Electromagnetic Park Brake Assembly for Motor Back-Drive Prevention
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Solution Overview
Problem
Existing vehicle brake systems lack an effective mechanism to prevent back drive of the motor when the parking brake is applied, leading to inefficiencies and potential safety issues.
Innovation Solution
A brake assembly incorporating a motor gear unit with an electromagnetic brake that prevents movement of the motor gear unit and pistons when the motor is turned off, utilizing a core with a press-fit inner and outer casing, and a rotor with contact surfaces to maintain the brake apply and prevent back drive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high efficiency rotary to linear actuator (e.g., ball screw or ball ramp) is used to move the piston, then the brake apply efficiency is improved, but the motor can be back driven when turned off causing safety issues
Solution Approach 1:
An electromagnetic brake is introduced as an intermediary component between the motor and the ball screw/ball ramp mechanism. This electromagnetic brake acts as a mediator that prevents the motor from being back driven by the piston while allowing the motor to efficiently drive the piston during brake application. The electromagnetic brake engages when the motor is turned off to block back drive, and disengages when the motor is running to allow efficient motion transmission.
2Reliability
If an electromagnetic brake is added to prevent back drive, then the safety and reliability are improved, but the device complexity increases
Solution Approach 1:
The electromagnetic brake is integrated with the existing motor assembly, merging the braking function into the motor housing. The electromagnetic brake shares the same rotational axis as the motor and is positioned to directly interact with the ball screw/ball ramp mechanism. This merging approach reduces overall system complexity by eliminating separate braking components and simplifying the mechanical linkage.
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 solution effectively maintains the brake apply and prevents back drive, ensuring the brake remains engaged when the motor is off, enhancing safety and efficiency by using an electromagnetic brake that defaults to a locked position when deactivated.
Implementation Method 1
an electromagnetic brake that prevents movement of the motor gear unit, the pistons, or both when the motor is turned off so that the brake apply is maintained
Data Source
AI summary
An electromagnetic brake to restrict or prevent movement of a motor in a vehicle brake system, the electromagnetic brake includes: a core; a static plate; a moving plate located between the core and the static plate; a rotor located between the core and the moving plate; one or more legs that extend from the core; and one or more fasteners that connect the one or more legs to the static plate, the core includes a cylindrical portion and a flange that extends around the cylindrical portion, the one or more legs extend from the flange radially around the cylindrical portion.