Two-Material Brake Actuator Gear for Compact High-Load Transmission
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Solution Overview
Problem
Existing brake actuators in motor vehicles require significant installation space and are costly due to the use of multi-stage gears, particularly in electromechanical brakes, which also demand weight-saving and cost-effective solutions.
Innovation Solution
A multi-component gear design featuring a sleeve-shaped support body made of a rigid plastic material and a gear body with lower rigidity and higher elasticity, both manufactured using 2K plastic injection molding, with the support body having a smaller outer diameter than the gear body and incorporating features like radial and axial bearings, rib-like support structures, and distal support fingers for enhanced strength and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multi-stage planetary gearboxes are used in electromechanical brakes, then the transmission function is achieved, but the installation space requirement increases considerably
Solution Approach 1:
The gear is divided into two functional components: a support body made of stiff reinforced plastic and a gear body made of elastic thermoplastic. This segmentation allows each component to be optimized for its specific function while reducing overall space requirements compared to multi-stage planetary gearboxes.
Solution Approach 2:
The patent replaces complex multi-stage planetary mechanical gear systems with a single-stage gear design using plastic injection molding. The elastic gear body deforms under load to achieve the transmission function, substituting traditional rigid mechanical gearing with elastic deformation mechanics.
2Power
If traditional multi-stage gearboxes are used, then the required transmission ratio is achieved, but the component weight increases
Solution Approach 1:
The support body uses glass fiber reinforced polyphenylene sulfide (PPS GF) providing high stiffness and strength, while the gear body uses polyoxymethylene (POM) providing elasticity and low weight. This composite material approach achieves the required transmission ratio with significantly reduced weight compared to traditional metal multi-stage gearboxes.
Solution Approach 2:
The patent changes the material parameters by using reinforced plastic for the support body and thermoplastic for the gear body. The reinforced plastic provides the necessary structural strength and stiffness, while the thermoplastic provides elasticity, allowing the gear to achieve transmission function with lower weight than traditional metal components.
3Ease of manufacture
If homogeneous plastic material is used for the gear, then manufacturing is simplified, but the necessary strength and elasticity requirements cannot be simultaneously met
Solution Approach 1:
The gear is segmented into two components made of different plastic materials: a stiff reinforced plastic support body and an elastic thermoplastic gear body. This segmentation allows each material to be optimized for its specific functional requirements while both components can be manufactured using standard injection molding processes.
Solution Approach 2:
The patent uses composite materials - glass fiber reinforced PPS for the support body and POM for the gear body - permanently molded together in a two-step injection molding process. This composite construction achieves the necessary strength and elasticity requirements that cannot be met by homogeneous plastic materials alone.
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 multi-component gear achieves a compact design with high strength, reducing installation space requirements and production costs while maintaining necessary mechanical stability, especially under high stress conditions.
Implementation Method 1
The multi-component gear (10) is manufactured by plastic injection molding using 2K technology
Data Source
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AI summary
The invention relates to a multi-component gear (10) for a transmission arrangement of a brake actuator, in particular of a motor vehicle, with the following features: - a sleeve-shaped support body (100) made of a first plastic material, - a gear body (200) made of a second plastic material, which has a lower stiffness and a higher elasticity than the first plastic material and is integrally molded onto the support body, - the gear body (200) has an outer toothing (210) and an internal spindle nut toothing (230) for receiving a spindle (50), - the spindle nut toothing (230) is arranged axially offset from the outer toothing (210) at least partially in one direction, - the support body projects axially at least partially into the area of the helical gear toothing and into the area of the spindle toothing (230), and - the support body (100) has a smaller outer diameter than the helical gear toothing.Furthermore, the invention relates to a brake actuator with such a multi-component gear (10) and a method for manufacturing such a multi-component gear (10).