Electric actuator with a fail-safe mode of operation
AssigneeMetso Flow Control USA Inc.
InventorLeonard T. Armstrong
Life of this patent
Estimating the term…
Abstract
Aspects of the disclosure provide an electric actuator including a first driving source coupled to an output through a first pathway created by a transmission, a second driving source coupled to the output though a second pathway created by the transmission that, upon the electric actuator losses electrical power to the electric actuator, causes the output to be positioned at a fail-safe position, a differential coupled to the first driving source and the second driving source through a third pathway created by the transmission to store energy from the first driving source in the second driving source, and a switching controller that is configured to control switching the transmission between the first pathway, the second pathway, and the third pathway.
Claims20
An electric actuator, comprising:
- a first driving source coupled to an output through a first pathway created by a transmission;
- a second driving source coupled to the output though a second pathway created by the transmission that, upon loss of electrical power to the electric actuator, causes the output to be positioned at a fail-safe position;
- a differential coupled to the first driving source and the second driving source through a third pathway created by the transmission to store energy from the first driving source in the second driving source, the differential including a carrier having three or more bevel gears arranged inside the carrier, wherein a first bevel gear of the differential is coupled to the first driving source, and a second bevel gear is coupled to the output, and a carrier gear fixed external to the carrier that is coupled to the second driving source;
- and
- a switching controller that is configured to control switching the transmission between the first pathway, the second pathway, and the third pathway.
A transmission of an electric actuator comprising:
- a differential including a carrier, three or more bevel gears arranged inside the carrier, and a carrier gear fixed to the carrier;
- a motor gear train driving a first bevel gear of the differential, where the motor gear train and the first bevel gear of the differential are locked to generate a second pathway allowing rotation of a spring gear train, the carrier gear of the differential, the second bevel gear of the differential, and an output gear train in the electric actuator;
- the spring gear train coupled to the carrier gear of the differential, where the spring gear train and the carrier gear are locked to generate a first pathway allowing rotation of the motor gear train, the three or more bevel gears of the differential, and the output gear train in the electric actuator;
- and
- the output gear train coupled to a second bevel gear of the differential, where the output gear train and the second bevel gear of the differential are locked to generate a third pathway allowing rotation of the motor gear train, the carrier gear of the differential, and the spring gear train in the electric actuator.
A method for driving an electric actuator, the method comprising:
- supplying electric power to a first driving source coupled to a differential driving a transmission coupled to an output or a second driving source;
- disengaging a first brake and engaging a second brake of the electric actuator to establish a first pathway that causes the first driving source to drive the differential causing the transmission to drive the output;
- disengaging the first brake and the second brake of the electric actuator, upon loss of electric power to the electric actuator, to establish a second pathway that causes the second driving source to drive the differential causing the transmission to drive the output;
- and
- engaging the first brake and dis-engaged the second brake to establish a third pathway that causes the first driving source to drive the differential causing the transmission to drive the second driving source.
Dependencies are inferred from the claim text.