DE102019217204A1 - Axial piston machine with drive shaft mounted in the distributor plate - Google Patents

Abstract

The invention relates to an axial piston machine (10) in swash plate design with a housing (30), a drive shaft (20), a cylinder drum (23) and a distributor plate (40; 40 '), the drive shaft (20) being connected to a first and a second Bearing point (21; 22) is mounted rotatably with respect to an axis of rotation (11), the cylinder drum (23) being arranged between the first and the second bearing point (21; 22), the cylinder drum (23) rotatably connected to the drive shaft (20) is connected, wherein the distribution plate (40; 40 ') is arranged between the cylinder drum (23) and the housing (30), so that the cylinder drum (23) in the direction of the axis of rotation (11) over the distribution plate (40; 40') is supported on the housing (30), the distribution plate (40; 40 ') being non-rotatably connected to the housing (30) with respect to the axis of rotation (11). According to the invention, the drive shaft (20) at the second bearing point (22) is radial to the axis of rotation (11) exclusively on the distribution plate (40; 40 ' ) supported, the distribution plate (40; 40 ') is supported on the housing (30) radially to the axis of rotation (11).

Description

The invention relates to an axial piston machine according to the preamble of claim 1.

From the DE 196 10 595 C1 an axial piston machine in swash plate design is known. The drive shaft is rotatably supported with respect to an axis of rotation by means of two tapered roller bearings which define a first and a second bearing point. Furthermore, a separate distribution plate is arranged between the cylinder drum and the housing, which serves to reduce wear.

One advantage of the present invention is that the axial piston machine can be operated with a high speed of the drive shaft. In particular, the orifices of the cylinder bores can be arranged very close to the axis of rotation, so that there a comparatively low centrifugal force acts on the pressure fluid there even at a high speed. In the above axial piston machine, this is not possible because the pivot bearing in the area of the mouth openings prevents a corresponding displacement of the mouth openings of the cylinder bores radially inward.

According to claim 1, it is proposed that the drive shaft is supported at the second bearing point, radially to the axis of rotation, exclusively on the distribution plate, the distribution plate being supported on the housing radially to the axis of rotation. The non-rotatable connection between the drive shaft and the cylinder drum is preferably established by means of a splined shaft toothing. The first and / or the second bearing point can be designed as roller bearings or slide bearings. The rotation lock between the distribution plate and the housing can take place, for example, with a cylinder pin, the cylinder pin engaging both in the distribution plate and in the housing away from the axis of rotation. It is also conceivable that the distribution plate is firmly connected to the housing via a press fit. The press fit can be designed, for example, in the manner of a cylindrical press fit. The axial piston machine is preferably operated with a pressure fluid, which is most preferably a liquid, in particular hydraulic oil.

Advantageous developments and improvements of the invention are specified in the dependent claims.

It can be provided that the drive shaft is supported at the second bearing point radially on the inside with respect to the axis of rotation on the distribution plate, the distribution plate being supported on the housing radially outside with respect to the axis of rotation. The distribution plate is preferably designed in the shape of a ring with respect to the axis of rotation. In this way, the mouth openings of the cylinder bores can be arranged particularly close to the axis of rotation.

It can be provided that the second bearing point is designed in the form of a sliding bearing, a corresponding sliding surface being formed directly by an outer surface of the distribution plate, the distribution plate being made in one piece. The distribution plate is preferably made of brass or bronze or a comparable plain bearing material. The bearing surface is preferably designed as a circular cylinder with respect to the axis of rotation. This embodiment makes use of the fact that the distribution plate typically consists of a plain bearing material. The distribution plate can therefore easily form a slide bearing for the drive shaft without the need for special bearing rings. The plain bearing therefore requires particularly little installation space in the radial direction. In this way, the mouth openings of the cylinder bores can be arranged particularly close to the axis of rotation.

It can be provided that the second bearing point is designed in the form of a needle bearing, with a corresponding running surface for corresponding needle-shaped rolling elements being formed directly by the distributor plate. In this way, a particularly compact roller bearing can be created for the drive shaft, so that the mouth openings of the cylinder bores can be arranged particularly close to the axis of rotation. The second bearing is preferably designed as a floating bearing, the first bearing being designed as a fixed bearing.

It can be provided that the distribution plate consists of steel which is hardened at least in the area of the running surface, the distribution plate having a coating towards the cylinder drum which consists of a plain bearing material. This means that both the rolling engagement at the second bearing point and the sliding engagement between the cylinder drum and the distributor plate have a long service life. A plain bearing material is to be understood as meaning, in particular, brass or bronze. The coating can be applied to the remaining distribution plate, for example, using the laser coating process or the flame spraying process.

It can be provided that the second bearing point is designed in the form of a sliding bearing, a corresponding sliding surface being formed by a separate bearing bush which is firmly connected to the remaining distribution plate. The bearing bush is preferably pressed into the remaining distribution plate. It preferably consists of a plain bearing material such as brass or bronze. The bearing bush preferably has one circular cylindrical inner peripheral surface, which forms the sliding surface, and a circular cylindrical outer peripheral surface, which rests on the remaining distribution plate.

It can be provided that the distribution plate is received in the housing with a press fit radially with respect to the axis of rotation. The press fit can be so strongly tensioned that it forms a non-rotatable connection between the distribution plate and the housing. However, it is also conceivable that a form-fitting anti-rotation device is additionally provided, for example using a cylindrical pin.

It can be provided that the distribution plate has, radially on the outside, a holding surface which is circularly cylindrical with respect to the axis of rotation and which rests against an adapted counter-holding surface on the housing. In this way, precise alignment of the distribution plate can be achieved in a simple manner. In particular, the position of the axis of rotation at the second bearing point is precisely defined.

It can be provided that the distribution plate is provided with recesses adjacent to the second bearing point in such a way that the rotary bearing can be elastically deformed in the region of the second bearing point. In particular, a tilting movement of the drive shaft relative to the axis of rotation should be possible at the second bearing point. This tilting movement is caused by a bending deformation of the drive shaft by the forces acting during operation of the axial piston machine. The drive shaft should be able to be rigidly supported at the second bearing point radially to the axis of rotation. With regard to the support in the direction of the axis of rotation, the second bearing point can be designed as a fixed or loose bearing, with a rigid support being preferred in the first case.

It can be provided that the housing is composed of a first and a separate second housing part, the distribution plate being supported directly on the second housing part in the direction of the axis of rotation and / or radially to the axis of rotation, the drive shaft at the first bearing point being radially to the axis of rotation on first housing part is supported. The first housing part is preferably designed like a pot, an open side of the first housing part being covered by the second housing part. The first and the second housing part are preferably firmly connected to one another, most preferably screwed to one another. The second housing part is preferably provided with a first and a second fluid connection, it being possible to generate a fluid flow between the first and the second fluid connection by rotating the cylinder drum. Said fluid flow is preferably passed through openings in the distribution plate running in the direction of the axis of rotation.

It can be provided that the distribution plate is penetrated by at least one opening in the direction of the axis of rotation, the smallest distance between the at least one opening and the drive shaft being between 10% and 50% of the diameter of the drive shaft there. With the design described above, particularly high speeds can be achieved, since particularly small centrifugal forces act on the pressure fluid exchanged between the cylinder drum and the distributor plate. This design cannot be achieved with a conventional axial piston pump in which the drive shaft is mounted in the second housing part. This is only possible with the axial piston pump according to the invention. The central axes of the pistons or the cylinder bores are preferably arranged inclined between 5 ° and 20 ° to the axis of rotation so that the above-mentioned distance can be achieved, while at the same time the cylinder drum is sufficiently strong.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or on their own, without departing from the scope of the present invention.

• 1 einen grobschematischen Längsschnitt einer erfindungsgemäßen Axialkolbenmaschine; und
• 2 einen grobschematischen Längsschnitt einer zweiten Ausführungsform einer erfindungsgemäßen Verteilplatte und der Antriebswelle.

The invention is explained in more detail below with reference to the accompanying drawings. It shows:

• 1 a roughly schematic longitudinal section of an axial piston machine according to the invention; and
• 2 a roughly schematic longitudinal section of a second embodiment of a distribution plate according to the invention and the drive shaft.

1 shows a roughly schematic longitudinal section of an axial piston machine according to the invention 10 . The axial piston machine 10 includes a housing 30th , which consists of a first and a second housing part 31 ; 32 is composed. The first housing part 31 is pot-shaped, with its open side from the second housing part 32 is covered fluid-tight. The first and second housing parts 31 ; 32 are firmly connected to each other, and they are preferably screwed. On the second part of the housing 32 is a first and a second fluid connection 33 ; 34 arranged, which is why the second housing part 32 is also referred to as a connection plate.

In the case 30th is a drive shaft 20th at a first and a second bearing point 21st with respect to an axis of rotation 11 rotatably mounted. The first depository 21st is from the bottom of the pot-like first housing part 31 educated. It can be designed as a slide or roller bearing. In the field of first depository 21st the drive shaft protrudes 20th with a drive pin 26th out of the case 30th out. The drive journal 26th can be provided with a feather key or with a splined shaft so that a rotary drive connection, for example with an electric motor (not shown), can be established.

Inside the case 30th is between the first and the second bearing point 21st ; 22nd a cylinder drum 23 recorded which is the drive shaft 20th surrounds, with it with respect to the axis of rotation 11 is rotatably connected. This can be done between the cylinder drum 23 and the drive shaft a (roughly schematically shown) spline shaft toothing 27 be provided. The cylinder drum 23 and the drive shaft 20th can also be formed integrally with one another. In the cylinder drum 23 are multiple pistons 25th in a respectively assigned cylinder bore 29 recorded linearly movable. The axis of movement of the pistons 25th is present inclined to the axis of rotation 11 arranged so that the mouth openings 28 of the cylinder bores 29 as close as possible to the axis of rotation 11 are arranged. In this way, particularly low centrifugal forces act on the pressure fluid flowing there. The axial piston machine 10 can subsequently be operated at a particularly high speed. Preferably there are multiple pistons 25th provided, which most preferably uniformly distributed around the axis of rotation 11 are arranged around.

At her first camp 21st facing end are the pistons 25th on a swivel cradle 50 supported. The swivel cradle 50 can with respect to a pivot axis 51 be pivotably mounted, the pivot axis 51 perpendicular to the axis of rotation 11 is aligned. The swivel cradle 50 but can also be fixed in the housing 30th be arranged. A hydraulic actuating cylinder is preferred 52 provided, means of which the rotary position of the swivel cradle 50 with respect to the pivot axis 51 is adjustable to the stroke volume of the axial piston machine 10 adjust.

The pistons 25th can with a hemispherical end directly on the swivel cradle 50 issue. Separate sliding blocks are preferably used at this point, each of which has a ball joint with the associated piston 25th are connected, whereby they are connected to the swivel cradle via a hydrostatic pressure field 50 are supported. In the area of contact with the pistons 25th is the swivel cradle 50 preferably flat, with the corresponding plane parallel to the pivot axis 51 is arranged.

Between the cylinder drum 23 and the second housing part 32 is a separate distribution plate 40 arranged. The distribution plate 40 is in the present case designed in one piece, consisting of a plain bearing material such as bronze or brass. The distribution plate 40 is in the direction of the axis of rotation 11 on the first housing part 31 supported, the cylinder drum 23 in the direction of the axis of rotation 11 on the distribution plate 40 is supported. The distribution plate 40 is with respect to the axis of rotation 11 non-rotatably with the first housing part 31 connected, being between the cylinder drum 23 and the distribution plate 40 a relative rotation takes place. Between the cylinder drum 23 and the distribution plate 40 A hydrostatic pressure field can be provided so that the wear there is particularly low. The contact area between the cylinder drum 23 and distribution plate 40 can be spherical as shown, a flat contact surface is also possible.

The second depository 22nd becomes of a sliding surface 43 on the distribution plate 40 Are defined. The sliding surface 43 is circular cylindrical with respect to the axis of rotation 11 formed, the drive shaft 20th on the sliding surface 43 is slidably rotatably mounted. Preferably there is a one-piece drive shaft 20th directly on the sliding surface 43 at. Radial with respect to the axis of rotation 11 is the drive shaft 20th at the second storage location 22nd exclusively on the distribution plate 40 supported. The distribution plate 40 is radial with respect to the axis of rotation 11 on its outer peripheral surface on the second housing part 32 supported. The corresponding holding surface 41 on the distribution plate 40 is circular cylindrical with respect to the axis of rotation 11 formed, whereby they are on an adapted counter-holding surface 35 in the second housing part 32 is applied. The holding surface 41 can under tension on the counter-holding surface 35 so that a cylindrical interference fit results. This type of bearing design enables the mouth openings 28 of the cylinder bores 29 particularly close to the drive shaft 20th move closer. The pressure fluid flowing there is accordingly exposed to particularly low centrifugal forces.

The mentioned mouth openings 28 stand breakthroughs 46 in the distribution plate 40 opposite, which are designed in a known manner so that each cylinder bore 29 during one revolution of the cylinder drum 23 periodically changing, either with the first or with the second fluid connection 33 ; 34 connected is. Typically a single such period occurs during one revolution. The cross-sectional shape of the mouth openings 28 is typically different from the, preferably circular, cross-sectional shape of the cylinder bores 29 executed. In particular, the cross-sectional area of the mouth openings 28 preferably smaller than the cross-sectional area of the cylinder bores 29 so that there is a hydraulic pressure on the cylinder drum 23 to the distribution plate 40 results.

2 shows a roughly schematic longitudinal section of a second embodiment of a distribution plate according to the invention 40 ' and the drive shaft 20th . With the exception of the differences described below, the second embodiment of the axial piston machine is designed identically to the first embodiment, so that the explanations relating to it 1 is referred. In the 1 and 2 Identical or corresponding parts are marked with the same reference numerals.

In the second embodiment, instead of the plain bearing at the second bearing point 22nd a roller bearing is provided. This is designed in the manner of a needle bearing so that it requires particularly little installation space in the radial direction. The corresponding rolling elements 24 are circular-cylindrical, their length in the direction of the axis of rotation 11 is considerably larger than its diameter. The rolling elements roll radially on the outside 24 on a tread 44 from, preferably directly from the distribution plate 40 ' is formed. The distribution plate 40 ' is preferably made of steel, at least in the area of the tread 44 is hardened. To the cylinder drum (No. 23 in 1 ) is the distribution plate 40 ' preferably with a coating 45 provided, which consists of a plain bearing material such as bronze or brass. The coating can be applied to the remaining distribution plate using the laser coating process or the flame spraying process 40 ' be applied.

Next is the recesses 42 to be pointed out, which is also used in connection with the in 1 Shown plain bearings can be used. Through the recesses 42 in the distribution plate 40 ' the latter is weakened so that it is in the area of the second bearing point 22nd is deformable. The corresponding pivot bearing can therefore cause a bending deformation of the drive shaft 20th elastically compensate by tilting it a little. The recesses 42 are designed so that the pivot bearing in the radial direction with respect to the axis of rotation 11 has a largely undiminished load-bearing capacity and rigidity.

List of reference symbols

10

Axial piston machine

11

Axis of rotation

20th

drive shaft

21st

first depository

22nd

second depository

23

Cylinder drum

24

Rolling elements

25th

piston

26th

Drive journal

27

Splines

28

Mouth opening

29

Cylinder bore

30th

casing

31

first housing part

32

second housing part

33

first fluid connection

34

second fluid connection

35

Counter holding surface

40

Distribution plate (first embodiment)

40 '

Distribution plate (second embodiment)

41

Holding surface

42

Recess

43

Sliding surface

44

Tread

45

Coating

46

breakthrough

50

Swivel cradle

51

Swivel axis

52

Adjusting cylinder

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• DE 19610595 C1 [0002]

Claims (11)

Axial piston machine (10) in swash plate design with a housing (30), a drive shaft (20), a cylinder drum (23) and a distribution plate (40; 40 '), the drive shaft (20) at a first and a second bearing point (21; 22) is rotatably mounted with respect to an axis of rotation (11), the cylinder drum (23) being arranged between the first and the second bearing point (21; 22), the cylinder drum (23) being non-rotatably connected to the drive shaft (20), with the distribution plate (40; 40 ') is arranged between the cylinder drum (23) and the housing (30), so that the cylinder drum (23) in the direction of the axis of rotation (11) over the distribution plate (40; 40') on the housing (30 ) is supported, the distribution plate (40; 40 ') being non-rotatably connected to the housing (30) with respect to the axis of rotation (11), characterized in that the drive shaft (20) at the second bearing point (22) is radial to the axis of rotation (11 ) is supported exclusively on the distribution plate (40; 40 '), wherein the distribution plate (40; 40 ') is supported on the housing (30) radially to the axis of rotation (11). Axial piston machine according to Claim 1 , wherein the drive shaft (20) is supported at the second bearing point (22) with respect to the axis of rotation (11) radially inside on the distribution plate (40; 40 '), the distribution plate (40; 40') being radially with respect to the axis of rotation (11) is supported on the outside of the housing (30). Axial piston machine according to one of the preceding claims, wherein the second bearing point (22) is designed in the form of a slide bearing, a corresponding sliding surface (43) being formed directly from an outer surface of the distribution plate (40; 40 '), the distribution plate (40; 40 ') is made in one piece. Axial piston machine according to Claim 1 or 2 , the second bearing point (22) being designed in the form of a needle bearing, a corresponding running surface (44) for corresponding needle-shaped rolling elements (24) being formed directly by the distribution plate (40 '). Axial piston machine according to Claim 4 , wherein the distribution plate (40 ') consists of steel which is hardened at least in the area of the running surface (44), the distribution plate (40') having a coating (45) towards the cylinder drum (23) which consists of a plain bearing material. Axial piston machine according to Claim 1 or 2 , wherein the second bearing point (22) is designed in the form of a slide bearing, a corresponding sliding surface (43) being formed by a separate bearing bush which is firmly connected to the remaining distribution plate (40; 40 '). Axial piston machine according to one of the preceding claims, wherein the distribution plate (40; 40 ') is received in the housing (30) with a press fit radially with respect to the axis of rotation (11). Axial piston machine according to one of the preceding claims, wherein the distribution plate (40; 40 ') has a holding surface (41) which is circular-cylindrical with respect to the axis of rotation (11) and which rests against an adapted counter-holding surface (35) on the housing (30). Axial piston machine according to one of the preceding claims, wherein the distribution plate (40; 40 ') adjacent to the second bearing point (22) is provided with recesses (42) in such a way that the rotary bearing is elastically deformable in the area of the second bearing point (22). Axial piston machine according to one of the preceding claims, wherein the housing (30) is composed of a first and a separate second housing part (31; 32), the distribution plate (40; 40 ') in the direction of the axis of rotation (11) and / or radially to the Axis of rotation (11) is supported directly on the second housing part (32), the drive shaft (20) being supported at the first bearing point (21) radially to the axis of rotation (11) on the first housing part (31). Axial piston machine according to one of the preceding claims, wherein the distribution plate (40; 40 ') is penetrated by at least one opening (46) in the direction of the axis of rotation, the smallest distance between the at least one opening (46) and the drive shaft (20) between 10 % and 50% of the diameter of the drive shaft (20) there.

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