| 摘要 |
<p>A master cylinder assembly has a low pressure, high volume displacement quick take-up chamber and a high pressure, low volume displacement pressurizing chamber formed by a stepped bore and a stepped piston. A compensation control and blow-off valve unit has a peripheral lip seal type valve providing compensation flow on brake release but preventing flow from the quick take-up chamber during brake apply. A normally closed check valve can open to provide communication between the quick take-up pressurizing chamber and the fluid reservoir. When the pressurizing cup for the high pressure chamber closes its compensation port, the check valve is subjected to the pressure in the quick take-up pressurizing chamber. Initial fluid flow is obtained from the quick take-up chamber past the pressurizing cup into the high pressure chamber. At a predetermined pressure level, arranged to be sufficient to take up lining clearance and initially apply the vehicle brakes, the pressure in the quick take-up chamber opens the normally closed check valve so that fluid from the quick take-up chamber then flows to the reservoir without further pressure buildup in that chamber. As the master cylinder is released, compensation fluid can flow past the peripheral compensation valve to both chambers. When the master cylinder is returned to the fully released position, the check valve is closed. A fluid flow restrictive orifice is provided which bypasses the normally closed check valve to provide a continuous fluid path controlled leak from the quick take-up chamber to the fluid reservoir.</p> |
