Patent ID: 8939519
Filing Date: 2015-01-27
Classification: B60T

Abstract:
1. A vehicle brake device comprising: a master cylinder in which a master piston is driven so as to move by a servo pressure in a servo chamber and in which a master pressure in a master chamber is changed by the movement of the master piston; a mechanical servo pressure generating unit that is connected to a high pressure source and the servo chamber and which generates a servo pressure within the servo chamber according to a pilot pressure within a pilot chamber on the basis of a brake fluid pressure of the high pressure source; an electrical pilot pressure generating unit that is connected to the pilot chamber and which generates a desired pilot pressure within the pilot chamber; and a master chamber-to-pilot chamber brake fluid line which connects between the master chamber with the pilot chamber, wherein when a power supply system operates normally, the pilot pressure is generated by the pilot pressure generating unit, while when the power supply system fails, the master pressure is used as a pilot pressure, and wherein the master chamber-to-pilot chamber brake fluid line branches off from a master chamber-to-wheel cylinders brake fluid line which connects between the master chamber and wheel cylinders.