| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance stability of braking effectiveness in a duo-servo type drum brake device. SOLUTION: A wheel cylinder which expands a space between the facing ends of one of a pair of brake shoes 3, 4 is equipped with a pair of wheel cylinder pistons 12, 13 which pressurize the end parts of the respective brake shoes 3, 4 by fluid pressure supplied in a shoe driving pressure chamber 10 through an anchor pin 15, and a pair of control pistons 22, 23 which are fitted to more central side of a drum than the wheel cylinder pistons 12, 13 and control hydraulic pressure supply into the shoe driving pressure chamber 10. The control pistons 22, 23 set the shoe driving pressure chamber 10 in a sealed condition when anchor reaction force reaches a prescribed magnification against the fluid pressure from a master cylinder by receiving the anchor reaction force at its front end part through the anchor pin 15 and a lever member 25.</p> |
