Hydraulic pump with swash plate tilt control
AssigneeNabtesco Corporation
InventorToshiya Akami
Life of this patent
Estimating the term…
Abstract
A hydraulic pump that allows a drive source to be started with a small torque includes a cylinder block having a plurality of cylinder bores and disposed so as to be rotatable. Pistons are each movably retained in an associated one of the cylinder bores. A swash plate controls the amount of movement of the pistons in accordance with the size of the tilt angle. A first pressing unit is configured for pressing the swash plate in such a direction as to reduce the tilt angle of the swash plate, and a second pressing unit is configured for pressing the swash plate to increase the tilt angle of the swash plate by the pressure supplied from the outside.
Claims6
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;
- 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;
- and
- a plurality of shoes, each of the plurality of shoes mounted on an associated one of a plurality of end portions of the plurality of pistons,
- wherein the swash plate has a primary surface receiving the plurality of shoes, a first portion being in contact with the first pressing unit and a second portion being in contact with the second pressing unit,
- wherein an axis of rotation for the tilting of the swash plate is positioned apart from a straight line connecting the first portion and the second portion of the swash plate and is positioned on a cylinder block side of the straight line,
- wherein the primary surface protrudes toward the cylinder block from the straight line connecting the first portion and the second portion of the swash plate,
- wherein an axis of rotation for the tilting of the swash plate extends perpendicular to an axis of rotation of the cylinder block,
- wherein the axis of rotation for the tilting of the swash plate is positioned apart from the axis of rotation of the cylinder block and is positioned on a first pressing unit side of the axis of rotation of the cylinder block, and
- wherein the pressure supplied from outside of the hydraulic pump is a pressure corresponding to a load-sensing flow control pressure, a pressure corresponding to a positive flow control pressure or a pressure corresponding to a lock lever pressure.
Dependencies are inferred from the claim text.