Pump apparatus and hydraulic actuator
AssigneeShowa Corporation
InventorsHayato Tsutsui, Kazuhiko Sadakata, Atsushi Kagawa
Life of this patent
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Abstract
A pump apparatus includes: a pump that ejects a hydraulic fluid; and a selector valve that switches a direction of a flow of the hydraulic fluid to be supplied to one of a first chamber and a second chamber of a cylinder apparatus, which is internally partitioned by a piston into the first chamber extending during an extending stroke of the cylinder apparatus, and the second chamber extending during a shortening stroke of the cylinder apparatus, and the selective valve has, at a channel connected to the second chamber, an orifice that is narrower than a channel connected to the first chamber.
Claims5
A pump apparatus for supplying a hydraulic fluid to a cylinder apparatus which is partitioned by a piston into a first chamber and a second chamber, the first chamber extending during an extending stroke of the cylinder apparatus, and the second chamber extending during a shortening stroke of the cylinder apparatus, said pump apparatus integrally comprising:
- a pump that ejects the hydraulic fluid;
- a selector valve that switches a direction of a flow of the hydraulic fluid to be supplied to one of the first chamber and the second chamber, the selector valve containing an actuation valve, a check valve, a first orifice and a second orifice, wherein
- the second orifice is provided at a second chamber-side channel, which is connected to the second chamber, said second orifice being narrower than the first orifice provided at a first chamber-side channel, which is connected to the first chamber,
- the second orifice is fluidly located between the actuation valve and the check valve, and
- the second orifice is configured to set a pressure in a portion of the second chamber-side channel closer to the pump than the second orifice higher than a pressure in a portion of the second chamber-side channel closer to the cylinder apparatus than the second orifice during the shortening stroke.
A hydraulic actuator comprising:
- a cylinder apparatus internally partitioned by a piston into a first chamber extending during an extending stroke of the cylinder apparatus and a second chamber extending during a shortening stroke of the cylinder apparatus;
- a pump apparatus integrally comprising a pump that ejects a hydraulic fluid and a selector valve that switches a direction of a flow of the hydraulic fluid to be supplied to one of the first chamber and the second chamber;
- and
- a case that houses the pump and includes a first case and a second case which is laid on the first case, wherein
- the selector valve has a second orifice formed as part of a second chamber-side channel, which is connected to the second chamber, said second orifice being narrower than a first orifice provided at a first chamber-side channel, which is connected to the first chamber,
- the selector valve has an actuation valve and a check valve, and
- the second orifice is formed as a part of the second chamber-side channel provided in the first case and is narrower than the first orifice provided at the first chamber-side channel provided in the first case,
- the second orifice is fluidly located between the actuation valve and the check valve, and
- the second orifice is configured to set a pressure in a portion of the second chamber-side channel closer to the pump than the second orifice higher than a pressure in a portion of the second chamber-side channel closer to the cylinder apparatus than the second orifice during the shortening stroke.
Dependencies are inferred from the claim text.