| 摘要 |
PURPOSE:To prevent a mechanical operative portion from lag by closing a shut-off valve when the maximum reduction gradient of wheel speed exceeds a predetermined value in braking and opening a relief valve to a reservoir for pressure reduction when the wheel speed is reduced to a considerable degree. CONSTITUTION:Wheel speed VW is reduced in braking at time point to. Time point t1 when the maximum reduction gradient theta' of wheel speed VW exceeds a predetermined value is regarded as a symtom of wheel lock to close a shut-off valve. Thus, brake liquid pressure is held constant. And on and after time point t2 in which pseudosignal VT a definite difference DELTAV lower than the wheel speed VW and having descend gradient theta smaller than theta' intersects the wheel speed VW is opened a Daykey valve to escape liquid pressure at the brake unit side to a reservoir and reduce this liquid pressure. Thereafter, the brake liquid pressure is again increased from time point t3 when the wheel speed VW is recovered to speed VT determined by low peak VLP and the wheel speed Vo at time point t2. |
