Power-off electromagnetic brake
AssigneeHarmonic Drive Systems Inc.
InventorKozo Sasaki
Life of this patent
Estimating the term…
Abstract
The power-off electromagnetic brake (2) attracts an armature that is pressed by spring force to a rotating member by magnetic attraction force that is generated by energizing an exciting coil, and brake force that is acting on the rotating member is released. A voltage control circuit (12) continuously energizes the exciting coil for a fixed length of time and generates a considerable magnetic attraction force in order to attract the armature to a yoke when a brake power source (14) is switched on during brake release. After the armature has been attracted to the yoke, the voltage control circuit (12) intermittently energizes the exciting coil at a set cycle and a set on/off duty ratio to hold the armature in an attracted state to the yoke, thereby reducing power consumption and heat generation.
Claims3
A power-off electromagnetic brake in which an armature that is pressed to a rotating member by a spring force is attracted to a yoke by electromagnetic attraction force generated by the energizing of an exciting coil, and a brake force operating on the rotating member is released, the brake comprising:
- a brake power supply;
- switching signal generation means for generating a switching signal that switches on and off at a prescribed cycle and a prescribed duty ratio;
- continuous energizing means for continuously energizing said exciting coil with a direct current at a constant voltage for a fixed length of time in order to attract said armature to said yoke when said brake power supply is switched on;
- and
- intermittent energizing means for intermittently energizing said exciting coil with a direct current at said constant voltage using said switching signal in order to hold a brake release state in which said armature is attracted to said yoke after a fixed length of time has elapsed.
Dependencies are inferred from the claim text.