Drive Axle Brake Actuator Assembly for Redundant EV Holding
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Solution Overview
Problem
Electric vehicles with single-speed transmissions often lack redundancy in their braking systems, as they may not have a parking lock or pawl, making them reliant solely on automatic parking brakes, which is a concern for highly automated vehicles that need robust and redundant braking mechanisms.
Innovation Solution
A controllable actuator device connected to the drive axle of an electric vehicle, controlled by the vehicle's onboard electronics, which can generate a braking or blocking effect, replacing the need for a separate actuator controller and bus connection, and incorporating a pawl or frictional connection for redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a separate actuator controller and bus connection are used for the actuator device, then the actuator can be controlled independently, but the device complexity and cost increase
Solution Approach 1:
The patent integrates the actuator control functionality directly into the existing brake system control unit, eliminating the need for a separate actuator controller. The control unit receives brake requests and directly controls both the braking system and the actuator device through integrated logic, thereby reducing device complexity while maintaining independent actuator control capability.
Solution Approach 2:
The brake system control unit is designed to perform multiple functions: controlling the braking system and controlling the actuator device for redundancy. This multi-functional approach allows a single control unit to manage both primary braking and redundant holding/braking operations, reducing the need for separate dedicated controllers.
2Reliability
If redundancy is achieved through traditional parking locks or pawls, then braking reliability improves, but the device complexity and installation space increase
Solution Approach 1:
The patent replaces traditional mechanical parking lock or pawl mechanisms with an electronically controlled actuator device. The actuator, driven by an electric motor and controlled through electronic signals from the brake system control unit, provides redundant holding and braking functionality without requiring complex mechanical linkages, thereby reducing device complexity while maintaining reliability.
Solution Approach 2:
The invention changes the operational parameters and control method of the redundant braking system from purely mechanical (traditional parking locks) to electromechanical (electronically controlled actuator). This allows for more flexible control, reduced mechanical complexity, and integration with existing electronic brake control systems.
3Ease of manufacture
If a pawl mechanism is used for the actuator device, then manufacturing cost is reduced, but the braking force and reliability may be limited
Solution Approach 1:
The patent employs a composite approach combining a simple pawl mechanism for basic holding function with an electric motor-driven actuator for active control and braking force generation. This hybrid design maintains manufacturing simplicity while enhancing reliability through electronic control and motor assistance, overcoming the limitations of a pure mechanical pawl system.
Solution Approach 2:
The electric motor acts as an intermediary between the electronic control system and the pawl mechanism. It translates electronic control signals into mechanical motion that engages or disengages the pawl and provides additional braking force, thereby enhancing the reliability and controllability of the otherwise simple pawl-based actuator device.
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 provides a cost-effective, robust, and redundant braking system that reduces hardware and software failure risks, allowing highly automated vehicles to operate without relying solely on automatic parking brakes, while minimizing additional installation space and weight.
Implementation Method 1
it includes an electric motor for actuating the pawl
Implementation Method 2
it comprises a clamp by means of which a frictional connection with the drive shaft can be established
Data Source
Figure 1~2
AI summary
The invention relates to a controllable actuator unit (1) having an electronic connecting device (AN), the actuator device (1) being connectable to a drive axle of an electrically operated vehicle (2), such that a braking or locking effect for a rotary movement of the drive axle can be produced, the actuator device (1) being controllable by a control device (SE) via the electronic connecting device (AN).