AXIAL PISTON MACHINE

Abstract

The invention relates to an axial piston machine comprising a drive shaft, a driving gear non-rotatably connected thereto with one or more driving gear pistons accommodated therein, whose piston stroke is adjustable by a swash plate, wherein at least one return spring acts on the swash plate and at least one adjusting piston is supported on the swash plate via an adjusting lever, a first and/or second stop is provided for the adjusting piston to limit the swivel angle of the swash plate, wherein a first stop is formed by the bottom of the blind hole within the connecting plate and/or a second stop is formed by a flat protrusion of the housing in the vicinity of the blind hole.

Claims

1. An axial piston machine comprising a drive shaft, a cylinder drum non-rotatably connected thereto and comprising one or more driving gear pistons accommodated therein, whose piston stroke is adjustable by a swash plate, wherein at least one return spring acts on the swash plate and at least one adjusting piston is supported on the swash plate via an adjusting lever, wherein a first and/or second stop is provided for the adjusting piston to limit the swivel angle of the swash plate, wherein a first stop is formed by the bottom of the blind hole within the connecting plate and/or a second stop is formed by a flat protrusion of the housing in the vicinity of the blind hole.

2. The axial piston machine according to claim 1, wherein in every functional position of the adjusting piston the longitudinal axis of the adjusting piston is aligned almost parallel to the drive shaft axis M and that the at least one adjusting piston is guided in a bore in the connecting plate.

3. The axial piston machine according to claim 2, wherein the drive shaft axis M, the longitudinal axis of the adjusting piston and the longitudinal axis of the adjusting lever are located on a plane E1, including on a half-plane E1* proceeding from the drive shaft axis M.

4. The axial piston machine according to claim 3, wherein the drive shaft axis M, the longitudinal axis of the adjusting piston, the longitudinal axis of the adjusting lever and the course of the central axis of the at least one return spring almost are located on a plane E1, including on a half-plane E1* proceeding from the drive shaft axis.

5. The axial piston machine according to claim 3, wherein the drive shaft axis M, the longitudinal axis of the adjusting piston, the longitudinal axis of the adjusting lever, the course of the central axis of the at least one return spring and the central axis of a control or regulating valve almost are located on a plane E1, including on a half-plane E1* proceeding from the drive shaft axis.

6. The axial piston machine according to claim 5, wherein the control or regulating valve is arranged coaxially to the adjusting piston and/or that the control or regulating valve is located in the same housing part as the adjusting piston.

7. The axial piston machine according to claim 6, wherein the drive shaft axis M, the longitudinal axis of the adjusting piston, the longitudinal axis of the adjusting lever, the course of the central axis of the at least one return spring and the central axis of a control or regulating valve almost are located on a plane E1, including on a half-plane E1* proceeding from the drive shaft axis, and the plane E1 or the half-plane E1* extends almost centrally with respect to the swash plate bearing.

8. The axial piston machine according to claim 7, wherein the adjusting lever provides for approximately parallel functional positions relative to the drive shaft axis M and/or approximately coaxial functional positions relative to the adjusting piston axis.

9. The axial piston machine according to claim 1, wherein the adjusting lever is configured rotationally symmetrical and/or mirror-symmetrical to a transverse axis of the adjusting lever.

10. The axial piston machine according to claim 2, wherein the adjusting lever has a spherical end region on both sides, wherein a spherical end region forms a ball joint connection with a spherical recess in the adjusting piston, and the spherical end region of the adjusting lever protrudes into the interior of the adjusting piston at least up to its equator and beyond its equator.

11. The axial piston machine according to claim 10, wherein at least in the contact region of the ball joint connections with the adjusting piston and the pivot cradle the adjusting lever undergoes a surface treatment which in relates to curing, coating and structuring, wherein here one or more methods of laser technology are applied.

12. The axial piston machine according to claim 1, wherein the adjusting lever is arrestable at least at a long-side end region.

13. The axial piston machine according to claim 1, wherein the adjusting lever comprises made of plastics, brass, aluminum or an aluminum alloy.

Description

[0018] Further advantages and properties of the invention will be explained in detail below with reference to an exemplary embodiment illustrated in the drawings, in which:

[0019] FIG. 1: shows a longitudinal section along the drive shaft through the axial piston machine according to the invention,

[0020] FIG. 2: shows a detail view of the upper half of the axial piston machine in the region of the adjusting lever, and

[0021] FIG. 3a: shows a detail view of the adjusting piston in a first limit stop position and in the illustrated second stop position,

[0022] FIG. 3b: shows a detail view of the adjusting piston in a first limit stop position, and of an alternative for a second stop position,

[0023] FIG. 4: shows a top view of a schematic representation of the axial piston machine according to the invention.

[0024] FIG. 1 shows an axial longitudinal section through the axial piston machine according to the invention. The invention will be described below with reference to an axial piston pump, but it is explicitly pointed out that the features of the invention can also be used without limitation in an axial piston motor. Furthermore, it is pointed out that the features of the invention can likewise be used for an axial piston machine which can operate in a multi-quadrant mode.

[0025] On the drive shaft 1 a driving gear drum 2 is non-rotatably arranged, in which a plurality of driving gear pistons 3 are inserted into cylinder bores 4 in the manner of a drum revolver. The driving gear pistons 3 each are supported on the swash plate 6 via a sliding shoe 5. The swash plate is supported on the main housing 8 via a compression spring 7. During a rotation of the drive shaft 1, the driving gear pistons 3 slide over the sliding surface of the swash plate 6 by means of their sliding shoes 5, and in dependence on the swivel angle of the swash plate 6 a stroke movement of the driving gear pistons 3 occurs. Depending on the operating mode of the axial piston machine, i.e. pump or motor mode, hydraulic energy or mechanical power is produced thereby.

[0026] A retaining device ensures that the treads of the sliding shoes 5 of the driving gear pistons 3 do not lose contact with the sliding surface of the swash plate 6 also during their suction phase. Among other things, the retaining device consists of a retraction plate 10 and of the retraction ball 9 coaxially sitting on the drive shaft 1. By means of the spring 12, said retraction ball is urged to the left in the direction of the swash plate 6 in the drawing plane (plane E1) and in the illustrated embodiment in a half-plane E1* proceeding from the drive shaft axis, and thereby is supported on the retraction plate 10. The retraction plate 10 thereby is in permanent contact with the sliding shoes 5 and presses their treads onto the swash plate 6. The driving gear drum 4 is urged in the direction of the control plate 13 by the central spring 12.

[0027] The stroke of the driving gear pistons 3 is specified by the swivel angle of the swash plate 6, which in operation can be changed via an adjusting device 20. The adjusting lever 12 preferably has a spherical end region on both sides, wherein the one side of the adjusting lever 21 each forms a joint connection, in particular a ball joint connection, with the swash plate 6, and the other side with the adjusting piston 22. The adjusting lever 21 can be rotationally symmetrical with respect to its longitudinal axis and/or be configured mirror-symmetrical to a vertical axis. The adjusting lever 21 extends in an axial direction from the swash plate 6 beyond the control plate 13 into a blind hole bore 11 a which is disposed within the connecting plate 11 and in which the adjusting piston 22 is guided. The adjusting lever can be arrested in its joint connection at at least one of the two longitudinal ends. Within the connecting plate 11 a control or regulating valve 30 can be accommodated.

[0028] The spherical adjusting lever end opposite the swash plate 6 forms a ball joint connection with the spherical recess in the adjusting piston 22. The adjusting piston 22 is axially shiftably mounted within the blind hole bore 11a of the connecting plate 11. On its end face opposite the spherical recess, the piston 22 has a small cylindrical tab 23 on which a compression spring of the control or regulating valve 30 can be supported.

[0029] The limitation of the adjusting movement for the swash plate 6 is effected by two stops for the adjusting piston 22 in the vicinity of the blind hole 11a. A first stop 24 for limiting the maximum swivel angle is formed by the bottom of the blind hole 11a so that here the maximum slide-in path of the adjusting lever 21 into the blind hole 11a is delimited. A second stop for the adjusting piston 22 to limit the minimum swivel angle is formed by a flat protrusion 25 or 25a of the machine housing 8 in the vicinity of the blind hole 11a.

[0030] The described arrangement allows to utilize the overall length of the connecting plate 11 for accommodating the control or regulating valve 30. The same can be inserted or screwed into the connecting plate 11 from outside so that a simple exchange of the valve 30 is possible.

[0031] Further advantages of the constructional arrangement:

[0032] By slightly changing the angle of the adjusting lever 21 to the middle axis of the adjusting piston 22 a power transmission almost free from transverse forces is achieved in the vicinity of the adjusting piston 22. This is also promoted by the spherical region of the adjusting lever 21 dipping into the inner region of the adjusting piston 22.

[0033] An adjusting lever 21 with two identical spherical end regions facilitates the assembly. The tribology in the functional region of the ball joint connections between the adjusting lever 21 and the adjusting piston 22 as well as the swash plate 6 can be further improved by supplying hydraulic oil. When a tubular material is used for the adjusting lever 21, the supply of the ball joint connection in the vicinity of the swash plate 6 with hydraulic oil is possible in a simple way.

[0034] Also taking account of the friction behavior, the weight and the cost, materials such as plastics, brass, aluminum or aluminum alloys can be used for the adjusting lever 21.

[0035] What furthermore is advantageous is the uniform loading of the swash plate bearing 40 by the forces centrally introduced to the bearing points from the adjusting device 20.

LIST OF REFERENCE NUMERALS

[0036] 1 drive shaft [0037] 2 driving gear drum [0038] 3 driving gear piston [0039] 4 cylinder bores [0040] 5 sliding shoe [0041] 6 swash plate [0042] 7 compression spring [0043] 8 main housing [0044] 9 retraction ball [0045] 10 retraction plate [0046] 11 connecting plate [0047] 11a blind hole [0048] 12 spring [0049] 13 control plate [0050] 20 adjusting device [0051] 21 adjusting lever [0052] 22 adjusting piston [0053] 23 cylindrical tab [0054] 24 blind hole bottom [0055] 25 flat protrusion [0056] 25a flat protrusion [0057] 30 control or regulating valve [0058] E1 plane [0059] E1* half-plane