Thermoplastic Monocoque Drone Housing Without Complex Molds

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Solution Overview

Problem

The monocoque structure for drone housings, while increasing rigidity, requires a different mold for thermoplastic resins, leading to economic inconvenience and manufacturing challenges.

Innovation Solution

A drone housing with a monocoque structure using a fiber-reinforced resin outer shell and thermoplastic resin reinforcing material, featuring a lattice shape and unidirectional fiber layers, allowing for injection molding and easy assembly without undercuts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a monocoque structure is used to increase rigidity, then the number of components is reduced and weight is decreased, but the mold becomes complex and manufacturing cost increases

Engineering Contradiction:
ImproverigidityVSAvoidmold complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The housing is divided into a lower body and an upper body, each with its own mold. The lower body includes an outer shell and reinforcing material, while the upper body includes an outer shell and reinforcing material. This segmentation allows each part to be molded separately using standard injection molding processes, avoiding the need for complex single-piece molds while still achieving the overall monocoque structure through assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reinforcing material is disposed on the inner surface of the outer shell, creating a nested structure. The lower body and upper body are joined together to form the complete housing. This nesting approach allows the reinforcing material to be integrated within the outer shell without requiring separate structural components, maintaining the monocoque appearance while simplifying manufacturing.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Strength

If a monocoque structure with undercut portions is used, then rigidity is improved, but the structure cannot be taken out from the mold by injection molding

Engineering Contradiction:
ImproverigidityVSAvoidmoldability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

By dividing the housing into lower and upper bodies that can be separately molded, the design avoids the undercut portion problem. Each body can be molded using standard injection molding processes without requiring complex mold opening mechanisms, while the assembly of the two bodies creates the overall monocoque structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of trying to remove the entire monocoque structure from the mold (which would require avoiding undercuts), the approach is inverted by assembling two separately molded bodies. The lower body and upper body are joined together, effectively creating the monocoque structure through assembly rather than single-piece molding, thus avoiding the mold removal problem.

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of manufacture

If a different mold is prepared for thermoplastic resins, then injection molding becomes possible, but manufacturing cost increases

Engineering Contradiction:
Improveinjection molding capabilityVSAvoidmold variety
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The housing is segmented into lower and upper bodies that can be molded using standard injection molding processes. This segmentation allows the use of conventional molds designed for thermoplastic resins, eliminating the need for specialized molds while maintaining injection molding capability. The reinforcing material can be integrated during the molding process using standard techniques.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mold design is made universal by using standard injection molding processes for both the outer shell and reinforcing material. The same mold technology can be applied to produce different configurations of the lower and upper bodies, making the manufacturing process flexible and cost-effective without requiring specialized mold varieties.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables the manufacturing of a lightweight, rigid drone housing using thermoplastic resins, reducing manufacturing complexity and costs while maintaining structural integrity.

Implementation Method 1

an outer shell made of a fiber-reinforced resin that includes reinforcing fibers and a thermoplastic resin spreading through the reinforcing fibers

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Implementation Method 2

when an attempt is made to produce a structure having a similar shape using thermoplastic resins, which are usually injection molded

Methodology Applied
Scientific EffectInjection molding:

Data Source

PatentEP4722107A1Housing for drone, method for manufacturing same, and drone
Publication Date: 2026.04.08 MITSUI CHEMICALS INC
  • EP4722107A1 patent drawingFigure 1
  • EP4722107A1 patent drawingFigure 2
  • EP4722107A1 patent drawingFigure 3A~3B

AI summary

Provided is a housing for a drone having a monocoque structure which can be manufactured even by using a thermoplastic resin. This housing for a drone includes: a lower body having a bottom surface part and a wall part formed at a peripheral edge part of the bottom surface part; and an upper body having an upper surface part and a wall part formed on a peripheral edge part of the upper surface part. The lower body has an outer shell made of a fiber-reinforced resin in which a thermoplastic resin is impregnated into reinforcing fibers, and a reinforcing material made of a thermoplastic resin and partially disposed inside the outer shell.