AXIALPISTON MACHINE

Abstract

Axial piston machine comprising a drive shaft, a drive mechanism that is connected thereto for conjoint rotation and comprises one or more drive-mechanism pistons, the piston stroke of which can be set by a swash plate, at least one return spring acting on the swash plate and a setting piston supporting on the swash plate, the axial piston machine comprising at least one control or regulating valve or at least one control or regulating unit, characterized in that a setting piston is guided in the connecting plate and a setting lever acts as a coupling member between the setting piston and the swash plate and the setting-piston axis and the setting-lever axis are positioned in a plane E1, in particular in a half plane E1* extending from the drive-shaft axis M.

Claims

1. Axial piston machine comprising a drive shaft, a drive mechanism that is connected thereto for conjoint rotation and comprises one or more drive-mechanism pistons, a piston stroke of which can be set by a swash plate, wherein at least one return spring acts on the swash plate and a setting piston is supported on the swash plate, wherein the axial piston machine comprises at least one control or regulating valve or at least one control or regulating unit, wherein a setting piston is guided in a connecting plate and a setting lever acts as a coupling member between the setting piston and the swash plate and a setting-piston axis and a setting-lever axis are positioned in a plane.

2. Axial piston machine according to claim 1, wherein the setting-lever axis are positioned in a plane, the plane being a half plane extending from a drive-shaft axis, and wherein the setting-piston axis extends in parallel with the drive-shaft axis and the setting-lever axis is positioned in the plane.

3. Axial piston machine according to claim 2, wherein the setting lever allows for approximately parallel functional positions relative to the drive-shaft axis and/or approximately coaxial functional positions relative to the setting-piston axis, wherein an angular deviation from the relevant axis of less than 3 is made possible.

4. Axial piston machine according to claim 3, wherein an extension of a central axis of the at least one return spring is positioned in the plane.

5. Axial piston machine according to claim 4, wherein the half plane extends centrally or almost centrally with respect to a swash-plate mount.

6. Axial piston machine according to claim 2, wherein a control or regulating valve is in the connecting plate, wherein the axis of said control or regulating valve is positioned in the half plane and the axis of said control or regulating valve is arranged in parallel with the drive shaft.

7. Axial piston machine according to claim 2, wherein at least one control or regulating unit is arranged on the connecting plate, wherein an axis of the control or regulating unit extends approximately at right angles to the half plane.

8. Axial piston machine according to claim 7, wherein a plurality of the control or regulating units are arranged on the connecting plate, wherein each axis of such control or regulating unit extends either approximately at right angles to the half plane or approximately in parallel with the half plane.

9. Axial piston machine according to claim 6, wherein each axis of the control or regulating valves installed in the connecting plate is approximately at right angles to at least one axis of a control or regulating unit arranged on the connecting plate.

Description

[0025] Other advantages and properties of the invention shall be explained in greater detail in the following with reference to an embodiment shown in the drawings, in which:

[0026] FIG. 1 is a longitudinal section along the drive shaft through the axial piston machine according to the invention,

[0027] FIG. 2 is a schematic view of the axial piston machine corresponding to the longitudinal section in FIG. 1,

[0028] FIG. 3 is another schematic plan view of the axial piston machine,

[0029] FIG. 4 is a simplified view of FIG. 3, with regulating axes being marked.

[0030] FIG. 1 is an axial longitudinal section through the axial piston machine according to the invention. The invention will be described in the following with reference to an axial piston pump, but it is explicitly noted that the claimed features of the invention can also be used in an axial piston motor, without restriction. Furthermore, it is noted that the features according to the invention can likewise be used for an axial piston machine which can operate in multiple-quadrant operation.

[0031] A drive-mechanism drum 2 is arranged on the drive shaft 1 for conjoint rotation, in which drum a plurality of drive-mechanism pistons 3 are inserted in cylinder bores 4 in a drum-revolver-like manner. The drive-mechanism pistons 3 are each supported on the swash plate 6 by a slide shoe 5. The swash plate is supported on the main housing 8 by a compression spring 7. When the drive shaft 1 rotates, the drive-mechanism pistons 3 slide over the sliding surface of the swash plate 6 by means of their slide shoes 5, and this results in a lifting motion of the drive-mechanism pistons 3 on the basis of the swivel angle of the swash plate 6. Depending on the operating mode of the axial piston machine, either pump operation or motor operation, hydraulic energy or mechanical power is generated thereby.

[0032] A retaining device ensures that the running surfaces of the slide shoes 5 of the drive-mechanism pistons 3 do not lose contact with the sliding surface of the swash plate 6 even during the suction phase of said pistons. The retaining device consists, inter alia, of a retainer plate 10 and the retainer ball 9, which rests coaxially on the drive shaft 1. Said retainer ball is pushed to the left in the direction of the swash plate 6 by a spring 12 in the drawing plane (plane E1) and, in the configuration shown, in a half plane E1* extending from the drive-shaft axis, and is supported on the retainer plate 10. As a result, the retainer plate 10 is in constant contact with the slide shoes 5 and pushes the running surfaces thereof against the swash plate 6. The drive-mechanism drum 2 is pushed by the central spring 12 in the direction of the control plate 13.

[0033] The stroke of the drive-mechanism pistons 3 is predetermined by the swivel angle of the swash plate 6, which can be altered during operation by means of an adjusting apparatus.

[0034] The setting lever 21 comprises a spherical end region at either end, one end of the setting lever 21 forming a ball-joint connection with the swash plate 6 and the other end forming a ball-joint connection with the setting piston 22. The setting lever 21 may be designed to be rotationally symmetrical with its longitudinal axis and/or may be designed to be mirror-symmetrical with a vertical axis. The setting lever 21 extends in the axial direction from the swash plate 6, over the control plate 13, and into a blind hole 11a, which is inside the connecting plate 11 and in which the setting piston 22 is guided.

[0035] A control or regulating valve 30 may be housed within the connecting plate 11.

[0036] The spherical setting-lever end opposite the swash plate 6 forms a ball-joint connection together with the spherical recess in the setting piston 22. The setting piston 22 is mounted so as to be axially movable within the blind hole 1 lain the connecting plate 11. On its end face opposite the spherical recess, the setting piston 22 shown in the embodiment comprises a small cylindrical projection 23, on which a compression spring of the control or regulating valve 30 can be supported. In such a design, the position of the setting piston 22 exerts a force on this compression spring, which is therefore also referred to as a feedback spring. As a result, the control or regulation to which the control or regulating valve contributes is influenced by the position of the setting piston 22, which is desired for regulating volume flow rate, for example.

[0037] Two stops for the setting piston 22 in the region of the blind hole 11a limit the adjusting movement for the swash plate 6. A first stop for limiting the maximum swivel angle is formed by the base of the blind hole 11a, such that the maximum slide-in path of the setting lever 21 into the blind hole 11a is limited here. A second stop for the setting piston 22 for limiting the minimum swivel angle is formed by a flat protrusion of the machine housing 8 in the region of the blind hole 11a.

[0038] The arrangement described makes it possible to utilize the overall length of the connecting plate 11 for housing the control or regulating valve 30. Said valve can be inserted and screwed into the connecting plate 11 from outside such that it is possible to easily replace the valve 30.

[0039] In the schematic view in FIG. 2, the axial piston machine is shown with a plurality of attached hydraulic components 50, 51, 52, which are stacked in a sandwich-like manner and are fastened to the connecting plate 11 on the housing side. Such a hydraulic component is also a control valve or regulating valve. In order to better differentiate it from a control or regulating valve 30 which is installed in the connecting plate, such a hydraulic component that is fastened to the outer lateral surface of the connecting plate 11 is referred to as a control or regulating unit. A plurality of control units may also be fastened to the outer lateral surface of the connecting plate 11. Likewise, a plurality of regulating units may be fastened to the outer lateral surface of the connecting plate 11. Equally, a control unit or a plurality of control units comprising a regulating unit or a plurality of regulating units may be fastened to the connecting plate 11 in the position corresponding to the units 50, 51, 52.

[0040] Said units 50, 51, 52 mounted on the connecting plate are in the immediate vicinity of the position in which, if present, a control or regulating valve 30 can be screwed into the connecting plate 11. This compact arrangement provides the advantage of short oil connections, which also extend into the solid valve housings or regulator housings and the connecting plate. This results in a sturdy construction, which is clearly advantageous when used in mobile machines, in which there are particularly high and frequently occurring loads due to shocks and vibrations.

[0041] A specific example of use of the schematic embodiment shown may be the following arrangement:

[0042] The unit 50 fastened directly to the connecting plate may be an electrically actuatable pressure-reducing unit. The desired control pressure is generated at the pressure output there by electrical actuation, which control pressure acts on the valve piston of the control valve 30. The control valve 30 may be a volume-flow-rate control valve. The units fastened above the pressure-reducing unit 50 may be a pressure-cut off 51 and a load-sensing unit 52.

[0043] The units 50, 51, 52 that are stacked in a sandwich-like manner can likewise be seen in the plan view in FIG. 3. FIG. 4 again shows the plan view from FIG. 3, but with the control or regulating axes 50a, 51a, 52a of the control or regulating units 50, 51, 52 shown by dashed lines and with the central longitudinal axis of the drive shaft 1 also shown by dashed lines. It can be clearly seen that all of said axes 50a, 51a, 52a of the units 50, 51, 52 are perpendicular to the longitudinal axis of the drive shaft 2. It can also be clearly seen that, in the embodiment, the respective longitudinal axes of the drive shaft 1, the setting lever 21, the setting piston 22 and the regulating or setting valve are all in a common half plane E1*. The half plane E1* is delimited by the longitudinal axis of the drive shaft. Irrespective of the position of the setting piston, this is always the same half plane E1*.

[0044] Furthermore, it can be seen from FIG. 4 that all the control or regulating axes 52a, 51a, 50a of the units 52, 51, 50 extend in parallel with one another in pairs.

[0045] The control or regulating units 50, 51, 52 can be used irrespective of the direction of rotation of the drive shaft or of the drive mechanism. If the direction of rotation is changed, these units merely need to be rotated by 180 relative to their longitudinal direction.

[0046] Other advantages of the structural arrangement relating to the axial piston machine according to the invention are as follows:

[0047] Owing to the low angular change of the setting lever 21 relative to the central axis of the setting piston 22, force transmission in the region of the setting piston 22 that is almost free of lateral forces is achieved. Inserting the spherical region of the setting lever 21 into the inner region of the setting piston 22 also contributes to this.

[0048] It is particularly advantageous to evenly load the swash-plate mount 40 by means of the forces from the adjusting apparatus that are introduced centrally with respect to the mounting points.

[0049] The arrangement of the control or regulating valves and the control or regulating units ensures that the installation space required for tandem operation of a plurality of axial piston machines is not obstructed by said valves or units.

TABLE-US-00001 List of reference characters: Drive shaft 1 Drive-mechanism drum 2 Drive-mechanism piston 3 Cylinder bores 4 Slide shoe 5 Swash plate 6 Compression spring 7 Main housing 8 Retainer ball 9 Retainer plate 10 Connecting plate 11 Blind hole 11a Spring 12 Control plate 13 Setting lever 21 Setting piston 22 Cylindrical projection 23 Control or regulating valve 30 Swash-plate mount 40 Pressure-reducing unit 50 Control or regulating axis 50a Pressure cut-off 51 Control or regulating axis 51a Load-sensing unit 52 Control or regulating axes 52a Plane E1 Half plane E1*