Brake control valve assembly for effecting increased rear braking action upon malfunction of the front system

摘要

The piston of a brake control valve assembly is balanced, during normal front hydraulic system operations, at a predetermined position to allow pressurized brake fluid from a rear master cylinder to flow into a rear wheel cylinder from between a head flange and a seal valve with a predetermined pressure. When the braking operation is sought during trouble or failure in the front hydraulic system, the piston loses its regulated balance and moves, together with a piston sleeve and the seal valve so that the effective area for receiving brake fluid pressure from a rear master cylinder becomes greater than that of the rear wheel cylinder thereby to increase brake fluid pressure transmitted to the rear wheel cylinder. The present invention features particularly the improvement, or reversewise utilization, of the conventional proportioning valve mechanism to permit a very rational brake fluid pressure boosting operation.