Hollow-Shaft Power Transmission Layout for Misalignment Tolerance
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Solution Overview
Problem
Mechanical power transmission systems face challenges in minimizing parasitic forces due to misalignment between main shafts, leading to potential damage and increased mass or bulk penalties in power transmission boxes, especially in compact designs where space constraints limit the tolerance of radial offsets.
Innovation Solution
A compact mechanical power transmission system design where the intermediate shaft passes through a hollow second main shaft, allowing for a large distance between coupling means while maintaining shafts close together, using diaphragm coupling means and a reversible connection system to pre-stress the intermediate shaft, enabling high torque transmission without large diameter components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the length of the intermediate shaft is maximized to minimize parasitic forces from misalignment, then the parasitic forces are reduced, but the device complexity and space requirements increase
Solution Approach 1:
The patent employs a flexible intermediate shaft with controlled flexibility to tolerate misalignments between main shafts. The shaft's flexibility allows it to bend and accommodate radial and angular offsets without generating excessive parasitic forces, eliminating the need for an excessively long rigid shaft.
Solution Approach 2:
The patent optimizes the flexibility parameter of the intermediate shaft by selecting appropriate materials and cross-sectional properties. This allows the shaft to have just enough flexibility to tolerate misalignments while maintaining sufficient stiffness to transmit torque effectively, avoiding both excessive flexibility and excessive rigidity.
2Object-affected harmful factors
If coupling means are added to minimize misalignment impact, then parasitic forces are reduced, but the device complexity increases
Solution Approach 1:
The patent combines the coupling function with the intermediate shaft itself, making the shaft inherently capable of accommodating misalignments through its flexibility. This integration eliminates the need for separate coupling devices while still achieving the goal of minimizing parasitic forces from misalignment.
3Reliability
If the power transmission box is oversized to tolerate misalignment, then reliability is improved, but the weight and bulk increase
Solution Approach 1:
The flexible intermediate shaft allows the power transmission box to be more compact because the shaft itself accommodates misalignments rather than requiring oversized bearings or rigid alignment mechanisms. This reduces the overall size and weight of the power transmission box while maintaining reliability.
4Object-affected harmful factors
If the intermediate shaft is made flexible to tolerate misalignment, then parasitic forces are minimized, but the torque transmission capacity may be reduced
Solution Approach 1:
The patent carefully balances the flexibility parameters of the intermediate shaft by optimizing material selection and cross-sectional geometry. The shaft is designed with sufficient flexural rigidity to transmit high torque while maintaining enough flexibility to tolerate misalignments. This involves adjusting the moment of inertia and material modulus to achieve the optimal trade-off between flexibility and strength.
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
This design effectively minimizes parasitic forces during misalignment, allowing for a compact and lightweight power transmission system that tolerates significant radial offsets without stress on mechanical members, reducing maintenance needs and enabling modular assembly.
Implementation Method 1
the intermediate shaft may have an intrinsic flexibility making it possible to tolerate misalignments between the main driving shaft and the main driven shaft without generating parasitic forces
Implementation Method 2
A diaphragm coupling means comprises two thin-thickness annular members called 'diaphragms'. Each annular member comprises a thin flexible annular disc
Data Source
Figure 1~3
Figure 4
AI summary
The present invention relates to a mechanical power transmission system (10) comprising a first main shaft (11) fixed to a first coupling means (15), a second main shaft (12) fixed to a second coupling means (16), and an intermediate shaft (13) fixed to the first coupling means (15). The intermediate shaft (13) passes through said second main shaft (12) to be connected to the second coupling means (16), said second main shaft (12) being arranged longitudinally in a space (17) located between said first coupling means (15) and said second coupling means (16).