Magnetorheological Brake-by-Wire Actuator to Prevent Motor Stalling
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Solution Overview
Problem
Conventional hydraulic disc-type brake systems are complex, heavy, and inefficient, leading to slow braking pressure transfer and potential safety issues, while current brake-by-wire systems fail to fully eliminate hydraulic components and address motor stalling during long-time braking.
Innovation Solution
A brake-by-wire actuator using a motor-magnetorheological fluid clutch, which includes a motor, a transmission mechanism with a magnetorheological fluid clutch, planetary gear set, and ball screw set, allowing for real-time torque control and rapid response, eliminating the need for complex hydraulic pipelines and valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydraulic disc-type brake systems are used, then reliable braking function is achieved, but system complexity and weight increase due to pipelines and valves
Solution Approach 1:
The patent extracts and eliminates the complex hydraulic pipeline system and valve components from the brake system, replacing them with a motor-driven direct actuation system. This removes the disturbing elements (pipelines, valves) while preserving the essential braking function through a simplified electromagnetic actuator design.
Solution Approach 2:
The patent replaces the mechanical-hydraulic transmission system with an electromagnetic actuation system. The motor directly generates braking force through electromagnetic fields, substituting the complex mechanical pipeline and valve system with an electric field-based actuator, thereby reducing structural complexity while maintaining braking reliability.
2Reliability
If conventional hydraulic disc-type brake systems are used, then braking function is achieved, but system weight increases which is unbeneficial to lightweight
Solution Approach 1:
The patent extracts and removes the heavy hydraulic components including master cylinder, brake pipelines, and valve assemblies from the system. By eliminating these substantial mechanical elements, the overall system weight is significantly reduced while the braking function is maintained through the lighter motor-driven actuator.
Solution Approach 2:
The patent substitutes the heavy mechanical-hydraulic system with a compact electromagnetic actuation system. The motor-driven design eliminates the need for heavy hydraulic infrastructure, achieving weight reduction while preserving essential braking functionality through electromagnetic force generation.
3Reliability
If conventional hydraulic disc-type brake systems are used, then braking pressure is generated, but braking response is slow due to long and sophisticated pipelines
Solution Approach 1:
The patent extracts and eliminates the long, sophisticated hydraulic pipelines from the system architecture. By removing these flow-restricting elements, the system achieves direct and rapid actuation from motor to brake pads, eliminating the transmission delay inherent in hydraulic systems.
Solution Approach 2:
The patent replaces the hydraulic pressure transmission mechanism with direct electromagnetic actuation. The motor generates braking force instantly through electromagnetic fields without requiring fluid pressure buildup and transmission through pipelines, achieving significantly faster braking response while maintaining functional reliability.
4Device complexity
If motor is used as single actuator in brake-by-wire system, then system simplification is achieved, but motor stalling occurs during long-time braking leading to burnout
Solution Approach 1:
The patent implements a dynamic control strategy for the motor actuator that adjusts operating parameters in real-time based on braking conditions. During prolonged braking events, the system dynamically modulates motor operation to prevent thermal accumulation and stalling, allowing continuous safe operation without burnout while maintaining system simplification.
Solution Approach 2:
The patent incorporates feedback control mechanisms that monitor motor operating conditions during braking. The system detects early signs of stalling or thermal stress and automatically adjusts motor parameters or braking force distribution to prevent burnout, ensuring reliable continuous operation of the simplified single-actuator system.
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
This solution reduces power consumption, prevents motor stalling, enhances braking response speed, and supports advanced safety systems like ABS, EBD, and AEB, while minimizing environmental pollution from hydraulic oil leakage.
Implementation Method 1
The magnetorheological fluid clutch is a typical application using the magnetorheological fluid, which is a smart material with rheological properties. When under electromagnetic fields, its material properties (i.e., the shear stress) can be adjusted rapidly between the Newtonian fluid and semi-solid state material in milliseconds
Implementation Method 2
The planetary gear set includes a sun gear, a ring gear, a plurality of planetary gears and a carrier
Implementation Method 3
The ball screw set includes balls, a ball screw and a sleeve
Data Source
AI summary
The present invention discloses a brake-by-wire actuator based on motor-magnetorheological fluid clutch. The system includes a motor, a transmission mechanism and a floating-caliper disc mechanism. The transmission mechanism includes a magnetorheological fluid clutch, a planetary gear set and a ball screw set. The ball screw set includes balls, a ball screw and a sleeve. The floating-caliper disc mechanism includes a brake pad back plate, left and right brake pads, a caliper body, a brake disc and a guide rail. The motor and the magnetorheological fluid clutch cascaded in series, the linear motion of the sleeve of the ball screw set is achieved by the magnetorheological fluid clutch and the transmission mechanism. The sleeve pushes forward the brake pad back plate of the floating-caliper disc mechanism to clamp the brake disc by left and right brake pads, which accomplishes braking. The present invention uses a brake-by-wire actuator based on motor-magnetorheological fluid clutch, which not only has the advantages of fast response and improved braking security, but also solves the problem of the motor stalling during long time braking.