Electric Brake System with Motor-Driven Pump and Buffer
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Solution Overview
Problem
Conventional electric brake systems have a complex structure and a lost travel section in the pedal stroke, leading to unstable pedal feel and potential malfunction during braking, which can cause dissatisfaction and safety issues.
Innovation Solution
An electric brake system with a simplified configuration, featuring a master cylinder with two hydraulic circuits, a pressure supply unit, a hydraulic control unit, and an electronic control unit that includes switching valves and a simulator to provide precise pressure control and stable pedal feel, allowing direct transfer of foot force to the wheel cylinders through backup channels in case of malfunction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional electric brake system with multiple solenoid valves and accumulators is used, then braking control capability is improved, but device complexity increases
Solution Approach 1:
The patent extracts and removes unnecessary components from the conventional brake system. Specifically, it eliminates the low-pressure accumulator, high-pressure accumulator, and multiple solenoid valves by using a direct motor-driven pump system that directly controls hydraulic pressure without complex intermediate storage and control mechanisms.
Solution Approach 2:
The motor-driven pump serves multiple functions: it generates hydraulic pressure, controls pressure regulation, and enables braking operations. This multi-functional component replaces the traditional separate accumulators and solenoid valves, simplifying the overall system while maintaining braking control capability.
2Ease of manufacture
If a gap is provided between the input rod and master cylinder, then assembly ease is improved, but pedal feel stability deteriorates
Solution Approach 1:
The patent introduces a buffer component as an intermediary element between the input rod and master cylinder. This buffer eliminates the harmful gap while maintaining assembly ease, providing stable pedal feel by ensuring direct force transmission from the driver's foot to the hydraulic system.
3Length of moving object
If a lost travel section is produced in pedal stroke, then mechanical clearance is improved, but braking responsiveness deteriorates
Solution Approach 1:
The patent removes the lost travel section by eliminating the gap between the input rod and master cylinder through the buffer mechanism. This ensures that pedal stroke is directly transmitted to the hydraulic system without dead zones, improving braking responsiveness and reducing the time delay between driver input and braking action.
4Volume of moving object
If multiple components are compactly installed in hydraulic block, then space utilization is improved, but system reliability deteriorates
Solution Approach 1:
The patent extracts and removes multiple components (accumulators, solenoid valves, check valves) from the hydraulic block, significantly reducing system complexity and potential failure points. The simplified design with fewer components maintains compactness while improving reliability by eliminating potential failure sources.
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 achieves precise pressure control and stable braking by converting rotational motor force into linear motion, eliminating the lost travel section and ensuring stable braking even when the system malfunctions, thus enhancing safety and user satisfaction.
Implementation Method 1
a hydraulic spring arranged in the pressure chamber to elastically support the hydraulic piston
Implementation Method 2
a ball-screw member configured with a screw and a bolt to convert rotational motion of the motor into rectilinear motion
Implementation Method 3
the hydraulic piston is connected to the screw adapted to rectilinearly move such that the oil in the pressure chamber is pressurized by the screw
Data Source
AI summary
Disclosed herein is an electric brake system for a vehicle including a reservoir, a master cylinder, an input rod, and a pedal displacement sensor. The electric brake system includes a pressure supply unit to receive oil and to output an electrical signal through the pedal displacement sensor, a hydraulic control unit to perform braking of a wheel, first and second switching valves connected to a channel connecting the pressure supply unit to the hydraulic control unit, a simulator connected to the master cylinder, and an electronic control unit to control the motor and the valves. The pressure supply unit includes a pressure chamber, a hydraulic piston arranged in the pressure chamber, a hydraulic spring to elastically support the hydraulic piston, the motor to generate rotational force, and a ball-screw member to convert rotational motion of the motor into rectilinear motion. The hydraulic piston is connected to the screw.