Vehicle Braking Device Regenerative Force Control
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Solution Overview
Problem
Existing vehicle braking devices require complex master cylinder configurations to optimize regenerative braking force generation, limiting the ratio of regenerative braking force in coordination with liquid pressure braking.
Innovation Solution
A braking device with a first valve unit adjusting differential pressure between the master cylinder and wheel cylinder, a storage unit for fluid storage, an electric pump, and a control unit that drives the pump to zero differential pressure during braking initiation, suppressing initial liquid pressure braking force and maximizing regenerative braking force without relying on master cylinder configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an invalid stroke mechanism is provided in the master cylinder to suppress liquid pressure braking force generation, then the ratio of regenerative braking force is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the invalid stroke mechanism from the master cylinder and relocates it to a separate reservoir connected via a communication passage. This separation allows the master cylinder to be simplified while maintaining the regenerative braking optimization function in the reservoir, directly resolving the contradiction between improving regenerative braking ratio and reducing device complexity.
Solution Approach 2:
The patent introduces a communication passage as an intermediary element connecting the master cylinder to the reservoir. This intermediary allows fluid communication and pressure equalization between the two components, enabling the reservoir to perform the invalid stroke function independently while maintaining system integration, thus reducing overall device complexity.
2Productivity
If fluid is supplied to the wheel cylinder at the beginning of braking operation, then the liquid pressure braking force is generated, but the regenerative braking force ratio decreases
Solution Approach 1:
The patent implements preliminary action by pre-positioning fluid in the reservoir and establishing the communication passage before braking occurs. When braking starts, the system is already configured to divert fluid to the reservoir first, preventing initial liquid pressure braking force generation and maximizing regenerative braking force ratio from the outset.
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 solution effectively suppresses initial liquid pressure braking force, allowing for maximum regenerative braking force generation by controlling valve units, independent of master cylinder configuration, and reduces the need for an invalid stroke mechanism, enhancing braking efficiency and simplicity.
Implementation Method 1
a liquid pressure braking device configured to impart a liquid pressure braking force, which corresponds to a liquid pressure in a wheel cylinder
Implementation Method 2
a first valve unit provided in a first liquid pressure circuit connecting the wheel cylinder and a master cylinder, and configured to adjust a first differential pressure being a differential pressure between a liquid pressure on the master cylinder side and a liquid pressure on the wheel cylinder side
Implementation Method 3
a second valve unit provided in a second liquid pressure circuit connecting the master cylinder and the storage chamber, and configured to adjust a second differential pressure being a differential pressure between a liquid pressure on the master cylinder side and a liquid pressure on the storage chamber side
Data Source
AI summary
An electric braking device includes: a first valve unit for adjusting a first differential pressure between a master cylinder side liquid pressure and a wheel cylinder side liquid pressure; a storage unit forming a fluid storage chamber; second valve units for adjusting a second differential pressure between the master cylinder side liquid pressure and a storage chamber side liquid pressure; an electric pump for discharging the fluid in the storage chamber; and a control unit which, while operating the electric pump during a time from initiation of braking force application until a request value acquired by a request braking force acquiring unit reaches a maximum value, controls the first valve unit such that the first differential pressure becomes zero, and controls the second valve units such that the second differential pressure becomes zero.