Braking Force Control Apparatus Stop-Time Boost
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Solution Overview
Problem
Conventional braking systems experience a decrease in braking force due to heat reduction and depression force reduction, leading to unintended vehicle movement when stopped.
Innovation Solution
A braking force control apparatus that includes a fluid pressure generation mechanism, a braking mechanism, and an electronic control unit, which performs stop-time boost control to maintain a higher braking force during heat reduction and depression force reduction, and adjusts fluid pressure through boost amount reduction and hold controls based on vehicle state changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the required fluid pressure is kept constant, then the braking mechanism structure is simple, but the braking force decreases due to heat reduction causing the vehicle to start moving unintentionally
Solution Approach 1:
The fluid pressure is dynamically adjusted based on vehicle state. When the vehicle is stopped, the required fluid pressure is increased by a predetermined amount compared to when the vehicle is moving, compensating for heat reduction effects and preventing unintended movement while maintaining system reliability.
Solution Approach 2:
The required fluid pressure parameter is changed based on vehicle operation state. The system switches between different pressure levels: a higher pressure when stopped and a lower pressure when moving, optimizing both reliability and preventing unintended vehicle movement.
2Reliability
If the required fluid pressure is increased to compensate for heat reduction, then the braking force is maintained, but the fluid pressure generation mechanism must handle higher pressures increasing system stress
Solution Approach 1:
The increased fluid pressure is applied locally only when the vehicle is in a stopped state, rather than continuously. This targeted approach maintains braking force reliability when needed most while minimizing overall system stress exposure.
Solution Approach 2:
The system dynamically adjusts pressure levels based on real-time vehicle state detection. By switching between high pressure (stopped) and low pressure (moving) states, the system maintains reliability only when necessary, reducing cumulative stress on the pressure generation mechanism.
3Ease of operation
If the braking member is pressed against the rotary member with constant force, then the control is simple, but the pressing force decreases due to thermal contraction causing reduced braking force
Solution Approach 1:
The system uses feedback from vehicle state detection (moving vs. stopped) to automatically adjust the required fluid pressure. This closed-loop approach maintains braking force consistency by compensating for thermal contraction effects without requiring complex manual control adjustments.
Solution Approach 2:
The braking system automatically compensates for its own thermal contraction issues through the ECU's automatic pressure adjustment. The system serves itself by detecting its operational state and making necessary pressure corrections without external intervention, maintaining both simplicity and reliability.
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 system effectively reduces the likelihood of the vehicle starting to move unintentionally by maintaining a sufficient braking force during heat reduction and depression force reduction, ensuring safety and reliability.
Implementation Method 1
The braking mechanism generates a braking force for braking rotation of the rotary member by pressing the braking member against the rotating rotary member through a fluid pressure generated by the fluid pressure generation mechanism, and converting rotational energy of the rotary member into thermal energy resulting from friction.
Implementation Method 2
both the members thermally expand due to the friction heat generated in a region of contact therebetween
Implementation Method 3
when a certain length of time elapses after the rotary member stops rotating, the volumes of both the members slightly decrease due to a fall in temperature. This is a well-known phenomenon called heat reduction.
Data Source
AI summary
A braking force control apparatus includes a fluid pressure generation mechanism, a braking mechanism and an electric control unit. The fluid pressure generation mechanism causes a braking mechanism to generate a required fluid pressure. The braking mechanism applies a braking force depending on the required fluid pressure to each of wheels through the pressing of a braking member against a rotating rotary member due to the required fluid pressure. The electronic control unit performs, when the required fluid pressure is generated and a vehicle state shifts from a running state to a stopped state at a first time point, stop-time boost control to boost the required fluid pressure at and after the first time point.