Differential Housing Thermal Expansion Suppression
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Solution Overview
Problem
Existing differential housing designs fail to effectively manage thermal expansion/contraction, leading to fluctuations in power transmission states due to changes in the relative positional relationships among bearings, causing noise and vibrations.
Innovation Solution
Incorporating bearing surrounding members and connecting members made of materials with smaller linear expansion coefficients, embedded within the differential housing's base material, to stabilize the positional relationships among input bearings and differential case bearings, and distributing thermal stress through projections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a tubular member having a smaller linear expansion coefficient than that of a base material of a differential housing is inserted in a part of an inner surface of the differential housing by insert casting, then the thermal expansion/contraction of the differential housing can be suppressed, but the tubular member is likely to be displaced with respect to the base material due to thermal expansion/contraction, causing change in relative positional relationships among bearings
Solution Approach 1:
The patent uses a composite structure consisting of a base material (e.g., aluminum alloy) and an inserted tubular member (e.g., steel) with different linear expansion coefficients. This composite construction allows the tubular member to suppress thermal expansion/contraction of the differential housing while maintaining structural integrity. The insert casting process creates a composite material system that combines the advantages of both materials.
Solution Approach 2:
The differential housing is segmented into multiple components: the base material structure and the inserted tubular member. This segmentation allows each component to be optimized independently - the base material provides overall structural support while the tubular member specifically addresses thermal expansion issues in critical areas. The connecting members further segment the bearing support structure to maintain positional relationships.
Solution Approach 3:
The patent changes the linear expansion coefficient parameter by selecting materials with appropriate properties for different components. The tubular member has a smaller linear expansion coefficient than the base material, allowing it to resist thermal expansion. This parameter change enables the system to maintain dimensional stability under temperature variations.
2Weight of moving object
If the entire structure of the differential housing is made of a material having a large linear expansion coefficient, then the weight of the differential housing can be reduced, but the thermal expansion/contraction increases, causing noise and vibrations in gears
Solution Approach 1:
The patent employs composite materials where the base material (e.g., aluminum alloy with larger linear expansion coefficient) provides lightweight structure, while the inserted tubular member (e.g., steel with smaller linear expansion coefficient) suppresses thermal expansion. This composite approach achieves both weight reduction and thermal stability.
Solution Approach 2:
Instead of making the entire differential housing from lightweight material, the patent applies the lightweight base material throughout but locally inserts tubular members in specific areas where thermal expansion control is critical. This local quality approach maintains overall weight advantages while providing targeted thermal expansion suppression.
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 suppresses changes in relative positional relationships and thermal stress, maintaining a stable power transmission state, reducing noise and vibrations, and minimizing the weight and cost of the differential housing.
Implementation Method 1
when a dimensional change occurs due to a temperature change, that is, thermal expansion/contraction occurs
Implementation Method 2
distributing thermal stress through projections
Data Source
AI summary
A differential housing is configured to support a plurality of bearings. The differential housing includes a first bearing surrounding member provided to surround a first bearing included in the plurality of bearings. The differential housing includes a second bearing surrounding member provided to surround a second bearing included in the plurality of bearings; and a connecting member that connects the first bearing surrounding member and the second bearing surrounding member, at least a part of the connecting member being embedded in a wall that is made of a base material of the differential housing. Each of the first bearing surrounding member, the second bearing surrounding member, and the connecting member is constructed of a material having a smaller linear expansion coefficient than that of the base material of the differential housing.