Compound Reduction Gear for Compact Rotation Reversal
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Solution Overview
Problem
Existing turboprop aircraft reduction gears face challenges in minimizing size while allowing rotation direction inversion between input and output shafts, as current solutions either result in bulkiness or lack the ability to reverse rotation.
Innovation Solution
A compound speed reducer design with two intermediate torque transmission lines, each comprising a shaft with integral stages of teeth and an additional pinion, allowing rotation direction inversion and minimizing size by axially offsetting or coplanar positioning of components, enabling the same parts to be used for different variants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an additional pinion is interposed between the input pinion and intermediate shaft to reverse rotation direction, then the rotation direction can be inverted, but the reducer becomes bulky due to single torque transmission line requiring oversized pinions
Solution Approach 1:
The single torque transmission line is segmented into two parallel intermediate transmission lines, allowing the torque to be distributed across multiple pinions. This segmentation enables rotation direction inversion while keeping individual pinion sizes and overall reducer volume reduced.
Solution Approach 2:
Two intermediate transmission lines are merged in parallel between the input and output shafts, combining their torque transmission capabilities. This merging allows the system to achieve rotation inversion through coordinated operation of both lines while maintaining compact dimensions.
2Volume of stationary object
If a compound reducer with two intermediate transmission lines is used to reduce size, then the pinions can be smaller, but the rotation direction inversion capability is lost
Solution Approach 1:
The system employs selectable engagement mechanisms that dynamically configure the two intermediate transmission lines. By selectively engaging or disengaging specific pinions and shafts, the reducer can switch between different operational modes including rotation direction inversion, while maintaining compact size through the compound structure.
Solution Approach 2:
The compound reducer structure with two intermediate transmission lines is designed to perform multiple functions: normal torque transmission, rotation direction inversion, and potentially different reduction ratios. This multi-functionality is achieved through selective engagement of the parallel transmission lines without requiring separate dedicated mechanisms for each function.
3Adaptability or versatility
If different parts are used for inverted and non-inverted variants, then each variant can be optimized, but manufacturing costs increase
Solution Approach 1:
The reducer employs a universal base structure with two intermediate transmission lines that can be selectively engaged. The same physical components (pinions, shafts, housing) are used across both inverted and non-inverted variants, with configuration differences achieved through selective engagement rather than different parts. This universality reduces manufacturing costs while maintaining variant-specific optimization.
Solution Approach 2:
The system uses selectable engagement mechanisms that allow the same hardware to dynamically configure for different operational variants. By engaging different combinations of the two intermediate transmission lines, the reducer can adapt to inverted or non-inverted configurations without requiring separate dedicated parts for each variant.
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 2c~2d
AI summary
The invention relates to a reduction gear (10) comprising -an input shaft (11) comprising an input gear (110), -an output shaft (12) comprising an output gear (120), and -two intermediate transmission lines (15), each intermediate transmission line comprising: an intermediate shaft (13) comprising a first stage of teeth (130) and a second stage of teeth (131), said stages rotating as one, and an additional gear (14) for meshing respectively with the first stage of teeth (130) and the input gear (110), or with the second stage of teeth (131) and the output gear (120), and the reduction gear being characterized in that the input gear (110) or the output gear (120) meshing with the additional gears (14) is axially offset with respect to the stage of teeth (130, 131) of the intermediate shafts (13) meshing with said additional gears (14).