Pressure control valve unit for hydraulic brake device

摘要

A pressure control valve unit for a hydraulic brake device is provided which considerably reduces noise, vibration, and harshness, and is compact and inexpensive. The pressure control valve unit comprises a switching valve and a normally-open inlet valve sequentially located in the main brake line in a housing cavity between the master cylinder and the wheel cylinder(s). During a brake pressure control action, the difference in pressure acting on the master cylinder side and that on the wheel cylinder side causes the switching valve to switch to a constricted channel, thereby noticeably reducing the amount of noise vibration harshness.