Hydrostatic Axialkolbenmaschine

Abstract

A hydrostatic axial piston machine with an adjustable displacement volume and with a fixed high-pressure side (14) and a fixed low-pressure side (16) is disclosed, and with a rotatably mounted cylinder drum (12) with cylinder bores (34) and axially displaceable working pistons (36) therein, which define hydrostatic working chambers (38) that can be brought into alternating contact with the high-pressure side (14) and the low-pressure side (16) when the cylinder drum (12) is rotated, wherein the working pistons (36) are slidably supported by sliding shoes (40) on a swashplate (42) of an adjustable pivoting cradle (6), which is pivotably mounted on a high-pressure-side first sliding bearing (30) with a first hydrostatic relief pressure field and on a low-pressure-side second sliding bearing with a second hydrostatic relief pressure field.wherein the first hydrostatic relief pressure field can be brought into pulsating pressure medium contact with the high-pressure side (14) via a first tapping channel (48) penetrating the pivot cradle (6) with a first opening (50; 150) in a high-pressure-side half-surface (52) of the inclined disk (42), as well as a sliding shoe opening (58) of the sliding shoe (40), which sweeps over the first opening (50; 150).

Description

The invention relates to a hydrostatic axial piston machine with a swivel cradle according to claim 1 mounted pivotably on hydrostatically relieved slide bearings.An axial piston machine of the generic type has a fixed high-pressure side and a fixed low-pressure side. That is, a high-pressure connection and a low-pressure connection of the axial piston machine are fixed as intended and do not change. Fundamentally, the axial piston machine is thus provided for single-quadrant operation and / or for two-quadrant operation, less advantageously for four-quadrant operation. With a rotation of its cylinder drum, hydrostatic working chambers come into alternating pressure medium connection with the high-pressure side and the low-pressure side. Hydrostatic working pistons which delimit the working spaces are supported in a sliding manner via sliding shoes on an swashplate of a swivel cradle which can be adjusted in terms of the swivel angle. The swivel cradle is mounted pivotably on the high-pressure side and on the low-pressure side via hydrostatically unloaded slide bearings, wherein the displacement volume of the axial piston machine is adjusted by adjusting the swivel angle. To reduce wear, a hydrostatic relief pressure field is provided on the respective slide bearing, which is supplied with pressure medium from the high-pressure side via a tapping channel passing through the swivel cradle and having an orifice in the swashplate, and a sliding shoe orifice of the sliding shoe, which passes over the orifice. Thus, the hydrostatic relief pressure fields come into pulsating pressure medium connection with the high-pressure side. A pressure of the relief pressure field is thus subject to pulsation and is referred to as pulse lubrication.Such pulse lubrication is provided by generic axial piston machines from the product family A10 of the applicant, as well as the axial piston machine according to the publication DD 136 285 A1. The orifice of the tapping channel is located between the dead points of the working pistons and the tapping channel supplies both relief pressure fields with the high-pressure side.A disadvantage of this is that, during each sliding shoe crossing, the relatively large volume of the tapping channel must be charged with high pressure and discharged again. This leads to repeated reduction of the relief pressure on the sliding shoe, which can lead to wear between the sliding shoe and the swashplate, and also represents a power loss. While the sliding shoe passes over the orifice, the relief pressure at the sliding shoe swashplate contact decreases and the mixed friction fraction increases, so that in the worst case, the sliding shoe can be lubricated or material transferred to the swashplate, which reduces the service life of the axial piston machine.In contrast, the object of the invention is to provide a hydrostatic axial piston machine of the generic type, the wear of which is reduced.The object is achieved by a hydrostatic axial piston machine having the features of claim 1.Advantageous further developments of the invention are described in the respective dependent claims.A hydrostatic axial piston machine has an adjustable displacement volume and a fixed high pressure side and a fixed low pressure side. Preferably, the fixed high-pressure side / fixed low-pressure side is provided in such a way that the axial piston machine has a fixed high-pressure chamber / high-pressure connection and a fixed low-pressure chamber / low-pressure connection. In the context of the disclosure, it is to be understood fixedly that operation of the axial piston machine is provided as intended without pressure side changes. The axial piston machine has a rotatably mounted cylinder drum with cylinder bores and working pistons accommodated therein in an axially displaceable manner. Hydrostatic working chambers are delimited by the working pistons, which can be brought into alternating pressure medium connection with the high-pressure side and the low-pressure side during a rotation of the cylinder drum. The working pistons are slidingly supported via sliding shoes on a swashplate of an adjustable swivel cradle. The swashplate is pivotably mounted on a high-pressure-side, first slide bearing with a first hydrostatic relief pressure field and on a low-pressure-side, second slide bearing with a second hydrostatic relief pressure field. In this case, the first hydrostatic relief pressure field can be brought into pulsating pressure medium connection with the high-pressure side via a first tapping channel which passes through the swivel cradle and which has a first orifice in a half surface of the swashplate on the high-pressure side, and a sliding shoe orifice of the sliding shoe which passes over the first orifice. According to the disclosure, the second hydrostatic relief pressure field can be brought into pulsating pressure medium connection with the high pressure side via a second tapping channel, which is separate from the first tapping channel and passes through the swivel cradle and has a second orifice in the half surface on the high pressure side, and the sliding shoe orifice, which sweeps over the second orifice. In addition, according to the disclosure, a distance of the first orifice from the second orifice is dimensioned, in particular matched to a diameter of the sliding shoe orifice, such that the respective sliding shoe orifice can be brought into pressure medium connection only with the first orifice or with the second orifice and not simultaneously with both.According to the disclosure, both relief pressure fields are thus each supplied with pressure medium in a pulsating manner via a separate, independent tapping channel with a separate orifice in the high-pressure-side half surface and come into pressure medium connection with the high-pressure side only sequentially, i.e. never simultaneously. The volume of the respective tapping channel is thus, according to the disclosure, smaller than that of the single, common tapping channel according to the prior art, via which both relief pressure fields are supplied with pressure medium in a pulsating manner. The fact that the two tapping channels are not simultaneously connected to the sliding shoe mouth at the same time as disclosed, but only sequentially, and that the volume of the tapping channel to be charged is smaller in each case, leads to the quantity of pressure medium to be provided from the sliding shoe mouth for charging the relief pressure field and the tapping channel being reduced. This in turn has the consequence that a relief pressure at the sliding shoe mouth collapses less strongly when sweeping over the first mouth, or the second mouth. A relief pressure field between the sliding shoe and the swashplate, which is bounded by the sliding shoe mouth, is thus more stable according to the disclosure, or has a lower pressure drop when sweeping over the respective mouth, such that the wear between the sliding shoe and the swashplate is reduced. The wear is thus reduced and the robustness is increased.Preferably, the sliding shoe mouth is permanently connected to the hydrostatic working chamber of the hydrostatic working piston.Preferably, a supply channel is provided for this purpose, which extends from the sliding shoe mouth through the sliding shoe and the working piston and opens into the hydrostatic working chamber.According to a further development, a distance between the first opening and the second opening is at most 200%, preferably at most 150%, of an outer diameter of a sliding surface of the sliding shoe on the swashplate. A greater distance is, of course, possible in principle.According to a further development, the high-pressure-side half surface of the swashplate extends on this side and a low-pressure-side half surface of the swashplate extends beyond a connecting line which is defined by an inner dead point at which the working piston located there is maximally retracted into its cylinder bore and an outer dead point at which the working piston located there is maximally extended out of its cylinder bore. At least one of the first orifice and the second orifice is arranged in a region of the high-pressure-side half surface in which a piston acceleration, which is effective in the direction of retraction into the cylinder bore, in particular imposed by the rotation of the cylinder drum and the pivot angle of the swashplate, is minimal or approaches a minimum with the rotation.The piston acceleration acting in the direction of retraction is maximum centrally between the dead points and decreases again towards the inner dead point. In an arrangement of the mouth(s) near the inner dead center, a reaction force between the sliding shoe and swashplate-and thus friction force-is thus lower than centrally between the dead centers. This arrangement thus increases the robustness against wear of the sliding shoe and the swashplate.According to a preferred development, this region is therefore arranged between the inner dead point and a central region of the high-pressure-side half surface, which lies half way between the dead points. The arrangement relates to the rotation of the cylinder drum from the outer dead center to the inner dead center.Preferably, this region, measured from the inner dead center, covers an angular interval between 15° and 40°.According to a possible development, both the first opening and the second opening are arranged in the region.The hydrostatic relief of the first high-pressure-side plain bearing fundamentally has a high priority on account of the high bearing forces acting there, and it is advantageous if the first high-pressure-side relief pressure field results in the greatest possible relief force. The second, low-pressure-side sliding bearing, on the other hand, has lower bearing forces, so that the relief force resulting from the second, low-pressure-side relief pressure field can be lower.According to an advantageous further development, these different requirements for the respective relief force can be implemented constructively in such a way that the first orifice, via which the first, high-pressure-side relief pressure field is supplied with pressure medium, is arranged (in time) before the second orifice, via which the low-pressure-side relief pressure field is supplied with pressure medium, with respect to the rotation of the cylinder drum from the outer dead point toward the inner dead point.A short first tapping channel, a small volume of the first tapping channel to be charged and a resulting low pressure drop at the slide shoe orifice / in the relief pressure field of the slide shoe can be realized with an advantageous development in which the first orifice is arranged in a central region of the half surface on the high-pressure side, which lies between the dead points, so that the first tapping channel is formed by a bore substantially perpendicular to the swashplate.The low-pressure-side relief pressure field can have a lower relief pressure-as already explained above.According to a further development, the second orifice, via which the second, low-pressure-side relief pressure field is supplied with pressure medium from the high-pressure side, is arranged downstream of the first orifice, with respect to the rotation from the outer dead center to the inner dead center.The second orifice is preferably arranged so close to the inner dead point that a pressure / working pressure in the hydrostatic working chamber, the working piston / sliding shoe of which sweeps over the second orifice, is already in a pressure reduction phase. At the second, low-pressure-side relief pressure field, a comparatively low pressure is thus present, which also decreases. An internal leakage via the second, low-pressure-side relief pressure field is thereby reduced. This reduced internal leakage results in an increase in the hydraulic efficiency of the axial piston machine. With higher hydraulic efficiency, the axial piston machine thus nevertheless has a high robustness against wear.According to a further development, the first bleed channel extends from its first orifice as far as the first, high-pressure-side relief pressure field within the swivel cradle and / or with a closed, first cross section.The first tapping channel preferably runs over its entire length within the swivel cradle as a closed channel.According to a further development, the second bleed channel extends from its second orifice as far as the second, low-pressure-side relief pressure field within the swivel cradle and / or with a closed, second cross section.The second tapping channel preferably runs over its entire length within the swivel cradle as a closed channel.According to a further development, at least one of the tap channels is formed by a single and / or straight, circular cylindrical bore.Alternatively or additionally, at least one of the tapping channels is formed by a sequence of circular cylindrical bore sections which are angled with respect to one another.The tapping channel / channels can / are formed as a simple bore(s) without tearing plugs. This reduces the manufacturing costs and leads to an increase in quality and to a reduction in discounts.According to one development, a high-pressure connection of the fixed high-pressure side has a first connection diameter and a low-pressure connection of the fixed low-pressure side has a second connection diameter which is larger in comparison therewith.According to a further development, a first, high-pressure-side relief pressure pocket, by which the first, high-pressure-side relief pressure field is limitable or bounded, has a first base area which is larger than a second base area of a second, low-pressure-side relief pressure pocket, by which the second, low-pressure-side relief pressure field is limitable or bounded.The relief pressure pocket is formed in the pivot cradle and / or in the slide bearing.Due to the different size of the base areas, a relief force resulting from the respective relief pressure field is set over the respective base area at the same pressure. This has the advantage that no separate throttle cross section has to be provided in the tapping channels for adjusting the relief force. Instead, the pressure is conducted from the sliding shoe orifice via the respective tapping channel unthrottled / substantially undiminished to the respective relief pressure pocket, wherein the required relief force results from this pressure and the respective base area.Exemplary embodiments of an axial piston machine according to the disclosure are illustrated in the drawings. The invention will now be explained with reference to the figures of these drawings.The following are shown: FIG. 1 shows a hydrostatic axial piston machine according to the disclosure, in a longitudinal section, FIG. 2 shows a pivoting cradle of the axial piston machine according to FIG. 1, according to a first exemplary embodiment, in a view from below, FIG. 3 shows the pivoting cradle according to FIG. 2, in a view from above, and FIG. 4 shows a pivoting cradle of the axial piston machine according to FIG. 1, according to a second exemplary embodiment, in a view from above.FIG. 1 shows a hydrostatic axial piston machine 1 designed in a swashplate construction with an adjustable displacement volume. The axial piston machine 1 has a pot-shaped housing 2 which is closed at the end face by a connection block 4. A shaft or drive shaft 10 is rotatably mounted in the housing 2 and a swivel cradle 6 is pivotably mounted. Connected to the shaft 10 in a rotationally fixed manner is a cylinder drum 12 which, with its end face pointing in the direction of the connection block 4, is in contact with a distributor plate or control plate 8 fixed to the housing.A high-pressure connection 14 and a low-pressure connection 16 are fixedly provided on the connection block 4. In the context of the disclosure, fixed means that the two pressure sides, or connections 14, 16, do not change axial piston machine 1 during proper operation. This means that the axial piston machine 1 is intended for single-quadrant operation or two-quadrant operation with fixed pressure sides, but not for four-quadrant operation with alternating pressure sides.The axial piston machine 1 can be provided and designed according to the disclosure for pump operation or motor operation, or for both operating modes, wherein the abovementioned boundary condition of the fixed pressure sides, i.e. fixed high-pressure connection 14 and fixed low-pressure connection 16, applies.For adjusting a displacement volume, the axial piston machine 1 has a hydrostatic adjusting cylinder 20, of which a lever 22 of the swivel cradle 6 is articulated. A restoring spring 24 acts on the lever 22 in a restoring manner.According to FIG. 1, cylinder bores 34 are formed in the cylinder drum 12, in each of which a working piston 36 is axially displaceably accommodated. Hydrostatic working spaces 38 are delimited by the working pistons 36. The working pistons 36 project with piston heads from the cylinder bores 34, which are supported in a sliding manner via pivotable sliding shoes 40 on a sliding surface or swashplate 42 of the swivel cradle 6.Upon a rotation of the cylinder drum 12, the working spaces 38 pass via through-recesses or pressure kidney of the control plate 8 into alternating pressure medium connection with the fixed high-pressure side 14 and the fixed low-pressure side 16, that is to say with the corresponding fixed pressure connection.According to FIGS. 1 and 2, the swivel cradle 6 has two part-cylindrical sliding surfaces 26, 28 arranged on both sides of the drive shaft 10, which, together with the housing-side plain bearing shell 30, of which only the first, high-pressure-side plain bearing shell 30 is visible in FIG. 1 on account of the section guidance, form two plain bearings of the swivel cradle 6.A first high-pressure-side sliding bearing is formed by the first high-pressure-side sliding bearing shell 30 and the first high-pressure-side sliding surface 28 (cf. FIGS. 1 and 2 ). A second, low-pressure-side sliding bearing is formed by a second, low-pressure-side sliding bearing shell (not shown as already mentioned) and the second, low-pressure-side sliding surface 26 (cf. FIG. 2 ).FIG. 2 shows the swivel cradle 6 according to FIG. 1 in a view from below, in which the sliding surfaces 26, 28 face the observer. To form hydrostatic relief pressure fields between the sliding surfaces 26, 28 and the sliding bearing shells 30, the sliding surfaces 26, 28 each have a relief pressure pocket or relief recess 44, 46. For this purpose, the relief pressure pockets 44, 46 delimit the hydrostatic relief pressure fields in cooperation with the opposing plain bearing shells.According to FIG. 2, both relief pressure pockets 44, 46 have a rectangular cross section which is elongate in the pivot direction. Transversely to the pivot direction, the relief pressure pockets 44, 46 have the same width. The first, high-pressure-side relief pressure pocket 44 has a greater length than the second, low-pressure-side relief pressure pocket 46. a first base area of the first, high-pressure-side relief pressure pocket 44 is thus greater than a second base area of the second, low-pressure-side relief pressure pocket 46. at the same pressure in the respective relief pressure pocket 44, 46, a greater hydrostatic relief force therefore results on the high-pressure side solely on account of the size of the base areas.According to FIGS. 1, 2 and 3, the swivel cradle 6, starting from the first, high-pressure-side relief pressure pocket 44 and toward the swashplate 42, is traversed by a first tapping channel 48.A first opening 50 of the first tapping channel 48 is arranged in a half surface 52 of the swashplate 42 on the high pressure side, close to an inner dead point IT, at which the working pistons 36 are retracted to the maximum.Furthermore, according to the disclosure, the swivel cradle 6 is penetrated by a second tapping channel 54 which extends from the second, low-pressure-side relief pressure pocket 46 toward the swashplate 42.The second tapping channel 54 also has a second orifice 56 in the high-pressure-side half surface 52 of the swashplate 42, which orifice is arranged, analogously to the first orifice 50 of the first tapping channel 48, close to the inner dead point IT. The second orifice 56 is arranged closer to the inner dead point IT than the first orifice 50.Both openings 50, 56 are arranged on an orbit of the sliding shoes 40 on the swashplate 42 so that they are swept over repeatedly by each of the sliding shoes 40 when the drive shaft 10 rotates. With reference to a direction of rotation of the cylinder drum 12 illustrated in FIGS. 2 and 3, the respective sliding shoe 40 first sweeps over the first opening 50 and subsequently over the second opening 56.According to FIG. 1 and with reference to FIG. 3, the sliding shoes 40 have a sliding surface 60 with which they slidingly abut the swashplate 42. Concentrically in the sliding surface, a sliding shoe opening 58 is provided, which sweeps over the openings 50, 56 of the tapping channels 48, 54 when the drive shaft 10 rotates.Starting from the sliding shoe mouth 58, a supply channel passes through the sliding shoe 40 and the working piston 36 and opens into the hydrostatic working chamber 38.With reference to FIG. 3, when the drive shaft 10 rotates, the sliding shoe orifice 58 first sweeps over the first orifice 50 of the first, high-pressure-side tapping duct 48. as long as the first orifice 50 and the sliding shoe orifice 58 have a (partial) pressure path, the first, high-pressure-side relief pressure pocket 44 is in pressure-medium communication with the high-pressure side 14. In the first, high-pressure-side relief pressure pocket 44, after a short phase of charging, the first relief pressure field is thus fully formed and the resulting relief pressure force relieves the high-pressure-side plain bearing.As the drive shaft 10 continues to rotate, the latter (partial) contact point of the first opening 50 ends with the sliding shoe opening 58, and as a result the sliding shoe opening 58 comes into (partial) contact with the second opening 56.As long as the second orifice 56 and the sliding shoe orifice 58 have a (partial) overlap, the second, low-pressure-side relief pressure pocket 46 is in pressure medium connection with the high-pressure side 14. In the second, low-pressure-side relief pressure pocket 46, after a short phase of charging, the second relief pressure field is thus fully formed and the resulting relief pressure force relieves the low-pressure-side plain bearing.The arrangement of the openings 50, 56 radially to the axis of rotation of the drive shaft 10, their distance in the direction of rotation and a diameter of the sliding shoe opening 58 are matched to one another in such a way that the openings 50, 56 can only come into (partial) overlapping with the sliding shoe opening 58 sweeping over them, respectively. It is thus ensured that only one of the relief pressure pockets 44, 46 always comes into pressure fluid connection with the high pressure side 14 and the respective other is separated from the high pressure side 14.The two tapping channels 48, 54 are thus never connected to the sliding shoe mouth 58 simultaneously according to the disclosure, but only sequentially. This has the positive effect that the quantity of pressure medium which flows out of the sliding shoe orifice 58 for hydrostatically charging the respective tapping duct 48, 54 and the respective relief pressure pocket 44, 46 is, according to the disclosure, smaller than if both tapping ducts 48, 54 and relief pressure pockets 44, 46 had to be hydrostatically charged simultaneously. This in turn has the consequence that a relief pressure at the sliding shoe orifice 58 collapses to a lesser extent when sweeping over the first orifice 50 or the second orifice 56. The relief pressure field between the sliding shoe 40 and the swashplate 42 which is respectively delimited by the sliding shoe mouth 58 is thus more stable according to the disclosure, or has a lower pressure drop when sweeping over the respective mouth 50, 56, such that the wear between the sliding shoe 40 and the swashplate 42 is reduced. The certainty of the axial piston machine 1 in the region of the tribological pairing of the sliding shoe 40 / swashplate 42 is thus reduced according to the disclosure and the robustness of the axial piston machine 1 is increased.FIG. 4 shows a second exemplary embodiment of a swivel cradle 106 for the axial piston machine 1 according to FIG. 1, the swivel cradle 106 here corresponding to the first exemplary embodiment according to FIGS. 1, 2 and 3 and differing therefrom only with respect to the course of the first tapping duct 148 and its orifice in the first, high-pressure-side relief pressure pocket 44 and its first orifice 150 in the high-pressure-side half surface 52 of the swashplate 42, for which reason the description will subsequently only be based on these differences.In contrast to the exemplary embodiment according to FIGS. 2 and 3, according to FIG. 4, the first orifice 150 is not arranged near the inner dead center IT, but in a central region of the high-pressure-side half surface 52 which extends between the dead centers AT, IT. The first tapping channel 148 therefore extends over a particularly short path, preferably substantially perpendicularly to the swashplate 42, toward the first, high-pressure-side relief pressure pocket 44. As a result, the pressure drop at the sliding shoe mouth 58 when sweeping over the first mouth 150 is even lower than in the first exemplary embodiment according to FIGS. 2 and 3. As a result, the hydrostatic relief on the sliding shoe 40 is even better and the robustness of the axial piston machine is further increased.List of reference characters1 Hydrostatic axial piston machine 2 Housing 4 Connection block 6 Swivel cradle 8 Control plate 10 Drive shaft 12 Cylinder drum 14 High-pressure side / high-pressure connection 16 Low-pressure side / low-pressure connection 20 Adjusting cylinder 22 Lever 24 Restoring spring 26 Second, low-pressure-side sliding surface 28 First, high-pressure-side sliding surface 30 Plain bearing shell 34 Cylinder bore 36 Working piston 38 Hydrostatic working chamber 40 Sliding shoe 42 Swashplate 44 First, high-pressure-side relief pressure pocket 46 Second, low-pressure-side relief pressure pocket 48 First tapping channel 50 First orifice 52 High-pressure-side half surface 54 Second tapping channel 56 Second orifice 58 Sliding shoe orifice 60 Sliding surface IT Inner dead point AT Outer dead pointReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDD 136 285 A1

[0003]

Claims

Hydrostatic axial piston machine with an adjustable displacement volume and with a fixed high-pressure side (14) and a fixed low-pressure side (16), and with a rotatably mounted cylinder drum (12) with cylinder bores (34) and working pistons (36) accommodated therein in an axially displaceable manner, by which hydrostatic working spaces (38) are delimited, which can be brought into alternating pressure medium connection with the high-pressure side (14) and the low-pressure side (16) during a rotation of the cylinder drum (12), wherein the working pistons (36) are supported in a sliding manner via sliding shoes (40) on an swashplate (42) of an adjustable swivel cradle (6), which is mounted in a pivotable manner on a high-pressure-side first sliding bearing (30) with a first hydrostatic relief pressure field and on a low-pressure-side second sliding bearing with a second hydrostatic relief pressure field, wherein the first hydrostatic relief pressure field can be brought into pulsating pressure medium connection with the high-pressure side (14) via a first tapping channel (48) passing through the swivel cradle (6) and having a first orifice (50; 150) in a half surface (52) of the swashplate (42) on the high-pressure side, and a sliding shoe orifice (58) of the sliding shoe (40) which passes over the first orifice (50; 150), characterized in that the second hydrostatic relief pressure field can be brought into pulsating pressure medium connection with the high-pressure side (14) via a second tapping channel (54) passing through the swivel cradle (6) and having a second orifice (56) in the half surface (52) on the high-pressure side and the sliding shoe orifice (58) which passes over the second orifice (56), and in that a spacing of the first orifice (50; 150) to the second opening (56) is dimensioned such that the sliding shoe opening (58) of an individual one of the sliding shoes (40) can be brought into pressure medium connection at most with one of the first opening (50; 150) and the second opening (56).Hydrostatic axial piston machine according to claim 1, characterised in that a distance between the first opening (50) and the second opening (56) is at most 200%, preferably at most 150%, of an outer diameter of a sliding surface (60) of the sliding shoe (40) on the swashplate (42).Hydrostatic axial piston machine according to Claim 1 or 2, characterized in that the high-pressure-side half surface (52) of the swashplate (42) extends on this side and a low-pressure-side half surface of the swashplate (42) extends beyond a connecting line which is spanned by an inner dead point (IT) at which the working piston (36) located there is maximally retracted into its cylinder bore (34) and an outer dead point (AT) at which the working piston (36) located there is maximally extended from its cylinder bore (34), and in that at least one (50, 56; 56) out of the first and second orifice (50, 56; 150, 56) is arranged in a region of the high-pressure-side half surface (52) in which a piston acceleration which is effective in the direction of retraction into the cylinder bore (34) is minimal or approaches a minimum with the rotation.Hydrostatic axial piston machine according to Claim 3, characterized in that the region between the inner dead point (IT) and a central region of the half surface (52) on the high-pressure side, which lies half way between the dead points (AT, IT), is arranged.Hydrostatic axial piston machine according to claim 3 or 4, characterised in that both the first orifice (50) and the second orifice (56) are arranged in the region.Hydrostatic axial piston machine according to one of Claims 3 to 5, characterized in that the first orifice (50; 150) is arranged before the second orifice (56) with respect to the rotation of the cylinder drum (12) from the outer dead point (AT) to the inner dead point (IT).Hydrostatic axial piston machine according to one of Claims 3 to 6, characterized in that the first orifice (150) is arranged in a central region of the half surface (52) on the high-pressure side, which lies between the dead points (AT, IT), and in that the first tapping duct (148) is formed by a bore substantially perpendicular to the swashplate (42).Hydrostatic axial piston machine according to one of the preceding claims, characterized in that the first bleed duct (48; 148) extends from its first orifice (50; 150) to the first hydrostatic relief pressure field within the swivel cradle (6; 106) and / or with a closed first cross section, and in that the second bleed duct (54) extends from its second orifice (56) to the second hydrostatic relief pressure field within the swivel cradle (6; 106) and / or with a closed second cross section.Hydrostatic axial piston machine according to one of the preceding claims, characterized in that at least one of the tapping channels (48, 54) is formed by a single or straight, circular cylindrical bore, and / or in that at least one of the tapping channels is formed by a sequence of circular cylindrical bore sections which are angled with respect to one another.Hydrostatic axial piston machine according to one of the preceding claims, characterized in that a high-pressure connection of the fixed high-pressure side (14) has a first connection diameter, and in that a low-pressure connection of the fixed low-pressure side (16) has a second connection diameter which is larger than this.

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