Vehicle Turn Signal Switch Length Reduction via Segmented Return Springs

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Solution Overview

Problem

Conventional turn signal switches for vehicles have a relatively large length in the pushing-in/returning direction due to the series connection of the switch operating element and return spring, which affects the switch's overall dimensions and operational feel.

Innovation Solution

The use of a return plate with a guide recess and a pair of return springs between the return plate and the switch case, where the guide recess is curved and the return springs are positioned on opposite sides of the valley, allows the switch operating element to be returned to the neutral position efficiently, reducing the switch's length and minimizing wobbling during operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a single return spring is provided between the switch case and the switch operating element in series connection, then the switch operating element can be urged toward the neutral position and returned position, but the switch has a relatively large entire length in the pushing-in/returning direction

Engineering Contradiction:
Improvelength of switch in pushing-in/returning directionVSAvoidstructural complexity of resiliently urging means
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The resiliently urging means is divided into two separate return springs instead of using a single return spring. Each return spring is positioned on opposite sides of the valley in the guide recess, working together to urge the switch operating element toward the neutral position. This segmentation reduces the overall length required for the resiliently urging means while distributing the urging function across multiple components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The return springs are arranged in a different spatial configuration within the guide recess, utilizing the width dimension across the valley rather than extending the length in the pushing-in/returning direction. This dimensional reorganization allows the resiliently urging means to fit within a shorter length while maintaining the necessary urging force through the curved path of the guide recess.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If the return spring is positioned to urge the switch operating element, then the switch operating element can be returned to neutral position, but wobbling may occur during operation

Engineering Contradiction:
Improvestability of switch operating elementVSAvoidoperational feel
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The guide recess features an asymmetric curved shape with a valley and inclined return cam faces on opposite sides. The two return springs are positioned asymmetrically relative to the valley, with each spring acting on one side to provide balanced urging forces that stabilize the switch operating element during its movement through the curved path, preventing wobbling while maintaining smooth operation.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The two return springs positioned on opposite sides of the valley act as counterbalancing forces against each other. As the switch operating element moves through the curved guide recess, one spring may be more compressed while the other is less compressed, but they work together to provide balanced urging forces that cancel out destabilizing lateral forces, preventing wobbling during operation.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

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 design reduces the overall length of the turn signal switch in the pushing-in/returning direction, enhances operational feel by suppressing wobbling, and increases the degree of freedom in arranging the operating portion, while ensuring effective switching and insulation between contacts.

Implementation Method 1

a pair of return springs provided between the return plate and the switch case to exhibit spring forces for urging the return plate

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP1862384B1Turn signal switch for vehicle
Publication Date: 2012.04.11 TOYO DENSO CO LTD
  • EP1862384B1 patent drawingFigure 1
  • EP1862384B1 patent drawingFigure 2
  • EP1862384B1 patent drawingFigure 3

AI summary

A turn signal switch for a vehicle includes: a resiliently urging means (32) provided between a switch operating element (26) and a switch case (25) so as to urge the switch operating element (26) toward a neutral position and a returned position. The resiliently urging means (32) includes: a return plate (45) having a guide recess (48) which is provided at one end and against which abuts a first pin (47) provided on the switch operating element (26), the return plate (45) being slidably supported on the switch case (25); a pair of return springs (46) exhibiting spring forces for urging the return plate (45) in a direction to bring the pin (47) into abutment against the guide recess (48). The guide recess (48) is curved into a substantially triangular shape, and includes a valley (50) and return cam faces (51,52) on opposite sides of the valley (50). The return springs (46) are provided on opposite sides of the valley (50) and between the return plate (45) and the switch case (25). Thus, it is possible to reduce the length of the turn signal switch in the direction of push-in/return of the switch operating element.