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US 8,474,339 B2Granted
Electric actuator
AssigneeNabtesco Corporation
InventorMasanori Hirai
Life of this patent
Estimating the term…
Abstract
An electric actuator includes a first port, a second port, and a cylinder chamber connecting passage. The first port is formed on an inner face of a rod-side cylinder chamber of a cylinder body. The second port is formed on an inner face of a head-side cylinder chamber of the cylinder body. The cylinder chamber connecting passage connects the first port and the second port. In the electric actuator, a piston part of a piston rod closes the first port 6 when the piston rod advances.
Claims9
An electric actuator comprising:
- a cylinder body which stores therein a fluid;
- a screw shaft which is provided in the cylinder body, and is rotated by an electric motor;
- a piston rod which moves linearly in accordance with rotation of the screw shaft;
- a first port formed on an inner face of a rod-side cylinder chamber of the cylinder body, which cylinder chamber is located in a direction in which the piston rod advances;
- a second port formed on an inner face of a head-side cylinder chamber of the cylinder body, which cylinder chamber is located in a direction in which the piston rod retracts;
- a cylinder chamber connecting passage connecting the first port and the second port, wherein the piston part of the piston rod closes the first port when the piston rod advances;
- a nut into which the screw shaft is screwed;
- and
- an elastic member provided between the nut and the piston part.
6 more elements
An electric actuator comprising:
- a cylinder body which stores therein a fluid;
- a screw shaft which is provided in the cylinder body, and is rotated by an electric motor;
- a piston rod which moves linearly in accordance with rotation of the screw shaft;
- a first port formed on an inner face of a rod-side cylinder chamber of the cylinder body, which cylinder chamber is located in a direction in which the piston rod advances;
- a second port formed on an inner face of a head-side cylinder chamber of the cylinder body, which cylinder chamber is located in a direction in which the piston rod retracts;
- a cylinder chamber connecting passage connecting the first port and the second port, wherein the piston part of the piston rod closes the first port when the piston rod advances;
- a reservoir which is fixed to a side portion of the cylinder body, and whose one chamber storing a fluid therein is connected to the rod-side cylinder chamber;
- and
- a check valve whose forward direction is from another chamber of the reservoir to the one chamber of the reservoir.
6 more elements
An electric actuator comprising:
- a cylinder body which stores therein a fluid;
- a screw shaft which is provided in the cylinder body, and is rotated by an electric motor;
- a piston rod which moves linearly in accordance with rotation of the screw shaft;
- a first port formed on an inner face of a rod-side cylinder chamber of the cylinder body, which cylinder chamber is located in a direction in which the piston rod advances;
- a second port formed on an inner face of a head-side cylinder chamber of the cylinder body, which cylinder chamber is located in a direction in which the piston rod retracts;
- a cylinder chamber connecting passage connecting the first port and the second port, wherein the piston part of the piston rod closes the first port when the piston rod advances;
- and
- a check valve which is provided to the piston part of the piston rod, and whose forward direction is from the rod-side cylinder chamber to the head-side cylinder chamber.
5 more elements
An electric actuator comprising:
- a cylinder body which stores therein a fluid;
- a screw shaft which is provided in the cylinder body, and is rotated by an electric motor;
- a piston rod which moves linearly in accordance with rotation of the screw shaft;
- a first port formed on an inner face of a rod-side cylinder chamber of the cylinder body, which cylinder chamber is located in a direction in which the piston rod advances;
- a second port formed on an inner face of a head-side cylinder chamber of the cylinder body, which cylinder chamber is located in a direction in which the piston rod retracts;
- a cylinder chamber connecting passage connecting the first port and the second port, wherein the piston part of the piston rod closes the first port when the piston rod advances;
- and
- a relief valve which is provided to the piston part of the piston rod, and which connects the head-side cylinder chamber and the rod-side cylinder chamber when pressure in the head-side cylinder chamber comes to be a predetermined value or more.
5 more elements
Dependencies are inferred from the claim text.