Variable Ratio Speed Reducer for Electromechanical Brake
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Solution Overview
Problem
Conventional electromechanical brake systems suffer from reduced responsiveness due to a fixed speed reduction ratio, which hampers fast control and braking performance, and generate noise during braking due to constant torque amplification.
Innovation Solution
An electromechanical brake system with a speed reducer that adjusts its reduction ratio based on load sensed by a force sensor, using a shifting mechanism involving a solenoid coil, guide rod, and internal gears to optimize rotational force transfer, allowing reduced rotation speed only when load is applied, thereby improving responsiveness and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fixed speed reducer with constant reduction ratio is used, then the structure is simple, but responsiveness is degraded and fast control cannot be implemented
Solution Approach 1:
The speed reducer is designed with variable reduction ratio capability, allowing it to dynamically adjust between different reduction states (first reduction ratio and second reduction ratio) based on operational requirements. This dynamic adjustment enables fast control and improved responsiveness while maintaining structural feasibility through controlled variability rather than complete redesign.
Solution Approach 2:
The reduction ratio parameter of the speed reducer is made changeable through the variable reduction mechanism. By adjusting the reduction ratio between first and second values, the system can optimize performance for different operating conditions, achieving both responsiveness and control capability without excessive structural complexity.
2Force
If torque is constantly amplified through the speed reducer, then braking force is sufficient, but noise is produced during braking
Solution Approach 1:
The torque amplification is made dynamic rather than constant. The speed reducer adjusts its reduction ratio based on load conditions detected by the force sensor, providing high torque amplification only when necessary (during actual braking) and reducing amplification during non-braking operations, thereby minimizing noise generation while maintaining sufficient braking force when needed.
Solution Approach 2:
The system uses the force sensor to automatically detect load conditions and control the motor to adjust the reduction ratio accordingly. This self-regulating mechanism ensures torque amplification occurs only when load is present, eliminating the need for constant high-torque mode that generates noise, while still providing adequate braking force when required.
3Speed
If a variable reduction ratio mechanism is added, then responsiveness is improved, but device complexity increases
Solution Approach 1:
The variable reduction mechanism is implemented with controlled dynamics, allowing the speed reducer to switch between two primary reduction ratios (first and second) based on operational needs. This approach provides the responsiveness benefits of variable reduction while limiting structural complexity by using discrete, well-defined states rather than continuous variability.
Solution Approach 2:
The reduction ratio parameter is made adjustable between specific values through the variable reduction mechanism. This controlled parameter change enables responsiveness improvement while managing complexity by defining specific operational states rather than requiring unlimited adjustment capabilities.
4Power
If torque amplification is continuously applied, then braking performance is maintained, but energy consumption increases
Solution Approach 1:
The force sensor continuously monitors load conditions and automatically controls the motor to adjust the reduction ratio. Torque amplification is activated only when load is detected (during braking), and deactivated when no load is present, creating an energy-efficient system that maintains braking performance when needed while minimizing energy consumption during normal operation.
Solution Approach 2:
The torque amplification operates periodically rather than continuously, being activated only during braking events when load is detected and deactivated during non-braking periods. This periodic operation pattern maintains braking performance when required while significantly reducing overall energy consumption compared to continuous amplification.
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 enhances responsiveness by adjusting speed reduction dynamically and reduces noise by amplifying rotational force only during load application, improving braking efficiency and minimizing noise during operation.
Implementation Method 1
a solenoid coil to move the guide rod in the accommodation portion when load is produced in the ball nut
Implementation Method 2
a pressing member including a ball nut installed at the caliper housing to convert rotational motion into rectilinear motion to apply pressure to the pad plates and a ball screw coupled to the ball nut
Implementation Method 3
The speed reducer includes a sun gear installed at a rotating shaft of the motor, a plurality of planetary gears disposed around the sun gear to engage with the sun gear
Data Source
AI summary
Disclosed herein is an electromechanical brake system includes a base carrier provided with a pair of pad plates for application of pressure to a disc, a caliper housing supported by the base carrier to be movable forward and backward to apply pressure to the pad plates, a pressing member including a ball nut installed at the caliper housing to convert rotational motion into rectilinear motion to apply pressure to the pad plates and a ball screw coupled to the ball nut, a force sensor installed at the ball nut to sense load produced by the ball nut, a motor to produce rotational force to operate the pressing member, and a speed reducer connected to a rotating shaft of the motor to transfer driving force to the pressing member, wherein the speed reducer may be adapted to change a reduction ratio depending on presence of load sensed by the force sensor.