| 摘要 |
PROBLEM TO BE SOLVED: To provide a braking device provided with a brake auxiliary mechanism capable of maintaining safety and operability and generating a large braking force in an emergency with simple control. SOLUTION: This device is structured so that, when stroke speed exceeds the reference value of a stroke speed threshold value, current passes through a solenoid 21 to attract an armature 23, an atmospheric valve 24 opens irrespective of the position of a plunger 20, and a power piston, in its turn an output rod 27 are moved forward by a thrust force according to a pressure difference between constant pressure chambers 7a and 7b and a variable pressure chamber 8 (8b) for full braking. In order to increase safety in a medium emergency, a reaction adjusting mechanism 32 is used for contribution and, when the degree of emergency is high, a forced full braking by the solenoid 21 can be utilized limitedly. Namely, under the condition where safety is secured, unnecessary braking can be prevented by largely setting the reference value Seo of the stroke speed threshold value. As a result, the necessity of strictly pursuing a compromise threshold value setting which was required in the prior art is eliminated. Thus the structure of a controller can be facilitated by that amount and the control can be made rapidly. |
