Vehicle Door Panel Hemming with Self-Piercing Rivets

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Solution Overview

Problem

Existing vehicle door designs require redundant components like adhesives and welding rods for joint formation, increasing cost and weight, and have a protruding upper edge in the vehicle width direction.

Innovation Solution

The vehicle door design employs hemming to join inner and outer panels, eliminating the need for adhesives and welding, reducing the step width by integrating the sash front edge and step, and using reinforcing members for stability and rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesive or MIG welding is used to join inner portion and outer portion, then joint strength is improved, but device complexity and cost increase due to redundant members

Engineering Contradiction:

Improvejoint strengthVSAvoiddevice complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the redundant joining members (adhesive or welding rod) from the joint structure. By using self-piercing rivet joining, the inner portion and outer portion are directly connected without requiring separate adhesive layers or welding rods, thereby reducing device complexity while maintaining joint strength.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the chemical bonding mechanism (adhesive) or thermal-mechanical bonding (MIG welding) with a mechanical self-piercing rivet joining system. This substitution eliminates the need for redundant members while providing reliable joint strength through the self-piercing rivet that mechanically interlocks the inner and outer portions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If outer portion is bent inward to obtain joint margins, then joint formation is enabled, but the upper edge projects in vehicle width direction increasing door width

Engineering Contradiction:

Improvejoint formationVSAvoiddoor width

Core Design Contradiction:

Ease of manufactureVSLength of moving object

Solution Approach 1:

Instead of bending the outer portion inward to create joint margins, the invention inverts the approach by having the self-piercing rivet pierce through both portions in their original aligned positions. This eliminates the need for bending the outer portion inward, allowing the upper edge to remain flush and reducing the door width in the vehicle width direction.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention extracts the bending step from the manufacturing process. By using self-piercing rivet joining, the method eliminates the need to bend the outer portion inward to create joint margins, thereby avoiding the projection of the upper edge and reducing the overall door width.

Inventive Principle:

Principle #2Taking out (Extraction)

3Strength

If adhesive or welding rod is used for joining, then joint strength is improved, but weight increases due to redundant members

Engineering Contradiction:

Improvejoint strengthVSAvoiddoor weight

Core Design Contradiction:

StrengthVSWeight of stationary object

Solution Approach 1:

The invention extracts and removes the redundant joining members (adhesive or welding rod) from the joint structure. The self-piercing rivet joining method directly connects the inner and outer portions without requiring additional materials, thereby reducing the overall door weight while maintaining joint strength.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention discards the unnecessary redundant members (adhesive or welding rod) that were previously required for joining. By adopting self-piercing rivet joining, the method eliminates these extraneous components, reducing weight while achieving the necessary joint strength through the rivet's mechanical interlocking action.

Inventive Principle:

Principle #34Discarding and recovering

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 approach reduces the vehicle door's width, weight, and production costs while enhancing aesthetic quality and stability by eliminating redundant components and achieving a flush, continuous surface between the sash and step.

Implementation Method 1

the step is formed by joining an inner portion of the inner panel corresponding to the step and an outer portion of the outer panel corresponding to the step together by hemming

Methodology Applied

Scientific EffectHemming:

Data Source

PatentUS9180815B2Vehicle door

Publication Date: 2015.11.10 HONDA MOTOR CO LTD

AI summary

In a vehicle door, a door panel is formed by joining an inner panel and an outer panel together, and the door panel is provided with a front door sash. The vehicle door includes a door front edge of the door panel, a sash front edge at a front end of the front door sash, and a step extending from the sash front edge to an upper end of the door front edge. In the step, an inner step portion of the inner panel and an outer step portion of the outer panel are joined together by hemming.