Hydrostatic axial piston machine in swash plate design

Abstract

The invention discloses a hydrostatic axial piston machine with a compact pressure chamber for the cylinder barrel, which is supplied with compact pressure by an arc-shaped long hole of the distribution plate or by a plurality of connecting channels of the cylinder barrel. The compact pressure chamber is limited radially externally by the cylinder barrel and radially internally by the transmission shaft. The compact pressure chamber is limited axially on both sides by seals, which are arranged between the radially internally rotating transmission shaft and the radially externally stationary component. The radially externally component can be the cylinder barrel or, in the case of a seal on the distribution plate side, also a gap seal between the transmission shaft and the bearing bushing of the distribution plate. Both seals are arranged on the distribution plate side with respect to the toothing or the retraction ball.

Description

Technical Field

[0001] The present invention relates to a hydrostatic axial piston machine with a swashplate structure according to the present disclosure. Background Technology

[0002] In axial piston machines, it is known that the cylinders are torsionally coupled to the drive shaft so that they rotate together. Cylinders extend along the drive shaft within the cylinders, which are distributed circumferentially, and the pistons are movably guided within these cylinders. The pistons are coupled to a stationary swashplate, tilted relative to the drive shaft, via corresponding piston feet and consequently surrounding sliders. Thus, each piston performs a stroke as it rotates around the drive shaft, the magnitude of which depends on the tilt position of the swashplate.

[0003] On the side opposite to the swashplate, each cylinder has a port on its end face, which connects to the corresponding cylinder via a corresponding connecting channel. Because the cylinder end face rotates with its port, the port extends along a circular track. The end face is tensioned relative to a stationary distribution plate with its port, thus the port extends sealingly over an arcuate or kidney-shaped elongated orifice in the distribution plate. More precisely, a high-pressure kidney and a low-pressure kidney are provided in the distribution plate.

[0004] By applying a pressure medium to the cylinder on the high-pressure side, the cylinder barrel is tensioned relative to the distribution plate on its high-pressure side. For this purpose, it is known from the prior art that, in order to increase the lifting speed and, in axial piston pumps, an additional clamping pressure chamber is provided to supplement and homogenize the clamping on the aforementioned unilateral side.

[0005] Document DE 10 2012 110 485 A1 discloses a clamping pressure chamber by which a cylinder is tensioned relative to a distribution plate. The clamping pressure chamber is concentric with the drive shaft. Here, the clamping pressure chamber is radially internally defined by a sleeve arranged on the outer circumference of the drive shaft, while the clamping pressure chamber is radially externally defined by a sleeve-shaped stepped clamping piston arranged on the inner circumference of the cylinder. When the clamping pressure chamber is loaded with high pressure, the clamping piston indirectly tensions the cylinder relative to the distribution plate through a stop constructed as a clamping ring.

[0006] In document DE 10 2018 205 446 A1, the spring chamber inside the retractable ball is used as a clamping pressure chamber. Furthermore, it is proposed that this clamping pressure chamber extends towards the distribution plate via a pressure medium connection through teeth formed between the drive shaft and the cylinder. Therefore, the clamping pressure chamber extends completely through the cylinder and also through the distribution plate to the bearing bushing configured as a clearance seal. The drive shaft is also supported in the connecting plate via this bearing bushing. On the cylinder towards the distribution plate, an annular end face arranged in the retractable ball and a radially stepped portion on the inner circumference of the cylinder act as pressure surfaces. Therefore, the clamping pressure chamber is defined by the drive shaft, the cylinder, and the retractable ball. Accordingly, a swashplate-side seal and a distribution plate-side seal are provided between the cylinder and the drive shaft, and an additional seal is provided between the retractable ball and the cylinder.

[0007] The disadvantage of the axial piston machine mentioned last is that the pressure chamber is defined by three seals, which means high costs in terms of device technology and assembly technology. Summary of the Invention

[0008] In contrast, the objective of this invention is to provide an axial piston machine whose pressure chamber is simpler in terms of device and assembly technology.

[0009] This task is accomplished by an axial piston machine featuring the characteristics of this invention.

[0010] Other advantageous designs of the present invention are described in this disclosure.

[0011] The claimed hydrostatic axial piston mechanism has multiple pistons guided in cylinders and coupled to a swashplate. The cylinders are torsionally coupled to a drive shaft and tensioned relative to a stationary distribution plate fixed to the housing by means of a hydrostatic clamping device. The clamping device has a clamping pressure chamber defined by the drive shaft and the cylinders, and further defined by a seal on the swashplate side and a seal on the distribution plate side. The two seals rest directly against the drive shaft with their respective inner sides. According to the invention, at least the seal on the swashplate side is directly arranged between the drive shaft and the cylinders. No third seal is provided. This simplifies the clamping pressure chamber in terms of both device and assembly techniques.

[0012] If a retractable ball is arranged between the drive shaft and the swashplate, then the two seals and thus the entire pressure chamber are arranged on one side of the retractable ball's distribution plate.

[0013] If a toothed section is formed between the drive shaft and the cylinder for anti-torsional coupling, then two seals are arranged on one side of the distribution plate of the toothed section.

[0014] Particularly preferred is that the two seals have a sealing diameter smaller than the root circle diameter of the teeth. Therefore, during the assembly of the axial piston mechanism, neither seal needs to be pushed onto the teeth, thus preventing damage.

[0015] If a shoulder is provided on the drive shaft between the two seals, and the sealing diameter of the seal on the distribution plate side is smaller than the sealing diameter of the seal on the swashplate side, a differential surface is provided that defines a clamping pressure surface arranged inside the cylinder.

[0016] The seal on the distribution plate side can be directly arranged between the drive shaft and the cylinder when the pressure chamber has a shorter configuration, or it can be arranged between the drive shaft and the distribution plate when the pressure chamber has a longer configuration.

[0017] Preferably, the seal on the distribution plate side is a sealing ring, such as an O-ring.

[0018] If the seal on the distribution plate side is a clearance seal on the bearing bushing, then it is particularly preferred that the drive shaft forms a direct drive on both sides. For this purpose, the drive shaft also extends on the distribution plate side through the housing of the axial piston machine, for example through its connecting plate.

[0019] If pressure-side transformation is not required, according to the first embodiment, a pressure medium connection can be formed between the high-pressure-loaded arc-shaped or kidney-shaped elongated orifice of the distribution plate and the pressure chamber. This pressure medium connection has a stationary radial groove and a stationary annular groove in the distribution plate, and at least one axial channel in the cylinder that is directly connected to the annular groove. At least one axial channel rotates with the cylinder. If the annular groove is circularly closed, one axial channel in the cylinder is sufficient. If the annular groove is not circularly closed, i.e., only arc-shaped, multiple axial channels are required in the cylinder.

[0020] If pressure-side transformation is not required, then according to the second embodiment, the pressure medium connection between the high-pressure elongated orifice and the pressure chamber can have a stationary radial groove in the distribution plate and an intermediate space formed between the distribution plate and the drive shaft, as well as at least one axial channel in the cylinder that is directly connected to the intermediate space. The axial channel rotates with the cylinder. Because the intermediate space is closed around the drive shaft, or rather, cylindrically closed, one axial channel in the cylinder is sufficient to maintain pressure medium contact with the intermediate space at all times.

[0021] Two main channels can be set in a housing, particularly in its connecting plate.

[0022] If a pressure-side change is required, the pressure medium connection, according to the third embodiment, can have a reversing valve between (on the one hand) the two main channels and (on the other hand) the clamping pressure chamber. This reversing valve connects to the two main channels on the input side and to a stationary annular groove of the distribution plate on the output side. The annular groove connects directly to at least one circumferential axial channel of the cylinder. If the annular groove is circularly closed, one axial channel in the cylinder is sufficient. If the annular groove is not circularly closed, that is, only closed in an arc shape, multiple axial channels are required in the cylinder.

[0023] A connecting channel may be provided in the cylinder between each cylinder and the corresponding port arranged on the end side of the cylinder barrel.

[0024] If a pressure-side change is required, the pressure medium connection between (on the one hand) multiple or all cylinders or connecting passages and (on the other hand) the clamping pressure chamber can have a check valve assembly arranged in the cylinder barrel. In the case of, for example, nine cylinders, at least three connecting passages are connected to the clamping pressure chamber via check valve assemblies.

[0025] According to the fourth embodiment, the check valve assembly has multiple check valves, each of which connects a cylinder or connecting channel to the pressure chamber. Preferably, the check valves are evenly distributed among the connecting channels. In the case of, for example, nine cylinders, at least three connecting channels are connected to the pressure chamber via corresponding check valve assemblies. Alternatively, all connecting channels are connected to the pressure chamber via corresponding check valves.

[0026] According to the fifth embodiment, each connecting channel is connected to the pressure chamber via a connecting branch channel and a branch channel port, wherein the check valve assembly has an elastic ring arranged on the outer circumference of the pressure chamber, the elastic ring being flexibly abutting against the branch channel port.

[0027] The clamping pressure in the clamping chamber must be reduced through a very small leak in order to match the decreasing high pressure. For this purpose, a defined leak can be formed on the elastic ring. Attached Figure Description

[0028] Several embodiments of the axial piston machine according to the present invention are shown in the accompanying drawings. Wherein:

[0029] Figure 1 A schematic longitudinal sectional view shows an axial piston machine according to the prior art, on which a pressure chamber according to the following embodiments can be provided.

[0030] Figure 2 A portion of the axial piston machine according to the invention, based on the first embodiment, is shown in longitudinal sectional view.

[0031] Figure 3 Show in a view Figure 2 The distribution board in the middle,

[0032] Figure 4 A portion of the axial piston machine according to the invention, based on the second embodiment, is shown in longitudinal sectional view.

[0033] Figure 5 Show in a view Figure 4 The distribution board in the middle,

[0034] Figure 6 A portion of the axial piston machine according to the invention, based on a third embodiment, is shown in a longitudinal sectional view.

[0035] Figure 7 As shown in the diagram Figure 6 The distribution plate and connecting plate in the middle,

[0036] Figure 8 A view is shown of the cylinder according to the fourth embodiment, and

[0037] Figure 9 A portion of the axial piston machine according to the invention, based on the fifth embodiment, is shown in longitudinal sectional view. Detailed Implementation

[0038] Figure 1 A schematic cross-sectional view shows the main parts of an axial piston machine in the form of a swashplate. Cylinders 1, 101, and 201 are torsionally coupled to drive shaft 2 via teeth 3, so that they rotate together. Cylinder 4 extends along drive shaft 2 within cylinders 1, 101, and 201, the cylinders being evenly distributed circumferentially, and piston 6 is movably guided within these cylinders. The piston foot of piston 6 is coupled to a stationary swashplate 8 via a corresponding surrounding slider 7, which is inclined relative to drive shaft 2. Thus, each piston 6 performs a stroke as it rotates around drive shaft 2, the magnitude of which depends on the inclination position of swashplate 8.

[0039] On the end side of the cylinders 1, 101, 201 opposite to the swashplate 8, a port 10 is provided for each cylinder 4. This port is connected to the corresponding cylinder 4 via a corresponding connecting channel 11. The end side rotates and is tensioned relative to the stationary distribution plates 12, 112, 212, 312 with its surrounding port 10. This connecting plate is fixed to the connecting plate 13 (shown only) of the housing of the axial piston machine (not shown in detail).

[0040] The embodiments described below can be set up Figure 1 On the axial piston machine shown, but according to Figure 1 It is not visible in the illustration.

[0041] Figure 2A portion of the axial piston machine according to the invention, based on the first embodiment, is shown in longitudinal section. The region on the distribution plate side of the drive shaft 2 and one side of the cylinder 1 are shown.

[0042] Cylinder 1 passes through the high pressure in cylinder 4 relative to the distribution plate 112 (in Figure 2 (From center to right) tensioning. To homogenize and increase this unilateral clamping pressure, a clamping pressure chamber 14 is provided, which is radially internally defined by the drive shaft 2 and radially externally defined by the cylinder 1. Viewed axially along the rotation axis 16 of the drive shaft 2 and the cylinder 1, the clamping pressure chamber 14 is defined on one hand by a seal 18 on the tooth side or swashplate side and on the other hand by a seal 20 on the distribution plate side (swashplate on...). Figure 2 Arranged in the middle on the left and only on the left side Figure 1 (As shown in the image).

[0043] From the swash plate toward the distribution plate 112 (in) Figure 2 From left to right along the rotation axis 16, a tooth 3 with a root circle diameter D3 is first provided, and then the diameter of the drive shaft 2 is reduced to the sealing diameter D. 18 A seal 18, constructed as an O-ring, is arranged on the swashplate side of the drive shaft 2, and then the diameter of the drive shaft 2 is further reduced to the sealing diameter D. 20 A seal 20 is arranged on the outer circumference of the distribution plate side. The diameter difference D between the two seals 18 and 20 is... 18 -D 20 A differential surface is defined inside the cylinder 1, on the cylinder in the direction toward the distribution plate 112 (in Figure 2 (From left to right) acts as a clamping force.

[0044] According to the present invention, the two seals 18, 20 are assembled together with the cylinder 1 when the assembly shown is assembled (in... Figure 2 The sleeve is pushed onto the end of the drive shaft as shown (from right to left). Here, there is no contact between the swashplate-side seal 18 and the teeth 3. Because the pressure chamber 14 does not contact other components, such as the retractable ball, no other seals are needed.

[0045] Figure 3 Show Figure 2 A view of the distribution plate 112 of the first embodiment (according to) Figure 2(From left to right). Because no pressure-side transformation is required in the axial piston machine shown, one of the two arc-shaped elongated holes 22 is always loaded with high pressure HD. In the radial interior of the two elongated holes 22, a circular annular groove 24 is introduced into the surface of the distribution plate 112 facing the cylinder 1. Furthermore, between the elongated hole 22 loaded with high pressure HD and the annular groove 24, a radial groove 26 is introduced into the surface of the distribution plate 112 facing the cylinder 1.

[0046] Depend on Figure 2 As can be seen, the annular groove 24 of the distribution plate 112 is connected to the axial channel 28 of the cylinder 1. The axial channel 28 rotates together with the cylinder 1 about the axis of rotation 16 and thus moves along the annular groove 24 on a circular track. The axial channel 28 finally leads into the pressure chamber 14. This achieves a continuous pressure medium connection between the elongated orifice 22 loaded with high pressure HD and the pressure chamber 14.

[0047] Figure 4 and Figure 5 A second embodiment is shown, which is similar to that according to Figure 2 and Figure 3 The first embodiment is described below. Only the differences between the second embodiment and the first embodiment are described below.

[0048] Because the drive shaft 2 forms a direct drive device 30 not only on the swashplate side but also on the distribution plate side, the seal 120 on the distribution plate side is formed by a gap seal, which is formed between the bearing bush 32 and the drive shaft 2, wherein the bearing bush 32 is inserted into the distribution plate 212 and the connecting plate 13.

[0049] Depend on Figure 5 It can be seen that the radial groove 26 of the distribution plate 212 (instead of the annular groove 24) passes into the intermediate space 124 formed between the drive shaft 2 and the distribution plate 212.

[0050] Depend on Figure 4 It can be seen that, on the one hand, the central space 124 of the circular ring around the entire circumference (in) Figure 4 The right side of the middle section is defined by bearing bushing 32, while the intermediate space 124 (and according to...) Figure 2 and 3 (Similar to the first embodiment) It is connected to the pressure chamber 14 via an axial channel 28, which is formed in the cylinder 1.

[0051] Finally, based on Figure 4 and 5 The second embodiment also differs in that the axial channel 28 is not fully constructed in the cylinder but is defined radially inside by the drive shaft 2.

[0052] according to Figures 6 to 9The following three embodiments illustrate the possibility that, when pressure-side switching is possible in an axial piston machine, high pressure HD is always supplied to the compression chamber 14 constructed according to the invention.

[0053] Figure 6 and Figure 7 A third embodiment is shown, in which the aforementioned pressure-side transformation is possible. The cylinder 1 and drive shaft 2, together with the pressure chamber 14 formed therebetween and the two seals 18, 20, correspond to... Figure 2 and 3 The seals of the first embodiment.

[0054] Unlike the first embodiment, the continuous pressure medium connection for supplying high pressure HD to the clamping pressure chamber 14 has two main channels 34 extending through the connecting plate 13, which are connected to the clamping pressure chamber 14 via a reversing valve 36 also integrated in the connecting plate 13. More specifically, the outlet of the reversing valve 36 is connected to the first embodiment via a channel section formed in the connecting plate 13 and a channel section formed in the distribution plate 312. Figure 2 and Figure 3 The annular groove 24 is connected.

[0055] Figure 7 A schematic view of the distribution plate 312 and its elongated orifice 22 and annular groove 24 together with the reversing valve 36 arranged in the connecting plate 13 is shown.

[0056] Figure 8 The cross-sectional view shows only the cylinder 101 with a drive shaft 2 according to a fourth embodiment of the axial piston mechanism according to the invention, wherein the axial piston mechanism is also designed for pressure-side switching.

[0057] Only two cylinders of cylinder 4 are shown, evenly distributed around the circumference of cylinder barrel 101. It can be seen that cylinder 4 is connected to the pressure chamber 14 formed between cylinder barrel 101 and drive shaft 2 via a corresponding check valve 38. Here, check valve 38 can also be connected to connection channel 11 (see...). Figure 1 ).

[0058] Here, only one component of all cylinders 4, evenly distributed on the circumference, is connected to the pressure chamber 14 via a check valve 38, in order to ensure that one of the cylinders 4 loaded with high pressure HD is always connected to the pressure chamber 14 via its check valve 38.

[0059] Figure 9The main parts of a fifth embodiment of the same design for pressure-side switching of an axial piston machine according to the invention are shown. The cylinder 201 has a connecting branch channel 40 extending toward the pressing pressure chamber 14 for each connecting channel 11. The corresponding branch channel openings formed on the inner circumference of the cylinder 201 are collectively covered by a radially outwardly tensioned elastic ring 42. This forms a check valve assembly that is technically simple, ensuring that only pressure medium from the cylinder 4 loaded with high pressure HD is always connected to the pressing pressure chamber 14 through its connecting channel 11 and its connecting branch channel 40 for supplying the pressing pressure chamber 14.

[0060] An axial piston machine with a hydrostatic pressure chamber for a cylinder is disclosed, the pressure chamber being supplied with pressure by an arcuate elongated orifice in a distribution plate or by multiple connecting channels in the cylinder. The pressure chamber is radially externally defined by the cylinder and radially internally defined by the drive shaft. The pressure chamber is axially defined on both sides by seals arranged between the radially internal rotating drive shaft and the radially external stationary component. The radially external component can be the cylinder, or, in the case of a seal on the distribution plate side, a clearance seal between the drive shaft and the bearing bushing of the distribution plate. These two seals are arranged on the distribution plate side with respect to teeth or retractable balls.

[0061] List of reference numerals

[0062] Cylinders 1, 101, and 201

[0063] 2. Drive shaft

[0064] 3. Teeth

[0065] 4 cylinders

[0066] 6 pistons

[0067] 7 Slider

[0068] 8. Sloping plate

[0069] 10 ports

[0070] 11 Connection Channel

[0071] 12, 112, 212, 312 distribution boards

[0072] 13 Connecting Plate

[0073] 14. Compression pressure chamber

[0074] 16. Rotation axis

[0075] 18. Seals on the swashplate side

[0076] 20, 120 Seals on the side of the distribution plate

[0077] 22. An elongated, arc-shaped hole

[0078] 24 Annular groove

[0079] 26 Radial grooves

[0080] 28 Axial Channels

[0081] 30 Direct drive

[0082] 32 bearing bushing

[0083] 34 Main Channel

[0084] 36. Reversing valve

[0085] 38 Check valve

[0086] 40 Connecting branch channels

[0087] 42 Elastic Ring

[0088] 120 Gap seal on the side of the distribution plate

[0089] 124 Intermediate Space

[0090] D3 Tooth Root Diameter

[0091] D 18 sealing diameter

[0092] D 20 sealing diameter

[0093] D 120 sealing diameter

[0094] HP High Voltage

[0095] ND Low pressure.

Claims

1. A hydrostatic axial piston machine, wherein the piston is guided in cylinders (1, 101, 201) and coupled to a swashplate (8), wherein, The cylinders (1, 101, 201) are torsionally coupled to the drive shaft (2), and wherein the cylinders (1, 101, 201) are tensioned relative to stationary distribution plates (12, 112, 212, 312) by means of a hydrostatic clamping device, wherein the clamping device has a clamping pressure chamber (14) defined by the drive shaft (2) and the cylinders (1, 101, 201) and by a swashplate-side seal (18) and a distribution plate-side seal (20, 120), wherein the two seals (18, 20, 120) are directly abutting the drive shaft (2), characterized in that the swashplate-side seal (18) is directly arranged between the drive shaft (2) and the cylinders (1, 101).

2. The axial piston machine according to claim 1, wherein, A toothed section (3) is formed between the drive shaft (2) and the cylinder (1, 101, 201), characterized in that two seals (18, 20, 120) are arranged on one side of the toothed section (3) on the distribution plate side.

3. The axial piston machine according to claim 2, wherein, The two seals (18, 20, 120) have a sealing diameter (D) 18 D 20 D 120 The sealing diameter is smaller than the root circle diameter (D3) of the tooth (3).

4. The axial piston machine according to claim 3, wherein, The sealing diameter (D) of the seals (20, 120) on the side of the distribution plate 20 D 120 The sealing diameter (D) of the seal (18) on the swashplate side is smaller than that of the seal on the swashplate side. 18 ).

5. The axial piston machine according to any one of claims 1 to 4, wherein, The seal (20) on the side of the distribution plate is also directly arranged between the cylinder (1, 101, 201) and the drive shaft (2).

6. The axial piston machine according to any one of claims 1 to 4, wherein, The seal (120) on the side of the distribution plate is arranged between the distribution plate (212) and the drive shaft (2).

7. The axial piston machine according to any one of claims 1 to 4, wherein, The seal (20) on the side of the distribution plate is a sealing ring.

8. The axial piston machine according to any one of claims 1 to 4, wherein, The seal on the distribution plate side is a gap seal (120) on the bearing bushing (32), characterized in that the drive shaft (2) forms a direct drive device (30) on the distribution plate side.

9. The axial piston machine according to any one of claims 1 to 4, wherein, The pressure medium connection between the arc-shaped elongated hole (22) loaded with high pressure (HD) on the distribution plate (112) and the pressure chamber (14) has a radial groove (26) of the distribution plate (112) and an annular groove (24) of the distribution plate (112), and at least one axial channel (28) of the cylinder (1) directly connected to the annular groove (24).

10. The axial piston machine according to any one of claims 1 to 4, wherein, The pressure medium between the arc-shaped elongated hole (22) loaded with high pressure (HD) on the distribution plate (212) and the pressure chamber (14) has a radial groove (26) of the distribution plate (212) and an intermediate space (124) formed between the distribution plate (212) and the drive shaft (2) and at least one axial channel (28) of the cylinder (1) directly connected to the intermediate space (124).

11. The axial piston machine according to any one of claims 1 to 4, wherein, Two main channels (34) are provided in the connecting plate (13) of the housing, characterized in that a reversing valve (36) is provided between the two main channels (34) and the pressure chamber (14) for the pressure medium connection, the reversing valve being connected to the two main channels (34) on the input side and to the annular groove (24) of the distribution plate (312) on the output side, wherein the annular groove (24) is directly connected to at least one circumferential axial channel (28) of the cylinder (1).

12. The axial piston machine according to any one of claims 1 to 4, wherein, A connecting channel (11) is provided between each cylinder (4) and a corresponding port (10) arranged on the end side of the cylinder barrel (101), characterized in that the pressure medium connection between the plurality of or all connecting channels (11) and the pressing pressure chamber (14) has a check valve assembly arranged in the cylinder barrel (101, 201).

13. The axial piston machine according to claim 12, wherein, The check valve assembly has multiple check valves (38) that connect the cylinder (4) or the connecting channel (11) to the pressing pressure chamber (14).

14. The axial piston machine according to claim 12, wherein, Each connecting channel (11) is connected to the pressing pressure chamber (14) via a connecting branch channel (40) and a branch channel port, wherein the check valve assembly has an elastic ring (42) arranged on the outer circumference of the pressing pressure chamber (14), the elastic ring being able to abut against the branch channel port and be able to be lifted from the branch channel port.

Images