Gearshift Lever Device with Composite Select Lever
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Solution Overview
Problem
The existing gearshift lever devices face a challenge in downsizing while maintaining the strength of the select lever, as increasing the thickness of the side wall portion to enhance engagement strength results in a larger overall device size.
Innovation Solution
The gearshift lever device incorporates a select lever with pair of shift direction side wall portions and engage portions that allow for engagement with the gearshift lever, where the thickness in the select direction is minimized by using a metallic cable pin and select lever plate with U-shape portions for reinforcement, enabling the gearshift lever and select lever to shift together or independently without increasing the overall device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the side wall portion is increased to enhance engagement strength, then the strength of the select lever is improved, but the size of the entire gearshift lever device increases
Solution Approach 1:
The patent applies composite materials by combining a resin material for the select lever body with a metal reinforcement plate. This composite structure allows the thin-side wall select lever to achieve the strength of a thick-side wall design without increasing the overall device size. The metal plate is embedded within the resin material to provide localized reinforcement at the engagement portion.
Solution Approach 2:
The patent transitions from a two-dimensional thickness increase approach to a three-dimensional reinforcement strategy by embedding a metal plate within the resin material. This dimensional approach allows strength enhancement without increasing the external dimensions of the select lever, effectively resolving the contradiction between strength and size.
2Strength
If the thickness of the side wall portion is increased to increase the area of engagement, then the engagement strength between coupling piece and coupling hole is improved, but the thickness of the select lever in the select direction becomes larger
Solution Approach 1:
The metal reinforcement plate embedded in the resin material provides enhanced engagement strength at the coupling hole without requiring an increase in the side wall thickness. The composite structure concentrates reinforcement where needed, maintaining a thin overall profile while achieving superior engagement strength.
Solution Approach 2:
The patent applies local quality by placing the metal reinforcement plate specifically at the engagement portion where strength is needed, rather than uniformly thickening the entire side wall. This localized reinforcement approach increases engagement strength without increasing the overall thickness of the select lever in the select direction.
Data Source
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AI summary
A gearshift lever device includes: a gearshift lever including an operation portion (knob) formed on an upper end portion and a shaft support portion formed on a lower end portion; and a select lever including a holding portion that holds the shaft support portion of the gearshift lever. The select lever further includes a pair of shift direction side wall portions which are disposed across the holding portion with a distance from each other in a shift direction of the gearshift lever, and engage portions which are disposed on the shift direction side wall portions and are to be engaged with the gearshift lever.