Patent ID: 6443534
Filing Date: 2002-09-03
Classification: B60T

Abstract:
A brake system for a vehicle comprising:a master cylinder having first and second chambers in each of which a master cylinder pressure is generated in response to brake operation by a vehicle driver; first and second wheel cylinders for exerting a first braking force on first and second vehicle wheels, respectively, by a first wheel cylinder pressure generated based on said master cylinder pressure in said first chamber of said master cylinder; a first brake circuit for connecting said master cylinder to said first and second wheel cylinders; third and fourth wheel cylinders for exerting a second braking force on third and fourth vehicle wheels, respectively, by a second wheel cylinder pressure generated based on said master cylinder pressure in said second chamber of said master cylinder; a second brake circuit for connecting said master cylinder to said third and fourth wheel cylinders; first brake assist means arranged in said first brake circuit to increase said first wheel cylinder pressure to a level higher than said master cylinder pressure in said first chamber and to conduct said increased first wheel cylinder pressure to at least one of said first and second wheel cylinders in response to at least one of a state of said brake operation by said vehicle driver and a braking state of said vehicle; and second brake assist means arranged in said second brake circuit to increase said second wheel cylinder pressure to a level higher than said master cylinder pressure in said second chamber and to conduct said increased second wheel cylinder pressure to at least one of said third and fourth wheel cylinders in response to at least one of said state of said brake operation by said vehicle driver and said braking state of said vehicle, wherein said second brake assist means includes a brake regulator mechanism that uses said increased first wheel cylinder pressure as a back pressure and adjusts said increased second wheel cylinder pressure to a pressure different by a predetermined value from said back pressure when said first and second brake assist means are activated.