Brushless Servo Miniaturization via Stacked PCBs
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Solution Overview
Problem
Brushed servos face issues with wear, heat generation, and limited miniaturization due to larger control circuits required for brushless motors, which increases size and weight, and reduces functionality.
Innovation Solution
A compact brushless servo design featuring a control circuit board with multiple layers of PCBs connected via flexible circuit boards, arranged to minimize space and weight, with the motor and gearbox configuration optimized to maintain stability and reduce dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a brushless motor is used instead of a brushed motor, then the servo life and thermal efficiency are improved, but the control circuit size increases and device complexity increases
Solution Approach 1:
The patent transitions from a planar circuit board layout to a three-dimensional stacked PCB configuration with multiple layers connected by flexible circuit boards. This vertical arrangement allows the control circuit to occupy less horizontal space while maintaining all necessary functional components, thereby reducing the overall circuit board area without compromising the brushless motor control capabilities
Solution Approach 2:
The patent implements a nested structure where multiple PCB layers are stacked within the same footprint area. The flexible circuit boards connect these layers in a compact arrangement, allowing the control circuit to be contained within a smaller volume while preserving all control functions required for brushless motor operation
2Adaptability or versatility
If the circuit board size is increased to accommodate the control circuit, then the control functionality is improved, but the servo size and weight increase
Solution Approach 1:
The control circuit is arranged in multiple stacked PCB layers connected by flexible circuit boards, transforming the layout from two-dimensional expansion to three-dimensional stacking. This approach maintains full control functionality within a compact vertical footprint, preventing increases in servo overall dimensions and weight
3Volume of moving object
If the circuit board size is kept unchanged to maintain compact size, then the servo size is reduced, but the control circuit functionality is limited
Solution Approach 1:
The control circuit is divided into multiple functional modules distributed across several PCB layers. Each layer contains specific control functions, and the flexible circuit boards interconnect these modular sections, enabling full control functionality to be achieved within the constrained circuit board area
Solution Approach 2:
By stacking PCB layers vertically and connecting them through flexible circuit boards, the patent expands the available circuit space in the vertical dimension rather than horizontally. This allows comprehensive control functionality to be integrated into a compact servo size without functional limitations
Data Source
AI summary
A brushless servo includes: a DC brushless motor having an output shaft; a reduction gearbox including a speed reduction mechanism; and a control circuit board including a number of layers of PCBs that are spaced apart from each other, and two adjacent PCBs are electrically connected to each other via a flexible circuit boards. The output shaft of the DC brushless motor is connected to the speed reduction mechanism in the reduction gearbox, and the brushless DC motor and the control circuit board are arranged side by side at one side of the reduction gearbox.