Hydraulic pump with swash plate tilt control
AssigneeNabtesco Corporation
InventorToshiya Akami
Life of this patent
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Abstract
A hydraulic pump includes a cylinder block, a plurality of pistons, a swash plate, a first pressing unit, and a second pressing unit. The cylinder block has a plurality of cylinder bores and is disposed so as to be rotatable. Each of the plurality of pistons is retained in associated one of the cylinder bores so as to be movable. The swash plate is configured for controlling the amount of movement of the plurality of pistons in accordance with the size of the tilt angle. The first pressing unit is configured for pressing the swash plate in such a direction as to reduce the tilt angle of the swash plate. The second pressing unit is configured for pressing the swash plate in such a direction as to increase the tilt angle of the swash plate by a pressure supplied from the outside of the hydraulic pump.
Claims10
A hydraulic pump comprising:
- a cylinder block having a plurality of cylinder bores and disposed so as to be rotatable;
- a plurality of pistons each retained in an associated one of the plurality of cylinder bores so as to be movable;
- a swash plate configured to control an amount of movement of the plurality of pistons in accordance with a size of a tilt angle of the swash plate;
- a first pressing unit configured to press the swash plate only by the elastic force of at least one spring in a tilt angle reducing direction so as to reduce the tilt angle of the swash plate;
- and
- a second pressing unit configured to press the swash plate in a tilt angle increasing direction so as to increase the tilt angle of the swash plate by a pressure supplied from outside of the hydraulic pump,
- wherein the pressure is a pressure corresponding to a negative flow control pressure provided by a negative flow control mechanism, and
- wherein as the negative flow control pressure is higher, the pressure input to the second pressing unit is lower, whereas as the negative flow control pressure is lower, the pressure input to the second pressing unit is higher.
Dependencies are inferred from the claim text.