DE102017208755A1 - HYDROSTATIC SUPPORT AND LUBRICATION ON VALV SEGMENT LOAD - Google Patents

Abstract

The invention relates to improved storage and lubrication between cylinder blocks (3) and valve segments (2) of hydraulic axial piston units (1) and their engines. First and second kidney-shaped ports (11, 21) are formed in the valve segments rotationally symmetrically with respect to an axis of rotation of the cylinder block to provide supply and discharge ports for supplying and discharging hydraulic fluid to and from cylinder bores (8) in the cylinder block. At the radially outer edge of the kidney-shaped terminals, a plurality of concave hydrostatic bearing recesses (50) are provided on a sliding surface (7) facing the cylinder block and intersect one of the kidney-shaped terminals. Alternatively, the bearing recesses may be disposed on a bottom surface (9) of the cylinder block and extend outwardly from outer edges of openings (35) for supplying and discharging hydraulic fluid to or from the cylinder bores.

Description

The present invention relates to a hydraulic axial piston unit of the swash plate or oblique axis type. Preferably, the axial piston unit of the variable Verdrängungsart; however, constant velocity hydraulic axial piston units are also included in the invention. The present invention particularly relates to valve segments used in such above-mentioned hydraulic axial piston units.

In hydraulic axial piston pumps and axial piston hydraulic motors, i. in hydraulic axial piston units, reciprocally movable working pistons are arranged generally in the axial direction of an axis of rotation of a cylinder block. It can be distinguished between two generally different types, hydraulic axial piston unit of the swash plate type and hydraulic axial piston pumps of the bent axis type. Since these types of hydraulic axial piston units are well known to a person skilled in the art, explanations regarding the operating principle of these hydraulic axial piston pumps can be dispensed with at this point. It should be noted that there are swash plate type hydraulic axial piston pumps having a rotating or stationary swash plate, respectively having a stationary or rotating cylinder block. Further, there are hydraulic axial axis piston units with rotating cylinder block, which is pivotable for the adjustment of the displacement volume. The latter is today the usual design for hydraulic axial piston pumps; however, the other type of hydraulic swash plate axial piston pump is also included in the inventive idea. The oblique axis type is often used in engine applications.

In all types of hydraulic axial piston units, hydraulic fluid is supplied / discharged via a non-rotating valve segment facing the cylinder block base which is the cylinder block side remote from the piston heads supported by the shaft or swash plate, particularly in slide shoes. In all cases, the valve segment is non-rotatably connected to the housing of the hydraulic axial piston unit and has a kidney-shaped inlet and a kidney-shaped outlet for supplying and discharging hydraulic fluid to the cylinder bores of the cylinder block. Both kidney-shaped ports are disposed on the valve segment in the circumferential direction with respect to the rotational axis of the cylinder block, and accordingly form a kidney-shaped inlet and a kidney-shaped outlet during the circular movement of the cylinder bores about the rotation axis. The radius or diameter of the centerline of these kidney-shaped ports in the valve segment coincides with the reference circle of the centers of the openings in the cylinder block base, the ports forming the ends of fluid channels connecting the cylinder bores to the cylinder block base. These fluid channels may be parallel to the axis of rotation of the cylinder block or oblique to the axis of rotation of the cylinder block, resulting in a smaller diameter of the reference circle of the centerlines of the kidney shaped ports in the valve segment, allowing a reduced diameter of the valve segment. A reduced diameter of the valve segment allows a reduction of the installation space.

In an alternative embodiment, the valve segment sliding surface that contacts the cylinder block base surface may be made planar, resulting in a disc-shaped valve segment, or may be curved, resulting in a spherical valve segment sliding surface. In further embodiments, bearing plates which can be produced in particular from bronze or in a bimetal method can be fastened in a torque-proof manner to the cylinder base region, which form the contact surface to the valve segment. Conversely, valve plates made in bronze or in a bi-metal process may be secured to the valve segment and form the valve segment sliding surface that faces the cylinder block base. In both cases, i. when using a rotating bearing plate or a stationary valve plate, friction is reduced if these plates are made of bronze or bi-metal or other material capable of reducing frictional forces. In the case of such a bearing plate, which is fixed to the Zylinderblockfuß, the bearing plate has passages connecting the openings of the cylinder bores with the kidney-shaped connections in the valve segment. In the other case, when a valve plate is used, the same must have kidney-shaped passages to connect the openings in the base of the cylinder block base with the kidney-shaped ports in the valve segment.

In all cases, regardless of whether a disc-shaped valve segment or a spherical valve segment is used, the cylinder block rotates with respect to the stationary valve segment during operation of the hydraulic axial piston unit, wherein different types of loads and loads are exerted on both important parts of a hydraulic axial piston unit, in particular on the valve segment and / or the valve plate or the bearing plate. Furthermore, during operation of a hydraulic axial piston pump one half of the number of cylinder bores is loaded with high pressure and the other Half with low pressure, which on the one hand leads to a tilting moment of the cylinder block, which leads to different friction conditions on each pressure side of the valve segment. On the other hand, since the pressure profile in the circumferential direction along the kidney-shaped ports is not constant, especially at high load conditions of the hydraulic axial piston unit, the valve segment can even be deformed in areas with pressure peaks. Viewed in the circumferential direction of the kidney-shaped connections, this leads to an unequal gap, ie to a non-constant distance between the cylinder block base surface and the Ventilsegmentgleitfläche. It is obvious to a person skilled in the art that such variable conditions in the circumferential direction of the valve segment are not conducive to the operation of the hydraulic axial piston unit, since these conditions lead to power losses and robustness losses as well as to increased friction and wear on the sliding surfaces.

CN 104 776 018 shows η-shaped grooves on the valve segment extending only from the outlet port in the radially outward direction to provide fluid dynamic pressure lubrication for reducing leakage, vibration and noise between the valve segment and the cylinder block and reducing cylinder stall torque.

It is therefore an object of the invention to improve these non-constant gap conditions between the valve segment and the cylinder block, especially under high load conditions of the hydraulic piston unit and to improve the robustness and reduce friction and wear of the components involved in the hydrostatic axial piston unit. These improvements should be of simple design and be effective for all types of hydraulic axial piston units. At the same time, these improvements should be easy to implement, implement, and inexpensive. Furthermore, the improvements according to the invention should also be applicable in existing hydraulic axial piston pumps.

The object of the invention is achieved by a valve segment of a hydraulic axial piston unit according to the preamble of claim 1, wherein the valve segment has a kidney-shaped first port and a kidney-shaped second port for providing in an alternating manner - depending on the direction of rotation - a suction port and a discharge port for supplying and discharging hydraulic fluid to and from cylinder bores of the cylinder block of the hydraulic axial piston unit. The valve segment according to the invention is characterized in that the first port and the second port are rotationally symmetrical with respect to a rotational axis of the cylinder block, and that a plurality of concave hydrostatic bearing recesses project at least from the radial outer edges of the first port and the second port the sliding side of the valve segment which faces the cylinder block extends. The valve segment according to the invention is further characterized in that each of the recesses of the plurality of hydrostatic bearing recesses intersects the first or second connection.

In this case, the sliding surface of the valve segment slides on the base of the cylinder block or on a base surface, which is provided by a bearing plate which is fixed to the cylinder block bottom. In another embodiment, a valve plate made of bronze or bi-metal or other friction-reducing material may be secured to the valve segment, with the sliding surface formed on the valve-plate-facing side of the cylinder block.

Since the openings of the fluid channels connecting the kidney-shaped ports in the valve segment to the cylinder bores in the cylinder block have the same radial width as the center line of the kidney-shaped ports, i. the radially outermost contours of these channels run on the outer edges of the kidney shaped ports, the hydrostatic bearing recesses disposed on the radially outer side of the kidney shaped ports provide improved hydrostatic support and lubrication between the cylinder head foot and the valve segment. According to the invention, these hydrostatic bearing recesses are preferably arranged in regions of the valve segment which are loaded with the highest loads during operation of the hydraulic axial piston unit. These regions carrying the highest loads are normally located at about half the circumferential path of the kidney shaped ports or at half the circumferential distance between the outer dead center and the inner dead center of the reciprocating moving working pistons in the cylinder bores.

In a first embodiment of the invention, a hydrostatic Abstützlagerausnehmung in the central region of the circumferential length of each kidney-shaped connection is performed at each port at least on the radially outer side. In a further embodiment, more than one hydrostatic bearing recess are arranged, preferably an odd number of hydrostatic bearing recesses equidistant from that of the hydrostatic bearing recess, which is arranged in the circumferential center of a kidney-shaped connection. In first experiments with the inventive concept it was found that 3 to 7 Bearing recesses disposed on the outside of each kidney-shaped port give a reasonable result for the reduction of frictional forces and abrasion between a base of the cylinder block and the sliding surface of a valve segment or valve plate.

It will be apparent to one of ordinary skill in the art that any number of hydrostatic bearing recesses are applicable depending on the geometric conditions and performance conditions for which the hydrostatic axial piston unit is designed. Therefore, it is just as obvious that the hydrostatic bearing recesses according to the invention can be arranged on each side of the kidney-shaped connections, i. also on the inner edge of these connections. Since the largest effect according to the invention of the hydrostatic bearing recesses is achieved with hydrostatic bearing recesses which are arranged on the high-pressure side kidney-shaped connection, it is not sufficient for an axial-piston hydraulic unit which is operated only in one direction of rotation, the hydrostatic bearing recesses according to the invention only on the high-pressure side of a valve segment to achieve more stable load and friction conditions between the valve segment and the cylinder block. Therefore, bi-directionally running hydraulic axial piston unit according to the invention incorporation of hydrostatic bearing recesses should be performed according to the invention on both kidney-shaped connections of the valve segment or the valve plate, since the suction port and the discharge port change with a change of direction of rotation.

One of ordinary skill in the art will readily recognize that the opening size and depth of the bearing recesses depend on the intended use and performance of the axial piston hydraulic unit. It is further conceivable to use different sizes of bearing recesses in a valve segment / valve plate at the same time, e.g. the largest bearing recess in the circumferential center region of the kidney-shaped connection and decreasing size of the bearing recesses in the valve segment in the direction of the regions which correspond to the dead centers of the working piston movement.

Although an odd number of bearing recesses on the kidney-shaped connections of the valve segment or the valve plate is preferred, one of ordinary skill in the art will recognize that an even number of bearing recesses are also applicable within the meaning of the invention. Since the bearing recesses according to the invention at the outer radial peripheral edges of the suction port and / or the Abführanschlusses, i. of the high-pressure port and / or the low-pressure port are arranged, the opening (s) of the bearing recesses facing the cylinder block are arranged in a region outside the fluid channel openings, so that they have a hydrostatic bearing effect on the components involved, i. for the cylinder block / bearing plate base and the valve segment or valve plate sliding surface. As previously noted, the cylinder block base may be formed by a bearing plate secured to the cylinder block base. The bearing plate rotates with the cylinder block. As also previously noted, the hydrostatic bearing recesses effectively provide a bearing effect of the cylinder block / bearing plate on the valve segment or on the valve plate when such plate is secured to the valve segment, thereby providing improved robustness of the valve segment and thus for the entire hydraulic axial piston unit becomes. At the same time, frictional forces and wear between the cylinder block and the valve segment are reduced because hydrostatic bearing areas are formed between the valve segment sliding surface and the bottom surface of the cylinder block. Further, the distance / gap between the cylinder block and the valve segment does not vary as much in the circumferential direction as between valve segments and cylinder blocks known in the art.

Heretofore, the invention has generally been described for an embodiment which introduces hydrostatic bearing recesses into the sliding surface of a valve segment or valve plate secured to the valve segment to provide a bearing and / or friction effect between the surfaces which move relative to one another achieve. The same bearing and lubrication effect for solving the underlying object of the invention is also achieved - according to the embodiment of claim 11 - by introducing the hydrostatic bearing recesses on the bottom surface of the cylinder block. Here, the hydrostatic bearing recesses according to the invention extend radially outwardly from the edges of the openings formed by the fluid channels in the cylinder block base. In this case, each hydrostatic bearing recess intersects with one of the openings and is thereby fluidly connected to the fluid channels in the cylinder block for supplying and discharging hydraulic fluid to and from the cylinder bores in the cylinder block.

The hydrostatic bearing recesses preferably extend radially outwardly with respect to the axis of rotation of the cylinder block, but preferably do not extend outside the outer sealing contour surrounding the openings in the bottom surface of the cylinder block. In this case, just as for the embodiment having the hydrostatic bearing recesses on the sliding surface of the valve segment, that the hydrostatic Bearing recesses may have a partially spherical, conical or cylindrical shape, which show a rounded or beveled radial end, wherein the depth of the hydrostatic bearing recesses decreases preferably in the radial outward direction perpendicular to the rotational direction of the cylinder block.

In a further embodiment according to the invention, the hydrostatic bearing recesses formed in the cylinder block bottom surface or in the bearing plate bottom surface may be fluidly connected to adjacent hydrostatic bearing recesses by means of a hydrostatic bearing groove extending circumferentially on the corresponding surface and at least two hydrostatic bearing recesses with each other combines.

Analogous to the previously described embodiment of attaching a friction reducing valve plate to the valve segment having a sliding surface, attaching a bearing plate in the cylinder block root area made of, for example, bronze or a bi-metal material or any other friction reducing material, a bearing plate can be attached to the cylinder block, which rotates with the cylinder block. When such a bearing plate is used, the hydrostatic bearing recesses according to the invention are introduced onto the surface, which faces the valve segment and thereby forms the bottom surface of the cylinder block. It will be apparent to one of ordinary skill in the art that this bottom surface may exhibit a planar or spherical configuration, depending on the general configuration of the hydrostatic axial piston unit in which the invention is to be used.

In general, the invention can be applied to all types of hydraulic axial piston units, whether they are of the swash plate type or the oblique axis type. In this case, the hydrostatic bearing recesses according to the invention can be applied either to the sliding surface on the valve segment or on the valve plate which is attached to the valve segment, or on the base of the cylinder block or on a bearing plate which is fixed to the cylinder block. From this, the relevant expert readily deduces that the invention can also be applied to replacement parts for already existing hydraulic axial piston units or engines of such hydraulic axial piston units, in particular those of the oblique axis type.

• 1 einen Querschnitt einer hydraulischen Axialkolbeneinheit der Schrägachsenbauweise;
• 2 einen Querschnitt einer hydraulischen Axialkolbeneinheit der Schrägscheibenbauart;
• 3 eine Draufsicht auf ein Ventilsegment gemäß dem Stand der Technik;
• 4 eine dreidimensionale Ansicht eines Ventilsegments gemäß der Erfindung;
• 5 eine Detailansicht des Ventilsegments der 4;
• 6 eine weitere Ausführungsform des Ventilsegments der 4 in einer detaillierten Ansicht;
• 7 eine Draufsicht auf eine Grundfläche eines Zylinderblocks gemäß der Erfindung;

In the following figures, exemplary embodiments of hydraulic axial piston units having a valve segment or cylinder block according to the invention are shown in further detail, but the invention is not limited to these embodiments. All features of the described and illustrated embodiments may be combined in any desired combination with each other within the scope of the invention. Show it:

• 1 a cross section of a hydraulic axial piston unit of the bent-axis design;
• 2 a cross section of a hydraulic axial piston unit of the swash plate type;
• 3 a plan view of a valve segment according to the prior art;
• 4 a three-dimensional view of a valve segment according to the invention;
• 5 a detailed view of the valve segment of the 4 ;
• 6 a further embodiment of the valve segment of the 4 in a detailed view;
• 7 a plan view of a base of a cylinder block according to the invention;

1 shows a hydraulic axial piston unit 1 the Schrägachsenbauart, comprising a cylinder block 3 with a rotation axis 5 , In a variety of cylinder bores 8th , which are circumferentially parallel about the axis of rotation 5 arranged, can be working piston 4 move reciprocally. As a result, due to the angle between the axis of rotation 5 and the axis of a shaft 6 leads each working piston 4 a (complete) stroke within the corresponding cylinder bore 8th out (see also 2 ). At the bottom of the cylinder block 3 ie at the far end of the cylinder block 3 which is from the wave 6 is a valve segment 2 rotationally fixed with respect to the axis of rotation 5 arranged, which together with the cylinder block 3 to different displacement volume of the hydraulic axial piston unit 1 can be pivoted. In the bent axis hydraulic axial piston unit 1 according to the 1 is between the valve segment 2 and the cylinder block 3 a bearing plate 20 on the cylinder block 3 attached, which with the cylinder block 3 rotates, allowing frictional forces during operation of the hydraulic piston unit 1 between the valve segment 2 and the bearing plate 20 occur. Because the bearing plate 20 Usually made of bi-metal material such as bronze, has the bearing plate 20 a lower friction index and a better wear resistance than the commonly used steel or the casting material of the cylinder block 3 , Bronze is often a preferred material for the bearing plate 20 to avoid feeding problems between the two surfaces that rub against each other. Of course, forms a valve plate 10 instead of the bearing plate 20 , which on the valve segment 2 attached, an alternative embodiment for a friction-reduced combination of a valve segment 2 and a cylinder block 3 for bent axis hydraulic axial piston units 1 according to 1 ,

During operation of the hydraulic axial piston unit 1 Hydraulic fluid is added to and from the cylinder bores 8th of the cylinder block 3 over the valve segment 2 supplied or removed. For this purpose, the valve segment shows 2 two kidney-shaped connections 11 . 21 in the circumferential direction with respect to the axis of rotation 5 run (see also 4 to 6 ). As in more detail with the swash plate hydraulic axial piston unit 1 according to the 2 As shown, these kidney-shaped ports are via fluid channels 35 in the bearing plate 20 in fluid communication with cylinder bores 8th of the cylinder block 3 ,

Analogous to 1 shows 2 a swash plate type hydraulic axial piston unit comprising a cylinder block 3 with a rotation axis 5 , which in this case concentric with the axis of the shaft 6 is. Inside the cylinder block 3 are working pistons 4 in cylinder bores 8th arranged and can move in the direction of the axis of rotation 5 move reciprocally. The reciprocal stroke of the working piston 4 is done by pivoting the swash plate 30 allows. On the swash plate 30 are the heads of the working pistons 4 in the axial and radial directions with respect to the axis of rotation 5 fixed, but rotation-free in the circumferential direction. Thus, every working piston leads 4 a complete stroke during a complete revolution of the cylinder block around the axis of rotation 5 out. Between the cylinder block 3 and an end plate 33 of the housing 40 is a valve segment 2 arranged stationary with the housing to hydraulic fluid to and from the cylinder bores 8th in the cylinder block 3 via fluid channels 36 to direct the openings 35 in the bearing plate 20 with the cylinder bores 8th in the cylinder block 3 connect.

In an alternative embodiment, the bearing plate 20 which - according to the embodiment of the 2 - on the cylinder block 3 is attached, through a valve plate 20 , which on the valve segment 2 is attached, replaced. In the latter embodiment, the sliding surface would 7 on the side of the valve plate 10 change which of the floor area 9 of the cylinder block 3 which now faces the surface of the cylinder block 3 is that of the valve plate 10 is facing. In both embodiments, the valve plate 10 as well as the bearing plate 20 preferably made of a bi-metal or bronze to friction between the sliding surface 7 and the floor area 9 to reduce.

An example of such a valve segment 2 according to the prior art CN 104 776 018 that was previously on page 3 was mentioned in is 3 shown, and shows a valve segment 2 for a hydraulic axial piston unit, which is drivable only in the direction of rotation ω. The valve segment 2 according to the prior art has kidney-shaped connections 11 . 21 on, with the kidney-shaped connection 11 on the left side of the 3 an oil discharge outlet for discharging pressurized oil from the cylinder bores (not shown). On the other side, the right side, is a non-symmetrical, kidney-shaped inlet port 21 with radially aligned straight control edges 15 . 16 at the beginning and at the end of the inlet connection 21 shown. η-shaped grooves extend from the discharge port 11 to the radially outer side of the valve segment 2 to provide fluid dynamic pressure lubrication and leaks between the valve segment 2 and reduce the cylinder block, not shown. With these one-sided η-shaped grooves, a hydrostatic support is achieved only on the high pressure side, wherein the pressure load on the low pressure side is increased here the right side in 3 ,

4 shows an embodiment of a valve segment according to the invention, which two rotationally symmetrical shaped kidney-shaped connections 11 . 21 shows. The rotationally symmetrical configuration enables the use of the valve segment according to the invention 2 in Hydraulikaxialkolbeneinheiten that are operable in both directions. On the corresponding outer sides of the kidney-shaped connections 11 . 21 are hydrostatic bearing recesses 50 arranged to provide a hydrostatic support of the bearing forces between a cylinder block 3 and a valve segment 2 provide. Preferably, the inventive arrangement of these hydrostatic bearing recesses 50 on both kidney-shaped connections 11 and 21 an effective compensation of the tilting moment of the cylinder block during the operation of the hydraulic axial piston unit. In the embodiment shown in FIG 4 shown are the hydrostatic bearing recesses 50 in the circumferential center regions of the kidney-shaped connections 11 and 21 arranged, ie in areas of highest pressure forces during operation of a hydraulic axial piston unit 1 ,

5 is a detailed view of the left kidney-shaped port 11 of the 4 which shows in detail that the radially outer edge 52 hydrostatic bearing recesses 50 not radially beyond the outer sealing contour 14 of the valve segment 2 goes out. Consequently, it is possible according to the invention, a hydrostatic support within the sealing contour of the outer sealing contour and the inner sealing contour 13 to generate a pressure force balance between the inlet side and the outlet side of the valve segment 2 a hydrostatic axial piston pump 1 to create.

In 6 a further embodiment of the hydrostatic bearing recesses according to the invention is shown. Here are adjacent hydrostatic bearing recesses 50 fluidly with each other via hydrostatic bearing grooves 55 within the radially outer sealing contour 14 of the valve segment 2 connected. Here, the hydraulic pressure is uniform over all hydrostatic bearing recesses 50 on the sliding surface 7 of the valve segment 2 distributed.

In particular of the 5 and 6 A person skilled in the art derives that the hydrostatic bearing recesses 50 according to the invention along the entire outer or inner edge 12 or 22 the kidney-shaped connections 11 and 21 can be distributed to the hydrostatic storage conditions between the rotating cylinder block and the stationary valve segment 2 to improve. A person skilled in the art further recognizes from these figures that the hydrostatic bearing recesses 50 may have a concave, spherical or cylindrical or any other concave shape, wherein they are within the sealing contours 13 . 14 High or low pressure hydraulic fluid to areas of the sliding surface between the valve segment 2 and the cylinder block 3 which are not supplied or supported in the prior art with hydrostatic pressure.

7 shows a further embodiment according to the invention, for example, a hydraulic axial piston unit 1 , in the 2 is shown. Shown is a floor area 9 a cylinder block 3 comprising a plurality of cylinder bores 8th , each of which has fluid channels 36 with openings 35 in the floor area 9 of the cylinder block 3 are fluidically connected. A plurality of hydrostatic bearing recesses according to the invention 50 is in a floor space 9 of the cylinder block 3 or in a bearing plate 10 introduced, the rotation with the cylinder block 3 connected is. This can be the bottom surface 9 show a planar or spherical configuration. Each of the plurality of concave shaped hydrostatic bearing recesses 15 extends radially from the outer edge 37 the openings 35 and cuts with one of the openings 35 , The hydrostatic bearing recesses are preferred 50 within an outer sealing contour 14 that the openings 35 surrounds, trained.

As before with the explanations to 4 executed - the embodiment of the hydrostatic bearing grooves according to the invention in the sliding surface 7 of the valve segment 2 - can the hydrostatic bearing recesses in the bottom surface 9 of the cylinder block 3 also have a partially spherical, conical or tubular shape with a rounded or beveled radially outer end 52 , In this case, the depth of the hydrostatic bearing recesses 15 in the radial outward direction perpendicular to the axis of rotation 5 lose weight.

In 7 is shown - in an analogous way as in 6 - that adjacent hydrostatic bearing recesses 50 fluidly with each other by means of a hydrostatic bearing groove 55 can be connected.

Especially with the embodiments of 4 and 7 The person skilled in the art derives that the hydrostatic bearing recesses according to the invention either in the bottom surface of the cylinder block 3 or in the sliding surface 7 of the valve segment 2 can be introduced. The same applies if on the corresponding cylinder block 3 or on the valve segment 2 a bearing plate 20 or a valve plate 10 attached to it. A person skilled in the art will further recognize, in particular 4 in that the hydrostatic bearing recesses according to the invention 50 also on an engine 60 applied, for example comprising a valve segment 2 , a bearing plate 10 , a cylinder block 3 with working pistons arranged therein 4 and a wave 6 , Such a person skilled in the art will readily appreciate from these embodiments that the invention also relates to spare parts for valve segments 2 , Valve plates 10 , Cylinder blocks 3 and / or bearing plates 20 is applicable.

Finally, one of ordinary skill in the art will readily appreciate these explanations that the invention also applies to replacement parts for valve segments 2 , Valve plates 10 , Cylinder blocks 3 and / or bearing plates 20 is applicable.

LIST OF REFERENCE NUMBERS

1

Hydraulic axial piston unit

2

valve segment

3

cylinder block

4

working piston

5

axis of rotation

6

wave

7

sliding surface

8th

bore

9

floor area

10

valve plate

11

first kidney-shaped connection

12

outer edges

13

inner seal contour

14

outer sealing contour

15

Initial control edge

16

closing control edge

20

bearing plate

21

second kidney-shaped connection

22

inner edge

30

swash plate

32

Foot area cylinder block

33

endplate

35

openings

36

liquid channels

37

outer edge

40

casing

50

hydrostatic bearing recess

52

radially outer end

55

bearing groove

60

engine

100

η-shaped grooves

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• CN 104776018 [0006, 0025]

Claims (19)

A hydraulic axial piston unit (1) valve segment (2) comprising a kidney shaped first port (11) and a kidney shaped second port (21) formed in the valve segment (2) to define a supply port and a discharge port for supplying and discharging To provide hydraulic fluid to and from openings (35) of fluid channels (36) in a cylinder block (3) of a hydraulic axial piston unit (1), characterized in that - the first port (11) and the second port (21) are rotationally symmetrical with respect to a rotational axis ( 5) of a cylinder block (3) are formed, - a plurality of concave hydrostatic bearing recesses (50) from the radially outer edges (12, 22) of the first terminal (11) and the second terminal (21) on a sliding surface (7 ) of the valve segment (2), and - each of the plurality of hydrostatic bearing recesses (50) has the first port (11) or the second port cut (21). Valve segment (2) after Claim 1 wherein the hydrostatic bearing recesses (50) are formed within an outer sealing contour (14) surrounding the first port (2) and the second port (21). After valve segment Claim 1 or 2 wherein the hydrostatic bearing recesses (50) have a partially spherical, conical or cylindrical shape having a rounded or bevelled radial outer end (52). Valve segment (2) according to one of the preceding claims, wherein the depth of the hydrostatic bearing recesses (50) decreases in the radial outward direction perpendicular to the axis of rotation (5). Valve segment (2) according to one of the preceding claims, wherein the sliding surface (7) is arranged on a valve plate (10) which is fastened to the valve segment (2). A valve segment (2) according to any one of the preceding claims, wherein adjacent hydrostatic bearing recesses (50) associated with one of the first port (11) and the second port (21) are in fluid communication with each other by means of a hydrostatic bearing groove (55). Valve segment (2) according to one of the preceding claims, wherein an odd number of hydrostatic bearing recesses (50) with the first port (11) or the second port (21) is associated. Valve segment (2) according to one of the preceding claims, wherein hydrostatic bearing recesses (50) are also arranged on the inner edge of the first terminal (11) and / or the second terminal (21). Valve segment (2) according to one of the preceding claims, wherein the valve segment (2) shows a planar or a spherical configuration. Hydraulic axial piston unit (1), comprising a valve segment (2) according to one of Claims 1 to 9 , Cylinder block (3) for a hydraulic axial piston unit (1), comprising a plurality of cylinder bores (8) arranged around a rotation axis (5) and fluidly via fluid channels (36) with openings (35) in a base (9) of the cylinder block ( 3) are connected, wherein the openings (35) for supplying and discharging hydraulic fluid to and from the cylinder bores (8) are provided, characterized in that - on the base (9) a plurality of concave hydrostatic bearing recesses (50 ) extends from the outer edges (37) of the openings (35) and - each of the plurality of hydrostatic bearing recess (50) intersects one of the openings (35). Cylinder block (3) after Claim 11 wherein the hydrostatic bearing recesses (50) are formed within an outer sealing contour (14) surrounding the openings (35). Cylinder block (13) after one of Claims 11 or 12 wherein the hydrostatic bearing recesses (50) have a partially spherical, conical or cylindrical shape having a rounded or bevelled radial outer end (52). Cylinder block after one of the Claims 11 to 13 , wherein the depth of the hydrostatic bearing recesses (50) decreases in the radial outward direction perpendicular to the axis of rotation (5). Cylinder block (3) after one of Claims 11 to 14 wherein adjacent hydrostatic bearing recesses (50) are fluidly interconnected by means of a hydrostatic bearing groove (55). Cylinder block (3) after one of Claims 11 to 15 , wherein the base (9) on a bearing plate (20) is arranged, which is non-rotatably mounted on the cylinder block (3). Cylinder block (3) after one of Claims 11 to 15 , wherein the base (9) shows a planar or spherical configuration. Hydraulic axial piston unit (1), comprising a cylinder block (3) according to one of Claims 11 to 17 , An engine for a hydraulic axial piston unit (1) of the bent-axis design, comprising a cylinder block (3) according to one of Claims 11 to 17 ,

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