Electric Brake Gear Train Load Sensing for Precise Force Control
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Solution Overview
Problem
Existing electric motor service brakes in vehicles lack precise control over braking force application and distribution, especially in varying conditions, leading to potential deviations due to tolerances and performance variations in components.
Innovation Solution
A load sensing device is integrated into the gear train of an electric brake actuator, comprising a sun gear and driven gear with a fast lead connection, to measure thrust load and adjust motor torque via a controller, ensuring precise braking force application and distribution across wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional electric motor service brakes are used without load sensing, then the system is simpler and lower cost, but precise control over braking force application and distribution cannot be achieved
Solution Approach 1:
The patent replaces complex mechanical linkage systems with an electric motor-driven gear train actuator. The motor controls the caliper assembly through a gear mechanism, eliminating the need for complex mechanical force distribution systems while enabling precise electronic control of braking force through motor torque regulation.
Solution Approach 2:
The patent introduces a load sensing device as an intermediary element between the gear train and the control system. This sensor measures the actual braking force applied by the caliper assembly and provides feedback to the controller, enabling closed-loop control that compensates for component variations and achieves precise braking force distribution.
2Reliability
If component tolerances and performance variations are not compensated, then the system is simpler, but braking force distribution consistency across wheels deteriorates
Solution Approach 1:
The patent implements feedback control by using the load sensing device to continuously monitor the actual braking force applied by each caliper assembly. The controller receives this feedback and actively adjusts the motor torque to compensate for component tolerances, wear, and performance variations, ensuring consistent braking force distribution across all wheels regardless of initial component variations.
3Manufacturing precision
If load sensing device and active control are implemented, then precise braking force control is achieved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent uses an electric motor with electronic control to replace traditional mechanical braking force adjustment mechanisms. The motor's torque can be precisely controlled through electronic signals, and the gear train provides mechanical advantage while maintaining simplicity. This substitution enables precise braking force application without requiring complex mechanical adjustment mechanisms.
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
Enables precise control of braking force by adjusting motor current based on sensed thrust load, accounting for component variations and wear, thereby ensuring consistent braking performance across all wheels.
Implementation Method 1
A load sensing device senses a thrust load applied by the sun gear in response to torque generated by the motor during a braking operation
Implementation Method 2
The gear train includes a two stage gear assembly comprising of a driven gear and a sun gear threadably connected to one another
Implementation Method 3
a sun gear threadably connected to one another
Implementation Method 4
an electric motor includes a gear train for converting torque from the electric motor to force applied on brake pads
Data Source
AI summary
An actuator for an electric brake of a vehicle having a caliper assembly driven by a motor includes a gear train for transferring torque from the motor to the caliper assembly to brake the vehicle. The gear train has an driven gear and a sun gear connected to one another. A load sensing device senses a thrust load applied by the sun gear in response to torque generated by the motor during a braking operation. A controller is connected to the load sensing device and configured to adjust the torque applied to the gear train in response to receiving signals from the load sensing device indicative of the thrust load.