Patent ID: 6708493
Filing Date: 2004-03-23
Classification: B60T,B62L

Abstract:
A variable ratio of force-enlargement master cylinder for transmitting a brake force into a braking device by a fluid, said variable ratio of force-enlargement master cylinder comprising:a cylinder having a first cavity, wherein the first cavity includes a first opening, second opening and third opening therein, said first cavity is filled with the fluid via said first opening, a first channel is positioned inside a sidewall of said cylinder, and said first channel connects said second opening with said third opening for transmitting the brake force; an outer piston coupled to said first cavity of said cylinder by using a first resilient body for reciprocal motion along said first cavity, said outer piston having a second cavity and a second channel therein, said second cavity connected to said first cavity of said cylinder via said second channel for filling said second cavity with the fluid, said outer piston having a fourth opening and a fifth opening therein for draining the fluid outwardly; and an inner piston coupled to said second cavity of said outer piston by using a second resilient body for reciprocal motion along said second cavity, said inner piston having a third channel therein for circulating the fluid around the braking device, a first cross region of said inner piston being smaller than a second cross region of said outer piston along an axial center, said third channel of said inner piston being aligned with said second channel and said fourth opening of said outer piston, respectively, and said fifth opening being shielded with the sidewall of said cylinder such that the fluid sequentially circulates into said second channel, said third channel and fourth opening, and drains away via said first channel.