Low noise axial piston machine

Abstract

The invention relates to an axial piston machine (1), in particular an axial piston pump, with a piston drum (2) that can be driven in at least one direction of rotation (22), with cylinders (10) arranged in the piston drum which are spaced apart from one another in the direction of rotation by a piston pitch (24) and are configured to slidably receive pistons (4) having a piston diameter (34), wherein the longitudinal axes (16) of the pistons are arranged parallel to one another on a pitch circle (28) having a pitch circle diameter (26), and wherein: 0.377zK ≤ DT,KdK ≤ 0.4948zK, where DT,K corresponds to the pitch circle diameter, dK to the piston diameter, and zK to the number of pistons. Such an axial piston pump is quiet in operation and yet compact.

Description

[0001] The present invention relates to an axial piston machine.

[0002] Axial piston machines are hydraulic machines that can be used as both pumps and motors. They typically feature a rotatable piston drum equipped with cylinders in which pistons are mounted for axial movement. During operation, the rotation of the piston drum is converted into a reciprocating motion of the pistons within the cylinders, causing a working medium, such as oil, to be periodically drawn in and expelled. The resulting pulsation of the flow and pressure leads to significant noise generation in conventional axial piston machines, especially at high power outputs. Attempts to reduce this noise have so far primarily come at the expense of the compactness of the axial piston machines.

[0003] The present invention is therefore based on the objective of providing a compact axial piston machine that is quiet in operation.

[0004] This task is solved by an axial piston machine, in particular an axial piston pump, with a piston drum that can be driven in at least one direction of rotation, with cylinders arranged in the piston drum which are spaced apart from each other in the direction of rotation by a piston pitch and are designed to slidably receive pistons having a piston diameter, wherein longitudinal axes of the pistons are arranged parallel to each other on a pitch circle having a pitch circle diameter, and wherein the following applies: 0 , 377 z K ≤ D T , K d K ≤ 0 , 4948 z K , where DT,K the pitch circle diameter d K the piston diameter and from K corresponds to the number of pistons.

[0005] Test series have shown that axial piston machines whose ratio of pitch circle diameter to piston diameter lies within the ratio range defined above, which depends on the number of pistons in the axial piston machine, are particularly quiet and compact. The lower limit of this ratio also ensures that the axial piston machine is sufficiently robust and durable.

[0006] The above invention can be further improved by the following features, each of which is advantageous in itself and can be combined with each other as desired.

[0007] The piston drum can be rotatable or driven in the direction of rotation and in the opposite direction. The axial piston machine can thus be designed and used as an axial piston pump or an axial piston motor. The direction of rotation can refer to the circumferential direction of the piston drum.

[0008] A deviation of approximately 5% from the factors 0.377 and / or 0.4948 may be tolerated.

[0009] The ratio between the pitch circle diameter and the piston diameter is the ratio that actually exists in the axial piston engine. The terms 0.377 from K and 0.4948 from K can define values ​​that the ratio of the pitch circle diameter to the piston diameter may take as minimum or maximum.

[0010] The term 0.377 from K can be a minimum ratio of the pitch circle diameter to the piston diameter, D T , K d K MIN , and the term 0.4948 from K can achieve a maximum ratio between the pitch circle diameter and the piston diameter D T , K d K MAX , correspond. Table 1 shows values ​​for the minimum and maximum ratio depending on the number of pistons. from K applied for illustrative purposes. Table 1 from K [ - ] 3 4 5 6 7 8 9 10 11 D T , K d K MAX 1,49 1,98 2,48 2,97 3,47 3,96 4,46 4,95 5,45 D T , K d K MIN 1,13 1,51 1,89 2,26 2,64 3,02 3,39 3,77 4,15 from K [ - ] 12 13 14 15 16 17 18 19 20 D T , K d K MAX 5,94 6,44 6,93 7,43 7,92 8,42 8,91 9,41 9,90 D T , K d K MIN 4,52 4,90 5,28 5,66 6,03 6,41 6,79 7,16 7,54 from K [ - ] 21 22 23 24 25 26 D T , K d K MAX 10,40 10,89 11,39 11,88 12,38 12,87 D T , K d K MIN 7,92 8,29 8,67 9,05 9,43 9,80

[0011] In one embodiment, the following condition can apply to the axial piston machine: 4 , 52 < D T , K d K < 12 , 87 .

[0012] In one embodiment, the pistons are part of the axial piston machine. The axial piston machine can have a predetermined number of pistons.

[0013] The pistons, or the cylinders in which the pistons are guided, are preferably equidistant from one another in the direction of rotation of the piston drum. This allows the piston pitch, by which two pistons adjacent in the direction of rotation are spaced apart, to be constant.

[0014] According to a structurally simple design, the axial piston machine can have a swiveling disk on which the pistons are at least indirectly supported, wherein the swiveling disk is pivotable about at least one pivot axis extending perpendicular to the longitudinal axes of the pistons.

[0015] The swivel disc can be pivoted through a swivel angle measured perpendicular to the longitudinal axes of the piston drum or pistons. The swivel disc can have a swivel angle range within which it can pivot. This swivel angle range can extend from a minimum to a maximum angle. For example, the minimum swivel angle could be approximately 0° and the maximum approximately 30°. Of course, other ranges are also possible.

[0016] The terms swivel disc, swivel cradle and inclined disc can be used synonymously.

[0017] In one embodiment, the axial piston machine can have a drive shaft that can be connected to, or is connected to, the piston drum for torque transmission. The drive shaft can be driven by a motor, for example, an electric motor. Similarly, the drive shaft can be connected to a generator for torque transmission.

[0018] To achieve a particularly quiet axial piston machine during operation, the machine can have more than 11 pistons, preferably 13, 15, 24, or 26 pistons. Of course, other configurations can also include other numbers of pistons, in particular fewer than 13, for example 4, 5, or 7, or more than 26, for example 28 or 30 pistons.

[0019] According to a further advantageous embodiment, the piston drum can continue to rotate in the direction of rotation by sweep angles during an entire compression or decompression phase of a cylinder, wherein the sweep angles satisfy the following condition: δ p , T = 360 ° a z K ± 2 , 5 ° , where δ p,T the sweep angles and from K corresponds to the number of pistons, and wherein a = 1 if from K straight and a = 2, if from K is odd.

[0020] An axial piston machine whose sweep angles meet the aforementioned condition is particularly quiet in operation. This is due to the fact that structure-borne noise resulting from the pulsating forces and moments is especially low for the deviations defined above.

[0021] In an even quieter design, the sweep angles can fulfill the following condition: δ p , T = 360 ° a z K ± 2 ° .

[0022] A deviation of approximately 0.1° from the values ​​2.5° or 2° can be tolerated.

[0023] The sweep angles can be measured in the direction of rotation of the piston drum.

[0024] The sweep angles can refer to a sweep angle for the compression phase and a sweep angle for the decompression phase. The sweep angle for the compression phase can be the angle by which the piston drum continues to rotate in the direction of rotation during an entire compression phase of a cylinder. Similarly, the sweep angle for the decompression phase can be the angle by which the piston drum continues to rotate in the direction of rotation during an entire decompression phase of a cylinder.

[0025] The compression phase can refer to the phase in which the pressure in a cylinder increases. The pressure can rise from a minimum pressure to a maximum pressure. Similarly, the decompression phase can refer to the phase in which the pressure in a cylinder decreases. The pressure can fall from a maximum pressure to a minimum pressure. The maximum pressure might be approximately 400 bar, for example. The term "approximately" can mean a deviation of about 2 bar from the maximum pressure.

[0026] The minimum pressure during the compression or decompression phase can be 1.5 bar higher than the average pressure level during an intake phase. The intake phase can be understood as the phase in which a piston moves within a cylinder from top dead center to bottom dead center, thereby increasing the volume.

[0027] The average pressure level during the intake phase can be at least approximately 1 bar absolute, where "approximately" can mean a deviation of approximately 0.2 bar to 0.5 bar.

[0028] The pressures defined above, in particular the minimum pressure, the maximum pressure and the average pressure level during the intake phase, can indicate the pressures that prevail in the cylinders.

[0029] According to a further advantageous aspect, a control disk of the axial piston machine can have control disk openings, wherein the piston drum can have piston drum openings on its side facing the control disk that open into the cylinders, wherein each piston drum opening can have at least one dead center position in which the piston of the cylinder belonging to this piston drum opening is at a dead center, and at least one limit position in which the piston drum opening is adjacent in the direction of rotation to the control disk opening that is closest in the direction of rotation to the piston drum opening in the dead center position, wherein the at least one dead center position is spaced from the at least one limit position by a reversing angle measured in the direction of rotation, and wherein the reversing angle satisfies the following condition: φ W = 360 ° a z K ± 2 , 5 ° , where φ W the reversing angle and from Kcorresponds to the number of pistons, and wherein a = 1 if from K straight and a = 2, if from K is odd.

[0030] The above design of the axial piston machine, in which the reversing angle deviates by no more than 2.5° from half the piston division in the case of an odd number of pistons and by no more than 2.5° from the whole piston division in the case of an even number of pistons, leads to a reduction of structure-borne noise and the noise caused by it.

[0031] In an even more advantageous embodiment, the reversing angle can fulfill the following condition: φ W = 360 ° a z k ± 2 ° .

[0032] A deviation of approximately 0.1° from the values ​​of 2.5° or 2° may be tolerated.

[0033] The reversing angle can be representative of the distance in the direction of rotation between a piston drum opening of a piston located at a dead center and the control disc opening nearest in the direction of rotation.

[0034] The term "dead center" can refer to the top and / or bottom dead center of a piston. A dead center can also refer to the position of a piston at which its direction of movement is reversed.

[0035] The fact that the piston drum opening is adjacent to the control disc opening in the direction of rotation can mean that the outline of the control disc opening just touches the outline of the piston drum opening, or that the projection of the control disc opening's outline along the longitudinal direction of the piston drum just touches the projection of the piston drum opening's outline along the longitudinal direction of the piston drum. The control disc opening and the piston drum opening may not yet overlap, particularly in the longitudinal direction of the piston drum.

[0036] In an advantageous embodiment, the piston drum openings and the control disc openings are kidney-shaped, but other shapes, such as circular, oval, or polygonal shapes, are also conceivable. Naturally, the piston drum openings and the control disc openings do not have to be the same shape.

[0037] The piston drum openings can be part of the cylinders or formed by them.

[0038] According to a further embodiment, the pistons can be supported, at least indirectly, on a sliding surface of the swivel disc facing the piston drum, wherein the sliding surface has at least one section that is inclined at an angle relative to a plane spanned by the swivel disc. This embodiment allows the decompression phase, and thus the variation of the sweep angle, to be made more constant, particularly over a larger swivel angle range.

[0039] The inclined section can be inclined about an axis of inclination that is oriented perpendicular to the pivot axis of the swivel disk.

[0040] In one embodiment, the section can extend over the entire sliding surface of the swivel disc.

[0041] In one embodiment, the pistons can be supported directly on the sliding surface. Furthermore, the axial piston machine can have sliding shoes against which the pistons are supported on the swivel disk or the sliding surface. The sliding shoes can, for example, be designed as bearings, such as ball bearings, or incorporate such a bearing.

[0042] To reduce the variation in the decompression phase depending on the swivel angle, the tilt angle can be between 0.5° and 5°. A deviation of 0.2° from these values ​​is acceptable.

[0043] The size of the tilt angle can depend on or be selected based on the design of the axial piston machine. For example, the tilt angle can depend on the rated speed, the swivel angle, the pitch circle diameter, the piston diameter, and / or the dead volume of the axial piston machine.

[0044] The axial piston machine is specifically designed to be operated as intended. Intended operation is the permissible operation for which the axial piston machine is designed, engineered, and suitable according to its technical purpose. Operating conditions that do not comply with the granted approval, enforceable subsequent orders, or legal regulations are not considered intended operation. Furthermore, operational processes that occur in the event of a malfunction of the axial piston machine may be considered intended operation, provided that no safety-related reasons preclude its continuation. Intended operation may also include maintenance procedures. The intended use or operation is defined, for example, in accordance with the EU Machinery Directive, by the operating instructions, or, according to DIN EN 82079-1, by the user manual.

[0045] Intended operation can be defined by parameters such as pressure, rotational speed, and / or swivel angle. The parameters that are present or permitted during intended operation can be specified, for example, in an operating manual for the axial piston machine.

[0046] In order to design the axial piston machine specifically for a particular application or operating condition, and to make it particularly quiet for this application or operating condition, for example, the axial piston machine can have a reference operating condition in which the axial piston machine fulfills at least one condition from the following group of conditions: The axial piston machine is operated at nominal pressure. The swivel angle of the swivel disk is between 50% and 100% of the maximum swivel angle. The axial piston machine is operated at nominal speed.

[0047] Preferably, at least two of the above conditions, and even more preferably all three of the above conditions, may be met.

[0048] The relationships defined in this document can therefore apply to a specific reference operating condition of the axial piston engine. For example, the relationship between the ratio of the pitch circle diameter to the piston diameter and the minimum and maximum ratios of the pitch circle diameter to the piston diameter can apply to this specific reference operating condition. Similarly, the relationship for the sweep angles and / or the reversing angle can apply to this specific reference operating condition.

[0049] The nominal pressure can be understood as the pressure at which the axial piston machine's performance is at its maximum. In one embodiment, the nominal pressure can be between approximately 350 bar and approximately 450 bar, preferably around 400 bar. The term "approximately" here can represent a deviation of 10 bar.

[0050] Alternatively or cumulatively, the swivel disk of the axial piston machine can have a swivel angle in the reference operating state that is between approximately 50% and approximately 100% of the maximum swivel angle. The term "approximately" here can be understood as a deviation of 5%. Possible values ​​for the maximum swivel angle have already been mentioned above.

[0051] The rated speed can be understood as the speed at which the power output of the axial piston engine is maximum. The speed can refer to the rotational speed of the piston drum and / or drive shaft. In an advantageous embodiment, the rated speed can, for example, be in the range of approximately 10,000 rpm to approximately 12,000 rpm, preferably approximately 11,000 rpm. The term "approximately" here can encompass a deviation of 500 rpm. For axial piston engines with a displacement of 500 cm³ or less, the rated speed can, for example, be approximately 1500 rpm, and for axial piston engines with a displacement of 50 cm³ or less, approximately 3500 rpm.

[0052] The problem is further solved for the use of an axial piston machine according to the invention for converting hydraulic energy into mechanical energy and / or mechanical energy into hydraulic energy. The axial piston machine can, in particular, be operated in a reference operating condition in which the axial piston machine fulfills at least one condition from the following group of conditions: The axial piston machine is operated at nominal pressure. The swivel angle of the swivel disk is between 50% and 100% of the maximum swivel angle. The axial piston machine is operated at nominal speed.

[0053] The above statements regarding the reference operating condition with respect to the axial piston machine according to the invention, in particular regarding the maximum swivel angle, the nominal pressure and the nominal speed, can also apply to the operating condition when using the axial piston machine according to the invention.

[0054] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying figures. Individual features present in the following exemplary embodiment may be omitted if, according to the embodiments described above, the technical effect associated with that feature is not important. Conversely, a feature described above but not present in a subsequent exemplary embodiment may be added to the exemplary embodiment if the technical effect associated with that feature is important for a particular application.

[0055] In the following, the same reference symbols are used for elements that correspond to each other in terms of structure and / or function.

[0056] They show: Fig. 1 a schematic sectional view of an axial piston pump according to one possible embodiment; Fig. 2 another schematic sectional view of the axial piston pump made of Fig. 1 ; Fig. 3 another schematic sectional view of the axial piston pump made of Fig. 1 Fig. 4 shows another schematic sectional view of the axial piston pump. Fig. 1 ; Fig. 5 a schematic perspective exploded view of the piston drum and control disc of the in Fig. 1 The axial piston pump shown; Fig. 6 a schematic representation of the relationship between the ratio of the pitch circle diameter and the piston diameter to the number of pistons; Fig. 7 a schematic representation of the piston drum and control disk of an axial piston machine according to another possible embodiment; and Fig. 8 a schematic perspective view of a swivel disk of an axial piston machine according to another possible embodiment.

[0057] The following describes an axial piston machine according to one possible embodiment with reference to the Figuren 1 bis 6 described. In the Figuren 1 bis 6 The axial piston machine shown is purely an example of an axial piston pump. Of course, the axial piston machine can also be designed and operated as an axial piston motor. In this case, hydraulic energy is converted into mechanical energy, not mechanical energy.

[0058] The axial piston machine 1 comprises a piston drum 2, piston 4 and - in the illustrated embodiment - a swivel disk 6 and a drive shaft 8.

[0059] The piston drum 2 can be essentially cylindrical and have several cylinders 10, each of which slidably holds a piston 4. In the illustrated embodiment, the piston drum 2 has, purely by way of example, thirteen cylinders 10 and thirteen pistons 4, with each of the thirteen cylinders 10 being provided with one of the thirteen pistons 4. In other embodiments, of course, other even or odd numbers of pistons 4 or cylinders 10 can be provided. A particularly quiet axial piston engine 1 can be achieved, for example, if it is provided with 15, 24, or 26 pistons 4 or cylinders 10. Naturally, other numbers of pistons 4, in particular fewer than 13 or more than 26 pistons, can also be provided.

[0060] The piston drum 2 can have piston drum openings 14 on its side facing away from the swivel disk 6 or on its side facing a control disk 12 (described in more detail later), each opening into one of the cylinders 10. In the illustrated embodiment, the piston drum openings 14 are kidney-shaped. Of course, the piston drum openings 14 can also have other shapes, for example, a circular or polygonal shape.

[0061] The pistons 4 have longitudinal axes 16 which, in the illustrated embodiment, extend parallel to each other and along a longitudinal axis 18 of the piston drum 2. However, according to other embodiments, it is also conceivable that the longitudinal axis 16 of at least one of the pistons 4 is inclined to the longitudinal axis 18 of the piston drum 2.

[0062] The longitudinal axes 16 of the pistons 4 and the piston drum 2 do not have to align as in the axial piston machine 1 designed as a so-called swashplate machine according to the Figuren 1 bis 6 - extend along a rotational axis 20 of the drive shaft 8. Thus, the longitudinal axes 16 of the pistons 4 and the piston drum 2 can be inclined relative to the rotational axis 20 of the drive shaft 8, for example, if the axial piston machine 1 is designed as a skewed-axis machine.

[0063] The cylinders 10 can be equidistant from one another in the piston drum 2 along a direction of rotation 22 extending around the longitudinal axis 18 of the piston drum 2. The distance in the direction of rotation 22 between two pistons 4 adjacent in the direction of rotation 22 corresponds to a piston pitch 24. The piston pitch 24 corresponds to the quotient of 360° and the number of pistons 4. In the illustrated embodiment, in which the axial piston engine 1 has thirteen cylinders 10 or thirteen pistons 4, the piston pitch 24 is therefore approximately 27.7°.

[0064] As from Fig. 2 and 3 As can be clearly seen, the cylinders 10 and the pistons 4 are arranged along a pitch circle 28 having a pitch circle diameter 26. This can mean that the longitudinal axes 16 of the pistons 4 and the longitudinal axes 30 of the cylinders 10, which coincide with the longitudinal axes 16 of the pistons 4, extend through the pitch circle 28 and perpendicular to the pitch circle 28.

[0065] As from Fig. 1 to 3 As can be seen, cylinders 10 have a cylinder diameter of 32 and pistons 4 have a piston diameter of 34. The piston diameter 34 essentially corresponds to the cylinder diameter 32, but is slightly smaller to ensure the pistons 4 can move freely within cylinders 10.

[0066] To ensure quiet operation, a compact design, and sufficient strength of the axial piston machine 1, the ratio of the pitch circle diameter 26 to the piston diameter 34 of the axial piston machine 1 lies between 0.377 and 0.4948 times the number of pistons 4. The ratio therefore follows the condition: 0 , 377 z K ≤ D T , K d K ≤ 0 , 4948 z K , where DT,K the pitch circle diameter 26, d K the piston diameter 34 and from K The number of pistons corresponds to 4. An axial piston engine 1 with, for example, thirteen pistons 4, such as one in Fig. 1 to 5As shown, this indicates a ratio D T , K d K on, which lies between 4.901 and 6.4324. In the Fig. 1 to 5 In the illustrated embodiment, the ratio is D T , K d K 5.38, therefore lies between 4.901 and 6.4324.

[0067] In Fig. 6 The above condition is clarified once again. In the Fig. 6The diagram shows the minimum and maximum ratios of the pitch circle diameter (26) and piston diameter (34) plotted against the number of pistons (4). The steeper, or upper, graph represents the linear relationship between the maximum ratio and the number of pistons. The less steep, or lower, graph represents the linear relationship between the minimum ratio and the number of pistons. Thus, for each number of pistons (4), there is a range of values ​​within which the ratio must lie.

[0068] In Fig. 1 and 2The swivel disk 6 of the axial piston machine 1 is visible. In the illustrated embodiment, the pistons 4 are supported at their ends facing the swivel disk 6 by means of sliding shoes 36 on the swivel disk 6. The sliding shoes 36 may have a bearing. Of course, in other embodiments it is also conceivable that the pistons 4 are supported directly on the swivel disk 6, in particular on a sliding surface 38 of the swivel disk 6 facing the piston drum 2.

[0069] The swivel disk 6 can be pivoted about a pivot axis 41 perpendicular to the longitudinal axes 16 of the pistons 4 by a pivot angle 40, which in the present embodiment is measured between a plane 42 spanned by the swivel disk 6 and a normal plane 44 perpendicular to the longitudinal axis 18 of the piston drum 2.

[0070] The pivot angle 40 of the pivot disk 6 can be changed to alter the stroke of the pistons 4 within the cylinders 10. A more steeply inclined pivot disk 6, i.e., a larger pivot angle 40, results in a greater stroke of the pistons 4, while a less steeply inclined pivot disk 6, i.e., a smaller pivot angle 40, results in a smaller stroke of the pistons 4. The pivot angle 40 can be adjustable, for example, within a pivot range extending from a minimum to a maximum angle. For example, the minimum pivot angle could be approximately 0°, and the maximum pivot angle approximately 17°. The term "approximately" here can be understood as a deviation of 5°.

[0071] As in the design in Fig. 8As shown, the sliding surface 38 of the swivel disk 6 can have at least one section 46 which is inclined at an angle 48 relative to the plane 42 spanned by the swivel disk 6. In the illustrated embodiment, a normal 50 of the section 46 points in the direction of rotation 22 of the piston drum 2. In an advantageous embodiment, the angle of inclination 48 can be between approximately 0.5° and 5°.

[0072] As in Fig. 4 and 5As can be clearly seen, the axial piston machine 1 can also have the control disk 12, which is arranged on the piston drum 2 on one side of the piston drum 2 as applied by the swivel disk 6. The control disk 12 can have control disk openings 52, which are kidney-shaped in the illustrated embodiment. Of course, other shapes are also conceivable, for example a polygonal or round, especially circular, shape. In the illustrated embodiment, the relative positions of the control disk 12 to the piston drum 2 change during operation as the piston drum 2 rotates.

[0073] In the Fig. 4 and 5In the illustrated embodiment, the axial piston machine 1 has, by way of example, three high-pressure control disc openings 52, 52a and three low-pressure control disc openings 52, 52b, i.e., a total of four control disc openings 52, 52a, 52b. The high-pressure control disc openings 52, 52a can be understood as the control disc opening 52 through which the operating medium is expelled from the cylinders 10 at high pressure. The low-pressure control disc opening 52, 52b can be the control disc opening 52 through which the operating medium is drawn into the cylinders 10 at low pressure.

[0074] Fig. 7Figure 1 shows the piston drum 2 and the control disk 12 of an axial piston machine 1 according to a further advantageous embodiment. The axial piston machine 1 shown here has only eight pistons 4 or cylinders 10. In this embodiment, the control disk 12 has four kidney-shaped control disk openings 52, namely one low-pressure control disk opening 52, 52b and three high-pressure control disk openings 52, 52a. The outline of a piston drum opening 14 of a cylinder 10, whose piston 4 is currently at bottom dead center, is schematically shown on the control disk 12. The piston drum opening 14 is in a dead center position 54. If the piston drum 2 continues to rotate in the direction of rotation 22 relative to the control disk 12 during operation, the relative position of the piston drum opening 14 to the control disk openings 52, 52a, 52b changes.If the piston drum 2 is rotated further by a reversing angle 56 measured in the direction of rotation 22, until the piston drum opening 14 is adjacent to the control disc opening 52 nearest in the direction of rotation 22, the piston drum opening 14 assumes a limit position 58. Fig. 7 The outline of the piston drum opening 14 in the limit position 58 is also shown with a dashed line.

[0075] The axial piston machine 1 is in Fig. 7 The illustrated embodiment is designed such that the reversing angle 56 satisfies the following condition: φ W = 360 ° a z k ± 2 , 5 ° , where φ W the reversing angle 56 and from K the number of pistons corresponds to 4, and where a = 1 if from K straight and a = 2, if from K is odd. In the illustrated embodiment, there is an even number of eight pistons 4, which is why the reversing angle 56 is consequently φ W = 360 ° 1 ∗ 8 ± 2 , 5 ° = 45 ° ± 2 , 5 ° amounts.

[0076] The following is a brief and purely exemplary explanation of the operating principle of an axial piston machine 1.

[0077] In pump mode, the axial piston machine 1 drives the drive shaft in the direction of rotation 22. The drive shaft 8 can be driven, for example, by an electric motor. The rotation, or torque, of the drive shaft 8 is transmitted to the piston drum 2, which is connected to the drive shaft 8 in a torque-transmitting manner, causing the piston drum 2 to rotate about its longitudinal axis 18 in the direction of rotation 22. The rotation of the piston drum 2 also moves the cylinders 10 and the pistons 4 contained therein about the longitudinal axis 18 of the piston drum 2, i.e., in the direction of rotation 22. During this movement, the pistons 4 slide along the swivel disk 6 with their ends facing the swivel disk 6. Since the swivel disk 6 is inclined by a swivel angle 40°, the position of the pistons 4 in the cylinders 10 changes as they slide along the swivel disk 6.In this way, the rotation of the piston drum 2, driven by the drive shaft 8, is converted into a reciprocating motion of the pistons 4 in the direction of the longitudinal axis 18 of the piston drum 2. This results in a periodic build-up and release of pressure in the cylinders 10, with alternating compression and decompression phases. This causes the operating medium used in the axial piston machine 1, for example oil, to be periodically drawn in and expelled.

[0078] During a complete compression or decompression phase of a cylinder 10, the piston drum 2 is rotated further by the sweep angle. The compression phase can be defined as the phase in which the pressure in a cylinder 10 increases from a minimum pressure to a maximum pressure. Similarly, the decompression phase can be defined as the phase in which the pressure in a cylinder 10 decreases from a maximum pressure to a minimum pressure.

[0079] According to a particularly advantageous embodiment, the sweep angles can fulfill the following condition: δ p , T = 360 ° a z K ± 2 , 5 ° , where δ p,T the sweep angle and from K the number of pistons corresponds to 4, and where a = 2, if from K odd and a = 1 if from K is right now. Bezugszeichen

[0080] 1 Axial piston machine 2 Piston drum 4 Piston 6 Swivel disk 8 Drive shaft 10 Cylinder 12 Control disk 14 Piston drum opening 16 Longitudinal axes of the pistons 18 Longitudinal axis of the piston drum 20 Axis of rotation of the drive shaft 22 Direction of rotation 24 Piston pitch 26 Pitch circle diameter 28 Pitch circle 30 Longitudinal axes of the cylinders 32 Cylinder diameter 34 Piston diameter 36 Sliding shoe 38 Sliding surface of the swivel disk 40 Swivel angle 41 Swivel axis 42 Plane spanned by the swivel disk 44 Normal plane 46 Section of the sliding surface 48 Inclination angle 50 Normal of the section 52 Control disk openings 52a High-pressure control disk opening 52b Low-pressure control disk opening 54 Dead center position 56 Reversing angle 58 Limit position

Claims

1. Axial piston machine (1), in particular axial piston pump, with a piston drum (2) that can be driven in at least one direction of rotation (22), with cylinders (10) arranged in the piston drum (2) which are spaced apart from each other in the direction of rotation (22) by a piston pitch (24) and are designed to slidably receive pistons (4) having a piston diameter (34), wherein longitudinal axes (16) of the pistons (4) are arranged parallel to each other on a pitch circle (28) having a pitch circle diameter (26), and wherein: 0 , 377 z K ≤ D T , K d K ≤ 0 , 4948 z K , where D T,K the pitch circle diameter (26), d K the piston diameter (34) and z K corresponds to the number of pistons (4).

2. Axial piston machine (1) according to claim 1, with a swivel disk (6) on which the pistons (4) are at least indirectly supported, wherein the swivel disk (6) is pivotable about at least one pivot axis (41) extending perpendicular to the longitudinal axes (16) of the pistons (4).

3. Axial piston machine (1) according to claim 1 or 2, wherein the number of pistons (4) is 13, 15, 24 or 26.

4. Axial piston machine (1) according to one of claims 1 to 3, wherein the piston drum (2) continues to rotate in the direction of rotation (22) by sweep angles during a complete compression phase or decompression phase of a cylinder (10), wherein the sweep angles satisfy the following condition: δ p , T = 360 ° a z K ± 2 , 5 ° , where d p,T the sweep angles and z K the number of pistons (4) corresponds to, and where a = 1 if z K straight and a = 2, if z K is odd.

5. Axial piston machine (1) according to any one of claims 1 to 4, wherein a control disk (12) of the axial piston machine (1) has control disk openings (52, 52a, 52b), and wherein the piston drum (2) has piston drum openings (14) on its side facing the control disk (12) opening into the cylinders (10), wherein each piston drum opening (14) has at least one dead center position (54) in which the piston (4) of the cylinder (10) belonging to this piston drum opening (14) is at a dead center, and at least one limit position (58) in which the piston drum opening (14) is adjacent in the direction of rotation (22) to the control disk opening (52, 52a, 52b) which is closest in the direction of rotation (22) to the piston drum opening (14) in the dead center position (54), wherein the at least one dead center position (54) of which is spaced apart from at least one limit position (58) by a reversing angle (56) measured in the direction of rotation (22),and wherein the reversing angle (56) satisfies the following condition: , φ W = 360 ° a z K ± 2 , 5 ° , where f W the reversing angle (56) and z K the number of pistons (4) corresponds to, and where a = 1 if z K straight and a = 2, if z K is odd.

6. Axial piston machine (1) according to one of claims 3 to 5 in combination with claim 2, wherein the pistons (4) are supported at least indirectly on a sliding surface (38) of the swivel disk (6) facing the piston drum (2), wherein the sliding surface (38) has at least one section (46) which is inclined relative to a plane (42) spanned by the swivel disk (6) by an angle of inclination (48).

7. Axial piston machine (1) according to claim 6, wherein the inclination angle (48) is between 0.5° and 5°.

8. Axial piston machine (1) according to any one of claims 1 to 7, wherein the axial piston machine (1) has a reference operating condition in which the axial piston machine (1) satisfies at least one condition from the following group of conditions: - The axial piston machine (1) is operated at nominal pressure, - The swivel angle (40) of the swivel disk (6) is between 50% and 100% of a maximum swivel angle (40), - The axial piston machine (1) is operated at nominal speed.

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