Axial piston machine

Abstract

The invention relates to an axial piston machine (10) having a cylinder barrel rotatable about an axis of rotation, the cylinder barrel being able to be pressed with its end face against a control face (54) by means of a control pressure (85) in the direction of the axis of rotation by means of the pressure loading of the piston-cylinder unit, at least one fluid channel being provided which is arranged between two directly adjacent cylinder bores and is fluidically connected to the control pressure. According to the invention, at least one transfer gap (55) is arranged on the control face, which is configured such that at least one second orifice (62) partially covers the transfer gap in each rotational position of the cylinder barrel, a continuously adjustable control flap (91) and a fluid source (21) are provided, the fluid source being fluidically connected to the at least one transfer gap by means of the control flap, and a control device (92) is provided which is arranged and connected to the control flap in such a way that the control flap can be adjusted at least in dependence on a high pressure (20) of the axial piston machine (10).

Description

TECHNICAL FIELD

[0001] The invention relates to an axial piston machine having a cylinder which can be rotated about an axis of rotation. BACKGROUND

[0002] An axial piston machine of swash plate design is known from DE 39 04 782 Al. Between a drive shaft and a cylinder, a piston-cylinder-unit is arranged, the end face of which can be pressed against a control face with the piston-cylinder-unit. A control pressure which is applied in the piston-cylinder-unit is extracted from a control gap in which a high pressure is applied. SUMMARY

[0003] The axial piston machine has the advantage that it can be operated with a high rotational speed of the cylinder and at the same time with a high working pressure. Here, the wear between the end face and the control face is less, wherein the leakage occurring there is likewise less. Furthermore, an operation with a rotational speed close to zero is possible.

[0004] According to the invention, at least one transit gap which is different from the first and the second control gap is arranged on the control face, wherein the at least one transit gap is constructed such that at least one second aperture partially covers the transit gap in each rotational position of the cylinder, wherein a continuously adjustable control flap is provided and a fluid source, wherein the fluid source is fluidically connected to the at least one transit gap via the control flap, wherein a control device is provided which is set up and connected to the control flap in such a way that the control flap can be adjusted at least in accordance with the high pressure of the axial piston machine.

[0005] The axial piston machine preferably comprises a housing in which the cylinder is rotatably supported about an axis of rotation. The piston-cylinder-unit is preferably at least indirectly supported on the housing. The axial piston machine preferably has a first and a second working connection, wherein a rotation of the cylinder is accompanied by a fluid flow between the first and the second working connection. The axial piston machine is preferably used with a pressure fluid, which is preferably a liquid and at most preferably a hydraulic oil. The high pressure is preferably formed by the higher pressure from the pressure on the first working connection and the pressure on the second working connection. The fluid source is preferably the high pressure. The piston-cylinder-unit preferably comprises two separate bodies which are movable relative to one another, which together define a fluid chamber in which the control pressure is applied. The mentioned movability is preferably oriented in the direction of the axis of rotation. The high pressure is preferably measured by means of a second pressure sensor which is connected to the control device.

[0006] The cylinder bores are preferably arranged uniformly around the axis of rotation, although an uneven distribution is also possible. The control surface can be formed directly by the housing. Preferably, the control surface is formed by a separate control plate. The control plate is preferably connected to the housing in a torsionally rigid manner, wherein the rotational position of the control plate about the axis of rotation can be adjusted. The control plate is preferably supported on the housing in the direction of the axis of rotation. Fluid channels are preferably arranged between all of the cylinder bores. The control flap is preferably adjustable in an electric manner, preferably by means of an electromagnet, wherein the control flap is electrically connected to the control device. The control device preferably comprises a digital computer.

[0007] The axial piston machine is preferably embodied in a swash plate design, wherein the piston-cylinder units are supported on the drive shaft. The axial piston machine can also be embodied in a swash axis design. The control surface and the end surface are preferably rotationally symmetrical about the axis of rotation, wherein the control surface and the end surface are preferably at most flat.

[0008] Advantageous refinements and improvements of the application include: the second orifices are arranged with respect to their radial spacing from the axis of rotation such that in any rotational position of the cylinder there is no fluid exchange connection between the first and second orifices other than the fluid exchange connection that is intended to be established via the control flap; wherein a plurality of transfer gaps are provided, which are arranged distributed around the axis of rotation, wherein the transfer gaps are connected in parallel to the control flap; wherein the first surface of the piston-cylinder unit that is active hydraulically is greater than the second surface that is active hydraulically, wherein the second surface that is active hydraulically is defined in total by all of the transfer gaps; wherein the cylinder bore has a cylindrical section in each case, the cross-sectional area of which is between 90% and 130% of the cross-sectional area of the assigned first orifice; wherein the first and second working connections of the axial piston machine are connected on the input side to a reversing valve, wherein the control flap is connected on the output side to the reversing valve; wherein the housing of the axial piston machine comprises a first and a second housing part, wherein the first housing part is configured as a pot, wherein the open side thereof is covered by the second housing part, wherein the first and second working connections are arranged on the second housing part, wherein the control flap is formed by a control valve that is mounted to the second housing part; wherein the at least one transfer gap is configured in the form of a circularly curved slot, wherein the respective center of the circle is defined by the axis of rotation; wherein a unique fluid channel is arranged in each case between all of the cylinder bores, wherein all of the fluid channels are connected in parallel to the piston-cylinder unit, wherein the second orifices all have the same radial spacing with respect to the axis of rotation; wherein a drive shaft is provided, which is surrounded by the cylinder, wherein the cylinder is connected to the drive shaft in a torsionally rigid manner with respect to the axis of rotation, wherein the piston-cylinder unit comprises a first and a second ring piston, which are arranged in each case between the drive shaft and the cylinder, wherein the first ring piston is supported on the drive shaft in the direction of the axis of rotation away from the end face, wherein the second ring piston is supported on the cylinder in the direction of the axis of rotation toward the end face, wherein the first and second ring pistons, the drive shaft and the cylinder together define a fluid chamber in which the control pressure is loaded; wherein the first and / or second ring piston has a protrusion in each case that points toward the other, second or first ring piston, wherein the protrusion is configured in each case such that the fluid chamber has a volume that is not equal to zero when the first and second ring pistons lie against one another in the region of the protrusion.

[0009] It can be provided that the two orifices are arranged with respect to their radial spacing relative to the axis of rotation such that in any rotational position of the cylinder there is no fluid exchange connection between the first and the second orifice other than the fluid exchange connection which is intended to be set by the control flap. Preferably all second orifices are arranged completely radially outside a reference circle whose center is defined by the axis of rotation and which extends through the radially outermost point of the first orifice. Thereby a hydraulic short circuit between the first and the second orifice around the control flap is avoided.

[0010] It can be provided that a plurality of transfer gaps are arranged distributed around the axis of rotation, wherein the transfer gaps are connected in parallel to the control flap. The transfer gaps are preferably arranged uniformly distributed around the axis of rotation. Preferably exactly two transfer gaps are provided which are arranged diametrically opposite with respect to the axis of rotation. The transfer gaps are preferably embodied identically to each other, wherein the transfer gaps have in particular the same shape of the frame and the same spacing relative to the axis of rotation. The transfer gaps are preferably configured in the form of circularly curved slits, wherein the respective center of the circle is defined by the axis of rotation. The width of the slits measured in radial direction is preferably equal to the respective diameter of the second orifice. The second orifice is preferably defined by a cylindrical hole which opens obliquely to the end face such that the second orifice has an elliptical contour. The mentioned diameter is the larger diameter of this ellipse measured in radial direction. The length of the transfer gaps or the length of the slits in circumferential direction is chosen as small as possible, wherein the conditions of the invention are observed.

[0011] It can be provided that the first hydraulically active surface of the piston-cylinder unit is larger than the second hydraulically active surface, wherein the second hydraulically active surface is generally defined by all transfer gaps. A "hydraulically active surface" shall be a surface which multiplied with the pressure acting there results in a hydraulic force in the direction of the axis of rotation. The area of the second hydraulically active surface is preferably between 5% and 50% of the area of the first hydraulically active surface. Thereby it is ensured that the cylinder can be pressed by the piston-cylinder unit with a sufficiently high force against the control face.

[0012] It can be provided that the cylinder bore has a cylindrical section each, the cross-sectional area of which is between 90% and 130% of the cross-sectional area of the assigned first aperture. The mentioned range is preferably 95% to 120%. If the first aperture is to be made even larger, the flow resistance upon suction does not decrease further, wherein at the same time the cylinder barrel is pushed away from the control surface. If the first aperture is to be made smaller, a meaningful adjustment of the pressing force is not possible, since the cylinder barrel is pressed too strongly by the pressure in the cylinder bore towards the control surface. The at least one first aperture preferably has a shape other than circular, the width of which in the radial direction is smaller than the diameter of the cylindrical section.

[0013] It can be provided that the first and second working connections of the axial piston machine are connected on the input side to a reversing valve, wherein the control flap is connected on the output side to the reversing valve. Thereby, a separate fluid source can be dispensed with. At the same time, a 4-quadrant operation of the axial piston machine is possible. It is unimportant which of the two working connections guides the higher pressure.

[0014] It can be provided that the housing of the axial piston machine comprises a first and a second housing part, wherein the first housing part is embodied as a pot, wherein its open side is covered by the second housing part, wherein the first and second working connections are arranged on the second housing part, wherein the control flap is formed by a control valve, which is mounted to the second housing part. The control valve is preferably embodied as a cartridge valve, which is partially mounted into a valve bore of the second housing part. The control valve is preferably a 2 / 2 proportional directional valve, which is at most preferably configured as a directly controlled structure, wherein it can be electrically adjusted.

[0015] It can be provided that the at least one transfer gap is configured in the form of a circularly curved slot, wherein the respective center of the circle is defined by the axis of rotation. The surface of the transfer gap is thereby minimal, so that the control pressure in the transfer gap exerts a small force onto the cylinder barrel. If the control surface is arranged on a separate control plate, the transfer gap is preferably formed by a perforation in the control plate. The perforation can have a constant cross-sectional shape through the control plate. However, it is also conceivable that the transfer gap is formed by a groove, on the groove bottom of which a plurality of holes are provided, which perforate the control plate. The last-mentioned alternative enables a higher working pressure.

[0016] It can be provided that one unique fluid channel is arranged between all cylinder bores, wherein all fluid channels are connected in parallel to the piston-cylinder-unit, wherein the second orifices all have the same radial spacing relative to the rotational axis. The second orifices are preferably arranged uniformly around the rotational axis. In this embodiment, the hydraulically active second surface of the transfer gap can be implemented particularly small.

[0017] It can be provided that a drive shaft is arranged which is surrounded by the cylinder barrel, wherein the cylinder barrel is connected to the drive shaft torsionally with respect to the rotational axis, wherein the piston-cylinder-unit comprises a first and a second ring piston which are arranged between drive shaft and cylinder barrel, respectively, wherein the first ring piston is supported on the drive shaft facing away from the end face in the direction of the rotational axis, wherein the second ring piston is supported on the cylinder barrel facing towards the end face in the direction of the rotational axis, wherein the first and the second ring piston, the drive shaft and the cylinder barrel together define a fluid chamber in which the control pressure is applied. The structural space required for this piston-cylinder-unit is particularly small. Furthermore, it can be produced cost-effectively. The fluid chamber is preferably connected to at least one fluid channel only, wherein the fluid channel is additionally closed in a fluid-tight and / or pressure-tight manner.

[0018] It can be provided that the first and / or the second ring piston has / have a protrusion which points towards the other, second or first ring piston, respectively, wherein the protrusion is configured such that the mentioned fluid chamber has a volume which is not equal to zero when the first and the second ring piston abut against each other in the region of the protrusion. Thereby, pressure fluid can always flow unhindered from the at least one fluid channel into the fluid chamber. If the two ring pistons abut against each other, the hydraulically active first surface is only slightly reduced relative to the state in which the first and the second ring piston abut against each other. The protrusion is preferably arranged beside the cylinder barrel, respectively, such that it does not cover the orifice of the at least one first fluid channel.

[0019] It goes without saying that the features mentioned above and explained below can be used not only in the combinations indicated, but also in other combinations or on their own, without leaving the scope of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0020] The application is explained in detail below with the help of the drawings. Therein:

[0021] Figure 1 A longitudinal section of an axial piston machine according to the application is shown;

[0022] Figure 2 A longitudinal section of an axial piston machine according to the application is shown;Figure 1 Hydraulic circuit diagram of an axial piston machine;

[0023] Figure 3 It shows Figure 1 The portion selected within the piston-cylinder-unit region;

[0024] Figure 4 The longitudinal section of the cylinder is shown;

[0025] Figure 5 It shows according to Figure 4 Side view of the cylinder;

[0026] Figure 6 A perspective view of the control panel is shown; and

[0027] Figure 7 It shows according to Figure 1 Circuit diagram for adjusting the axial piston machine. Detailed Implementation

[0028] Figure 1 A longitudinal section of an axial piston machine 10 according to the invention is shown. The axial piston machine 10 includes a housing 40, which is composed of first and second housing members 41 and 42. The first housing member 41 is implemented in a canister shape, with its open side covered by a plate-shaped second housing member 42, thereby creating a closed internal space. In the housing 40, a drive shaft 33 is supported by first and second rotary bearings 31 and 32 in a manner rotatable about a rotational axis 30. The first and second rotary bearings 31 and 32 are configured as tapered roller bearings. The drive shaft 33 extends from the housing 40 via a journal 34, which is provided with a splined shaft tooth.

[0029] Inside the housing 40, the drive shaft 33 is surrounded by a cylinder 60, which is connected by a splined shaft tooth (in... Figure 4 (Ref. 66) is torsionally connected to the drive shaft 33 about the axis of rotation 30. The cylinder 60 has an end face 63 pointing along the axis of rotation 30, with which it rests against the control surface 54. The end face 63 is flat and arranged perpendicular to the axis of rotation 30. However, a rotationally symmetrical end face 63 about the axis of rotation 30, such as one that is concavely curved, can also be used. The latter is commonly used, for example, for axial piston machines with a slanted shaft structure. A plurality of linearly movable working pistons 13 are received in the cylinder 60, preferably evenly distributed around the axis of rotation 30. The axis of motion of the working pistons 13 is arranged slightly inclined relative to the axis of rotation 30.

[0030] The control surface 54 is arranged here on a separate control plate 50, wherein the control surface can also be arranged directly on the housing 40. The control plate 50 is connected to the housing 40 in a torsionally rigid manner with respect to the rotational axis 30, wherein the control plate is supported on the housing 40 in the direction of the rotational axis 30. A relative rotation between the end surface 63 and the control surface 54 is thus produced during operation of the axial piston machine 10, wherein a hydrostatic lubricating film is formed there. The advantage of the present application is that the leakage caused by this lubricating film is minimal under all operating conditions, wherein at the same time minimal wear can be observed. The axial piston machine 10 can be operated here in particular with high pressures and / or high rotational speeds. In addition, the axial piston machine can be operated with rotational speeds close to zero.

[0031] The present axial piston machine 10 is constructed in a swash plate design, wherein the present application can also be used in axial piston machines of the swash shaft design. The swivel cradle 15 can be moved in a swivel motion about a swivel axis arranged perpendicular to the rotational axis 30. Here, the swivel axis intersects the rotational axis 30, wherein the swivel axis can also be arranged at a distance with respect to the rotational axis 30. The working pistons 13 are each supported on a flat surface of the swivel cradle 15 by means of a slide 14, wherein the respective contact surface is preferably hydraulically unloaded. The swivel angle of the swivel cradle can be adjusted here by means of a first and a second adjusting cylinder 16, 17, which are each constructed as single-acting cylinders. The present axial piston machine 10 can be adjusted over zero, that is to say the throughflow direction can be reversed only by a deflection of the swivel cradle 15, whereas the rotational direction of the cylinder barrel is not changed. However, the present application can also be used in axial piston machines which can only be adjusted in one direction starting from a zero displacement volume or in axial piston machines whose displacement volume is constant.

[0032] It is also pointed out that the piston-cylinder unit 80, with which the cylinder barrel 60 can be defined in a defined manner hydraulically against the control surface 54, is explained in more detail with respect to Figure 3 .

[0033] Figure 2 A hydraulic circuit diagram of the axial piston machine 10 according to Figure 1 is shown. The axial piston machine 10 has a first and a second working port 11, 12, which are arranged here on a second housing part (in Figure 1The axial piston machine 10 has here a 4-quadrant capability, that is to say it can be operated with two opposite rotational directions of the drive shaft, wherein in both cases two opposite throughflow directions are possible. The pressures on the first and second working connections 11, 12 can here be largely arbitrary. The axial piston machine 10 can thus alternately be operated as a pump and as a motor. The drive shaft of the axial piston machine 10 is in rotational driving connection with a motor 12, which can be embodied as an electric motor or be configured as a combustion motor. The rotation of the drive shaft is accompanied by a fluid flow between the first and second working connections 11, 12, provided that the adjusted displacement volume is not equal to zero.

[0034] The adjusted swivel angle and indirectly the displacement volume can here be measured with a swivel angle sensor 113. The temperature and indirectly the viscosity of the pressure fluid can here be measured with a temperature sensor 115, which can be connected to the first and second working connections 11, 12. The rotational speed of the drive shaft or of the cylinder barrel can here be measured with a rotational speed sensor 114.

[0035] The first and second working connections 11, 12 are connected on the input side to a reversing valve 22. On the output side of the reversing valve the higher of the pressure on the first working connection 11 and the pressure on the second working connection 12 is thus loaded. This pressure is referred to in the context of the present application as high pressure 20. This high pressure is used here as a fluid source 21 for supplying pressure fluid to a control valve 90. It is stated here that a separate control oil pump can also be used as fluid source. The high pressure 20 is measured here with a second pressure sensor 112.

[0036] The high pressure 20 is conducted by means of the control valve 90 to two transfer gaps 55 in the control plate 50, which are connected in parallel to the control valve 90. The control valve 90 comprises a continuously adjustable control flap 91, the opening cross section of which can be adjusted from zero up to a predefined maximum. The adjustment is preferably carried out electrically, preferably by means of an electromagnet 94, whose adjustment force acts directly on the valve core or valve cone of the control valve 90. The control valve 90 is here pretensioned into a latched position by means of a spring 93. The control valve is here configured as a 2 / 2-way proportional valve. The pressure loaded downstream of the control flap 91 is referred to as control pressure 85. The control pressure 85 is measured here by means of a first pressure sensor 111. All in all Figure 2Sensors 111, 112, 113, 114, and 115, shown in the diagram, are connected to a control device 92, where the electromagnet 94 of the control valve 90 is also connected, allowing the control valve 90 to be adjusted by the control device 92. The control device 92 implements the following... (refer to...) Figure 7 The described adjustment. The control device preferably includes a programmable digital computer.

[0037] Figure 3 It shows Figure 1 The portion cut off in the region of the piston-cylinder-unit 80. The piston-cylinder-unit 80 includes first and second annular pistons 81 and 82, which are respectively received between the drive shaft 33 and the cylinder 60. Correspondingly, preferably cylindrical contact gaps about the axis of rotation 30 are respectively sealed substantially fluid-tightly with sealing rings 86, especially O-rings. The first annular piston 81 faces away from the control surface along the direction of the axis of rotation 30 (in Figure 1 (See reference numeral 54 in the attached figure) is form-fitted on a shoulder on the drive shaft 33. The second annular piston 82 is oriented towards the control surface (in the direction of the rotation axis 30). Figure 1 (See reference numeral 54 in the attached diagram) is supported on the cylinder 60 by a safety ring 84. The cylinder 60, drive shaft 33, and first and second annular pistons 81, 82 together define a fluid chamber 84, which is substantially fluid-tightly closed except for the fluid passage 65. The cylinder 60 is capable of minimal movement relative to the drive shaft 33 along the axis of rotation 30, such that the control pressure 85 present in the fluid chamber 84 pushes the cylinder 60 toward the control surface (in... Figure 1 (See attached figure 54) Extrusion. The corresponding reaction force is supported by the drive shaft 33 on the first rotary bearing (in... Figure 1 As shown in the attached figure (reference numeral 31), the mounting positions of the corresponding tapered roller bearings were selected accordingly, such that the two tapered roller bearings form an O-type arrangement.

[0038] Furthermore, the protrusions 83 on the first and second annular pistons 81, 82 should be noted. These protrusions are arranged such that the first and second annular pistons 81, 82 do not cover the orifice 68 of the fluid passage. Additionally, the corresponding surface—where the first and second annular pistons 81, 82 can contact—is implemented relatively small relative to the overall end face of the first or second annular pistons 81, 82. Thus, in each position of the annular pistons 81, 82, it is ensured that the control pressure 85 causes a sufficiently large action of the cylinder 60 on the control surface (in...). Figure 1 Sufficient clamping force on the attached figure (54).

[0039] Figure 4A longitudinal section of the cylinder barrel 60 is shown. The cylinder bore 64 can be seen, wherein all cylinder bores 64 are identically embodied. The cylinder bore 64 has a cylindrical section 67, in which the assigned working piston (in Figure 1 Fig. 13) is received in linearly movable and substantially fluid-tight manner. The cylindrical section can be formed by a separate bushing composed of a sliding bearing material, such as bronze. The cylinder bore 64 opens into the end face 63 with a first aperture 61. The cross-sectional area of the first aperture 61 can be the same as or somewhat smaller than the cross-sectional area of the cylindrical section 67. In the latter case, the result of the pressing of the cylinder barrel 60 onto the control face (in Figure 1 Fig. 54) is brought about only by the hydraulic pressure in the cylinder bore 64. Within the scope of the invention, this force is less great than the force that can be obtained with the piston-cylinder unit (in Figure 3 Fig. 80) in order to be able to make a meaningful adjustment of the corresponding pressing force. The invention permits a particularly large first aperture 61, so that the axial piston machine does not form cavitation in the suction region even at a high rotational speed of the cylinder barrel 60.

[0040] Between two adjacent cylinder bores 64, a fluid channel 65 is respectively arranged, which extends obliquely with respect to the rotational axis 30 in such a way that it opens into the end face 63 with a second aperture 62 on the one hand, wherein the fluid channel opens into a fluid chamber (in Figure 3 Fig. 84) on the opposite end with a third aperture 68. All fluid channels 65 are identically configured with respect to one another. The fluid channel is embodied straight, wherein it is embodied here as a cylindrical stepped bore. The section forming the second aperture 62 has a smaller diameter here than the other section. Thereby, a minimization of the surface of the assigned transfer gap (in Figure 6 Fig. 55) should be able to be achieved in order for the hydraulic pressure acting there to be less great than the force of the piston-cylinder unit.

[0041] The cylinder barrel 60 is configured here as a one-piece structure. In particular in the region of the cylindrical section 67 and the end face 63, the cylinder barrel is treated, for example, by surface hardening, for example, by nitrocarburizing. The cylinder barrel 60 is composed, for example, of steel or cast iron.

[0042] Figure 5 A longitudinal section of the cylinder barrel 60 is shown. The cylinder bore 64 can be seen, wherein all cylinder bores 64 are identically embodied. The cylinder bore 64 has a cylindrical section 67, in which the assigned working piston (in Figure 4A side view of the cylinder barrel 60 is shown. The shape of the first orifices 61 deviating from a circular shape can be seen. In particular, their width along the radial direction is implemented to be smaller than their length along the peripheral direction. The first orifices 61 are arranged as close as possible to the spline shaft toothing 66, in order to act on the pressure fluid there with particularly small centrifugal forces. By this measure, the maximum permissible rotational speed of the cylinder barrel 60 can be increased. The first orifices 61 define a reference circle 70, the center of which is the rotational axis 30. The radially outermost point of each first orifice 61 lies on this reference circle 70. The second orifices 62 are all arranged radially outside the reference circle 70. Thereby, there is no direct fluid connection between the cylinder bore 64 and the control pressure (in Figure 2 the figure 85) in any position of the cylinder barrel 60. In other words, the fluid connection always takes place via an adjustable control flap (in Figure 2 the figure 91).

[0043] Here, a total of nine cylinder bores 64 are provided, which are arranged uniformly around the rotational axis 30. Between all cylinder bores 64, here a fluid channel with a respective second orifice 62 is arranged. The spacing (in Figure 4 the figure 71) of all second orifices relative to the rotational axis 30 is implemented identically. In principle, it can be considered to provide fluid channels only between a part of the cylinder bores 64. The transfer gap (in Figure 6 the figure 55) would then necessarily extend over a larger section of the periphery, so that there a larger hydraulic pressure would occur, which is not desirable.

[0044] Figure 6 A more precise perspective view of the control plate 50 is shown, more precisely from the control face 54. The control plate 50 is essentially implemented as a flat plate with constant thickness. Its back side, which is not visible in Figure 6 the figure, is implemented completely flat. In contrast, the control face 54 is provided with an inner annular gap 57, an annular groove 56 and an outer annular gap 58. The inner annular gap 57 and the annular groove 56 define a surface against which the control face 54 lies against the end face of the cylinder barrel in the area of the first and second control gaps 51, 52. This surface defines the leakage occurring there. This surface is designed in such a way that under all operating conditions a hydrostatic lubrication film is formed which is so thick that the end face is essentially completely separated from the control face 54. However, the mentioned lubrication film should not be thicker.

[0045] The first and second control gaps 51, 52 are each configured as a circularly curved slot, wherein the respective center of the circle is defined by the rotational axis 30. The control gaps are arranged in the area of the first orifices (inFigure 6 The control gaps 51, 52 are arranged in alignment with the reference numerals 61). They can be provided with notches 53 on both ends along the peripheral direction, with which the pressure peaks during the operation of the axial piston machine are reduced to a minimum. The first and second control gaps 51, 52 pass through the control plate 50 in the direction of the rotational axis 30. The control gaps are configured as mirror-symmetrical structures, since the axial piston machine has a 4-quadrant capability.

[0046] Between the annular groove 56 and the outer annular gap 58, two transit gaps 55 are arranged. These transit gaps pass through the control plate 50 in the direction of the rotational axis 30. The transit gaps are respectively configured as circularly curved slits, wherein the respective center of the circle is defined by the rotational axis 30. The width of the transit gaps in the radial direction is equal to the respective width of the second orifices (in the Figure 4 The transit gaps are arranged in alignment with the reference numerals 72) with the second orifices. The length of the transit gaps in the peripheral direction is chosen such that in each rotational position of the cylinder barrel at least one second orifice is located above the transit gap 55. The length of the transit gaps is somewhat larger than half the separation distance of the second orifices, which can be seen in Figure 5 The two transit gaps 55 are arranged mirror-symmetrically to each other. It goes without saying that any arbitrary number of transit gaps 55 can be used, provided that their length in the peripheral direction is designed accordingly.

[0047] The annular groove 56 is provided with a second bore 132 at the groove bottom, which passes through the control plate 50 in the direction of the rotational axis 30. There, the leakage volume accumulated in the annular groove 56 is led towards the interior space of the housing for further guidance there through a leakage connection on the housing into the tank. The first bore 131 in the center of the control plate 50 is passed through by the drive shaft (in the Figure 1

[0048] Figure 7 It is shown in accordance with Figure 1 ​A circuit diagram for the regulation of an axial piston machine. The corresponding regulator 100 is preferably a continuous linear regulator, wherein the regulator is implemented, for example, as a PI regulator. The regulation deviation 105 is formed by the difference between the rated parameter 103 and the actual parameter 102. The actual parameter is the control pressure measured by the first pressure sensor 111. The rated parameter 102 is determined by means of a first combined characteristic curve 121. The input parameter of the first combined characteristic curve is a high pressure measured by the second pressure sensor 112, wherein the measurements of the speed sensor 114 and / or the rotation angle sensor 113 and / or the temperature sensor 115 can be used as additional input parameters. The first combined characteristic curve 121 is designed such that the regulation produces a substantially constant thickness of the hydrostatic lubricating film between the end face of the cylinder and the control surface.

[0049] The regulating parameter 101 of the regulator acts on the regulating valve 90. This regulating valve 90 can include a single adjustable control baffle 91 because unavoidable leakage will cause the control pressure (at...) Figure 2 The continuous decrease of (reference numeral 85) in the attached diagram, without overcoming this effect through the corresponding opening in the control baffle 91, demonstrates that remarkably stable system performance can be achieved through this particularly simple adjustment.

[0050] The regulator 100 can be supplemented by pre-control. A corresponding pre-control parameter 104 is preferably added to the regulation parameter 101 of the regulator 100. The regulation parameter 104 can be determined using a second combined characteristic curve 122. The input parameter of the second combined characteristic curve 122 can be the measured value of the second pressure sensor 112 and / or speed sensor 114 and / or rotation angle sensor 113 and / or temperature sensor 115. The second combined characteristic curve (Kennfeld) 112 can be determined, for example, by running the system without pre-control using constant measured values ​​from the aforementioned sensors until the constant regulation parameter 101 reaches an average value. This regulation parameter is then used as the pre-control parameter. This measure can shorten the time required to reach the adjusted state.

[0051] List of reference numerals in the attached diagram:

[0052] n cylinder rotation speed

[0053] T is the temperature of the pressure fluid.

[0054] α rotation angle

[0055] 10-axis piston press

[0056] 11 First working joint

[0057] 12 second working connection

[0058] 13 working piston

[0059] 14 slide

[0060] 15 swivel cradle

[0061] 16 first adjusting cylinder

[0062] 17 second adjusting cylinder

[0063] 20 high pressure

[0064] 21 fluid source

[0065] 22 change-over valve

[0066] 23 motor

[0067] 30 rotational axis

[0068] 31 first rotational bearing

[0069] 32 second rotational bearing

[0070] 33 drive shaft

[0071] 34 journal

[0072] 40 housing

[0073] 41 first housing part

[0074] 42 second housing part

[0075] 50 control plate

[0076] 51 first control recess

[0077] 52 second control recess

[0078] 53 gap

[0079] 54 control surface

[0080] 55 transfer recess

[0081] 56 annular groove

[0082] 57 inner annular recess

[0083] 58 outer annular recess

[0084] 60 cylinder

[0085] 61 first orifice

[0086] 62 second orifice

[0087] 63 end face

[0088] 64 cylinder bore

[0089] 65 fluid channel

[0090] 66 spline shaft toothing

[0091] 67 cylindrical section of the cylinder bore

[0092] 68 third orifice

[0093] 70 reference circle

[0094] 71 radial spacing of the second orifice relative to the axis of rotation

[0095] 72 diameter of the second orifice measured in the radial direction

[0096] 80 piston-cylinder unit

[0097] 81 first annular piston

[0098] 82 second annular piston

[0099] 83 protrusion

[0100] 84 fluid chamber

[0101] 85 control pressure

[0102] 86 sealing ring

[0103] 87 retaining ring

[0104] 90 control valve

[0105] 91 control flap

[0106] 92 control device

[0107] 93 spring

[0108] 94 electromagnet

[0109] 100 regulator

[0110] 101 regulated variable

[0111] 102 actual variable

[0112] 103 rated variable

[0113] 104 pre-control variable

[0114] 105 regulation deviation

[0115] 111 first pressure sensor

[0116] 112 second pressure sensor

[0117] 113 rotation angle sensor

[0118] 114 rotation speed sensor

[0119] 115 temperature sensor

[0120] 121 first combined characteristic curve

[0121] 122 second combined characteristic curve

[0122] 131 first perforation

[0123] 132 second perforation

Claims

1. An axial piston machine (10) having a cylinder (60) rotatable about a rotation axis (30), the cylinder having an end face (63) pointing in the direction of the rotation axis (30), wherein the cylinder (60) is pressed against a control face (54) at the mentioned end face (63) by a control pressure (85) via a piston-cylinder-unit (80) pressure loading in the direction of the rotation axis, wherein the cylinder (60) has a plurality of cylinder bores (64) distributed around the rotation axis. The cylinder bores are arranged in a line (30), wherein each bore opens to the end face (63) through a first orifice (61), wherein at least one fluid channel (65) is provided, the fluid channel being arranged between two directly adjacent cylinder bores (64), wherein the fluid channel is fluidly connected to the control pressure (85), wherein the fluid channel opens to the end face (63) through a second orifice (62), wherein the first orifice (61) is allocated first and second control gaps (51, 52) on the control surface (54). Its features are, At least one transition gap (55) different from the first and second control gaps (51, 52) is arranged on the control surface (54), wherein the at least one transition gap (55) is constructed such that at least one second orifice (62) partially covers the transition gap (55) in each rotational position of the cylinder (60), wherein a continuously adjustable control baffle (91) and a fluid source (21) are provided, wherein the fluid source (21) is fluidly connected to the at least one transition gap (55) through the control baffle (91), wherein a control device (92) is provided, which is configured and connected to the control baffle (91) such that the control baffle (91) can be adjusted at least according to the high pressure (20) of the axial piston machine (10).

2. The axial piston machine according to claim 1, in, The second orifice (62) is arranged such that there is no fluid exchange connection between the first and second orifices (61, 62) in any rotational position of the cylinder (60), except for a fluid exchange connection that is desired to be provided and guided by the control baffle (91).

3. The axial piston machine according to any one of the preceding claims, in, Multiple transition gaps (55) are provided, which are distributed around the rotation axis (30) and are connected in parallel to the control baffle (91).

4. The axial piston machine according to claim 1 or 2, in, The first hydraulically functional surface of the piston-cylinder-unit (80) is larger than the second hydraulically functional surface, wherein the second hydraulically functional surface is defined together by all the transition gaps (55).

5. The axial piston machine according to claim 1 or 2, in, The cylinder bore (64) has a cylindrical section (67) with a cross-sectional area between 90% and 130% of the cross-sectional area of ​​the assigned first orifice (61).

6. The axial piston machine according to claim 1 or 2, in, The first and second working joints (11, 12) of the axial piston machine (10) are connected to the directional valve (22) on the input side, wherein the control baffle (91) is connected to the directional valve (22) on the output side.

7. The axial piston machine according to claim 1 or 2, in, The housing (40) of the axial piston machine (10) includes first and second housing parts (41, 42), wherein the first housing part (41) is configured as a canister, wherein its open side is covered by the second housing part (42), wherein first and second working joints (11, 12) are arranged on the second housing part (42), wherein the control baffle (91) is formed by a control valve (90) which is mounted on the second housing part (42).

8. The axial piston machine according to claim 1 or 2, in, The at least one transition gap (55) is constructed in the form of a circularly curved elongated hole, wherein the corresponding center of the circle is defined by the axis of rotation (30).

9. The axial piston machine according to claim 1 or 2, in, A unique fluid passage (65) is arranged between each of the cylinder bores (64), wherein all fluid passages (65) are connected in parallel to the piston-cylinder-unit (80), wherein the second orifices (62) all have the same radial spacing (71) relative to the axis of rotation (30).

10. The axial piston machine according to claim 1 or 2, in, A drive shaft (33) is provided, which is surrounded by the cylinder (60), wherein the cylinder (60) is torsionally connected to the drive shaft (33) about the axis of rotation (30), wherein the piston-cylinder-unit (80) includes first and second annular pistons (81, 82), which are respectively arranged between the drive shaft (33) and the cylinder (60), wherein the first annular piston (81) is supported on the drive shaft (33) away from the end face (63) along the direction of the axis of rotation (30), wherein the second annular piston (82) is supported on the cylinder (60) towards the end face (63) along the direction of the axis of rotation (30), wherein the first and second annular pistons (81, 82), the drive shaft (33) and the cylinder (60) together define a fluid chamber (84) in which the control pressure (85) is applied.

11. The axial piston machine according to claim 10, in, The first and / or second annular pistons (81, 82) each have a protrusion (83) pointing toward another, second or first annular piston (82, 81), wherein the protrusions are configured such that the fluid chamber (84) mentioned above has a volume not equal to zero when the first and second annular pistons (81, 82) are in contact with each other in the region of the protrusion (83).

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