Motorcycle Frame Pivot Plate Attachment for Weight Reduction

Solution Overview

Problem

Conventional motorcycle frame structures face a challenge in firmly fastening the front end of a seat rail to a pivot plate without increasing the weight of the pivot plate, as existing designs require increased thickness and rigidity to withstand loads, leading to weight gain.

Innovation Solution

The motorcycle frame structure features a pivot plate with two vertically spaced attachment portions, where the first attachment portion is fastened from the horizontal external side with a bolt, and the second from the rear side with a bolt, reducing the load on the pivot plate and allowing for a simpler screw hole, while a cross member and cushion support enhance rigidity and strength without weight increase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the two upper and lower front ends of the seat rail are fastened to the pivot plate from the left-right direction outside of the body frame, then the strength of the fastened portion is improved, but the thickness of the attachment boss must be increased which leads to an increase in the weight of the pivot plate

Engineering Contradiction:

Improvestrength of fastened portionVSAvoidweight of pivot plate

Core Design Contradiction:

StrengthVSWeight of stationary object

Solution Approach 1:

The attachment structure is divided into two separate attachment portions: a first attachment portion for lateral fastening and a second attachment portion for rearward fastening. This segmentation allows each attachment portion to be optimized independently, with the second attachment portion using a simpler screw hole structure that does not require increased thickness, thereby reducing overall pivot plate weight while maintaining fastening strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-direction (lateral) attachment approach to a multi-dimensional attachment system. The first attachment portion fastens from the lateral direction while the second attachment portion fastens from the rearward direction, creating a three-dimensional attachment configuration that distributes loads more effectively and eliminates the need for thickened attachment bosses.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Strength

If the thickness of the attachment boss is increased to ensure the strength of the fastened portion, then the strength is improved, but the weight of the pivot plate increases

Engineering Contradiction:

Improvestrength of fastened portionVSAvoidweight of pivot plate

Core Design Contradiction:

StrengthVSWeight of stationary object

Solution Approach 1:

The attachment structure is divided into two separate attachment portions: a first attachment portion for lateral fastening and a second attachment portion for rearward fastening. This segmentation allows each attachment portion to be optimized independently, with the second attachment portion using a simpler screw hole structure that does not require increased thickness, thereby reducing overall pivot plate weight while maintaining fastening strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different attachment portions are designed with different structural characteristics suited to their specific functions. The first attachment portion uses a boss structure for lateral fastening, while the second attachment portion uses a simpler structure optimized for rearward fastening with minimal material, achieving local optimization that reduces overall weight while maintaining sufficient strength at each attachment point.

Inventive Principle:

Principle #3Local quality

3Weight of stationary object

If a simple screw hole is used at the second attachment portion, then the weight of the pivot plate is reduced, but the load bearing capacity may be compromised

Engineering Contradiction:

Improveweight of pivot plateVSAvoidload bearing capacity

Core Design Contradiction:

Weight of stationary objectVSStrength

Solution Approach 1:

The first and second attachment portions work together in combination to provide complete load bearing capacity. The first attachment portion handles lateral fastening forces while the second attachment portion handles rearward fastening forces, and their combined effect ensures that the seat rail is securely fastened to the pivot plate without requiring either attachment portion to be overly robust, thus maintaining weight efficiency.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention transitions from a single-direction (lateral) attachment approach to a multi-dimensional attachment system. The first attachment portion fastens from the lateral direction while the second attachment portion fastens from the rearward direction, creating a three-dimensional attachment configuration that distributes loads more effectively and eliminates the need for thickened attachment bosses.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS7845451B2Motorcycle frame structure

Publication Date: 2010.12.07 HONDA MOTOR CO LTD

AI summary

A motorcycle frame structure includes pivot plates at rear portions of left and right main frames extending rearwardly and downwardly from a head pipe. A seat rail is fastened to an upper portion of the pivot plate at two positions which are vertically spaced apart from each other, and also at the front end of the seat rail. A first attachment portion and a second attachment portion are attached to a front end of the seat rail. The first attachment portion is fastened to the pivot plate from the horizontally external side of the seat rail with a first bolt, and laterally overlaps a rear upper lateral surface of the pivot plate. The second attachment portion is fastened to the pivot plate from the rear side of the pivot plate with a second bolt, and overlaps a rear portion of the pivot plate.