Solenoid actuator and multi-solenoid actuator exerting constant force
View Patent ↗Disclosed are a solenoid actuator and a multi-stage solenoid actuator for transmitting a constant force. The solenoid actuator includes a tubular solenoid, a power unit capable of applying current to the solenoid, and a magnetic pair member having two magnetic members providing magnetic fields formed such that respective first poles thereof face each other and respective second poles thereof different from the first poles are located at both distal ends, and extending through the tub of the solenoid. The multi-stage solenoid actuator includes a solenoid assembly where at least two tubular solenoids are regularly aligned such that inner spaces of the tubes of the solenoids are arranged in series, a power unit capable of individually applying current to each solenoid of the solenoid assembly, at least one magnetic pair moveable unit having two magnetic members providing magnetic fields formed such that respective first poles thereof face each other and respective second poles thereof different from the first poles are located at both distal ends, and extending through the tub of the solenoid assembly, and a controller for determining and controlling a solenoid to receive the current from the power unit depending on a position of the magnetic pair moveable unit.
1 . A solenoid actuator for transmitting a constant force, the solenoid actuator comprising:
at least two tubular solenoids;
a controller;
a power unit coupled to the controller; and
a magnetic pair member having two magnetic members providing magnetic fields formed such that respective first poles thereof face each other and respective second poles thereof different from the first poles are located at both distal ends, and extending through a tube of the at least two tubular solenoids,
wherein the controller is configured to control the power unit to apply current to one of the at least two tubular solenoids based on a position of the magnetic pair member,
wherein one of a distance between the first poles and a distance between the second poles of the respective two magnetic members is 0.9 to 1.1 times the length of the tube of the at least two tubular solenoids,
wherein the solenoid actuator further includes a spacer disposed and fixed between the two magnetic members to keep a distance between the two magnetic members constant when the first poles of the respective two magnetic members are spaced apart from each other.
2 . The solenoid actuator of claim 1 , wherein the distance between the first poles of the respective two magnetic members is 0.9 to 1.1 times the length of the tube of the at least two tubular solenoids, wherein a length of each of the two magnetic members is 0.9 to 1.1 times the length of the tube of the at least two solenoids.
3 . The solenoid actuator of claim 1 , wherein the distance between the second poles of the respective two magnetic members is 0.9 to 1.1 times the length of the tube of the at least two solenoids, wherein a length of each of the two magnetic members is equal to or smaller than 0.55 times the length of the tube of the at least two solenoids.
4 . The solenoid actuator of claim 3 , wherein the at least two tubular solenoids and the two magnetic members are cylindrical, wherein the length of each of the two magnetic members is smaller than 0.55 times the length of the tube of the at least two solenoids by 0.09 to 0.11 times the diameter of the magnetic member.
5 . The solenoid actuator of claim 4 , wherein the length of the solenoid is 2.3 to 2.7 times the diameter of the magnetic member, and the length of each of the two magnetic members is 1.0 to 1.2 times the diameter of the magnetic member.