Brake Piston Actuator Isolation for High-Speed Retraction
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Solution Overview
Problem
Electromechanical-hydraulic piston actuators face the risk of self-destruction during rapid retraction due to electrical malfunctions, where the motor control unit fails to brake the electric motor before reaching the rear stop, leading to potential damage.
Innovation Solution
An isolation device is implemented to mechanically decouple the rotational coupling between the electric motor and the threaded nut, using a conical tooth system and spring mechanism to prevent further movement and isolate the rotational coupling, ensuring safe operation and reliable re-coupling independent of rotation angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electric motor is allowed to rotate freely during rapid retraction, then the actuator can retract quickly, but the electric motor may cause self-destruction due to uncontrolled inertia
Solution Approach 1:
The isolation device is pre-configured with a separable positive connection between the drive element and the threaded nut. Before the electric motor can cause damage during rapid retraction, the isolation device is already in place to mechanically decouple the motor from the transmission mechanism, preventing self-destruction while allowing quick retraction to proceed
Solution Approach 2:
The actuator is divided into separable components through the positive connection mechanism. The drive element and threaded nut can be mechanically decoupled when needed, allowing the system to segment the power transmission path and isolate the electric motor from the retraction mechanism during critical situations
2Reliability
If a mechanical isolation device is added to prevent self-destruction, then actuator safety is improved, but the device complexity increases
Solution Approach 1:
The isolation device operates autonomously through its separable positive connection mechanism. When rapid retraction occurs, the device automatically isolates the electric motor without requiring external control systems, sensors, or additional energy input, thereby improving safety while minimizing the increase in device complexity
Solution Approach 2:
The isolation device acts as an intermediary element between the electric motor and the threaded nut. This mediator component provides the necessary safety function by mechanically decoupling the motor from the transmission mechanism, adding minimal complexity while significantly improving actuator reliability
3Reliability
If the threaded nut is decoupled from the drive element during rapid retraction, then damage is prevented, but the coupling must be re-established after malfunction correction
Solution Approach 1:
The patent replaces complex control systems with a purely mechanical separable positive connection. The coupling and decoupling actions are achieved through mechanical means rather than electronic control, simplifying the re-coupling process and reducing the time required to restore functionality after a malfunction
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 prevents damage during high-speed retraction and ensures reliable re-coupling upon electrical malfunction correction, maintaining actuator functionality and providing a compact, mechanically protected design.
Implementation Method 1
An isolation device is implemented to mechanically decouple the rotational coupling between the electric motor and the threaded nut, using a conical tooth system and spring mechanism to prevent further movement and isolate the rotational coupling
Implementation Method 2
a rotation-translation mechanism which is driven in rotation by the electric motor and which has a rotatable threaded nut and a threaded spindle which is prevented from rotating and is mounted so as to be displaceable in its axial direction
Implementation Method 3
a hydraulic cylinder having a hydraulic chamber which is filled with pressure medium and into which the piston is displaceable by translational movement of the spindle from a rear piston position in the direction towards a forward piston position in order to pressurize the pressure medium
Data Source
AI summary
An electromechanical-hydraulic piston actuator providing pressurized pressure medium for a brake system of a vehicle, including an electric motor having a stator and a rotor, a rotation-translation mechanism driven by the electric motor and which has a rotatable threaded nut and a threaded spindle prevented from rotating and displaceable in its axial direction, a piston coupled with the threaded spindle in the axial direction thereof, a hydraulic cylinder having a hydraulic chamber filled with pressure medium into which the piston is displaceable from a rear piston position towards a forward piston position to pressurize the pressure medium and/or expel it from the chamber. A hydraulic connection is connected to the chamber via which pressure medium can be expelled from the chamber. An isolation device is provided for the piston-travel-controlled isolation of the rotational coupling between the rotor of the electric motor and the threaded nut.