Back to results
US 10,519,990 B2Granted
Hydraulic apparatus
AssigneeYanmar Co., Ltd.
InventorsKazuhiro Owada, Keishi Yamanaka, Kensuke Kaneda, Hidekazu Niu
Life of this patent
Estimating the term…
Abstract
The hydraulic apparatus is set so that the ratio of the pressure-receiving area of the respective bottom oil chambers of the boom cylinder, the arm cylinder and the bucket cylinder to the pressure-receiving area of the respective rod oil chambers matches the ratio of the extruded volume drawn into or discharged from the bottom oil chambers per single rotation by the respective extrusion members of the first hydraulic pump motor, the second hydraulic pump motor and the third hydraulic pump motor to the volume discharged from or drawn into the rod oil chambers.
Claims20
A hydraulic apparatus comprising:
- double-acting single-rod cylinders, which are a boom cylinder, an arm cylinder, and a bucket cylinder;
- and
- rotationally driven hydraulic pump/motors, which are a first hydraulic pump/motor, a second hydraulic pump/motor, and a third hydraulic pump/motor, wherein:
- the first hydraulic pump/motor, the second hydraulic pump/motor, and the third hydraulic pump/motor are coupled to a single driving shaft coupled to an output shaft of an engine or a motor,
- inflow/outflow ports of the boom cylinder communicate with discharge/suction ports of the first hydraulic pump/motor via oil lines to constitute a closed hydraulic oil circuit, inflow/outflow ports of the arm cylinder communicate with discharge/suction ports of the second hydraulic pump/motor via oil lines to constitute a closed hydraulic oil circuit, and inflow/outflow ports of the bucket cylinder communicate with discharge/suction ports of the third hydraulic pump/motor via oil lines to constitute a closed hydraulic oil circuit,
- each closed hydraulic oil circuit comprising a corresponding single hydraulic pump/motor comprising axial piston hydraulic pump/motor including a movable swash plate,
- an operating speed and a direction of motion, extending or contracting, of the boom cylinder, the arm cylinder, and the bucket cylinder are changed by tilting the movable swash plates, and
- for each of the boom cylinder, the arm cylinder, and the bucket cylinder, a ratio of a pressed-area in a bottom oil chamber to the pressed-area in a rod oil chamber is set identical to a ratio of an amount of hydraulic oil suctioned into or discharged from the bottom oil chamber to an amount of hydraulic oil discharged from or suctioned into the rod oil chamber by a single revolution of a pushing member of corresponding one of the first hydraulic pump/motor, the second hydraulic pump/motor, and the third hydraulic pump/motor;
- and
- wherein at least one of the discharge/suction ports of at least one of the first hydraulic pump/motor, the second hydraulic pump/motor, or the third hydraulic pump/motor define an arc slit having:
- a first triangular notch at a first end, a second triangular notch at a second end, or both.
8 more elements
A hydraulic apparatus comprising:
- an oil tank;
- a single driving shaft coupled to an output shaft of an engine or a motor;
- one or more closed hydraulic oil circuits comprising:
- a double-acting single-rod cylinder comprising a boom cylinder, an arm cylinder, or a bucket cylinder, the double-acting single-rod cylinder including:
- a bottom oil chamber;
- and
- a rod oil chamber;
- and
- a rotationally driven hydraulic pump/motor coupled to the single driving shaft and comprising an axial piston hydraulic pump/motor, the rotationally driven hydraulic pump/motor comprising:
- a movable swash plate, wherein an operating speed and a direction of motion, extending or contracting, of the double-acting single-rod cylinder are changed by tilting the movable swash plate;
- and
- a valve plate having:
- a first discharge/suction port coupled to an inflow/outflow port of the bottom oil chamber via a first oil line;
- a second discharge/suction port coupled to an inflow/outflow port of the rod oil chamber via a second oil line;
- and
- a third discharge/suction port coupled to the oil tank, wherein each of the first discharge/suction port, the second discharge/suction port, and the third discharge/suction port of the valve plate comprises:
- an arc slit of the same width;
- a first end notch coupled to a first end of the arc slit;
- and
- a second end notch coupled to a second end of the arc slit;
- wherein each of the first end notch and the second end notch has a width and a depth that decrease toward a corresponding distal end of the end notch;
- and
- a ratio of a pressed-area in the bottom oil chamber to a pressed-area in the rod oil chamber is set identical to a ratio of an amount of hydraulic oil suctioned into or discharged from the bottom oil chamber to an amount of hydraulic oil discharged from or suctioned into the rod oil chamber by a single revolution of a pushing member of a corresponding pump/motor.
20 more elements
A hydraulic apparatus comprising:
- an oil tank;
- a single driving shaft coupled to an output shaft of an engine or a motor;
- and
- one or more closed hydraulic oil circuits comprising a double-acting single-rod cylinder comprising:
- a bottom oil chamber;
- and
- a rod oil chamber;
- and
- a rotationally driven hydraulic pump/motor coupled to the single driving shaft, the rotationally driven hydraulic pump/motor comprising:
- a first discharge/suction port coupled to an inflow/outflow port of the bottom oil chamber via a first oil line;
- a second discharge/suction port coupled to an inflow/outflow port of the rod oil chamber via a second oil line;
- and
- a third discharge/suction port coupled to the oil tank;
- wherein:
- at least one of the first discharge/suction port, the second discharge/suction port, and the third discharge/suction port of the rotationally driven hydraulic pump/motor comprises:
- an arc slit having a first end and a second end;
- and
- a first end notch coupled to the first end;
- and
- the first end notch has a width and a depth that decrease toward a corresponding distal end of the first end notch.
17 more elements
Dependencies are inferred from the claim text.