position (e.g., at maximum compression and minimum chamber volume) and a lower stroke limit position (e.g., at minimum compression and maximum chamber volume). These stroke limit positions are reached during one full rotation of the cylinder body around the first axis of rotation.

[0005] Each piston may include a first terminal end disposed outside the respective cylinder and contacting a swash plate that does not normally rotate. Between each cylinder and a second terminal end of each piston disposed inside the respective cylinder, a chamber for holding a working fluid or liquid, such as oil, may be defined. The volume of the chamber may vary between a maximum volume, which is normally reached when the piston is in a lower stroke position, and a minimum volume, which is normally reached when the piston is in an upper stroke position. The size of these volumes may be set by a swivel angle of the swivel plate, which determines the axial position of the first terminal end of the piston (and therefore the axial movement of the piston) during rotation of the cylinder. Typically, the machine includes an actuator, such as a servo piston for adjusting the swivel angle. The swivel axis typically extends orthogonally to the first axis of rotation. Typically, the swivel plate does not rotate about the first axis of rotation.

[0006] The geometric cubic capacity of such an axial piston hydraulic machine can be defined as the sum of the individual geometric cubic capacities of the cylinder / piston mounted in the cylinder block, wherein the individual geometric cubic capacity can be derived from the product of the cross section of the chamber and the stroke of the piston.

[0007] Typically, each cylinder includes at least one supply / discharge opening through which fluid can enter or leave the chamber. The at least one supply / discharge opening can be fluidly connected to a distributor, which typically includes a working fluid distribution circuit at high pressure and a working fluid distribution circuit at low pressure.

[0008] This distribution circuit is functionally connected to high-pressure and low-pressure working fluid pipelines outside the hydraulic machine. These working fluid pipelines are functionally connected to high-pressure and low-pressure fluid sources (such as pumps, storage, utilities, etc.), respectively.

[0009] Each distribution circuit comprises an opening which is fluidically connected to a distributor opening (such as a plate port) in a distributor plate. The distributor plate, which may also be referred to as a valve plate, is axially located between the distributor and the cylinder body. Each distributor opening extends around the first rotation axis to form a distribution arc, thereby forming a high-pressure working fluid distribution arc and a low-pressure working fluid distribution arc. For this purpose, such a distribution opening usually has a circumferentially slotted shape, also referred to as a "kidney shape" in professional terminology.

[0010] The relative position of the distributor openings in the distributor plate and the openings in the distributor can determine the angular segment of the rotational movement about the first rotational axis in which the fluid connection between the respective distribution circuit and the cylinder-piston arrangement is realized. In more detail, during the rotation of the cylinder, the supply / discharge opening of each chamber faces the low-pressure distribution circuit in a first angular position range and faces the high-pressure distribution circuit in a second (different) angular position range.

[0011] Thus, the relative (angular) position between the distributor plate and the distributor can be used to set the operating characteristics of the hydraulic machine by determining the angular range in which a fluid connection between the distribution circuit and the chamber is achieved.

[0012] Until now, once assembled, the distributor plate and the distributor have been stationary, in particular about the first axis of rotation. Therefore, these components, once assembled, can be moved. On the contrary, to change the angular position of the distributor plate relative to the distributor about the first axis of rotation, it is necessary to disassemble the hydraulic press. This will make the machine inoperable and requires time and skill. However, the fixed position of the distributor plate may not enable efficient operation of the hydraulic press in all operating situations. Utility Model Content

[0013] Therefore, the object of the present disclosure is to improve the operating efficiency of an axial piston hydraulic machine. In particular, it is to improve said operating efficiency in a simple manner, for example without disassembling the axial piston hydraulic machine.

[0014] Therefore, the currently proposed axial piston hydraulic press includes:

[0015] a swash plate, a first fluid port and a second fluid port,

[0016] Wherein, a fluid bypass may be provided to fluidically connect the first fluid port with the second fluid port, and

[0017] The tilt angle (or in other words, the rotation angle) of the swash plate can be self-adjusted according to the flow cross section of the fluid bypass. The self-adjusting angle range may include + / -1.5° (e.g. relative to a non-tilted and / or fully vertical angle position and / or a non-self-adjusting position, e.g. before self-adjustment).

[0018] Except for the self-adjustable functions of the fluid bypass and the swash plate, according to certain embodiments, the hydraulic machine may be constructed similarly to known solutions. Thus, it may, for example, include any of the distributor, cylinder, swash plate actuator and distributor plate as described above and in detail below. Furthermore, the hydraulic machine may operate substantially as described above, while additionally providing the self-adjustment disclosed herein.

[0019] The first fluid port and the second fluid port may be included by the distributor and / or may include or form a high pressure working fluid line and a low pressure working fluid line, respectively. Additionally or alternatively, the first fluid port and the second fluid port may be fluidly connected to an opening in the distributor, which in turn may be fluidly connected to an optional distributor arc in an optional distributor plate.

[0020] The fluid bypass may also be referred to as a fluid short circuit between the first fluid port and the second fluid port, in particular a fluid short circuit between the high pressure side and the low pressure side associated with the first fluid port and the second fluid port, respectively. The flow cross section of the fluid bypass may define the extent or size of the fluid bypass. The flow cross section may affect the angular position at which the pistons reach their upper and / or lower limits of their stroke, for example, due to a sudden change in pressure when the corresponding chamber receiving the piston is fluidically connected to the fluid bypass. As a result, the reaction forces experienced by the swash plate, as well as, for example, the reaction forces transmitted from the working fluid in the chamber to the piston and the reaction forces transmitted from the piston to the swash plate, vary depending on the flow cross section of the fluid bypass.

[0021] Specifically, depending on the flow cross section of the fluid bypass, the swash plate may be subject to reaction forces of a certain magnitude. These reaction forces may force the swash plate to change its position around its rotation axis. Therefore, the swash plate can self-regulate its rotation angle.

[0022] Generally, such self-regulation may include adjusting the swivel angle of the swash plate without the need for additional forces to be generated by any actuator. For example, a swash plate actuator may be present and may be used to actively adjust the swivel angle. However, the actuator may not be controlled to achieve the self-regulation and / or may be overridden by the self-regulation. The self-regulation may specifically not include any feedback control or closed control loop, such as actively setting the swivel angle of the swash plate.

[0023] By achieving self-adjustment of the swivel angle of the swash plate, the geometric cubic capacity of the hydraulic press can be adjusted accordingly (automatically). It has been observed that this feature can improve the overall operating efficiency of the hydraulic press. In particular, the swivel angle determines the volume of fluid received and / or displaced by each chamber of the cylinder during rotation. By achieving self-adjustment of the swivel angle, the fluid volume can also be self-adjusted to achieve a more efficient operation. In particular, and as described in detail below, under increased load, the fluid volume can be reduced, which can reduce the power consumption of the hydraulic press and, therefore, reduce energy consumption.

[0024] For example, the fluid bypass may be provided by a distributor plate of an axial piston hydraulic machine. The distributor plate may be configured (eg structurally) according to known examples, but may be configured (eg according to the embodiments below) to vary and thereby adjust the fluid bypass.

[0025] For example, the angular position of the distributor plate (e.g. about the first rotation axis) may be variable so that the flow cross section of the fluid bypass varies. The angular position may, for example, vary by up to 3°. Such a variation may occur when the hydraulic press is operated. It may not be necessary to disassemble the hydraulic press. It may not be necessary to have a dedicated and, for example, electronically powered and / or controlled actuator. Instead, the variation may be driven based on hydraulic pressure, and in particular, a pressure difference of the hydraulic working fluid. This improves the efficiency of the hydraulic press with a limited structural complexity.

[0026] According to one embodiment, the distributor plate has at least one plate port (e.g., distributor opening) which can be fluidically connected to both the first fluid port and the second fluid port in order to set up a fluid bypass. As explained above for known prior art solutions, the plate ports can form a distribution arc. There can be two plate ports forming two distribution arcs, wherein the distribution arcs can extend in different angular sections of the distributor plate. For example, the distribution arcs can each include an angular section greater than 40°, greater than 90°, and, for example, between 90° and 160°. The distribution arcs can be angularly spaced apart from each other.

[0027] More precisely, the plate port may be simultaneously fluidly connectable to the first fluid port and the second fluid port. For example, a fluid connection between the ports may be provided while bridging a structural separation of the fluid ports. Such a structural separation may, for example, be comprised by the distributor and may form a wall section of the distributor.

[0028] By using plate ports to implement the fluid bypass, the structural changes to the hydraulic machine may be minor compared to existing designs. In addition, the fluid bypass can be reliably set and accurately adjusted.

[0029] As described above, according to one embodiment, the first fluid port and the second fluid port may be included by a distributor, and the distributor plate may be arranged at the distributor. In other words, the first fluid port and the second fluid port may be provided in the distributor of the axial piston hydraulic machine.

[0030] According to another aspect, an axial piston hydraulic machine may have a cylinder body that is rotatable about an axis of rotation and includes a plurality of cylinders, in each of which a piston is received. Each received cylinder may form a cylinder-piston arrangement. Each cylinder and received piston may (at least partially) define a chamber in which a fluid (i.e., a working fluid) may be received. During rotation of the cylinder body about the axis of rotation, each chamber may be fluidically connected to a fluid bypass.

[0031] For example, the chamber may comprise (e.g. supply / discharge) openings which, during the rotation of the cylinder, are similar to the fluid connections made with the distribution arc according to known prior art solutions, which openings may be fluidly connected to the fluid bypass in at least one angular section of the rotation. Such a connection may be made via and / or through a plate port of a distributor plate as described above. In this way, modifications to the components of the hydraulic machine may be minor compared to existing designs. The desired transmission of the reaction force to the swash plate may thus be achieved with a lower structural complexity.

[0032] Thus, in one example, fluid connection (of each chamber) to the fluid bypass is achieved by fluidly connecting each chamber to a plate port, at least temporarily and / or at least in one angular segment, for example, as the cylinder rotates.

[0033] According to another embodiment, by means of the fluid bypass, the piston in the compression stage (and, for example, has not yet reached its upper stroke limit position) can be fluidly connected to the low-pressure port of the first fluid port and the second fluid port (and simultaneously connected to the high-pressure port of the first fluid port and the second fluid port). Additionally or alternatively, by means of the fluid bypass, the piston in the suction stage (and, for example, has not yet reached its lower stroke limit position) can be fluidly connected to the high-pressure port of the first fluid port and the second fluid port (and simultaneously connected to the low-pressure port of the first fluid port and the second fluid port).

[0034] This is in contrast to existing solutions in which a fluid connection can only be made to one of the fluid ports until its upper or lower stroke position is reached, respectively. In particular, in known solutions, simultaneous connection to two ports is not possible at any angular segment of rotation.

[0035] In one example, the flow cross section of the fluid bypass is increaseable under an increase in fluid pressure received by one of the first and second fluid ports, and in particular, under an increase in fluid pressure received by the high pressure port of the first and second fluid ports. The pressure may be, for example, the fluid pressure received from the cylinder when operating as a pump. The increased pressure may correspond to an increased load. By increasing the fluid bypass under increased pressure and load, the reaction force exerted by the cylinder on the swash plate may be reduced. The swash plate may then adjust its rotation angle to reduce the fluid discharge of the hydraulic press. This helps reduce the power consumption of the hydraulic press, resulting in higher operating efficiency.

[0036] Therefore, one embodiment includes that when the fluid pressure received by one of the first fluid port and the second fluid port increases and / or when the flow cross-section of the fluid bypass increases, the inclination angle of the swash plate can be self-adjusted so as to reduce the fluid displacement due to the axial piston hydraulic machine.

[0037] The flow cross section of the fluid bypass is self-adjustable. This may exclude adjustment by any dedicated (e.g. electric) actuator, in particular based on any feedback control, thereby reducing complexity. For example, there may be no dedicated controllable actuator to adjust the angular position of the distributor plate. Furthermore, there may be no specific sensor to determine the angular position of the distributor plate.

[0038] In contrast, the flow cross section of the fluid bypass can be self-adjustable based on the fluid pressure of at least one of the first fluid port and the second fluid port. For example, it can be self-adjustable based on the pressure difference between the first fluid port and the second fluid port. This can provide a self-adjustable capability to quickly and accurately adjust the existing pressure with low complexity and substantially no additional energy consumption.

[0039] The axial piston hydraulic machine may comprise a (particularly self-regulating) control arrangement for setting a fluid bypass, which control arrangement is pressure driven. For example, the control arrangement may comprise a mechanism configured to rotate a distributor plate when driven by pressure. The control arrangement may be pressure driven only and may, for example, be without any electric actuator. The control arrangement may also be referred to as a control mechanism and / or a control valve arrangement. The pressure may be hydraulic pressure, in particular the hydraulic pressure of a working fluid. The control arrangement may also be referred to as a hydraulic control arrangement.

[0040] For example, the control arrangement may be fluidly connected or connectable to the one of the first and second fluid ports having a higher fluid pressure. In particular, the control arrangement may be configured to automatically switch its fluid to the one of the first or second fluid ports having a higher fluid pressure, for example, in response to a corresponding pressure change between the first and second fluid ports. According to one aspect, the control arrangement may always (e.g., due to having the above-mentioned automatic switching function) be fluidly connected to the one of the first or second fluid ports having a higher fluid pressure.

[0041] The control arrangement may include a shuttle valve that is fluidly connected to both the first fluid port and the second fluid port. The shuttle valve may also be fluidly connected to a movable member for moving the distributor plate discussed below. Additionally or alternatively, it may also be fluidly coupled to some members configured to set and / or adjust a fluid bypass. The shuttle valve may be configured to fluidly connect its output port (e.g., any of the above-mentioned components may be fluidly connected thereto) to any of the first or second fluid ports, and in particular to switch the fluid connection between the first or second fluid ports. That is, the first fluid port and the second fluid port may be alternately connected to and disconnected from the output port of the shuttle valve. For example, the shuttle valve may be configured to always connect its output port to the one of the first fluid port and the second fluid port with a higher fluid pressure.

[0042] The control arrangement may include at least one movable member that is movable according to the fluid pressure applied to the movable member. The movable member may be connected to an output port of a reciprocating valve, for example as described above. The movable member may be rotatable or linearly movable, for example. It may be mechanically connected to the distributor plate and, as a function of its own movement, be used to adjust the angular position of the distributor plate. In this way, the range of the fluid bypass may be adjusted.

[0043] The movable member may be received in a cylinder and / or may be configured as a piston. A chamber is at least partially defined by the movable member and the cylinder and may receive a fluid and in particular a working fluid. The chamber may be fluidically coupled to a reciprocating valve and / or a control arrangement as described above.

[0044] The movable member may be spring loaded into a first position. The first position may correspond to a closed fluid bypass. This helps ensure a defined operating state, such as in the absence of excessive fluid pressure in either of the first and second fluid ports. Specifically, given that the fluid bypass remains closed, this may ensure efficient operation in the absence of excessive fluid pressure in either of the first and second fluid ports. Excessive fluid pressure may be a pressure of the working fluid above a defined threshold. When the pressure is excessive, the efficiency gain by the self-adjusting tilt angle of the swash plate may outweigh the potential efficiency loss caused by opening the fluid bypass.

[0045] Thus, in the first position of the movable member, the flow cross section of the fluid bypass may be reduced to zero.The flow cross section may be enlarged depending on the movement of the movable member and / or depending on the pressure difference between the first fluid port and the second fluid port.

[0046] For example, the axial piston hydraulic machine may include a first movable member, which is a linearly displaceable member (and, for example, received in a cylinder as described above). In addition, a second movable member may be provided, which is rotatable and connected to the distributor plate (e.g., mechanically). When displaced, the linearly displaceable component may be configured to rotate the rotatable member. The rotatable member may be configured to change the angular position of the distributor plate when rotated. For example, one of the second movable member and the distributor plate may include a (e.g., non-circular) protrusion, which is received in a groove of the corresponding other of the second movable member and the distributor plate. When the second movable member is rotated, a torque may be generated that is transmitted to the distributor plate via the connection between the protrusion and the groove. Other mechanical connections for rotating the distributor plate, such as gear connections, may also be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Embodiments of the present disclosure will be discussed below with reference to the accompanying drawings. In all drawings, recurring features are identified with the same reference numerals.

[0048] FIG. 1 shows a cross-sectional view of an axial piston hydraulic machine according to the prior art.

[0049] Figure 2 A perspective view of a distributor included by an axial piston hydraulic machine according to one embodiment of the present disclosure is shown.

[0050] Figure 3 Shows Figure 2 The distributor in Figure 2 A partial cross-sectional view of the area marked A.

[0051] Figure 4 Shows Figure 2 The distributor in Figure 2 Another partial cross-sectional view of the area marked B.

[0052] Figure 5 Shows Figure 2 The distributor in Figure 2 Detailed view of the area marked B.

[0053] Figure 6 Shown Figure 2 Schematic diagram of a hydraulic control arrangement for regulating a fluid bypass in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] FIG. 1 depicts a cross-sectional view of an axial piston hydraulic machine 10 according to the prior art. The axial piston hydraulic machine 10 includes a shaft 12 that rotates about an axis of rotation R. The cross-sectional plane of FIG. 1 includes the axis of rotation R. A cylinder body 14 is coupled to the shaft 12 to rotate with the shaft 12. The cylinder body 14 includes a plurality of cylinders 16, each of which receives a piston 18. Each cylinder 16 and a piston 18 form a piston-cylinder arrangement and together define at least a portion of a chamber 20 in which a working fluid can be received. Each chamber 20 is fluidly connected to the surrounding environment through an opening (or channel) 21, forming a supply opening / discharge opening. A plurality of piston-cylinder arrangements are regularly spaced about the axis of rotation R, however only one of the piston-cylinder arrangements is located in the cross-section of FIG. 1 .

[0055] The hydraulic machine 10 further includes a swash plate 22. The swash plate 22 can be tilted about a swivel axis S (or tilting axis) extending orthogonally to the image plane of FIG. 1 and intersecting the rotation axis R. Therefore, even though the swash plate 22 is indicated as a substantially upright orientation in FIG. 1 , it can be tilted about the swivel axis S. Therefore, when the swivel angle (or tilting angle) is adjusted about the swivel axis S, the upper portion of the swash plate 22 in FIG. 1 , to which the upper reference numeral 22 refers, can be tilted forward or backward (i.e., to the left or right in FIG. 1 ). The lower portion of the swash plate 22 in FIG. 1 , to which the lower reference numeral 22 refers, performs a relatively opposite tilting motion compared to the upper portion.

[0056] The hydraulic machine 10 also includes an actuator 23 (e.g., a hydraulically driven bolt) that engages an engagement structure 25 that is coupled to the swash plate 22. In this way and in a known manner, the inclination angle of the swash plate 22 can be actively controlled to adjust the capacity (e.g., geometric cubic capacity) of the hydraulic machine 10.

[0057] Each piston 18 comprises a first terminal end 19 mechanically coupled to a swash plate 22. An opposite second terminal end 24 delimits a chamber 20. When the cylinder block 14 rotates about the axis of rotation R, in a conventionally known manner and depending on the swivel angle of the swash plate 22, the pistons 18 are thus displaced axially in the respective cylinders 16 along the axis of rotation R. The axial movement of the pistons 18 reduces and increases the volume of the chambers 20.

[0058] The hydraulic machine 10 also includes a distributor 26 that is not rotatable about the rotation axis R but rotatably supports the shaft 12. The distributor 26 includes a first fluid port 28 and a second fluid port 30, as more clearly seen in other figures discussed below. The first fluid port 28 and the second fluid port 30 may include (or be connected to) an internal fluid passage within the distributor 26, i.e., a fluid distribution circuit of the distributor 26. For example, depending on the operating mode of the hydraulic machine 10 as a hydraulic pump or a hydraulic engine, one of the first fluid port 28 and the second fluid port 30 forms a high-pressure fluid port, while the other forms a low-pressure fluid port.

[0059] The hydraulic machine 10 also includes a distributor plate 32. The distributor plate 32 is disc-shaped and is axially disposed between the cylinder block 14 and the distributor 26. It includes a central opening through which the shaft 12 extends. However, the distributor plate 32 is not coupled to the shaft 12 for common rotation therewith.

[0060] The distributor plate 32 abuts against the faces of the distributor 26 and the cylinder body 14, which faces each other. The distributor plate 32 has openings, not shown, forming a distribution arc, for example, and the working fluid can pass through these openings. Specifically, these openings can fluidly connect the chamber 20 of each cylinder piston arrangement of the cylinder body 14 to the first fluid port 28 and the second fluid port 30 of the distributor 26. To this end, the opening 21 of each cylinder piston arrangement can fluidly connect (via the distributor plate 32) at least one angular segment of the rotational movement of the shaft 12 to each of the first fluid port 28 and the second fluid port 30. This operation is well known in the prior art and is therefore not described in detail. Please refer to the background introduction section of the present disclosure, which discusses further details of this known operation.

[0061] Figure 1 also indicates some other hydraulic machine components 34. These will not be described in further detail here.

[0062] about Figure 2-6 , an embodiment according to the present disclosure will be discussed below. Only a portion of the hydraulic machine 10 according to this embodiment can be seen in these figures. The non-illustrated components of the hydraulic machine 10 can be generally constructed similar to the components in Figure 1. That is, the present embodiment differs from the known solution in Figure 1 in particular with respect to the distributor 26 and the distributor plate 32, which will be discussed in detail below. The other components of the hydraulic machine 10 can be constructed and operate similarly to the example of Figure 1.

[0063] Figure 2A perspective view of a distributor 26 according to an embodiment of the present disclosure is depicted, showing a face facing a cylinder block not shown, and at which a distributor plate 32 is arranged. The distributor plate 32 includes two distribution arcs 36. Each distribution arc 36 includes a plurality of angularly spaced openings 38, which may also be provided in the form of a single continuous opening. Each opening 38 may be referred to as a plate port. Each distribution arc 36 is fluidly connected to one of the first fluid port 28 and the second fluid port 30 of the distributor 26. At the outermost angular ends of the two distribution arcs 36, the distribution arcs 36 (more precisely, the corresponding openings 38 positioned at said ends) optionally include a groove 40. At Figure 2 In the diagram, only one of the grooves 40 is marked with a corresponding reference number. In a conventionally known manner, these grooves 40 can gradually increase or decrease the degree of fluid coupling between the distribution arc 36 and the opening 21 of the cylinder 14 rotating along the distribution arc 36. This prevents sudden pressure fluctuations.

[0064] Figure 3 The distributor 26 is depicted in Figure 2 A cross-sectional view of the A region, Figure 2 The cutting plane P is marked in Figure 3 , a portion of a (hydraulic) control arrangement 42 is shown to enable self-adjustment of the angular position of the distributor plate 32 about the rotation axis R and relative to the fixed distributor 26. The control arrangement 42 comprises a shuttle valve 44. Two ports 46 (e.g. input ports) of the shuttle valve 44 are shown, each port 46 being coupled to one of the first fluid port 28 or the second fluid port 30 via a respective fluid channel 48. In a conventionally known manner, the shuttle valve 44 is configured to fluidically connect the first fluid port 28 or the second fluid port 30 (more specifically, its respective input port 46, the first fluid port 28 and the second fluid port 32 being connected to the respective input port 46) to a non-illustrated output port 51 (see Figure 6 ). More specifically, the shuttle valve 44 is configured to always connect the port having a higher fluid pressure among the first fluid port 28 and the second fluid port 30 to the output port 51 .

[0065] Figure 4 The distributor 26 is depicted in Figure 2 Another cross-sectional view of region B. Figure 4 The cross-sectional plane is not shown in detail, but Figure 2 is parallel to the cross-sectional plane P and is positioned closer towards the observer.

[0066] Figure 4Another part of the hydraulic control arrangement 42 is shown, namely a cylinder 53 receiving a linearly movable piston 50 (i.e. a first movable member of the hydraulic control arrangement 42). Together with optional sealing and stop members 54, the cylinder 53 and the piston 50 define a hydraulic chamber 56 which is connected to the output port 51 of the shuttle valve 44 (see Figure 3 and Figure 6 ). The piston 50 is loaded by the elastic force of the spring 60 and enters the Figure 4 In the location shown in the figure.

[0067] The piston 50 engages a second movable member 60 of the hydraulic control arrangement 42, which is movable about a second movable member 60 parallel to the rotation axis R (see Figure 3 ) extends along a non-illustrated rotation axis. Therefore, the angular position of the second movable member 60 is variable according to the linear movement of the piston 50.

[0068] For completeness, Figure 4 Also shown is a fluid passage opening 64, (in Figure 4 The fluid channel openings 64 are arranged at the distributor plate 32 (not shown in the figure). Each of these fluid channel openings 64 is fluidly connected to one of the first fluid port 28 and the second fluid port 30 (for example, via the fluid distribution circuit of the distributor 26). In this way, they establish a fluid connection between the first fluid port 28 and the second fluid port 30 and the cylinder body 14 via the distributor plate 32 and its distribution arc 36.

[0069] Figure 5 The diagram shows the location Figure 2 Detailed view of the rotatable member 62 in area B of FIG. Figure 5 The distributor plate 32 is not shown in the figure, and the depicted surface of the rotatable member 62 faces the rear side of the distributor plate 32 (eg, facing the Figure 3 The rotatable member 62 includes a protrusion 66 which is received in a not shown recess in the rear face of the distributor plate 32. When the rotatable member 62 and thus the protrusion 66 are rotated, torque is transmitted to the distributor plate 32 to change the angular position of the distributor plate 32 about the rotation axis R (see Figure 3 ). By way of example only, the protrusion 66 has a non-circular shape (particularly a non-circular cross-section) that may provide particularly efficient torque transmission when rotating.

[0070] Figure 6 4 is a schematic illustration of a hydraulic control arrangement 42. Again, each input port 46 of the shuttle valve 44 is shown connected to one of the first fluid port 28 and the second fluid port 30. The port exhibiting the higher fluid pressure of the first fluid port 28 and the second fluid port 30 is fluidly connected to the output port 51 through the shuttle valve 44 and is thus connected to the output port 51. Figure 4 If the pressure at one of the connected first and second fluid ports 28, 30 exceeds the force of the spring 60, the piston 50 is linearly displaced, thereby rotating the only schematically illustrated rotatable member 62 to rotate the distributor plate 32. This rotation Figure 6 are marked by corresponding curved arrows. Please note that Figure 6 The number of openings 38 of the distribution arc 36 depicted in FIG. Figure 3 However, this is irrelevant to the intended function of the hydraulic machine 10 and any number of openings 38 may be provided.

[0071] As a result of the rotation, at least one of the distribution arcs 36 that is normally (i.e., when not rotating) fluidly coupled to only one of the first and second fluid ports 28, 30 is also fluidly coupled to the other of the respective first and second fluid ports 28, 30. Figure 4 , the distribution arc 36 can be, for example, fluidically connected to both fluid passage openings 64 simultaneously, for example by at least slightly overlapping both fluid passage openings. This creates a highly schematically indicated fluid bypass 80 between the different pressure states, i.e. between the first fluid port 28 and the second fluid port 30 and the fluid flows they receive respectively.

[0072] As a result, the cylinder 14 and in particular its chamber 20 is fluidly coupled to the fluid bypass 80 in at least one angular section when rotating about the rotation axis R. This changes the normal working cycle when rotating the cylinder 14 (e.g., the linear movement and axial position of the piston 18 relative to the angular position of the cylinder 14).

[0073] Specifically, this results in that the cylinder piston, which is still in the compression phase (e.g., where the piston 18 has not reached its respective associated stroke limit), is arranged to be coupled to the low-pressure port of the first fluid port 28 and the second fluid port 30. In addition, this results in that the cylinder piston, which is still in the suction phase (e.g., where the piston 80 has not reached its respective associated stroke limit), is arranged to be coupled to the high-pressure port of the first fluid port 28 and the second fluid port 30.

[0074] As a result, the reaction force applied by the piston 18 to the swash plate 22 changes. The swash plate 22 in turn self-adjusts its tilt angle to achieve a force balance for different degrees of reaction force adjustment experienced. To enable this, the swash plate tilt mechanism including the actuator 23 and the engagement structure 25 is designed to generate sufficiently small resistance. They cannot withstand the self-adjusting tilting movement of the swash plate 22. For example, the self-locking effect of the engagement between the actuator 23 and the engagement structure 25 may be intentionally weakened. In one example, the force applied to the swash plate 22 to overcome the resistance of the actuator 23 and the engagement structure 25 for achieving self-adjustment of the swash plate 22 is between 1000N and 2500N, for example, between 1800N and 2200N.

[0075] The operation of the hydraulic machine 10 according to an embodiment of the present disclosure may be as follows: In a first operating mode without any self-regulation, the port exhibiting a higher fluid pressure among the first fluid port 28 and the second fluid port 30 is fluidly coupled to the output port 51 of the shuttle valve 44. As long as the pressure at the port is too low to compress Figure 4 The spring 60 keeps the distributor plate 32 in its Figure 6 In the initial angular position of , no fluid bypass 80 is created in this angular position. In this state, each distribution arc 36 of the distributor plate 32 is fluidly coupled to only one of the first fluid port 28 and the second fluid port 30.

[0076] When the pressure at one of the first fluid port 28 and the second fluid port 30 fluidly coupled to the output port 51 increases above a threshold, Figure 4 The piston 50 is linearly displaced while compressing the spring 60. This translates into a rotation of the rotatable member 62, thereby rotating the distributor plate 32 about the rotation axis R. At a sufficiently large amount of rotation, one of the distribution arcs 36 of the distributor plate 32 is fluidly coupled to both the first fluid port 28 and the second fluid port 30, thereby creating a fluid bypass 80. The higher the pressure at one of the first fluid port 28 and the second fluid port 30 that is fluidly connected to the output port 51, the larger the flow cross section of the fluid bypass 80.

[0077] Please note that the flow cross section of the fluid bypass 80 is set in a self-regulating manner and is set only by hydraulic actuation. The operation of any dedicated non-hydraulic actuator is not required.

[0078] As a result of the establishment of the fluid bypass 80, the above-mentioned self-regulation of the inclination angle of the swash plate 22 can be achieved. The degree of this self-regulation depends on the flow cross section of the fluid bypass 80. This regulation can take place in such a way that the fluid displacement of each piston 18 of the cylinder 14 and therefore the fluid displacement of the entire hydraulic machine 10 is reduced. This reduces the energy consumption of the hydraulic machine 10, thereby enabling a more efficient operation. Again, this is achieved in a self-regulating manner and is achieved solely by hydraulic drive. No special operation of the actuator 23 of FIG. 1 or any other non-hydraulic actuator is required.

[0079] Furthermore, the self-adjusting functions disclosed above for setting the cross-section of the fluid bypass 80 and for adjusting the inclination angle of the swash plate 22 do not require any sensors or complicated feedback control loops.

[0080] List of reference numerals:

[0081] 10. Hydraulic press

[0082] 12 Axis

[0083] 16 cylinders

[0084] 18 Piston

[0085] 19 First Terminal

[0086] 20 Chamber

[0087] 21 Opening

[0088] 22 Swash plate

[0089] 23 Actuator

[0090] 25 Joint structure

[0091] 24 Second Terminal

[0092] 26 Distributor

[0093] 28 First fluid port

[0094] 30 Second fluid port

[0095] 32 Distributor plate

[0096] 34 Mechanical parts

[0097] 36 Distribution Arc

[0098] 38 openings / plate ports

[0099] 40 grooves

[0100] 42 Control Arrangement

[0101] 44 Reciprocating valve

[0102] 46 Input Ports

[0103] 48 Fluid Channels

[0104] 50 Piston / first movable member

[0105] 53 cylinder

[0106] 54 Sealing and stopping components

[0107] 56 Chamber

[0108] 60 Spring

[0109] 62 Rotatable member / second movable member

[0110] 64 Fluid channel opening

[0111] 66 bulge

[0112] 80 Fluid Bypass

[0113] R Rotation axis

[0114] S Rotation axis

[0115] P Cross-sectional plane

[0116] A, B are described in more detail in other figures Figure 2 Area

Claims

1. An axial piston hydraulic press (10), characterized in that: include: a swash plate (22), a first fluid port (28) and a second fluid port (30), wherein a fluid bypass (80) can be provided to fluidically connect the first fluid port (28) with the second fluid port (30); and The inclination angle of the swash plate (22) can be self-adjusted according to the flow cross section of the fluid bypass (80).

2. The axial piston hydraulic machine (10) according to claim 1, characterized in that: The fluid bypass (80) can be provided by a distributor plate (32) of the axial piston hydraulic machine (10).

3. The axial piston hydraulic machine (10) according to claim 2, characterized in that: The angular position of the distributor plate (32) is variable so that the flow cross section of the fluid bypass (80) varies.

4. The axial piston hydraulic machine (10) according to claim 2, characterized in that: The distributor plate (32) has at least one plate port (38) which is fluidly connectable to both the first fluid port (28) and the second fluid port (30) in order to provide the fluid bypass (80).

5. The axial piston hydraulic machine (10) according to claim 1, characterized in that: The first fluid port (28) and the second fluid port (30) are provided in a distributor (26) of the axial piston hydraulic machine (10).

6. The axial piston hydraulic machine (10) according to claim 4, characterized in that: The axial piston hydraulic machine (10) has a cylinder body (14) which can rotate about a rotation axis (R) and includes a plurality of cylinders (16), each of which receives a piston (18), each of which (16) and the received piston (18) at least partially define a chamber (20) capable of containing a fluid therein, each of which (20) can be fluidically connected to the fluid bypass (80) during rotation of the cylinder body (14) about the rotation axis (R).

7. The axial piston hydraulic machine (10) according to claim 6, characterized in that: Connection to the fluid bypass (80) is achieved by fluidly connecting each of the chambers (20) and the plate ports (38).

8. The axial piston hydraulic machine (10) according to claim 6, characterized in that: By means of the fluid bypass (80), the piston (18) in the compression phase is fluidly connected to a low-pressure port among the first fluid port (28) and the second fluid port (30), and / or the piston (18) in the suction phase is fluidly connected to a high-pressure port among the first fluid port (28) and the second fluid port (30).

9. The axial piston hydraulic machine (10) according to claim 1, characterized in that: When the pressure of the fluid received by one of the first fluid port (28) and the second fluid port (30) increases, the flow cross section of the fluid bypass (80) can increase.

10. The axial piston hydraulic machine (10) according to claim 1, characterized in that: When the fluid pressure admitted by one of the first fluid port (28) and the second fluid port (30) increases and / or when the flow cross section of the fluid bypass (80) increases, the inclination angle of the swash plate (22) can be self-adjusted to reduce the fluid displacement due to the axial piston hydraulic machine (10).

11. The axial piston hydraulic machine (10) according to claim 1, characterized in that: The flow cross section of the fluid bypass (80) is self-adjustable.

12. The axial piston hydraulic machine (10) according to claim 10, characterized in that: The flow cross section of the fluid bypass (80) is self-adjustable according to the fluid pressure of at least one of the first fluid port (28) and the second fluid port (30).

13. The axial piston hydraulic machine (10) according to claim 2, characterized in that: The axial piston hydraulic machine (10) comprises a control arrangement (42) for setting the fluid bypass (80), the control arrangement (42) being pressure driven.

14. The axial piston hydraulic machine (10) according to claim 13, characterized in that The control arrangement (42) is fluidly connected or connectable to the one of the first fluid port (28) and the second fluid port (30) having a higher fluid pressure.

15. The axial piston hydraulic machine (10) according to claim 14, characterized in that The control arrangement (42) includes a shuttle valve (44) fluidly connected to both the first fluid port (28) and the second fluid port (30).

16. The axial piston hydraulic machine (10) according to claim 13, characterized in that: The control arrangement (42) includes at least one movable member (50, 62) movable in response to fluid pressure applied to the movable member (50, 62).

17. The axial piston hydraulic machine (10) according to claim 16, characterized in that The movable member (50, 62) is spring loaded into a first position.

18. The axial piston hydraulic machine (10) according to claim 17, characterized in that In the first position, the flow cross section of the fluid bypass (80) is reduced to zero.

19. The axial piston hydraulic machine (10) according to claim 16, characterized in that: The first movable member (50) is a linearly displaceable member, and the second movable member (62) is rotatable and connected to the distributor plate (32), wherein the first movable member (50) is configured to rotate the second movable member (62) when linearly displaced, and wherein the second movable member (62) is configured to change the angular position of the distributor plate (32) when rotated.

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