Vehicle Brake Device Servo Pressure Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle brake devices fail to control braking force when the power supply system fails, as they rely on electrically controlled servo pressure, which cannot be increased by the brake pedal operation amount without power.
Innovation Solution
A vehicle brake device is designed with a mechanical servo pressure generating unit and an electrical pilot pressure generating unit, allowing the master pressure to be used as pilot pressure when the power supply fails, ensuring braking force is exhibited according to the brake pedal operation amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an electrical pilot pressure generating unit is used to control servo pressure, then braking force control precision is improved, but reliability deteriorates when power supply fails
Solution Approach 1:
The system changes the pressure source parameter from electrical control to mechanical pressure transmission when power supply fails. The master chamber pressure automatically becomes the pilot chamber pressure, maintaining braking function through parameter substitution rather than system redesign.
Solution Approach 2:
The brake fluid line connecting the master chamber and pilot chamber acts as an intermediary medium. This fluid pathway enables automatic pressure transmission from the master chamber to the pilot chamber, serving as a backup control mechanism when electrical systems fail.
2Reliability
If a mechanical servo pressure generating unit is added for backup, then reliability is improved, but device complexity increases
Solution Approach 1:
The master chamber serves dual functions: it generates braking pressure for the wheel cylinders and simultaneously serves as a pilot pressure source for the servo pressure generating unit when power supply fails. This multi-functionality eliminates the need for separate backup pressure generation equipment.
Solution Approach 2:
The patent merges the normal braking pressure generation function and the backup pilot pressure generation function into a single integrated system. The brake fluid line and pressure transmission pathway are shared between normal operation and failure mode, reducing overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device maintains the ability to control braking force based on brake pedal operation even without a power supply, ensuring safe braking by mechanically generating servo pressure and utilizing master pressure as pilot pressure.
Implementation Method 1
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 based on a brake fluid pressure of the high pressure source
Implementation Method 2
a master cylinder in which master piston is driven so as to move by a servo pressure in a servo chamber and a master pressure which is a pressure of master chambers is changed by the movement of the master pistons
Data Source
AI summary
A vehicle brake device includes a master cylinder having a master piston moved by servo pressure in a servo chamber and master pressure of a master chamber is changed by movement of the master piston. A mechanical servo pressure generating unit is connected to a high pressure source and the servo chamber, and generates a servo pressure within the servo chamber according to pilot pressure within a pilot chamber based on brake fluid pressure of the high pressure source. An electrical pilot pressure generating unit is connected to the pilot chamber and generates desired pilot pressure within the pilot chamber, and a master chamber-to-pilot chamber brake fluid line connects the master chamber with the pilot chamber so pilot pressure is generated by the pilot pressure generating unit during normal operation of a power supply system, and the master pressure is used as pilot pressure when the power supply system fails.