Patent ID: 8414090
Filing Date: 2013-04-09
Classification: B60T

Abstract:
1. An assistance-limit recognizing device for recognizing a limit of assistance made by a vacuum booster that is configured to assist an operating force applied to a brake operating member of a vehicle from an operator of the vehicle, the vacuum booster having a negative pressure chamber and a variable pressure chamber that is to be selectively brought into communication with the negative pressure chamber and an atmosphere, such that a communication between the variable pressure chamber and the negative pressure chamber is established, when the operating force is not being applied to the brake operating member from the operator, and such that a communication between the variable pressure chamber and the atmosphere is established while the communication between the variable pressure chamber and the negative pressure chamber is being cut off, when the operating force is being applied to the brake operating member, whereby the operating force applied to the brake operating member is assisted based on a pressure difference between a pressure in the negative pressure chamber and a pressure in the variable pressure chamber, said assistance-limit recognizing device being configured, upon reduction of the pressure in the variable pressure chamber in a process of change of the pressure in the variable pressure chamber increasing toward a pressure of the atmosphere with application of the operating force to the brake operating member, to recognize the limit of the assistance made by the vacuum booster.