Shift Lever Assembly Accuracy via Biasing and Through-Shaft Alignment

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Solution Overview

Problem

Existing shift lever devices face challenges in achieving high detection accuracy of shift positions due to inaccuracies in the relative assembly positions of detection sensors and magnets.

Innovation Solution

The shift device incorporates a biasing mechanism that ensures precise alignment of facing portions and holes, allowing a through-shaft to penetrate and fit accurately, enhancing the assembly accuracy of detection sections and means, and includes multiple corresponding facing portions and holes for improved alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the detection sensors and magnet are assembled without precise alignment features, then the assembly process is simpler, but the detection accuracy of shift position deteriorates

Engineering Contradiction:
Improvedetection accuracy of shift positionVSAvoidrelative assembly position accuracy
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

A through-shaft is introduced as an intermediary alignment tool during assembly. The through-shaft passes through the magnet and detection sensor, serving as a physical mediator that ensures precise coaxial alignment between these components. This intermediary element temporarily facilitates accurate positioning during assembly, which is then maintained in the final assembled state.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs preliminary alignment actions by providing facing portions and facing holes that guide the relative positioning of components before final assembly. The facing surfaces are prepared in advance to ensure that when components are brought together, they automatically achieve the correct relative orientation and position, pre-establishing the conditions for accurate detection.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the shift body is held in a specific position during assembly without biasing means, then the structure is simpler, but the alignment accuracy of detection elements deteriorates

Engineering Contradiction:
Improveassembly position accuracyVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The biasing means is designed to automatically return the shift body to its specific position (such as neutral position) when no operating force is applied. This self-service mechanism eliminates the need for external fixtures or complex positioning devices during assembly, as the biasing means inherently maintains the required position, simplifying the overall assembly process while ensuring precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The biasing means acts as a counteracting force mechanism that opposes any deviation of the shift body from its specific position. Similar to how counterweights balance forces, the biasing means provides a restoring force that maintains the shift body in the desired position during assembly, ensuring stable and accurate alignment of detection elements.

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

3Manufacturing precision

If multiple facing portions and facing holes are provided, then the alignment accuracy is improved, but the device complexity increases

Engineering Contradiction:
Improverelative assembly position accuracyVSAvoidnumber of components
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The alignment system is segmented into multiple independent facing portions and corresponding facing holes distributed at different locations. Rather than relying on a single complex alignment feature, the patent divides the alignment function into multiple simpler segments, each contributing to the overall positional accuracy. This segmentation allows for modular manufacturing and assembly while maintaining high precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The facing portions and facing holes are designed to nest together during assembly, with each facing feature fitting into its corresponding counterpart. This nesting arrangement ensures that multiple alignment points work together harmoniously, with each feature contributing to the precise positioning without creating excessive complexity. The nested structure naturally guides components into their correct relative positions.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 configuration significantly improves the detection accuracy of shift positions by ensuring precise assembly of detection elements, reducing the pivot angle between shift positions, and maintaining the shift lever in a specific position without external operating force.

Implementation Method 1

a biasing means that causes the shift body to move to the specific position by biasing force when there is no operating force acting on the shift body

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3056768B1Shift device
Publication Date: 2020.06.24 KK TOKAI RIKA DENKI SEISAKUSHO
  • EP3056768B1 patent drawingFigure 1
  • EP3056768B1 patent drawingFigure 2
  • EP3056768B1 patent drawingFigure 3

AI summary

In a shift lever device (10), a first facing cavity (24A) and a second facing cavity (24B) of a lever (22), and a first facing hole (42) and a second facing hole (44) of a printed wiring board (38), respectively face each other when the lever is disposed in an "H" position. Thus, in a state in which the lever is disposed in the "H" position when the shift lever device is being assembled, the first facing cavity and the second facing cavity respectively face the first facing hole and the second facing hole, thereby enabling the accuracy of relative assembly positions of a magnet (46) of the lever and detection elements of the printed wiring board to be increased, and enabling the detection accuracy of a shift position of the lever to be improved.