Axial Piston Machine with Fastening Flange with Off-Center Fastening Openings

Abstract

An axial piston machine with a known swashplate design having a displacement volume which can be adjusted above zero is disclosed. The corresponding swivel cradle is pivotable by way of an adjustment cylinder, which is arranged transversely to the axis of rotation. The axial piston machine is equipped with a fastening flange having four fastening openings. The fastening flange transitions integrally and without interruption into the adjustment cylinder. No further fastening openings are arranged in the corresponding transition area, which pass through the fastening flange in the direction of the axis of rotation.

Description

[0001] This application claims priority under 35 U.S.C. § 119 to patent application no. DE 10 2024 211 590.8, filed on Dec. 4, 2024 in Germany, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The disclosure relates to an axial piston machine.BACKGROUND

[0003] From the data sheet “A4VG series 60 axial piston variable displacement pump” from the Bosch Rexroth AG (order no. RD 92038; edition 2024-10-15), an axial piston machine in a swashplate design is known, which has a displacement volume that can be adjusted above zero, wherein the corresponding swivel cradle is pivoted with an adjustment cylinder arranged transversely to the axis of rotation. The axial piston machine is equipped with a fastening flange which is configured in accordance with the SE J744 FEB2013 standard in the variant with two fastening openings. This fastening flange is suitable for small sizes of an axial piston machine. The axial piston machine is characterized by a short design length in the direction of the axis of rotation, in particular the fastening flange being arranged very close to the adjustment cylinder.

[0004] From the data sheet “A4VG series 35 axial piston displacement pump,” a similar axial piston machine is known, which is less optimized for a short design length. For example, the nominal size 71 is equipped with a so-called 6-hole flange, in which the two variants, two fastening openings and four fastening openings have been integrated into a single fastening flange in accordance with SE J744 FEB2013. It would be desirable to transfer this fastening flange to the axial piston machine discussed above. Due to the short design length, however, not enough design space for the screw heads or the nuts of the fastening screws is available for the fastening openings near the adjustment cylinder.

[0005] An advantage of the present disclosure is that the short design length of the axial piston machine first explained above may be maintained, although it is nonetheless provided with a fastening flange that allows for rigid fastening. In this case, two axial piston machines are mounted directly next to each other along the axis of rotation in a tandem arrangement. The corresponding connection must be rigid, especially in the case of large axial piston machines, to prevent excessive vibrations during operation caused by unavoidable pressure pulsations within the axial piston machines.SUMMARY

[0006] According to the disclosure, it is proposed that the fastening flange transitions integrally and without interruption into the adjustment cylinder, wherein no further fastening openings are arranged in the corresponding transition area, which pass though the fastening flange in the direction of the axis of rotation.

[0007] The direction of movement of the working pistons is preferably parallel or somewhat inclined to the axis of rotation. The first to fourth fastening opening can each be configured as a circular opening, wherein it is preferably configured as a recess that is open radially outwards with respect to the axis of rotation. The plane of symmetry preferably contains the axis of rotation. It is contemplated that the pivot axis will be at a distance from the plane of symmetry, such that the hydraulic forces acting in the axial piston machine exert a total torque on the swivel cradle.

[0008] Advantageous developments and improvements of the disclosure are specified in the description set forth below.

[0009] It may be contemplated that the fastening flange forms a flat fastening surface that is aligned perpendicular to the axis of rotation, wherein the fastening surface is machined in such a manner that a border line or border edge to the directly adjacent, non-cutting machined surface of the housing is formed towards the adjustment cylinder, wherein a distance between the mounting plane defined by the fastening surface and the adjustment axis is at most 60% of a largest hydraulically effective diameter of the first or the second adjustment chamber. This makes it almost impossible to move the fastening surface closer to the adjustment cylinder. It should be noted here that the fastening surface often abuts against a flat surface of a higher-level assembly, which must not collide with the adjustment cylinder. At the same time, the fastening surface protrudes slightly above the non-machined surface to ensure that the higher-level assembly rests exclusively against the fastening surface. The hydraulically effective diameter of the first and second adjustment chambers are preferably equal in size.

[0010] It may be provided that the aforementioned border line in the area of the adjustment cylinder has a first section which extends in a circle, wherein the corresponding center of the circle coincides with the axis of rotation, wherein a straight second section of the edge line directly tangentially adjoins each of the two opposite ends of the first section. The border line is preferably the same shape as the 2-hole flange in accordance with the SE J744 FEB2013 standard. Thus, the axial piston machine according to the disclosure can be used wherever fastening flanges previously compliant with the standards have been used.

[0011] It may be provided that said edge line in the area of the adjustment cylinder comprises a third section which runs convexly with two straight legs, wherein the two straight legs are arranged in a mirror-symmetrical manner with respect to the plane of symmetry, wherein they extend at most 5° inclined towards the adjustment axis, wherein said third section extends at least 70% of the length of the adjustment cylinder. With this shape of the border line, a maximum possible stiffness of the fastening flange results because the transition area is reduced to a small area, namely a corner radius. The aforementioned angle of inclination is preferably selected such that a casting blank of the housing can be easily removed from the corresponding mold. One also talks of a deformation chamfer, wherein said deformation chamfer is arranged primarily in the area of the adjustment cylinder. However, the slight distance between the fastening plane and the adjustment axis explained above results in the deformation slope also being depicted on the border line via the corner radius explained above.

[0012] It may be provided that the first and second adjustment chambers are each associated with an adjustment valve, which is configured as a built-in valve, wherein it is installed directly in the housing, wherein a central axis of the adjustment valve is arranged parallel to and at a distance to the plane of symmetry, wherein a distance between said central axis and said adjustment axis is at most 80% of the largest hydraulically effective diameter of the first or the second adjustment chamber, wherein the fastening flange and the adjustment valves are each arranged in the direction of the axis of rotation on opposite sides of the adjustment axis. Similar adjustment valves are known from the axial piston machines described above. The adjustment valve is preferably installed directly in the pot-like housing part.

[0013] It may be provided that an angle of inclination between the central axis of the adjustment valve and the reference plane is between 30° and 60°, wherein a bead-like protrusion is provided on the housing in the area of the adjustment valve, wherein the bead-like protrusion extends around the adjustment cylinder from the relevant adjustment valve to the fastening flange, wherein the bead-like protrusion is integrally connected to the adjustment cylinder and the fastening flange, such that it causes stiffening of the fastening flange. In the axial piston machines described above, a bead-like projection is already used in the area of the adjustment valves, but it does not extend to the fastening flange so that it cannot stiffen it. Instead, the path to the fastening flange is interrupted by recesses for the heads or nuts of screw bolts there. Due to the design of the bead-like protrusion according to the disclosure, a significant stiffening of the fastening flange can be achieved with the least amount of material.

[0014] A recess can be provided on the outside of the housing in the area of the third and the fourth fastening openings, wherein the recess is arranged on the side of the fastening flange on which the cylinder drum is located. The recess is intended to create space for the head or the nut of the fastening bolt. The recess is preferably formed directly on the pot-like housing part.

[0015] It can be provided that the housing comprises a pot-like housing part, which is integrally formed, wherein it completely forms the fastening flange, wherein it is a component of the adjustment cylinder, such that the fastening flange in the area of the pot-like housing part transitions integrally and without interruption into the adjustment cylinder, wherein the swivel cradle is arranged within the pot-like housing part. The corresponding fastening flange is particularly stiff, wherein the axial piston machine can be manufactured particularly cost-effectively.

[0016] It may be provided that the bead-like protrusion is provided integrally on the pot-like housing part. The corresponding fastening flange is particularly stiff, wherein the axial piston machine can be manufactured particularly cost-effectively.

[0017] Of course, the above-mentioned features and those to be explained below can be used not only in the combination indicated in each case, but also in other combinations or on their own, without going beyond the scope of the present disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The disclosure is explained in more detail below with reference to the enclosed drawings. The figure shows:

[0019] FIG. 1 a longitudinal section of an axial piston machine according to the disclosure;

[0020] FIG. 2 a partial section of the axial piston machine according to FIG. 1 in the area of the adjustment cylinder;

[0021] FIG. 3 a perspective view of the axial piston machine of FIG. 1, with the side of the fastening flange visible;

[0022] FIG. 4 a perspective view of the axial piston machine of FIG. 1; and

[0023] FIG. 5 a perspective view of a pot-like housing part according to a second embodiment of the disclosure.DETAILED DESCRIPTION

[0024] FIG. 1 shows a longitudinal section of an axial piston machine 10 according to the disclosure. The sectional plane includes the axis of rotation 11, which is aligned perpendicular to the pivot axis 12. The axial piston machine 10 comprises a housing 20, which is composed of a pot-like housing part 21 and a plate-like housing part 27, wherein the housing parts 21; 27 mentioned are each formed integrally, wherein they are produced by casting. In the present case, an optional feed pump 15 is integrated in the plate-like housing part 27.

[0025] The housing 20 comprises a plate-like fastening flange 40 which is oriented perpendicular to the axis of rotation 11. The fastening flange 40 is arranged at an end of the housing 20 facing the direction of the axis of rotation 11, wherein it is a component of the pot-like housing part 21. In the area of the fastening flange 40, a drive shaft 16 projects out of the housing 20, which is rotatably supported on the housing 20 with respect to the axis of rotation 11, preferably by way of rolling bearings.

[0026] A cylinder drum 22 is arranged inside the housing 20, which is connected to the drive shaft 16 in a rotationally fixed manner with respect to the axis of rotation 11, for example by way of splined gearing. In the direction of the axis of rotation 11, the cylinder drum 22 is slidably supported on the plate-like housing part 27, preferably via a separate distribution plate, which is provided with two kidney-shaped control openings. In the cylinder drum 22, a plurality, for example nine, working pistons 23 are arranged linearly towards a swivel cradle 25.

[0027] In the present case, the working pistons 23 are somewhat inclined towards the axis of rotation 11, wherein they can also be aligned parallel to the axis of rotation 11. Each working piston 23 is supported on a flat control surface of the swivel cradle 25 via a sliding shoe, which is connected to the relevant working piston 23 via a ball joint. The swivel cradle 25 is pivotably mounted on the housing 20, in particular on the pot-like housing part 21, with respect to a pivot axis 12, whereby the pivot axis 12 is aligned perpendicular to the drawing plane of FIG. 1. In the present case, the pivot axis 12 intersects the axis of rotation 11. By pivoting the swivel cradle 25, the displacement volume of the axial piston machine 10 can be continuously adjusted. The displacement volume of the present axial piston machine 10 can be adjusted above zero, so that the direction of rotation of the drive shaft 16 can be reversed by adjusting the swivel cradle 25 while the direction of flow through the axial piston machine 10 remains the same.

[0028] FIG. 2 shows a partial section of the axial piston machine according to FIG. 1 in the area of the adjustment cylinder 30. The corresponding cutting plane contains the adjustment axis 13, which is perpendicular to the axis of rotation. The adjustment cylinder 30 is configured as a double-acting cylinder, comprising a first and second adjustment chamber 31; 32, which are separated from each other by an adjustment piston 33. The first and the second adjustment chambers 31; 32 are otherwise limited by the housing 20, in particular by the pot-like housing part 21. The first adjustment chamber 31 is also delimited by a separate cover 38. The adjustment piston 30 is linearly movable towards the adjustment axis 13, wherein the adjustment axis 13 forms a central axis of the adjustment piston 33 and the first and second adjustment chambers 31; 32. A return spring 36 is arranged within the adjustment piston 33, which biases the adjustment piston 33 to a central position in which the displacement volume of the axial piston machine is zero. The adjustment piston 33 is coupled to the swivel cradle 25 in a motion-coupled manner 34. In the present case, the swivel cradle 25 has a pin for this purpose, which is arranged at a distance from the pivot axis, whereby the pin engages in a groove on the adjustment piston 33 running around the adjustment axis 13.

[0029] Reference should also be made to the pivot bearing 37 visible in FIG. 2, with which the swivel cradle 25 is mounted so that it can pivot in relation to the pivot axis. In the present case, the pivot bearing 37 is configured as a rolling bearing, in particular as a cylindrical roller bearing, wherein it can also be configured as a sliding bearing.

[0030] Also shown in FIG. 2 is the largest hydraulically effective diameter 35 of the two adjustment chambers 31; 32, in which case both adjustment chambers 31; 32 have the same hydraulically effective diameter.

[0031] FIG. 3 shows a perspective view of the axial piston machine 10 of FIG. 1 with the side of the fastening flange 40 visible. The fastening flange 40 forms a flat fastening surface 45 which faces away from the adjustment cylinder 30. It further comprises a circular cylindrical centering projection 46 with respect to the axis of rotation 11. In particular, the diameter and length of this centering projection 46 are the subject of the standard SE J744 FEB2013. This standard also defines possible locations and sizes of the fastening openings 41-44. In particular, a 2-hole version is provided, which comprises the first and the second fastening openings 41; 42. The first and second fastening opening 41; 42 are arranged in a mirror-symmetrical manner with respect to each other, wherein the corresponding plane of symmetry contains the axis of rotation 11, wherein it is parallel to the pivot axis (no. 12 in FIG. 1). The first and second fastening openings 41; 42 are arranged on a reference plane containing the axis of rotation 11, wherein it is arranged perpendicular to the symmetry plane mentioned. They are preferably formed in a mirror-symmetric manner with respect to the mentioned reference plane.

[0032] The aforementioned standard also describes a 4-hole version of the fastening flange, wherein the third and fourth fastening openings 43; 44 are arranged according to the 4-hole version, namely at a distance to the aforementioned reference plane and also mirror-symmetrical with respect to the aforementioned plane of symmetry. The two further fastening openings of the 4-hole version were omitted according to the disclosure. This is due to the fact that this axial piston machine 10 is very short in the direction of the axis of rotation 11. This was achieved, among other things, by moving the fastening surface 45 very close to the adjustment axis 13.

[0033] For example, the named 4-hole version is needed when multiple axial piston machines 10 are assembled along the axis of rotation 11 to form a tandem assembly, wherein this tandem assembly is self-supportingly attached to a higher-level assembly. The fastening flange 40 must then also transmit significant torques, which are absorbed by the fastening screws that pass through the fastening openings 41-44. The omission of two fastening openings of the 4-hole version results in a loss of stiffness even if the first and second fastening openings 41; 42 of the 2-hole version are used instead. In order to minimize this loss of rigidity, the fastening flange 40 is designed in such a way that it is stiffened by the adjustment cylinder 30. It is therefore no longer a plate that is largely free from the housing radially outwards in relation to the axis of rotation 11. Rather, a transition area 14 is provided between the fastening flange 40 and the adjustment cylinder 30, in which the fastening flange 40 transitions integrally and without interruption into the adjustment cylinder 30. The fastening flange 40 and the adjustment cylinder 30 are formed for this purpose by the integrally formed pot-like housing part 21.

[0034] In the first embodiment of the pot-like housing part 21 shown in FIG. 3, the border line 50 is designed in accordance with the example for the 2-hole flange in the aforementioned standard. The border line 50 is the edge that is formed towards the adjustment cylinder 30 when the blank of the pot-like housing part 21 produced in casting is machined at the fastening surface 45. The border line 50 comprises a middle first portion 51 which is formed in a circularly curved fashion, wherein the corresponding circle center point coincides with the axis of rotation 11. At both opposite ends of the first section 51, a second section 52, which is straight, immediately adjoins tangentially. The transition area 14 between the border line 50 and the adjustment cylinder 30 is already filled with material on the cast blank, such that there is no depression that extends beyond the unavoidable shoulder in the area of the border line 50. The transition area 14 is approximately flat, transitioning tangentially into the approximately circular cylindrical adjustment cylinder 30, wherein it is arranged parallel to the fastening surface 45. The deviation from the ideal shapes explained above results in particular from the existing deformation chamfers preferably present on the casting.

[0035] The first to fourth fastening openings 41-44 each pass through the fastening flange 40 in the direction of the axis of rotation 11. They are preferably each configured as a recess that is open radially outwards with respect to the axis of rotation 11, so that fastening screws can be easily inserted into the associated fastening recesses 41-44.

[0036] FIG. 4 shows a perspective view of the axial piston machine 10 of FIG. 1. The two adjustment valves 60, which are each associated with the first or second adjustment chamber, can be seen in particular. These are each designed in the form of a built-in valve, which may be a pressure reducing valve, a pressure control valve, or a 3 / 2-way valve. The adjustment valve 60 has a central axis 60, which in the present case is oriented approximately 45° inclined towards the reference plane explained above, wherein the adjustment valve 60 is arranged on the side of the adjustment cylinder 30 facing away from the fastening flange 40 in the direction of the axis of rotation 11, wherein it is also arranged on the same side of the reference plane as the adjustment cylinder 30. In order to provide the installation space required to receive the adjustment valve 60, the pot-like housing part 21 is provided with a bead-like protrusion 62. This is guided around the adjustment cylinder 30 up to the fastening flange 40 and integrally transitions into it. This bead-like protrusion 62 causes a noticeable stiffening of the fastening flange 40 without the need for significantly more casting material compared to a bead-like protrusion sufficient to receive the adjustment valve 60.

[0037] FIG. 4 also shows the recess 47, which is arranged in the area of the third and fourth fastening openings 44 on the pot-like housing part 21.

[0038] The recess 47 is intended to create installation space for the screw head or the nut of the fastening screw (not shown).

[0039] FIG. 4 also shows the plate-like housing part 27, with which the open side of the pot-like housing part 21 is closed, so that an enclosed interior space is created in which the cylinder drum and the swivel cradle (no. 22; 25 in FIG. 1) are accommodated.

[0040] FIG. 5 shows a perspective view of a pot-like housing portion 21′ according to a second embodiment of the disclosure. The direction of view corresponds to that of FIG. 3. The second embodiment of the pot-like housing part 21′ is identical to the first embodiment, apart from the differences explained below, so that reference is made in this respect to the explanations relating to FIGS. 1 to 4.

[0041] In the second embodiment 21′, the flat fastening surface 45 has been enlarged to such an extent that the transition area 14 between the fastening flange 45 and the adjustment cylinder 30 is now only formed by a corner radius. This results in a border line 50′ in the area of the adjustment cylinder 30 with a third section 53, which is slightly convex with two straight legs 54. The two straight legs 54 are arranged in a mirror-symmetrical manner with respect to the plane of symmetry, wherein they extend inclined by a maximum of 5° towards the adjustment axis 13. For example, the third portion 53 extends over at least 80% of the length of the adjustment cylinder 30. This results in a particularly stiff fastening flange 40.REFERENCE NUMERALS10 Axial piston machine

[0043] 11 Axis of rotation

[0044] 12 Pivot axis

[0045] 13 Adjustment axis

[0046] 14 Transition area

[0047] 15 Feed pump

[0048] 16 Drive shaft

[0049] 20 Housing

[0050] 21 Pot-like housing part (first embodiment)

[0051] 21′ Pot-like housing part (second embodiment)

[0052] 22 Cylinder drum

[0053] 23 Working piston

[0054] 24 Sliding shoe

[0055] 25 Swivel cradle

[0056] 26 Non-machined surface of the housing

[0057] 27 Plate-like housing part

[0058] 30 Adjustment cylinder

[0059] 31 First adjustment chamber

[0060] 32 Second adjustment chamber

[0061] 33 Adjustment piston

[0062] 34 Motion coupling between swivel cradle and adjustment piston

[0063] 35 Largest hydraulically effective diameter

[0064] 36 Return spring

[0065] 37 Pivot bearing

[0066] 38 Cover

[0067] 40 Fastening flange

[0068] 41 First fastening opening

[0069] 42 Second fastening opening

[0070] 43 Third fastening opening

[0071] 44 Fourth fastening opening

[0072] 45 Fastening surface

[0073] 46 Centering projection

[0074] 47 Recess (for fastening screws)

[0075] 50 Border line (first embodiment)

[0076] 50′ Border line (second embodiment)

[0077] 51 First portion

[0078] 52 Second portion

[0079] 53 Third portion

[0080] 54 Straight leg

[0081] 60 Adjustment Valve

[0082] 61 Central axis of the adjustment valve

[0083] 62 Bead-like protrusion

Examples

Embodiment Construction

[0024]FIG. 1 shows a longitudinal section of an axial piston machine 10 according to the disclosure. The sectional plane includes the axis of rotation 11, which is aligned perpendicular to the pivot axis 12. The axial piston machine 10 comprises a housing 20, which is composed of a pot-like housing part 21 and a plate-like housing part 27, wherein the housing parts 21; 27 mentioned are each formed integrally, wherein they are produced by casting. In the present case, an optional feed pump 15 is integrated in the plate-like housing part 27.

[0025]The housing 20 comprises a plate-like fastening flange 40 which is oriented perpendicular to the axis of rotation 11. The fastening flange 40 is arranged at an end of the housing 20 facing the direction of the axis of rotation 11, wherein it is a component of the pot-like housing part 21. In the area of the fastening flange 40, a drive shaft 16 projects out of the housing 20, which is rotatably supported on the housing 20 with respect to the ...

[0001] This application claims priority under 35 U.S.C. § 119 to patent application no. DE 10 2024 211 590.8, filed on Dec. 4, 2024 in Germany, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The disclosure relates to an axial piston machine.BACKGROUND

[0003] From the data sheet “A4VG series 60 axial piston variable displacement pump” from the Bosch Rexroth AG (order no. RD 92038; edition 2024-10-15), an axial piston machine in a swashplate design is known, which has a displacement volume that can be adjusted above zero, wherein the corresponding swivel cradle is pivoted with an adjustment cylinder arranged transversely to the axis of rotation. The axial piston machine is equipped with a fastening flange which is configured in accordance with the SE J744 FEB2013 standard in the variant with two fastening openings. This fastening flange is suitable for small sizes of an axial piston machine. The axial piston machine is characterized by a short design length in the direction of the axis of rotation, in particular the fastening flange being arranged very close to the adjustment cylinder.

[0004] From the data sheet “A4VG series 35 axial piston displacement pump,” a similar axial piston machine is known, which is less optimized for a short design length. For example, the nominal size 71 is equipped with a so-called 6-hole flange, in which the two variants, two fastening openings and four fastening openings have been integrated into a single fastening flange in accordance with SE J744 FEB2013. It would be desirable to transfer this fastening flange to the axial piston machine discussed above. Due to the short design length, however, not enough design space for the screw heads or the nuts of the fastening screws is available for the fastening openings near the adjustment cylinder.

[0005] An advantage of the present disclosure is that the short design length of the axial piston machine first explained above may be maintained, although it is nonetheless provided with a fastening flange that allows for rigid fastening. In this case, two axial piston machines are mounted directly next to each other along the axis of rotation in a tandem arrangement. The corresponding connection must be rigid, especially in the case of large axial piston machines, to prevent excessive vibrations during operation caused by unavoidable pressure pulsations within the axial piston machines.SUMMARY

[0006] According to the disclosure, it is proposed that the fastening flange transitions integrally and without interruption into the adjustment cylinder, wherein no further fastening openings are arranged in the corresponding transition area, which pass though the fastening flange in the direction of the axis of rotation.

[0007] The direction of movement of the working pistons is preferably parallel or somewhat inclined to the axis of rotation. The first to fourth fastening opening can each be configured as a circular opening, wherein it is preferably configured as a recess that is open radially outwards with respect to the axis of rotation. The plane of symmetry preferably contains the axis of rotation. It is contemplated that the pivot axis will be at a distance from the plane of symmetry, such that the hydraulic forces acting in the axial piston machine exert a total torque on the swivel cradle.

[0008] Advantageous developments and improvements of the disclosure are specified in the description set forth below.

[0009] It may be contemplated that the fastening flange forms a flat fastening surface that is aligned perpendicular to the axis of rotation, wherein the fastening surface is machined in such a manner that a border line or border edge to the directly adjacent, non-cutting machined surface of the housing is formed towards the adjustment cylinder, wherein a distance between the mounting plane defined by the fastening surface and the adjustment axis is at most 60% of a largest hydraulically effective diameter of the first or the second adjustment chamber. This makes it almost impossible to move the fastening surface closer to the adjustment cylinder. It should be noted here that the fastening surface often abuts against a flat surface of a higher-level assembly, which must not collide with the adjustment cylinder. At the same time, the fastening surface protrudes slightly above the non-machined surface to ensure that the higher-level assembly rests exclusively against the fastening surface. The hydraulically effective diameter of the first and second adjustment chambers are preferably equal in size.

[0010] It may be provided that the aforementioned border line in the area of the adjustment cylinder has a first section which extends in a circle, wherein the corresponding center of the circle coincides with the axis of rotation, wherein a straight second section of the edge line directly tangentially adjoins each of the two opposite ends of the first section. The border line is preferably the same shape as the 2-hole flange in accordance with the SE J744 FEB2013 standard. Thus, the axial piston machine according to the disclosure can be used wherever fastening flanges previously compliant with the standards have been used.

[0011] It may be provided that said edge line in the area of the adjustment cylinder comprises a third section which runs convexly with two straight legs, wherein the two straight legs are arranged in a mirror-symmetrical manner with respect to the plane of symmetry, wherein they extend at most 5° inclined towards the adjustment axis, wherein said third section extends at least 70% of the length of the adjustment cylinder. With this shape of the border line, a maximum possible stiffness of the fastening flange results because the transition area is reduced to a small area, namely a corner radius. The aforementioned angle of inclination is preferably selected such that a casting blank of the housing can be easily removed from the corresponding mold. One also talks of a deformation chamfer, wherein said deformation chamfer is arranged primarily in the area of the adjustment cylinder. However, the slight distance between the fastening plane and the adjustment axis explained above results in the deformation slope also being depicted on the border line via the corner radius explained above.

[0012] It may be provided that the first and second adjustment chambers are each associated with an adjustment valve, which is configured as a built-in valve, wherein it is installed directly in the housing, wherein a central axis of the adjustment valve is arranged parallel to and at a distance to the plane of symmetry, wherein a distance between said central axis and said adjustment axis is at most 80% of the largest hydraulically effective diameter of the first or the second adjustment chamber, wherein the fastening flange and the adjustment valves are each arranged in the direction of the axis of rotation on opposite sides of the adjustment axis. Similar adjustment valves are known from the axial piston machines described above. The adjustment valve is preferably installed directly in the pot-like housing part.

[0013] It may be provided that an angle of inclination between the central axis of the adjustment valve and the reference plane is between 30° and 60°, wherein a bead-like protrusion is provided on the housing in the area of the adjustment valve, wherein the bead-like protrusion extends around the adjustment cylinder from the relevant adjustment valve to the fastening flange, wherein the bead-like protrusion is integrally connected to the adjustment cylinder and the fastening flange, such that it causes stiffening of the fastening flange. In the axial piston machines described above, a bead-like projection is already used in the area of the adjustment valves, but it does not extend to the fastening flange so that it cannot stiffen it. Instead, the path to the fastening flange is interrupted by recesses for the heads or nuts of screw bolts there. Due to the design of the bead-like protrusion according to the disclosure, a significant stiffening of the fastening flange can be achieved with the least amount of material.

[0014] A recess can be provided on the outside of the housing in the area of the third and the fourth fastening openings, wherein the recess is arranged on the side of the fastening flange on which the cylinder drum is located. The recess is intended to create space for the head or the nut of the fastening bolt. The recess is preferably formed directly on the pot-like housing part.

[0015] It can be provided that the housing comprises a pot-like housing part, which is integrally formed, wherein it completely forms the fastening flange, wherein it is a component of the adjustment cylinder, such that the fastening flange in the area of the pot-like housing part transitions integrally and without interruption into the adjustment cylinder, wherein the swivel cradle is arranged within the pot-like housing part. The corresponding fastening flange is particularly stiff, wherein the axial piston machine can be manufactured particularly cost-effectively.

[0016] It may be provided that the bead-like protrusion is provided integrally on the pot-like housing part. The corresponding fastening flange is particularly stiff, wherein the axial piston machine can be manufactured particularly cost-effectively.

[0017] Of course, the above-mentioned features and those to be explained below can be used not only in the combination indicated in each case, but also in other combinations or on their own, without going beyond the scope of the present disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The disclosure is explained in more detail below with reference to the enclosed drawings. The figure shows:

[0019] FIG. 1 a longitudinal section of an axial piston machine according to the disclosure;

[0020] FIG. 2 a partial section of the axial piston machine according to FIG. 1 in the area of the adjustment cylinder;

[0021] FIG. 3 a perspective view of the axial piston machine of FIG. 1, with the side of the fastening flange visible;

[0022] FIG. 4 a perspective view of the axial piston machine of FIG. 1; and

[0023] FIG. 5 a perspective view of a pot-like housing part according to a second embodiment of the disclosure.DETAILED DESCRIPTION

[0024] FIG. 1 shows a longitudinal section of an axial piston machine 10 according to the disclosure. The sectional plane includes the axis of rotation 11, which is aligned perpendicular to the pivot axis 12. The axial piston machine 10 comprises a housing 20, which is composed of a pot-like housing part 21 and a plate-like housing part 27, wherein the housing parts 21; 27 mentioned are each formed integrally, wherein they are produced by casting. In the present case, an optional feed pump 15 is integrated in the plate-like housing part 27.

[0025] The housing 20 comprises a plate-like fastening flange 40 which is oriented perpendicular to the axis of rotation 11. The fastening flange 40 is arranged at an end of the housing 20 facing the direction of the axis of rotation 11, wherein it is a component of the pot-like housing part 21. In the area of the fastening flange 40, a drive shaft 16 projects out of the housing 20, which is rotatably supported on the housing 20 with respect to the axis of rotation 11, preferably by way of rolling bearings.

[0026] A cylinder drum 22 is arranged inside the housing 20, which is connected to the drive shaft 16 in a rotationally fixed manner with respect to the axis of rotation 11, for example by way of splined gearing. In the direction of the axis of rotation 11, the cylinder drum 22 is slidably supported on the plate-like housing part 27, preferably via a separate distribution plate, which is provided with two kidney-shaped control openings. In the cylinder drum 22, a plurality, for example nine, working pistons 23 are arranged linearly towards a swivel cradle 25.

[0027] In the present case, the working pistons 23 are somewhat inclined towards the axis of rotation 11, wherein they can also be aligned parallel to the axis of rotation 11. Each working piston 23 is supported on a flat control surface of the swivel cradle 25 via a sliding shoe, which is connected to the relevant working piston 23 via a ball joint. The swivel cradle 25 is pivotably mounted on the housing 20, in particular on the pot-like housing part 21, with respect to a pivot axis 12, whereby the pivot axis 12 is aligned perpendicular to the drawing plane of FIG. 1. In the present case, the pivot axis 12 intersects the axis of rotation 11. By pivoting the swivel cradle 25, the displacement volume of the axial piston machine 10 can be continuously adjusted. The displacement volume of the present axial piston machine 10 can be adjusted above zero, so that the direction of rotation of the drive shaft 16 can be reversed by adjusting the swivel cradle 25 while the direction of flow through the axial piston machine 10 remains the same.

[0028] FIG. 2 shows a partial section of the axial piston machine according to FIG. 1 in the area of the adjustment cylinder 30. The corresponding cutting plane contains the adjustment axis 13, which is perpendicular to the axis of rotation. The adjustment cylinder 30 is configured as a double-acting cylinder, comprising a first and second adjustment chamber 31; 32, which are separated from each other by an adjustment piston 33. The first and the second adjustment chambers 31; 32 are otherwise limited by the housing 20, in particular by the pot-like housing part 21. The first adjustment chamber 31 is also delimited by a separate cover 38. The adjustment piston 30 is linearly movable towards the adjustment axis 13, wherein the adjustment axis 13 forms a central axis of the adjustment piston 33 and the first and second adjustment chambers 31; 32. A return spring 36 is arranged within the adjustment piston 33, which biases the adjustment piston 33 to a central position in which the displacement volume of the axial piston machine is zero. The adjustment piston 33 is coupled to the swivel cradle 25 in a motion-coupled manner 34. In the present case, the swivel cradle 25 has a pin for this purpose, which is arranged at a distance from the pivot axis, whereby the pin engages in a groove on the adjustment piston 33 running around the adjustment axis 13.

[0029] Reference should also be made to the pivot bearing 37 visible in FIG. 2, with which the swivel cradle 25 is mounted so that it can pivot in relation to the pivot axis. In the present case, the pivot bearing 37 is configured as a rolling bearing, in particular as a cylindrical roller bearing, wherein it can also be configured as a sliding bearing.

[0030] Also shown in FIG. 2 is the largest hydraulically effective diameter 35 of the two adjustment chambers 31; 32, in which case both adjustment chambers 31; 32 have the same hydraulically effective diameter.

[0031] FIG. 3 shows a perspective view of the axial piston machine 10 of FIG. 1 with the side of the fastening flange 40 visible. The fastening flange 40 forms a flat fastening surface 45 which faces away from the adjustment cylinder 30. It further comprises a circular cylindrical centering projection 46 with respect to the axis of rotation 11. In particular, the diameter and length of this centering projection 46 are the subject of the standard SE J744 FEB2013. This standard also defines possible locations and sizes of the fastening openings 41-44. In particular, a 2-hole version is provided, which comprises the first and the second fastening openings 41; 42. The first and second fastening opening 41; 42 are arranged in a mirror-symmetrical manner with respect to each other, wherein the corresponding plane of symmetry contains the axis of rotation 11, wherein it is parallel to the pivot axis (no. 12 in FIG. 1). The first and second fastening openings 41; 42 are arranged on a reference plane containing the axis of rotation 11, wherein it is arranged perpendicular to the symmetry plane mentioned. They are preferably formed in a mirror-symmetric manner with respect to the mentioned reference plane.

[0032] The aforementioned standard also describes a 4-hole version of the fastening flange, wherein the third and fourth fastening openings 43; 44 are arranged according to the 4-hole version, namely at a distance to the aforementioned reference plane and also mirror-symmetrical with respect to the aforementioned plane of symmetry. The two further fastening openings of the 4-hole version were omitted according to the disclosure. This is due to the fact that this axial piston machine 10 is very short in the direction of the axis of rotation 11. This was achieved, among other things, by moving the fastening surface 45 very close to the adjustment axis 13.

[0033] For example, the named 4-hole version is needed when multiple axial piston machines 10 are assembled along the axis of rotation 11 to form a tandem assembly, wherein this tandem assembly is self-supportingly attached to a higher-level assembly. The fastening flange 40 must then also transmit significant torques, which are absorbed by the fastening screws that pass through the fastening openings 41-44. The omission of two fastening openings of the 4-hole version results in a loss of stiffness even if the first and second fastening openings 41; 42 of the 2-hole version are used instead. In order to minimize this loss of rigidity, the fastening flange 40 is designed in such a way that it is stiffened by the adjustment cylinder 30. It is therefore no longer a plate that is largely free from the housing radially outwards in relation to the axis of rotation 11. Rather, a transition area 14 is provided between the fastening flange 40 and the adjustment cylinder 30, in which the fastening flange 40 transitions integrally and without interruption into the adjustment cylinder 30. The fastening flange 40 and the adjustment cylinder 30 are formed for this purpose by the integrally formed pot-like housing part 21.

[0034] In the first embodiment of the pot-like housing part 21 shown in FIG. 3, the border line 50 is designed in accordance with the example for the 2-hole flange in the aforementioned standard. The border line 50 is the edge that is formed towards the adjustment cylinder 30 when the blank of the pot-like housing part 21 produced in casting is machined at the fastening surface 45. The border line 50 comprises a middle first portion 51 which is formed in a circularly curved fashion, wherein the corresponding circle center point coincides with the axis of rotation 11. At both opposite ends of the first section 51, a second section 52, which is straight, immediately adjoins tangentially. The transition area 14 between the border line 50 and the adjustment cylinder 30 is already filled with material on the cast blank, such that there is no depression that extends beyond the unavoidable shoulder in the area of the border line 50. The transition area 14 is approximately flat, transitioning tangentially into the approximately circular cylindrical adjustment cylinder 30, wherein it is arranged parallel to the fastening surface 45. The deviation from the ideal shapes explained above results in particular from the existing deformation chamfers preferably present on the casting.

[0035] The first to fourth fastening openings 41-44 each pass through the fastening flange 40 in the direction of the axis of rotation 11. They are preferably each configured as a recess that is open radially outwards with respect to the axis of rotation 11, so that fastening screws can be easily inserted into the associated fastening recesses 41-44.

[0036] FIG. 4 shows a perspective view of the axial piston machine 10 of FIG. 1. The two adjustment valves 60, which are each associated with the first or second adjustment chamber, can be seen in particular. These are each designed in the form of a built-in valve, which may be a pressure reducing valve, a pressure control valve, or a 3 / 2-way valve. The adjustment valve 60 has a central axis 60, which in the present case is oriented approximately 45° inclined towards the reference plane explained above, wherein the adjustment valve 60 is arranged on the side of the adjustment cylinder 30 facing away from the fastening flange 40 in the direction of the axis of rotation 11, wherein it is also arranged on the same side of the reference plane as the adjustment cylinder 30. In order to provide the installation space required to receive the adjustment valve 60, the pot-like housing part 21 is provided with a bead-like protrusion 62. This is guided around the adjustment cylinder 30 up to the fastening flange 40 and integrally transitions into it. This bead-like protrusion 62 causes a noticeable stiffening of the fastening flange 40 without the need for significantly more casting material compared to a bead-like protrusion sufficient to receive the adjustment valve 60.

[0037] FIG. 4 also shows the recess 47, which is arranged in the area of the third and fourth fastening openings 44 on the pot-like housing part 21.

[0038] The recess 47 is intended to create installation space for the screw head or the nut of the fastening screw (not shown).

[0039] FIG. 4 also shows the plate-like housing part 27, with which the open side of the pot-like housing part 21 is closed, so that an enclosed interior space is created in which the cylinder drum and the swivel cradle (no. 22; 25 in FIG. 1) are accommodated.

[0040] FIG. 5 shows a perspective view of a pot-like housing portion 21′ according to a second embodiment of the disclosure. The direction of view corresponds to that of FIG. 3. The second embodiment of the pot-like housing part 21′ is identical to the first embodiment, apart from the differences explained below, so that reference is made in this respect to the explanations relating to FIGS. 1 to 4.

[0041] In the second embodiment 21′, the flat fastening surface 45 has been enlarged to such an extent that the transition area 14 between the fastening flange 45 and the adjustment cylinder 30 is now only formed by a corner radius. This results in a border line 50′ in the area of the adjustment cylinder 30 with a third section 53, which is slightly convex with two straight legs 54. The two straight legs 54 are arranged in a mirror-symmetrical manner with respect to the plane of symmetry, wherein they extend inclined by a maximum of 5° towards the adjustment axis 13. For example, the third portion 53 extends over at least 80% of the length of the adjustment cylinder 30. This results in a particularly stiff fastening flange 40.REFERENCE NUMERALS10 Axial piston machine

[0043] 11 Axis of rotation

[0044] 12 Pivot axis

[0045] 13 Adjustment axis

[0046] 14 Transition area

[0047] 15 Feed pump

[0048] 16 Drive shaft

[0049] 20 Housing

[0050] 21 Pot-like housing part (first embodiment)

[0051] 21′ Pot-like housing part (second embodiment)

[0052] 22 Cylinder drum

[0053] 23 Working piston

[0054] 24 Sliding shoe

[0055] 25 Swivel cradle

[0056] 26 Non-machined surface of the housing

[0057] 27 Plate-like housing part

[0058] 30 Adjustment cylinder

[0059] 31 First adjustment chamber

[0060] 32 Second adjustment chamber

[0061] 33 Adjustment piston

[0062] 34 Motion coupling between swivel cradle and adjustment piston

[0063] 35 Largest hydraulically effective diameter

[0064] 36 Return spring

[0065] 37 Pivot bearing

[0066] 38 Cover

[0067] 40 Fastening flange

[0068] 41 First fastening opening

[0069] 42 Second fastening opening

[0070] 43 Third fastening opening

[0071] 44 Fourth fastening opening

[0072] 45 Fastening surface

[0073] 46 Centering projection

[0074] 47 Recess (for fastening screws)

[0075] 50 Border line (first embodiment)

[0076] 50′ Border line (second embodiment)

[0077] 51 First portion

[0078] 52 Second portion

[0079] 53 Third portion

[0080] 54 Straight leg

[0081] 60 Adjustment Valve

[0082] 61 Central axis of the adjustment valve

[0083] 62 Bead-like protrusion

Examples

Embodiment Construction

[0024]FIG. 1 shows a longitudinal section of an axial piston machine 10 according to the disclosure. The sectional plane includes the axis of rotation 11, which is aligned perpendicular to the pivot axis 12. The axial piston machine 10 comprises a housing 20, which is composed of a pot-like housing part 21 and a plate-like housing part 27, wherein the housing parts 21; 27 mentioned are each formed integrally, wherein they are produced by casting. In the present case, an optional feed pump 15 is integrated in the plate-like housing part 27.

[0025]The housing 20 comprises a plate-like fastening flange 40 which is oriented perpendicular to the axis of rotation 11. The fastening flange 40 is arranged at an end of the housing 20 facing the direction of the axis of rotation 11, wherein it is a component of the pot-like housing part 21. In the area of the fastening flange 40, a drive shaft 16 projects out of the housing 20, which is rotatably supported on the housing 20 with respect to the ...

Claims

1. An axial piston machine, comprising:a cylinder drum rotatable with respect to an axis of rotation;a swivel cradle pivotable with respect to a pivot axis;a housing in which the cylinder drum and the swivel cradle are accommodated;a plurality of working pistons accommodated in the cylinder drum so as to be linearly movable in the direction of the swivel cradle, wherein the working pistons are supported on the swivel cradle such that a displacement volume of the axial piston machine is adjustable by pivoting the swivel cradle; andan adjustment cylinder provided with an adjustment piston which can move linearly along an adjustment axis, wherein the adjustment piston is configured to delimit a first adjustment chamber and a second adjustment chamber from each other,wherein the pivot axis is oriented perpendicular to the axis of rotation,wherein the adjustment axis (i) forms a central axis of the adjustment piston, (ii) is oriented perpendicular to the axis of rotation and the pivot axis, and (iii) is arranged at a distance to the axis of rotation and at a distance to the pivot axis,wherein the adjustment piston is motion-coupled to the swivel cradle,wherein the housing comprises a plate-type fastening flange which is oriented perpendicular to the axis of rotation,wherein a first fastening opening, a second fastening opening, a third fastening opening, and a fourth fastening opening in the direction of the axis of rotation pass though the fastening flange in the direction of the axis of rotation,wherein a plane of symmetry (i) contains the axis of rotation, and (ii) extends parallel to the pivot axis,wherein a reference plane (i) is arranged perpendicular to the plane of symmetry, and (ii) contains the axis of rotation,wherein the first fastening opening and the second fastening opening are (i) arranged in the area of the reference plane, and (ii) mirror-symmetrically to each other with respect to the plane of symmetry,wherein the third fastening opening and the fourth fastening opening are (i) arranged mirror-symmetrically with respect to the plane of symmetry, and (ii) arranged on the side of the reference plane facing away from the adjustment axis,wherein the fastening flange transitions integrally and without interruption into the adjustment cylinder, andwherein no further fastening openings are arranged in the corresponding transition area, which pass though the fastening flange in the direction of the axis of rotation.

2. The axial piston machine according to claim 1, wherein:the fastening flange is configured to form a flat fastening surface which is oriented perpendicular to the axis of rotation,the fastening surface is machined in such a way that a border line is formed towards the adjustment cylinder with respect to the directly adjacent surface of the housing, anda distance between the fastening plane defined by the fastening surface and the adjustment axis is at most 60% of a largest hydraulically effective diameter of the first adjustment chamber or the second adjustment chamber.

3. The axial piston machine according to claim 2, wherein:the border line in the area of the adjustment cylinder has a first section which extends in a circle,the corresponding center of the circle coincides with the axis of rotation, anda straight second section of the border line directly tangentially adjoins each of the two opposite ends of the first section.

4. The axial piston machine according to claim 2, wherein:the border line in the area of the adjustment cylinder comprises a third section which runs convexly with two straight legs,the two straight legs are arranged in a mirror-symmetrical manner with respect to the plane of symmetry,the two straight legs extend at most 5° inclined towards the adjustment axis, andthe third section extends at least 70% of the length of the adjustment cylinder.

5. The axial piston machine according to claim 1, wherein:the first adjustment chamber and the second adjustment chamber are each associated with an adjustment valve which is configured as a built-in valve,the adjustment valve is installed directly in the housing,a central axis of the adjustment valve is arranged parallel to and at a distance to the plane of symmetry,a distance between the central axis and the adjustment axis is at most 80% of the largest hydraulically effective diameter of the first adjustment chamber or the second adjustment chamber, andthe fastening flange and the adjustment valves are each arranged in the direction of the axis of rotation on opposite sides of the adjustment axis.

6. The axial piston machine according to claim 5, wherein:an angle of inclination between the central axis of the adjustment valve and the reference plane is between 30° and 60°,a bead-like protrusion is provided on the housing in the area of the adjustment valve,the bead-like protrusion extends around the adjustment cylinder from the relevant control valve to the fastening flange, andthe bead-like protrusion is integrally connected to the adjustment cylinder and the fastening flange such that the bead-like protrusion causes a stiffening of the fastening flange.

7. The axial piston machine according to claim 1, wherein:a recess is provided on the outside of the housing in the area of the third fastening opening and the fourth fastening opening, andthe recess is arranged on the side of the fastening flange on which the cylinder drum is located.

8. The axial piston machine according to claim 1, wherein:the housing comprises a pot-like housing part, which is integrally formed,the pot-like housing part completely forms the fastening flange,the pot-like housing part is a part of the adjustment cylinder, such that the fastening flange transitions integrally and without interruption into the adjustment cylinder in the area of the pot-like housing part, andthe swivel cradle is arranged within the pot-like housing part.

9. The axial piston machine according to claim 6, wherein:the housing comprises a pot-like housing part, which is integrally formed,the pot-like housing part completely forms the fastening flange,the pot-like housing part is a part of the adjustment cylinder, such that the fastening flange transitions integrally and without interruption into the adjustment cylinder in the area of the pot-like housing part, andthe swivel cradle is arranged within the pot-like housing part.

10. The axial piston machine according to claim 9, wherein the bead-like protrusion is provided integrally on the pot-like housing part.

Images