Electromechanical Brake Actuator With Passive Generator Braking
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Solution Overview
Problem
In electromechanical brake actuators, uncontrolled pressure drops due to control signal failures can lead to uncontrolled transmission operation and component damage, necessitating rapid pressure reduction to initiate compensatory measures.
Innovation Solution
A drive assembly with an electric motor, gearbox, and passive electronic brake circuit that activates only when the actuating element reaches a predetermined position, allowing the transmission to run freely before braking, using the motor as a generator to supply the brake circuit and counteract the restoring force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a brake actuator is integrated into the brake caliper, then the number of components is reduced and installation space is saved, but the actuator is exposed to high temperatures and contamination from the brake disc area
Solution Approach 1:
The brake actuator is segmented from the brake caliper assembly. Instead of integrating the actuator directly into the caliper, the patent uses a separate actuator unit that can be mounted independently on the vehicle chassis, thereby reducing the actuator's exposure to harmful thermal and contaminant environments while maintaining system compactness through coordinated design.
Solution Approach 2:
A brake hose or actuation line serves as an intermediary element between the remotely mounted actuator and the brake caliper. This intermediary allows the actuator to be positioned in a thermally favorable location while still transmitting the actuation force to the brake caliper, effectively mediating between the conflicting requirements of thermal protection and functional integration.
2Temperature
If the brake actuator is mounted away from the brake disc, then temperature exposure is reduced, but the actuator requires additional mounting space and may increase system complexity
Solution Approach 1:
The vehicle chassis structure is designed to serve multiple functions: it provides structural support, mounting locations for the remotely positioned actuator, and routing pathways for actuation lines. This multi-functional use of existing chassis elements allows thermal separation without adding significant complexity to the mounting arrangement.
3Temperature
If the actuator housing is designed for thermal separation, then heat resistance is improved, but the housing design becomes more complex requiring additional insulation or cooling features
Solution Approach 1:
The thermal management function is extracted from the actuator housing design itself and relocated to the system-level arrangement. By positioning the actuator housing away from the brake disc and using the vehicle chassis as a thermal barrier, the housing design remains simple while achieving adequate thermal protection through spatial separation rather than complex insulation features.
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
Facilitates rapid pressure reduction by allowing the transmission to initially run freely, followed by controlled braking, reducing the time required for pressure release and preventing component damage.
Implementation Method 1
an electric motor (20) having a stator (21) and a rotor (22)
Data Source
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AI summary
The invention relates to a drive assembly for an electromechanical brake actuator, comprising: an electric motor; a gear mechanism which is kinematically coupled to the motor and has an actuating member that can be coupled to a pressure-generating device and can be linearly shifted by the motor in a first direction against a restoring force in order to actuate the pressure-generating device; a control device which is electrically connected to the motor for controlling the motor; a switch which can be activated by the gear mechanism as a result of a movement of the actuating member in a second direction; and an electrical brake circuit which is electrically connected to the motor and to the switch and can be activated by activating the switch and an electrical activation voltage, wherein the activation voltage is generated by the motor when, if the control device fails, the motor acts as a generator by absorbing the restoring force which acts on the actuating member, and wherein the brake circuit is designed to brake the motor in order to generate a force which counteracts the restoring force by means of the motor.