The disclosure relates to a hydraulic axial piston machine which has a housing, a drive shaft which is rotatably mounted in the housing, a swashplate, which for the purpose of varying its inclination relative to the axis of the drive shaft can be pivoted about a pivot axis, and an actuating piston, which extends with its longitudinal axis spaced apart from a central plane, which is perpendicular to the pivot axis and extends through the axis of the drive shaft, of the swashplate and at least approximately parallel to the axis of the drive shaft. The actuating piston is situated, so to speak, very far outward in a corner of the housing. Said actuating piston, at a first end, engages on the swashplate for the purpose of adjusting the latter and, at a second end, delimits an actuating chamber into which control fluid flows for the purpose of pivoting the swashplate in one direction and out of which control fluid can be displaced in the event of a pivoting movement of the swashplate in the other direction. On the actuating piston there is arranged an elongate feedback element by means of which the position of the actuating piston and thus the oblique position of the swashplate are input to control a regulating valve.
In a hydraulic axial piston machine of said type known from DE 10 2007 022 569 A1, the longitudinal axis of the actuating piston and the longitudinal axis of the feedback element which projects perpendicularly from the actuating piston span a plane which is perpendicular to the pivot axis of the swashplate.
A feedback element of said type is provided in particular if the axial piston machine is to be adjusted in a torque-regulated manner, or proportionally to an input signal. In the case of torque regulation, the feedback element is also provided with a small piston which is subjected to the working pressure and which, depending on the position of the actuating piston and thus of the swashplate, engages on a lever at a different distance from an axis of rotation and exerts a torque on said lever. The valve piston of a regulating valve is supported counter to said torque on the same arm, or on a second arm, of the lever at a fixed distance from the axis of rotation, said valve piston being subjected to a constant or remote-controlled variable force which seeks to increase the swept volume. The swept volume of the axial piston machine is then set in each case such that torque equilibrium prevails at the lever.
In the case of a proportional adjustment of the swept volume, the feedback element varies the preload of a spring which exerts load on a valve piston of the regulating valve, said valve piston being acted on counter to the spring by an input force generated predominantly by an electromagnet or a hydraulic pressure. Depending on the magnitude of the input force, the spring force and thus the position of the actuating piston and thus of the swashplate must vary such that, when the valve piston is in the zero position, the spring force and input force maintain the equilibrium.
A high degree of flexibility with regard to the arrangement of the regulating valve should be possible.
This is achieved in that the feedback element is positioned within its range of movement in each case such that its longitudinal axis and the longitudinal axis of the actuating piston span a plane which differs from a plane perpendicular to the pivot axis of the swashplate. The positioning of the feedback element is determined for example by a guide in the housing or on the regulating valve or by a particular arrangement on the actuating piston if the latter is not rotatable about its longitudinal axis.
According to the disclosure, it is possible for a regulating valve to be arranged at different locations on the outside of the housing. It is necessary in each case merely to provide a corresponding opening on the housing. The actuating piston and feedback element and also the regulating valve can always be identical.
Advantageous embodiments of a hydraulic axial piston machine according to the disclosure emerge from the description below.