| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To determine the abnormality of a parking brake mechanism in its actuated state, in an electric disc brake. <P>SOLUTION: The rotation of an electric motor is slowed down by a differential speed reducing mechanism, and is converted into a linear motion by a ball ramp mechanism so as to advance a piston, which then presses a brake pad against a disk rotor D to generate a brake force. A parking brake mechanism 21 locks the rotation of a rotor of the electric motor and maintains a braked state by rotating an engagement pawl 24 through a plunger 29 of a solenoid 25 to be engaged with a ratchet wheel 22 coupled to the rotor of the electric motor. A play is provided at a coupling portion of the engagement pawl 24 and the plunger 29. The play enables the plunger 29 to move within the range of the play while the engagement pawl 24 is engaged with the ratchet wheel 22, thereby enabling determination whether the parking brake mechanism operates normally or abnormally based on whether the plunger 29 moves or not upon application of an electric current to the solenoid 25 while the parking brake mechanism 21 is in an actuated state. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
