Bearing Support Structure for Moisture-Stable Power Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The support member in power transmission devices expands due to moisture absorption, leading to a decrease in bearing support rigidity as it bulges and deforms radially, causing a gap between the support member and the bearing to widen, which has not been effectively addressed by existing technologies.
Innovation Solution
Incorporating a fitting member made of a material with lower hygroscopicity than the support member, which is fitted to the outer peripheral portion of the support member, constraining the bulging deformation in a radial inward direction to maintain bearing support rigidity by reducing the gap between the support member and the rotary shaft bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the support member is made of a hygroscopic material, then the support member can be manufactured with lower cost and weight, but the support member expands due to moisture absorption causing bearing support rigidity to decrease
Solution Approach 1:
The support member is constructed as a composite structure combining a hygroscopic material (for weight reduction) with a low-hygroscopicity fitting member (for dimensional stability). This composite approach allows the structure to benefit from both the light weight of hygroscopic materials and the dimensional stability of low-hygroscopicity materials, resolving the contradiction between weight and reliability.
Solution Approach 2:
Different portions of the support member structure are assigned different material properties: the main body uses hygroscopic material for weight savings, while the critical fitting portion uses low-hygroscopicity material to maintain bearing support rigidity. This local differentiation of material quality allows simultaneous optimization of both weight and reliability.
2Ease of manufacture
If the support member is made of a hygroscopic material, then the support member can be manufactured with lower cost, but the support member expands due to moisture absorption causing bearing support rigidity to decrease
Solution Approach 1:
The support member is constructed as a composite structure combining a hygroscopic material (for weight reduction) with a low-hygroscopicity fitting member (for dimensional stability). This composite approach allows the structure to benefit from both the light weight of hygroscopic materials and the dimensional stability of low-hygroscopicity materials, resolving the contradiction between weight and reliability.
Solution Approach 2:
Different portions of the support member structure are assigned different material properties: the main body uses hygroscopic material for weight savings, while the critical fitting portion uses low-hygroscopicity material to maintain bearing support rigidity. This local differentiation of material quality allows simultaneous optimization of both weight and reliability.
3Adaptability or versatility
If the support member expands radially due to moisture absorption, then the material can accommodate humidity changes, but the gap between the support member and bearing widens causing shaft runout to increase
Solution Approach 1:
The low-hygroscopicity fitting member acts as an intermediary element between the hygroscopic support member and the bearing. It mediates the dimensional changes by absorbing minimal moisture itself, thereby preventing the transmission of expansion effects to the bearing interface and maintaining manufacturing precision despite humidity changes.
Solution Approach 2:
Different portions of the support member structure are assigned different material properties: the main body uses hygroscopic material for weight savings, while the critical fitting portion uses low-hygroscopicity material to maintain bearing support rigidity. This local differentiation of material quality allows simultaneous optimization of both weight and reliability.
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 configuration increases the support rigidity of the rotary shaft bearings by maintaining the gap closure even in high-humidity environments, reducing shaft runout and stabilizing the meshing between gears, while also potentially reducing component costs and weight.
Implementation Method 1
The support member expands due to moisture absorption, leading to a decrease in bearing support rigidity as it bulges and deforms radially
Data Source
AI summary
There is provided a technique capable of increasing support rigidity of a bearing when a support member expands due to moisture absorption. A power transmission device includes: a rotary shaft; a support member disposed outside the rotary shaft in a radial direction; a bearing disposed between the rotary shaft and the support member; and a fitting member fitted to an outer peripheral portion of the support member. The fitting member is made of a material having lower hygroscopicity than hygroscopicity of a material of the support member.