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US 2016/0237993 A1Published application
Axial piston pump having a swash-plate type construction
AssigneeHydac Drive Drive Center GmbH
InventorsRalf BOSCH, Manuel KRONPASS
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AssigneeHydac Drive Drive Center GmbH
InventorsRalf BOSCH, Manuel KRONPASS
Estimating the term…
The invention relates to an axial piston pump having a swash-plate type construction, in particular for hydraulic systems, comprising a cylinder drum (3) which can be rotationally driven about a rotational axis (7) in a pump housing (1) and in which pistons (9) are arranged in an axially displaceable manner, supporting by means of the actuation end thereof (11) which is accessible from the outside of the cylinder drum (3), at least indirectly a awash plate (15), said swash plate can be pivoted by means of an adjusting device (21) to the desired angles of inclination with respect to the rotational axis (7) for adjusting, the stroke, of the piston (9) and also the fluid system pressure generated thereby. Said adjust device comprises an adjusting, piston (35) in a hydraulically actuated adjusting cylinder (31), the movement thereof can be transmitted to the awash plate (15) by means of at least one driven connection comprising a pivot joint (37, 39; 29, 43), characterized in that the pivot joint is formed by a ball joint (37, 39) which is arranged between the piston (35) and the piston and (41) of the adjusting cylinder (31).
(Original) An axial piston pump having a swash plate type construction, in particular for hydraulic systems, having a cylinder drum (3) that can be rotatably driven about a rotational axis (7) in a pump housing (1), in which pistons (9) are disposed such that they are axially displaceable, which support, at least indirectly, a swash plate (15) with their actuation ends (11) that are accessible outside the cylinder drum (3), which swash plate can be pivoted to a desired angle of inclination in relation to the rotational axis (7) by means of an adjustment device (21), in order to adjust the stroke of the piston (9), and thus the fluid system pressure generated by said piston, which has an adjustment piston (35) in an adjustment cylinder (31) that can be hydraulically actuated, the movement of which can be transferred to the swash plate (15) via at least one driven connection having a joint (37, 39;
The axial piston pump according to claim 1, characterized in that a second joint is formed by a second ball joint (29, 43) between the piston rod (41) and an actuating part (23) of the swash plate (15).
The axial piston pump according to claim 1, characterized in that a spring assembly (61) is provided, that retains the ball head (29, 39) and ball socket (37, 43) of the ball joint in position, in a force-locking manner.
The axial piston pump according to claim 1, characterized in that the spring assembly (61) pre-loads the swash plate (15) in the pivotal position corresponding to the maximum pump capacity.
The axial piston pump according to claim 1, characterized in that a second adjustment cylinder (45) is provided, counter to the first adjustment cylinder (31) and sharing the same cylinder axis, which is perpendicular to the rotational axis (7), in that the adjustment piston (47) of the second adjustment cylinder (45) can be moved hydraulically counter to the movement of the adjustment piston (35) of the first adjustment cylinder (31), and in that the piston rod (55) of the second adjustment cylinder (45) is connected to the associated adjustment piston (47) at one end via a third ball joint (51, 53), and on the other end, together with the piston rod (41) of the first adjustment cylinder (31), forms the second ball joint (29, 43, 57) at the actuating part (23) of the swash plate (15).
The axial piston pump according to claim 1, characterized in that the actuating part is formed by a pivot lever (23) connected to the swash plate (15), which extends parallel to the rotational axis (7) when set to zero pump capacity, laterally to the swash plate (15) and the cylinder drum (3), and the second ball joint (29, 43, 57) is located at its free end.
The axial piston pump according to claim 1, characterized in that the spring assembly has a compression spring (61), which pre-loads the piston rod (55) of the second adjustment cylinder (45) for the movement that corresponds to the extension of the adjustment piston (49) of the second adjustment cylinder (45) and the retraction of the adjustment piston (35) of the first adjustment cylinder (31) and thus the pivoting of the pivot lever (23) from the setting in which the axes are parallel, toward the setting for the maximum pump capacity.
The axial piston pump according to claim 1, characterized in that the first adjustment cylinder (31) can be subjected to a control pressure for adjusting the pump capacity, and the second adjustment cylinder (45) can be subjected to the prevailing system pressure.
The axial piston pump according to claim 1, characterized in that the piston surface of the piston (35) of the first adjustment cylinder (31) that can be subjected to the control pressure is selected such that it is larger than the piston surface of the piston (49) of the second adjustment cylinder (45) that can be subjected to the system pressure.
The axial piston pump according to claim 1, characterized in that ball joints on the adjustment pistons (35, 49) are formed by a ball socket (37, 51) on the respective piston (35, 49) and a ball head (39, 53) on the piston rod (41, 55).
The axial piston pump according to claim 1, characterized in that the ball joint on the actuating part is formed by a ball head (29) located on the free end of the pivot lever (23) and by dome-shaped surfaces that are formed on the allocated ends of the piston rods (41, 55), and which form ball sockets (43, 57).
The axial piston pump according to claim 1, characterized in that a continuous lubrication hole (67) is formed in the piston (49) that can be subjected to system pressure, which forms the entrance for a lubrication channel (69, 71, 73) for lubricating the ball joint.
Dependencies are inferred from the claim text.