Brake Actuator Retraction Detection to Prevent Over-Stroking

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Solution Overview

Problem

Existing brake systems face challenges in accurately determining when actuators or brake components have reached specific positions, leading to potential over-stroking issues that can cause damage to the actuator, motor, and other components.

Innovation Solution

A control method and brake system that utilize a spindle and nut assembly to determine when the actuator is in extended or retracted positions, using motor characteristics to control the position of the nut relative to the spindle stop, thereby preventing over-stroking and ensuring precise positioning of brake pads or shoes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the actuator is moved to determine when it has reached a specific position, then positioning accuracy is improved, but the risk of over-stroking and component damage increases

Engineering Contradiction:

Improveposition detection accuracyVSAvoidactuator and motor reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system continuously monitors motor characteristics (current, voltage, speed) during actuator movement and compares them against expected values. When deviations indicating proximity to the stop position are detected, the control system automatically adjusts or halts movement, preventing over-stroking while maintaining accurate positioning.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces traditional mechanical position detection methods (such as physical switches or limit stops) with electrical sensing based on motor characteristic analysis. This substitution enables precise position determination through electrical parameter monitoring without requiring additional mechanical components that could cause over-stroking.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional position determination methods are used, then component damage is reduced, but positioning accuracy deteriorates

Engineering Contradiction:

Improvecomponent protectionVSAvoidposition determination accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system replaces coarse mechanical position indicators with precise electrical sensing through motor characteristic monitoring. By analyzing current, voltage, and speed parameters, the system achieves accurate position determination without the imprecision and lag associated with mechanical switches or limit stops.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The motor itself serves as the sensing element by providing position information through its own operational characteristics. The system utilizes the motor's inherent electrical parameters (current draw, voltage drop, speed changes) to determine actuator position, eliminating the need for separate sensing mechanisms and enabling both accurate positioning and component protection simultaneously.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11542997B2Brake system and control method thereof

Publication Date: 2023.01.03 AKEBONO BRAKE IND CO LTD

AI summary

A method of controlling a brake system that includes a motor and an actuator. The method includes moving the actuator towards a retracted position; activating a timer; monitoring a motor characteristic of the motor and monitoring the timer; and determining the actuator has reached the retracted position after the timer meets or exceeds a predetermined time threshold before the motor characteristic has reached or exceeded a predetermined motor characteristic threshold.