Motorcycle Side Stand Switch Engagement Pin Torque Resistance
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Solution Overview
Problem
Existing side stand switches for motorcycles face damage to the engagement pin due to torque loads during tightening, especially when the rotor member is made of low-strength materials like resin.
Innovation Solution
The engagement pin is designed with a wider base portion than tip portion, and optionally with a skirt shape or protrusions and indentations, to distribute torque loads and reduce stress concentration, while being made of metal for enhanced strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the engagement pin is made with uniform width, then the structure is simple and easy to manufacture, but the stress concentration point is located at the base portion which causes damage during tightening
Solution Approach 1:
The engagement pin is designed with non-uniform width where the width varies along its length. Specifically, the width at the base portion (inside the rotor member) is larger than the width at the tip portion (protruding from rotor member). This local variation in geometry redistributes the stress concentration point to a location closer to the tip portion, away from the critical base portion, thereby preventing damage during tightening while maintaining manufacturing feasibility.
2Ease of manufacture
If the rotor member is made of resin material, then manufacturing cost is reduced, but the engagement pin is damaged by torque load during tightening
Solution Approach 1:
The engagement pin's non-uniform width design concentrates the stress away from the base portion. When combined with resin rotor members, this geometric optimization allows the engagement pin to withstand torque loads during tightening without requiring the rotor member to be made of high-strength materials, thus maintaining low manufacturing costs while ensuring sufficient strength.
Solution Approach 2:
The side stand switch employs a composite structure where the rotor member is made of resin (low-cost material) and the engagement pin is made of metal (high-strength material). This material combination leverages the cost advantage of resin for the main body while using metal for the critical load-bearing engagement pin, achieving both cost reduction and strength enhancement.
3Strength
If the engagement pin width increases at the base portion, then the strength against torque load is enhanced, but the device complexity increases
Solution Approach 1:
The engagement pin features a localized width variation rather than a completely complex geometry. The width changes along the length of the pin, being larger at the base and smaller at the tip, but this can be achieved through standard manufacturing processes like forging or molding. This approach enhances strength by positioning the stress concentration point away from the base while keeping the overall structure relatively simple and manufacturable.
Data Source
AI summary
A side stand switch includes a case member having a fixed contact; and a rotor body having a moving contact that can come into contact with the fixed contact, mounted by tightening a securing bolt, and turned together with a side stand bar with respect to the case member. The rotor body has an engagement pin inserted therein and to be inserted into an engagement hole formed in the side stand bar. A width of the engagement pin in the turning direction of the rotor body is larger at a base portion inside the rotor body than at a tip portion protruding from the rotor body.