Electric Vehicle Brake System Preventing Slope Slippage
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Solution Overview
Problem
Electric vehicles with traction electric motors experience uncomfortable driving behavior when electricity supply is stopped, leading to unintended vehicle movement on slopes due to lack of braking force, unlike hydraulic motor-driven vehicles.
Innovation Solution
A brake system with a rotatable brake shaft, friction plate, and braking spring, driven by a brake releasing motor, which maintains braking force even when electricity is off, and includes a protection unit to enhance motor endurance and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the hydraulic motor is replaced with an electric motor in a hydraulic motor driven vehicle, then energy can be conserved and equipment space can be reduced, but the vehicle may slip downhill when power supply is stopped due to lack of braking force
Solution Approach 1:
The brake releasing motor is activated in advance before the main power supply is stopped to pre-apply the brake, ensuring braking force is available when power is interrupted. This preliminary action prevents the vehicle from slipping downhill during power outages while still allowing normal operation when power is supplied.
2Reliability
If the brake releasing motor is continuously operated to maintain braking force, then vehicle stability on slopes is improved, but power consumption increases and motor endurance decreases
Solution Approach 1:
Instead of continuous operation, the brake releasing motor operates periodically - activated only when the main power supply is stopped or reduced. The motor applies the brake during power interruptions and remains inactive during normal operation, reducing overall power consumption while maintaining vehicle stability when needed.
3Reliability
If the brake releasing motor is activated when main power supply is reduced, then braking force is maintained during power interruptions, but the motor may overheat due to frequent activation
Solution Approach 1:
The brake releasing motor is designed to operate at high power only when absolutely necessary (during power supply interruptions), rather than maintaining a continuous low-level operation. This partial action approach - using full braking capability only when needed - reduces cumulative operating time and heat generation while still providing adequate braking force maintenance.
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 reduces driver discomfort by maintaining braking force during electricity supply interruptions, preventing vehicle slippage on slopes and improving motor reliability and power efficiency.
Implementation Method 1
a braking spring which applies an elastic force to the brake shaft in a direction to rotate the brake shaft in the brake realizing direction
Implementation Method 2
a friction plate which is operatively connected to the traction electric motor and which is frictionally braked when the brake shaft is rotated in the brake realizing direction
Implementation Method 3
the brake releasing motor rotates the brake shaft against the elastic force of the braking spring in the brake releasing direction through the displacement member and the displacement permitting spring
Data Source
AI summary
An electric vehicle comprising a drive wheel which is driven by a traction electric motor, a brake command device, a brake releasing unit, a brake shaft, a friction plate, and a braking spring. The brake shaft is rotatable in a brake realizing direction which is one direction by an operation of the brake command device, and is rotatable in a brake releasing direction which is the other direction by driving of the brake releasing unit. The friction plate is operatively connected to the traction electric motor, and is frictionally braked when the brake shaft is rotated in the brake realizing direction. The braking spring applies an elastic force to the brake shaft in a direction to rotate the brake shaft in the brake realizing direction.