Hydrostatic axial piston machine with pressure side replacement

Abstract

A hydrostatic axial piston machine with pulse damping is disclosed. The pulse damping has an opening or connection in the transition area in front of the kidney-shaped long hole on the high-pressure side of the distribution plate. The connection or the opening is connected to a high-pressure accumulator by one or two hydraulically passively controlled reversing valves. This serves for pre-compression and thus for pulse damping. In the improvement, the distribution plate also has an opening or connection in the transition area behind the kidney-shaped long hole on the high-pressure side. The connection or the opening is connected to a low-pressure accumulator by one or two hydraulically passively controlled reversing valves. This serves for decompression and thus likewise for the pulse damping.

Description

Technical Field

[0001] The present invention relates to a pulse reduction device for an axial piston machine for hydrostatic pressure, the axial piston machine being designed for pressure-side replacement. Background Technology

[0002] As is well known in axial piston machines, multiple cylinders extend parallel to the axis of rotation of the cylinder barrel. These cylinders are evenly distributed around their perimeter within the cylinder barrel. In each cylinder, a piston is movably guided approximately parallel to the axis of rotation.

[0003] In an axial piston machine with a swashplate configuration, the pistons are coupled to a stationary swashplate via their respective piston feet, the swashplate being tilted relative to the axis of rotation. Therefore, each piston completes one stroke in one revolution around the axis of rotation, the magnitude of which depends on the tilt position of the swashplate. The drive shaft of the axial piston machine also extends along the axis of rotation of the cylinder.

[0004] In an axial piston engine with a swashplate configuration, the swashplate is mounted on the drive shaft in the form of a flange. The drive shaft and the swashplate are tilted relative to the cylinder's axis of rotation. Therefore, in this configuration, each piston completes one stroke during one revolution around the axis of rotation, the magnitude of which depends on the tilt position of the drive shaft and the tilt position of the flange-type swashplate.

[0005] For both configurations of the axial piston machine, an opening is provided on the end face of the cylinder (facing the swashplate or the inclined drive shaft) for each cylinder. The opening is connected to its respective cylinder via a connecting channel constructed inside the cylinder. As the cylinder, along with its end face, rotates, the opening travels along a circular path. The end face is tightened towards two arcuate, or kidney-shaped, elongated orifices, such that the opening operates sealingly over these orifices. During operation, one of the two orifices serves as the high-pressure kidney, while the other serves as the low-pressure kidney. In most cases, the two orifices are configured as channel holes on a distribution plate.

[0006] This invention relates to an axial piston press in which pressure-side switching is possible for the two elongated orifices. In the case of a pump, this pressure-side switching can be achieved, for example, by a change in the drive direction of the drive shaft and a subsequent change in the transport direction of the pressure medium. This is also referred to as two-quadrant operation for such pumps. If an axial piston press designed for pressure-side switching can operate as a motor in addition to pump operation, beyond the aforementioned conditions, it is referred to as four-quadrant operation.

[0007] A closed transition region is provided on the distribution plate between the two elongated holes when viewed circumferentially along the opening. When the opening passes through this transition region, the associated piston passes through the return point or dead point.

[0008] The problem with these types of axial piston machines is pressure medium pulses, which occur when the cylinder opening, in a low-pressure state, travels from the closed transition region through the edge of the elongated orifice on the high-pressure side, and the cylinder is suddenly subjected to high pressure. Considering the entire axial piston machine, such a pressure medium pulse is formed once per revolution in all the openings.

[0009] Document EP 2 324 245 B1 discloses a pulse reduction device for an axial piston machine with pressure-side changing. A pre-compression volume is displayed in a common storage element, which can be connected via two two-position three-way directional valves to respective connection positions called outlets (Ausmündung). These connection positions are respective orifices in the two closed transition regions. More precisely, the first connection position is arranged circumferentially in front of a first elongated orifice, while the second connection position is arranged circumferentially opposite to the first elongated orifice on the distribution plate. The two two-position three-way directional valves are periodically and electrically switched. In this way, the pressurized material in each cylinder is further pre-compressed before each cylinder passes through the elongated orifice under applied high pressure.

[0010] The disadvantage of these types of axial piston machines is the cost of equipment technology, and especially the cost of control technology, which arises from the operation of the two electrically operated two-position three-way directional valves that are to be switched in coordination with the rotation of the cylinder. Summary of the Invention

[0011] In contrast, the objective of this invention is to create an axial piston machine with a pulse reduction device, thereby reducing the cost of its equipment and control technologies.

[0012] The task is accomplished by a hydrostatic axial piston machine. The hydrostatic axial piston machine has a rotating cylinder in which multiple cylinder bodies are constructed. These cylinder bodies are connected to the end face of the cylinder through respective openings, wherein the openings are movable along a circular path and are tightened toward a first arc-shaped elongated hole and toward a second arc-shaped elongated hole. A first connection position is provided adjacent to the first elongated hole in a first transition region between the two elongated holes, and a second connection position is provided adjacent to the second elongated hole in a second transition region between the two elongated holes. The two connection positions are connected to a high-pressure storage device via a first directional valve system. The first directional valve system is fluidly connected to the two elongated holes via a pressure control pipe such that when high pressure is applied to one of the two elongated holes, the adjacent connection position connects to the high-pressure storage device, while the connection position adjacent to the other elongated hole blocks the high-pressure storage device.

[0013] Other advantageous designs of the present invention are described below.

[0014] The claimed hydrostatic axial piston press has a rotating cylinder in which multiple cylinder bodies are formed, each cylinder body connected to an end face of the cylinder via a respective opening, wherein the openings are movable along a preferably common circular path. The openings face a first arcuate elongated orifice and are clamped toward a second arcuate elongated orifice. The two elongated orifices serve as a transition geometry. Because the axial piston press is designed for pressure-side replacement, the two elongated orifices are high-pressure resistant. In a first transition region arranged between the two elongated orifices, a first connection position is provided adjacent to the first elongated orifice along the circumferential direction, not far in front of it. In a second transition region arranged between the two elongated orifices, a second connection position is provided adjacent to the second elongated orifice along the circumferential direction, not far in front of it. The two transition regions extend from one elongated orifice to the other. The two connection positions are connectable to a high-pressure storage device via a first reversing valve system.

[0015] According to the invention, the first reversing valve system is fluidly connected to the two elongated orifices via a pressure-controlled conduit in such a way that when one of the two elongated orifices is subjected to high pressure, an adjacent connection position arranged along the circumferential direction not far in front of the elongated orifice in question connects to the high-pressure storage device, while a connection position adjacent to the other elongated orifice, arranged along the circumferential direction not far in front of the elongated orifice in question, blocks the high-pressure storage device. The connection position “adjacent” to the arc-shaped elongated orifice should be understood as being located closer to the adjacent elongated orifice than to the other elongated orifice.

[0016] In the axial piston machine according to the invention, the pre-compression of the cylinder moving circumferentially towards the elongated orifice on the high-pressure side is passively and reliably controlled via a pressure control conduit based on the current pressure relationship at the two elongated orifices. During pressure-side switching, the first directional valve system passively and reliably switches, connecting another connection point to the high-pressure storage device. This reduces the cost of the equipment and control technologies. Structural space requirements are also reduced.

[0017] In many configurations of axial piston machines, the two arc-shaped elongated holes are configured as channel holes and arranged in a distribution disc.

[0018] In a first embodiment, the first directional control valve system comprises a two-position three-way directional control valve. In the first open position of this two-position three-way directional control valve, the high-pressure storage device is connected to the first connection position, while the second connection position blocks the high-pressure storage device. In the second open position of the two-position three-way directional control valve, the high-pressure storage device is connected to the second connection position, while the first connection position blocks the high-pressure storage device. Furthermore, the pressure in the first elongated orifice applies pressure to the valve body of the two-position three-way directional control valve towards the first open position, while the pressure in the second elongated orifice applies pressure to the valve body of the two-position three-way directional control valve towards the second open position. In the first embodiment, the axial piston machine with pressure-side replacement according to the present invention can be pre-compressed using only one directional control valve.

[0019] To minimize the length of the pipe from the elongated orifice to the directional valve system, it is advantageous to eliminate the control edge. Therefore, in the second embodiment, the first directional valve system comprises a first two-position two-way directional valve and a second two-position two-way directional valve. The pressure in the first elongated orifice applies to the valve body of the first two-position two-way directional valve in the open position, while the pressure in the second elongated orifice applies to the valve body in the closed position. The pressure in the first elongated orifice applies to the valve body of the second two-position two-way directional valve in the closed position, while the pressure in the second elongated orifice applies to the valve body in the open position. The two two-position two-way directional valves are very simple and can utilize standard components. Furthermore, drilling costs are low.

[0020] In a particularly pulse-reduced axial piston machine, a third connection position is provided in the second transition region adjacent to the first elongated orifice, along the circumferential direction, not far behind the first elongated orifice. A fourth connection position is also provided in the first transition region adjacent to the second elongated orifice, along the circumferential direction, not far behind the second elongated orifice. The third and fourth connection positions can be connected to a low-pressure reservoir via a second directional valve system. Furthermore, the second directional valve system is fluidly connected to the two elongated orifices via a pressure-controlled conduit such that when high pressure is applied to one of the two elongated orifices, the third or fourth connection position, located circumferentially behind it, connects to the low-pressure reservoir, while the other third or fourth connection position blocks the low-pressure reservoir. This also allows for the additional decompression of cylinders that move away from the elongated orifice where high pressure is applied, via the low-pressure reservoir.

[0021] As an improvement to the first embodiment, the second directional control valve system comprises a two-position three-way directional control valve. In the first open position of this two-position three-way directional control valve, the low-pressure storage device is connected to the third connection position, while the fourth connection position blocks the low-pressure storage device. In the second open position of the second two-position three-way directional control valve, the low-pressure storage device is connected to the fourth connection position, while the third connection position blocks the low-pressure storage device. Furthermore, the pressure in the second elongated orifice applies pressure to the valve body of the two-position three-way directional control valve towards the second open position, while the pressure in the first elongated orifice applies pressure to the valve body of the two-position three-way directional control valve towards the first open position.

[0022] As an improvement to the second embodiment, the second directional valve system is composed of a third two-position two-way directional valve and a fourth two-position two-way directional valve. Attached Figure Description

[0023] Two embodiments of the axial piston machine according to the present invention are shown in the accompanying drawings.

[0024] In the attached image:

[0025] Figure 1 The main parts of the axial piston machine are shown in the longitudinal sectional view, in which the two embodiments of the present invention are based on Figure 1 and Figure 2 To achieve;

[0026] Figure 2 A distribution plate with hydraulic circuitry is shown in a first embodiment of the invention; and

[0027] Figure 3A distribution plate with hydraulic circuitry is shown in a second embodiment of the invention.

[0028] List of reference numerals in the attached diagram:

[0029] 1. Cylinder;

[0030] 2. Drive shaft;

[0031] 4. Cylinder block;

[0032] 6. Pistons;

[0033] 7. Slide;

[0034] 8. Sloping plate;

[0035] 10. Opening;

[0036] 12; 112 Distribution disk;

[0037] 14. Circular path;

[0038] 16. First transition zone;

[0039] 18. Second transition zone;

[0040] 20 First connection position;

[0041] 22 Second connection position;

[0042] 24. Pre-stressing pipeline;

[0043] 26. Two-position three-way directional valve;

[0044] 28. Pressure-controlled piping;

[0045] 30 (Another) two-position three-way directional valve;

[0046] 32. Third connection position;

[0047] 34. Fourth connection position;

[0048] 36. Pressure-reducing pipeline;

[0049] 126a First and second position two-way directional control valve;

[0050] 126b Second two-position two-way directional valve;

[0051] A. Second long hole;

[0052] B. First long hole;

[0053] a. Connection position;

[0054] b. Connection position;

[0055] HD high-voltage memory;

[0056] ND Low-voltage memory. Detailed Implementation

[0057] Figure 1 The main components of an axial piston machine with a swashplate configuration are shown in schematic cross-sectional view. Cylinder 1 is torsionally coupled to drive shaft 2, causing them to rotate together. Cylinder blocks 4 extend along drive shaft 2 within cylinder 1, the cylinder blocks being evenly distributed around their periphery, and pistons 6 are movably guided within these cylinder blocks. The pistons 6 are coupled to a stationary swashplate 8 via their respective piston feet and thus via surrounding slides 7, the swashplate being mounted at an angle relative to drive shaft 2. Therefore, each piston 6 completes one stroke in one revolution around drive shaft 2, the magnitude of which depends on the tilt position of the swashplate 8.

[0058] On the side opposite to the swashplate 8, an opening 10 is provided on the end face of the cylinder 1 for each cylinder 4, and the opening is connected to the respective cylinder 4 through a connecting channel. The end face is rotated and tightened together with the opening 10 around it toward a stationary distribution plate 12; 112, which is fixed to the housing of the axial piston machine (not shown).

[0059] Figure 2 and Figure 3 Distributor discs 12 and 112 are shown respectively. It can be seen that distributor discs 12 and 112 have arc-shaped or kidney-shaped elongated holes A and B. Depending on the operating state, one of the elongated holes A and B is located on the high-pressure side, while the other elongated hole B and A is located on the low-pressure side. The surrounding opening 10 is guided in a sealed manner along a circular path 14 above the elongated holes A and B.

[0060] exist Figure 2 and Figure 3 Assuming the opening 10 is mentioned (see...) Figure 1 The cylinder 4 rotates counterclockwise along the circular path 14, assuming the first elongated hole B is on the high-pressure side and the second elongated hole A is on the low-pressure side. A flat first transition region 16 is provided behind the second elongated hole A on the low-pressure side and in front of the first elongated hole B on the high-pressure side, while a second transition region 18 is provided diametrically opposite, behind the first elongated hole B on the high-pressure side and in front of the second elongated hole A on the low-pressure side. According to the prior art, the two transition regions 16, 18 seal the corresponding opening 10 and thus the corresponding cylinder 4 relative to the housing cavity.

[0061] according to Figure 2 and Figure 3In the first transition region 16, a first connection position 20 is provided circumferentially in front of the elongated hole B on the first high-pressure side, while a second connection position 22 is provided circumferentially in front of the second elongated hole A on the low-pressure side. The two connection positions 20 and 22 are constructed as small holes perpendicular to the surface of the distribution disc 12, and thus serve as openings that fluidly contact the opening 10 of the cylinder 4, which operates above this opening (see...). Figure 1 ).

[0062] according to Figure 2 In the first embodiment, the two connection positions 20, 22 are connected to a common 2 / 2-Wege-Schaltventil 26 via their respective pre-pressurization pipes 24. The valve body of the 2 / 2-Wege-Schaltventil 26 is pressurized via a pressure control pipe 28 towards (in...) Figure 2 The working pressure of the elongated orifice B on the first high-pressure side (as shown in the diagram) in the direction of the connected position a is such that the high-pressure storage device HD is connected to the first connection position 20. Conversely, the valve body of the two-position three-way directional valve 26 is subjected to pressure via the pressure control pipe 28 in the direction of the connected position b, on the second low-pressure side, where the second connection position 22 is connected to the high-pressure storage device HD.

[0063] If high pressure is applied to the second elongated orifice A and low pressure is applied to the first elongated orifice B, then the two-position three-way directional valve 26 passively and automatically switches. Therefore, the second connection position 22 is connected to the high-pressure storage HD, so that the opening 10 (see [link to original text]) rotates counterclockwise. Figure 1 Compression is achieved before the machine enters the second elongated hole A.

[0064] From Figure 3 The second embodiment and Figure 2 The first embodiment described herein is comparable in principle to the first embodiment in terms of functional results. Here, in... Figure 3 From Figure 2The two-position three-way directional valve 26 is replaced by two separate two-position two-way directional valves 126a and 126b. The first two-position two-way directional valve 126a connects the first connection position 20 to the high-pressure storage device HD, and this first connection position is arranged circumferentially in front of the first elongated orifice B that guides the high pressure. Here, the second two-position two-way directional valve 126b blocks the second connection position 22 of the high-pressure storage device HD, which is arranged circumferentially in front of the second elongated orifice A on the low-pressure side. Furthermore, the two two-position two-way directional valves 126a and 126b respectively have connections to the first elongated orifice B and to the second elongated orifice A via a pressure control conduit 28.

[0065] According to Figure 3 In the second embodiment, if a pressure-side change occurs between the elongated orifices A and B, when the second elongated orifice A, which guides high pressure, begins to enter from this point, the second connection position 22 is also connected to the high-pressure storage device HD, while the first connection position 20 is disconnected from the high-pressure storage device HD. At this time, the two two-position two-way directional valves 126a and 126b are connected to their respective... Figure 3 In the ON position not shown in the diagram.

[0066] refer to Figure 2 The second part of the first embodiment of the pulse attenuation device shown is described. This second part includes a low-voltage memory ND and an additional two-position three-way directional valve 30 with a double-sided pressure control pipe 28. Furthermore, a third connection position 32 is provided in the first transition region 16 between the second elongated orifice A and the first connection position 20. Similarly, a fourth connection position 34 is provided in the second transition region 18 between the first elongated orifice B and the second connection position 22. The third connection position 32 and the fourth connection position 34 are also arranged on the circular path 14.

[0067] The third connection position 32 and the fourth connection position 34 are connected to the additional two-position three-way directional valve 30 via their respective pressure-reducing pipes 36. By means of the second part of the pulse attenuation device according to the invention, the opening 10 or the cylinder 4 (see above) located circumferentially behind the elongated holes A and B where high pressure is applied, is positioned. Figure 1 This produces a pressure reduction effect. When high pressure is applied to the first elongated orifice B, the pressure reduction occurs at the fourth connection position 34 before the corresponding opening 10 moves above the elongated orifice A, which is under low pressure. Additionally, at the other two-position three-way directional valve 30... Figure 2The connection position a is shown. When a pressure-side change occurs and high pressure is applied to the second elongated orifice A, the pressure reduction occurs at the third connection position 32, for which the additional two-position three-way directional valve 30 is adjusted to the connection position b.

[0068] A hydrostatic axial piston press with a pulse attenuation device is disclosed. This pulse attenuation device has openings, or connection positions 20, 22, in front of the kidney-shaped elongated orifices A, B on the high-pressure side of the distribution discs 12, 112 in the transition regions 16, 18. The connection positions 20, 22, or the openings, are connected to a high-pressure storage device HD via one or two hydraulically passively controlled directional valves 26, 126a, 126b. This is used for pre-compression and therefore for pulse attenuation.

[0069] In the improved design, the distribution disc 12 also has openings, or connection points 32 and 34, behind the kidney-shaped elongated holes A and B on the high-pressure side in the transition regions 16 and 18. These connection points 32 and 34, or the openings, are connected to the low-pressure memory ND via one or two hydraulically passively controlled directional valves 30. This is used for pressure reduction and therefore also for pulse attenuation.

Claims

1. A hydrostatic axial piston machine having a rotating cylinder (1) in which a plurality of cylinder bodies (4) are constructed, the plurality of cylinder bodies being connected to the end face of the cylinder (1) through their respective openings (10), wherein, The opening (10) is movable along a circular path (14) and tightens toward the first arc-shaped elongated hole (B) and the second arc-shaped elongated hole (A), wherein a first connection position (20) is provided adjacent to the first elongated hole (B) in a first transition region (16) between the two elongated holes (A, B), and wherein a second connection position (22) is provided adjacent to the second elongated hole (A) in a second transition region (18) between the two elongated holes (B, A), wherein the two connection positions (20, 22) are connected to the high-pressure storage device (HD) via a first reversing valve system, characterized in that the first reversing valve system is fluidly connected to the two elongated holes (A, B) via a pressure control pipe (28) such that when one of the two elongated holes (A, B) is subjected to high pressure, the adjacent connection position (20, 22) is connected to the high-pressure storage device (HD), while the connection position (22, 20) adjacent to the other elongated hole (B, A) blocks the high-pressure storage device (HD).

2. The axial piston machine according to claim 1, wherein, The first directional control valve system is composed of a two-position three-way directional control valve (26). In the first open position (a) of the two-position three-way directional control valve, the high-pressure storage device (HD) is connected to the first connection position (20), while the second connection position (22) blocks the high-pressure storage device (HD). In the second open position (b) of the two-position three-way directional control valve (26), the high-pressure storage device (HD) is connected to the second connection position (22), while the first connection position (20) blocks the high-pressure storage device (HD). The pressure of the first elongated orifice (B) applies to the valve body of the two-position three-way directional control valve (26) in the direction of the first open position (a), while the pressure of the second elongated orifice (A) applies to the valve body of the two-position three-way directional control valve (26) in the direction of the second open position (b).

3. The axial piston machine according to claim 1, wherein, The first directional control valve system comprises a first two-position two-way directional control valve (126a) and a second two-position two-way directional control valve (126b). The pressure of the first elongated orifice (B) applies to the valve body of the first two-position two-way directional control valve (126a) in the direction of the open position, while the pressure of the second elongated orifice (A) applies to the valve body of the first two-position two-way directional control valve (126a) in the direction of the closed position. The pressure of the first elongated orifice (B) applies to the valve body of the second two-position two-way directional control valve (126b) in the direction of the closed position, while the pressure of the second elongated orifice (A) applies to the valve body of the second two-position two-way directional control valve (126b) in the direction of the open position.

4. The axial piston machine according to claim 2, wherein, A third connection position (32) is provided adjacent to the first elongated hole (B) in the second transition region (18), and a fourth connection position (34) is provided adjacent to the second elongated hole (A) in the first transition region (16), and the third and fourth connection positions (32, 34) are connected to the low-pressure memory (ND) through a second reversing valve system, wherein the second reversing valve system is fluidly connected to the two elongated holes (A, B) through a pressure control pipe (28) such that when one of the two elongated holes (A, B) is subjected to high pressure, the adjacent third or fourth connection position (32, 34) is connected to the low-pressure memory (ND), while the third or fourth connection position (34, 32) adjacent to the other elongated hole (A, B) blocks the low-pressure memory (ND).

5. The axial piston machine according to claim 4, wherein, The second directional valve system is composed of a two-position three-way directional valve (30). In the first open position (a) of the two-position three-way directional valve, the low-pressure memory (ND) is connected to the third connection position (32), while the fourth connection position (34) blocks the low-pressure memory (ND). In the second open position (b) of the two-position three-way directional valve (30), the low-pressure memory (ND) is connected to the fourth connection position (34), while the third connection position (32) blocks the low-pressure memory (ND). The pressure of the second elongated orifice (A) is applied to the valve body of the two-position three-way directional valve (30) in the direction of the second open position (b), while the pressure of the first elongated orifice (B) is applied to the valve body of the two-position three-way directional valve (30) in the direction of the first open position (a).

6. The axial piston machine according to claim 4, wherein, The second directional valve system consists of a third two-position two-way directional valve and a fourth two-position two-way directional valve.

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