Resin Monocoque Subframe Engine Mounting
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Solution Overview
Problem
The existing methods for mounting an engine in a monocoque vehicle with a reinforced resin body either increase the vehicle's weight and reduce torsional rigidity or risk damaging the resin due to heat exposure, especially when using a large rear frame or separate fastening of the monocoque body and rear frame.
Innovation Solution
A monocoque vehicle design featuring a subframe made of highly thermal-resistant resin, directly mounting the engine on the rear surface of the subframe, which is integrated with the monocoque body and reduces the vehicle's weight and maintains torsional rigidity by using a smaller subframe and specific resin materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large rear frame is used for rubber-mount of an engine, then the engine vibration damping is improved, but the vehicle mass increases
Solution Approach 1:
The patent extracts the engine mounting function from a separate rear frame and integrates it directly into the monocoque body structure. The monocoque body itself serves as the mounting structure, eliminating the need for a dedicated rear frame and reducing overall vehicle mass while maintaining engine support and vibration damping capabilities.
Solution Approach 2:
The patent merges the engine mounting function with the monocoque body structure. The rear frame is eliminated and the engine is mounted directly to the monocoque body, combining the structural support and engine mounting functions into a single integrated component, thereby reducing weight.
2Ease of manufacture
If the monocoque body and rear frame are separately formed and fastened with bolts, then the manufacturing flexibility is improved, but the torsional rigidity decreases
Solution Approach 1:
The patent merges the monocoque body and rear frame into a single integral structure. The engine is mounted directly to the monocoque body without a separate rear frame, eliminating bolted joints and improving torsional rigidity while maintaining manufacturing flexibility through integrated molding processes.
3Strength
If an engine is directly mounted on the monocoque body, then the torsional rigidity is maintained, but the reinforced resin deteriorates due to heat from the engine
Solution Approach 1:
The patent uses a composite material structure where a heat-resistant resin layer is applied to the monocoque body in the engine mounting area. This heat-resistant coating protects the underlying reinforced resin from thermal deterioration while allowing direct engine mounting to maintain torsional rigidity.
Solution Approach 2:
The patent introduces a heat-resistant resin layer as an intermediary between the engine and the monocoque body. This intermediate layer acts as a thermal barrier, protecting the reinforced resin from direct heat exposure while still allowing mechanical mounting and load transfer.
4Temperature
If a highly thermal resistant resin is used for the monocoque body, then the engine heat resistance is improved, but the molded monocoque body may be cracked during demolding
Solution Approach 1:
The patent segments the monocoque body into two material zones: the main body uses standard reinforced resin for optimal strength and demolding characteristics, while only the engine mounting area uses heat-resistant resin. This segmentation allows the use of heat-resistant material where needed without compromising the overall structural integrity and demolding performance of the entire monocoque body.
Data Source
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AI summary
Each of a monocoque body (10) and a subframe (30) is integrally formed of reinforced resin. The subframe (30) has a bottom portion (32) and an upstanding portion (34). The bottom portion (32) is fixed to the lower portion of the rear wall (20) of the monocoque body (10) and extends rearward of the vehicle. The upstanding portion (34) extends upward from the bottom portion (32). An engine (70) is directly mounted on the rear surface of the upstanding portion (34).