Drum Brake Reduction Gearbox Layout for Compact Wheel Integration
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Solution Overview
Problem
Existing geared motors for drum brakes are bulky and inflexible, requiring significant space and adapting to varying vehicle models is challenging due to their fixed shape and size.
Innovation Solution
A geared motor with a stepped gear train comprising coaxial pinions and toothed wheels, allowing for a flexible arrangement of axes to fit into various space configurations, including a flat and thin design with orthogonal motor placement and right-angle gearbox, enabling adaptation to different vehicle models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a traditional reduction module with epicyclic gear trains is used, then effective speed reduction is achieved, but the geared motor occupies significant space and has fixed shape
Solution Approach 1:
The reduction module is divided into multiple independent reduction stages, each with its own pinion and toothed wheel. These stages are arranged in series along the drum axis, with each stage providing partial reduction. The segmented architecture allows the overall reduction ratio to be achieved while distributing the mechanical components along the axial direction, reducing the radial footprint and allowing adaptation to available spaces of varying shape and size.
Solution Approach 2:
The invention transitions from a compact but bulky epicyclic gear train arrangement to a linear/axial arrangement of reduction stages. By extending the reduction mechanism along the axial dimension rather than packing it radially, the design achieves the same reduction ratio with a different spatial distribution, reducing the overall footprint in the radial direction while maintaining effectiveness.
2Power
If the motor axis is arranged parallel to the axes of epicyclic gear trains, then proper power transmission is achieved, but the geared motor size increases significantly
Solution Approach 1:
The power transmission path is segmented into multiple reduction stages arranged axially. Each stage transmits power sequentially along the drum axis, allowing the motor axis to remain parallel to the drum axis while distributing the gear train components along the axial direction. This segmentation enables efficient power transmission without requiring a large radial footprint.
3Ease of manufacture
If a fixed-shape geared motor is used, then manufacturing is simplified, but adaptation to varying vehicle wheel spaces becomes difficult
Solution Approach 1:
The geared motor design incorporates adjustable elements that allow modification of the reduction module's configuration. The axial arrangement of reduction stages can be adapted in number and positioning along the drum axis, and the toothed wheel can be positioned at different axial locations. This dynamic configurability enables the same basic design to be adapted to different vehicle models and wheel space constraints without requiring completely different designs.
Solution Approach 2:
The invention creates a universal geared motor design that can serve multiple vehicle models and applications. The modular reduction stage architecture allows the same basic components to be configured in different arrangements to suit various space constraints, making the design universally applicable across different vehicle platforms while maintaining manufacturing efficiency through component standardization.
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 solution provides a compact and adaptable geared motor that can be easily integrated into diverse vehicle wheel spaces, offering reduced bulk and enhanced integration flexibility without altering the reduction ratio.
Implementation Method 1
a cascade of pinions and toothed wheels, advantageously formed by stepped gears
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A reduction motor for a parking brake mechanical actuator (7) of a drum brake comprising an electric motor (21) comprising an output shaft (24) extending along a first axis, and a reduction gearbox (32) comprising an output shaft extending along a second axis, in which said reduction gearbox (32), comprises stepped tangentially-meshing spur gears (34, 35, 36, 37, 38), each stepped gear comprising a gearwheel and a coaxial pinion, these being superposed on and secured to each other in terms of rotation, said stepped gears (34, 35, 36, 37, 38) being mounted with the ability to rotate about mutually parallel axes (AX34, AX35, AX36, AX37, AX38).