Electric Actuator Unit for Drum Brake Assembly
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Solution Overview
Problem
Conventional vehicle brake systems rely on hydraulic or pneumatic actuation for drum and disc brake assemblies, which can be less efficient and less adaptable for parking and emergency braking, particularly in electric actuation scenarios.
Innovation Solution
An electric actuator unit is introduced, comprising a motor, gear-set, spindle nut, pull rod, and brake shoe actuation link assembly, allowing for selective movement of brake shoes between braking and non-braking positions, with a spring member for follow-up force and a cartridge housing for compact integration, suitable for various vehicle types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hydraulic or pneumatic actuation is used for drum brake assemblies, then braking force can be generated, but the system becomes less efficient and less adaptable for parking and emergency braking
Solution Approach 1:
The patent replaces the conventional hydraulic or pneumatic actuation system with an electric actuator system specifically for parking and emergency braking functions. The electric motor-driven mechanism with gear-set, spindle nut, and pull rod assembly provides direct mechanical actuation of the brake shoes, eliminating the need for hydraulic fluid or compressed air in these specific braking applications, thereby improving energy efficiency and adaptability.
2Adaptability or versatility
If an electric actuator unit is introduced with multiple components (motor, gear-set, spindle nut, pull rod, link assembly), then adaptability and braking performance are enhanced, but the device complexity increases
Solution Approach 1:
The patent combines multiple functional components into a single integrated electric actuator unit assembly. The electric motor, gear-set, spindle nut, pull rod, and brake shoe actuation link assembly are merged into one compact unit that replaces what would otherwise be separate systems, thereby enhancing adaptability while managing complexity through integration rather than proliferation of separate components.
3Ease of manufacture
If a compact cartridge housing is used for integration, then ease of integration with vehicle systems is improved, but the volume available for internal components is reduced
Solution Approach 1:
The patent employs a nested arrangement where the gear-set is housed within the cartridge housing, the spindle nut is contained within the gear-set assembly, and the pull rod is positioned within the spindle nut mechanism. This nesting of components within one another allows all necessary parts to be accommodated in a compact cartridge housing, achieving ease of integration without sacrificing the space needed for internal components.
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 electric actuator unit provides efficient, adaptable, and compact actuation for drum brake assemblies, enhancing the braking performance and ease of integration with different vehicle systems, particularly for parking and emergency braking functions.
Implementation Method 1
an electric actuator unit including a motor
Implementation Method 2
a spring member for follow-up force
Data Source
AI summary
An improved structure for an electric actuator unit for use in a brake assembly. According to an embodiment, a drum brake assembly comprises a mounting flange having an abutment; a backing plate secured to the mounting flange, the backing plate having a pair of brake shoes supported thereon; and an electric actuator unit for actuating the drum brake assembly to selectively move the brake shoes between a braking and a non-braking position, the electric actuator unit including a motor, a gear-set operatively coupled to be driven by the motor, a spindle nut operatively coupled to be rotationally driven by the gear-set, a pull rod operatively coupled to be translatorily driven by the spindle nut, and a brake shoe actuation link assembly operatively coupled to be actuated by the pull rod to thereby move the brake shoes between the braking and non-braking positions, the pull rod being operatively coupled to the brake shoe actuation link assembly by a link, the link having a first end pivotally connected to the pull rod and a second end pivotally connected to a second member of the brake shoe actuation link assembly.