| 摘要 |
A brake booster is provided to communicate a variable pressure chamber with atmosphere, to raise pressure of the variable pressure chamber rapidly, and to increase output of the brake booster immediately by catching a sleeve at a catching device and maintaining gaps between the poppet valve and the sleeve and between the poppet valve and a sheet part. A brake booster comprises a cell, a valve device(20), a cylindrical sleeve(41), and a catching device(50). The cell has a constant pressure chamber and a variable pressure chamber. The valve device is moved by pressure difference of the constant pressure chamber and a variable pressure chamber to press an output shaft(18). The valve device has a valve body(21) and a plunger(22). The valve body has first and second paths. The plunger, installed in the valve body, has a sheet part(30) contacted with a poppet valve(23) in the valve body. The sleeve, advanced and retreated at the outer part of the plunger, opens the first and second paths selectively. The catching device, installed in the valve body, releases the restriction of the sleeve. An opening and closing spring(42), installed at the outer part of the sleeve, applies elasticity to move the sleeve to the poppet valve. The catching device has a guide member(51), first and second catching protrusions(52,54), and extended parts(53). |
